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SOUTHERN CALIFORNIA ACADEMY OF SCIENCES

BOLLETIN

Volume 100 Number 1

BCAS-A100(1) 1-58 (2001) APRIL 2001

Southern California Academy of Sciences
Founded 6 November 1891, incorporated 17 May 1907

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Date of this issue 12 April 2001

SOUTHERN CALIFORNIA ACADEMY
OF SCIENCES

2001 ANNUAL MEETING
May 4-5, 2001
CALIFORNIA STATE UNIVERSITY
AT LOS ANGELES

WA cORpoRATED 1%

Symposia:
Nutrient Dynamics in Marine and Estuarine Environments; Dr. Krista Kamer, (SCCWRP), kristak @
sccwrp.org—Friday Morning

Dealing with Contaminated Runoff; Dr. John Dorsey, (City of Los Angeles), (213) 847-6347, jdorsey @
san.lacity.org—Friday Morning and Afternoon

Spatially Explicit Ecology; Dr. Carlos Robles, CEA-CREST Director (CSULA), (323) 343-2067,
crobles @calstatela.edu—Friday Morning and Afternoon

Neuronal Degeneration, Growth and Repair Throughout the Lifespan; Dr. Amelia Russo-Neustadt
(CSULA), (323) 343-2074, arusson @calstatela.edu—Friday Afternoon

Virtual Ocean; Dr. Judith Doino Lemus, (University of Southern California), (213) 740-1965;
jdlemus @usc.edu—Friday Afternoon

Environmental Chemistry; Dr. Carlos Robles, CEA-CREST Director (CSULA), (323) 343-2067,
crobles @calstatela.edu—-Saturday Morning and Afternoon

Marine Ecology of Rocky Reefs and Areas of Special Biological Significance; Robert Grove, (Southern
California Edison), (626) 302-9735, grovers@sce.com or, Dan Pondella, (Occidental College), (323)
259-2955—Saturday Morning and Afternoon

The Puente-Chino Hills Wildlife Corridor and Wildlife Corridors in the Los Angeles Basin; Dr. Daniel
Guthrie, (Claremont Colleges), (909) 607-2836, dguthrie @jsd.claremont.edu—Saturday Morning
and Afternoon

CALIFORNIA
ACADEMY OF SCIENCES

MAY 1 4 2008

LIBRARY

CALL FOR MENTORS

The Research Training Program of the Southern California Academy of Sciences is receiving a
large number of applications from students for the 2001—2002 academic year. This is in large part due
to an excellent article in the Los Angeles Times about the program and success of students enrolled
in it. The program involves the placement of high school students with excellent scientific backgrounds
from throughout southern California in scientific laboratories to conduct research under research men-
tors. The projects are usually designed by the mentor. Students spend about 8 hours a week on their
projects, commencing in September and concluding in May with the presentation of their results at
the Annual Meeting of the Academy.

We are seeking scientists who might like to become mentors for these outstanding students in the
coming year. If you or your graduate students have room in your lab for a student, please let us know.
We need your name, address, contact numbers (include e-mail) and an indication of research area.
Forward the above information to:

Dan Guthrie
dguthrie @ jsd.claremont.edu
909 607 2836

Bull. Southern California Acad. Sci.
100(1), 2001, pp. 1-11
© Southern California Academy of Sciences, 2001

Pliocene Amphibians and Reptiles from
Clark County, Nevada

JIM I. MEAD! and CHRISTOPHER J. BELL?

'Department of Geology and Quaternary Sciences Program,
Northern Arizona University, Flagstaff, Arizona 86011
?Department of Geological Sciences, University of Texas at Austin, Austin,
Texas 78712

Abstract.—Pliocene herpetofaunas are uncommon in the published literature. Here
we report on a small Pliocene (Blancan Land Mammal Age) herpetofauna from
the White Narrows local fauna (Clark Co., Nevada) dating approximately 4.9 to
4.3 Ma. At least two species of Bufo, a phrynosomatid lizard, Xantusia, and a
colubrine snake were recovered from sediments deposited in a basin that held a
small lake. Climate was probably subhumid, but a cooling and aridification trend
was occurring. The vegetation may have been a mosaic of oak-juniper (?) wood-
land and a riparian community. The White Narrows herpetofauna is depauperate
in comparison to the present community which is probably due to sampling bias
and not a climatic factor.

In contrast with the mammalian faunas, there are relatively few described am-
phibian and reptile faunas from the late Tertiary of what is now the Intermountain
Region of western North America. This paucity of localities, and the consequent
gaps in our understanding of herpetofaunal biogeography and biodiversity in this
region renders any new information noteworthy. In this paper we describe the
amphibian and reptile components of a small, relatively diverse vertebrate assem-
blage (White Narrows local fauna) recovered from a locality in Clark County,
Nevada, and discuss their biogeographic significance in relation to the changing
physiographic setting.

The fossils reported here were recovered from San Bernardino County Museum
locality 2.12.16, which was discovered and collected as a result of paleontological
mitigation efforts conducted in the late 1980s by the museum along the right-of-
way for the Kern River Gas Transmission Line. The locality is situated at 520 m
elevation, approximately 2 km south of the Muddy River in Moapa Valley, about
8 km upstream from the confluence with Meadow Valley Wash at Glendale, Clark
County, Nevada. The San Bernardino County Museum Regional Paleontologic
Locality Inventory places the locality (referred to as Moapa Bluffs) at the SW %4
of the NE % of the SW % of the SW % of Section 7, T15S, R66E (Mount Diablo
Base and Meridian), Moapa West quadrangle, on US Bureau of Land Management
holdings. Abbreviations for museums include: MCZ, Museum of Comparative
Zoology, Harvard University; SBCM, San Bernardino County Museum; UCMP,
University of California Museum of Paleontology.

Overview, Stratigraphic Setting, and Chronology

The establishment of ancient drainage systems in the region of the Muddy River
in Moapa Valley in southeastern Nevada were governed by major structural fea-

Z SOUTHERN CALIFORNIA ACADEMY OF SCIENCES

tures that developed during the Miocene. These events and their consequences
were discussed by Longwell (1936), Lucchitta (1972, 1979, 1990), Dicke (1985),
Duebendorfer and Wallin (1991), Schmidt et al. (1996), and Williams (1996).
During the Miocene, extensional stress, subsidence, and normal faulting set up
the development of the basins and ranges of Nevada and relative uplift of the
western margins of the Colorado Plateau. Slow subsidence and basin filling oc-
curred from approximately 24 to 13 Ma. From about 13 to 10 Ma, normal faulting
became prevalent, resulting in the rise of mountain ranges and subsidence of
basins. In some of these basins, including the one in which the fossils discussed
herein were deposited, large lakes and lake systems formed. The ancestral Col-
orado River began flowing into and through the Muddy Creek basin at approxi-
mately 5.5 Ma and ultimately breached the lake basin, establishing external drain-
age.

Late Tertiary alluvial deposits in the vicinity of Moapa Valley and nearby
Meadow Valley received the attention of geologists and paleontologists for many
decades. Early studies placed all the sediments into a single unit, the Muddy Creek
Formation. Although published reports of fossils from the Muddy Creek Forma-
tion exist (Lucchitta 1979; Taylor and Smith 1981; Taylor 1983; Reynolds and
Lindsay 1999), remains of fossil vertebrates are relatively uncommon. Vertebrate
fossils from the Muddy Creek Formation were first studied by Stock (1921) who
assigned the sediments a Mio-Pliocene age based on vertebrate taxa present within
the unit.

Recent evaluation of a discrete sedimentary package in the upper portion of
the Muddy Creek Formation resulted in a proposal for the recognition of a new
formation, tentatively named the White Narrows (Schmidt et al. 1996). This cur-
rently informal formation (no description outside of the 1996 Open-File report
has yet appeared; see Salvador 1994:23) was described as a white calcic claystone
and clayey limestone, with two distinct subfacies: 1) green claystone, and 2)
channel fill deposition in degradational channels. A fossiliferous marl bed, 20 cm
thick and about 2 m above the base of the formation, produced the mammals
described by Reynolds and Lindsay (1999) and the amphibian and reptilian re-
mains presented here (SBCM 2.12.16; see Schmidt et al. 1996). It is this package
of vertebrate remains that compose the White Narrows local fauna.

No radiometric dates are available for the White Narrows formation, and age
estimates provided by Schmidt et al. (1996) were based on preliminary identifi-
cations of the rodents SBCM 2.12.16. Unfortunately, the mammalian biochron-
ology does not provide unambiguous evidence upon which an age can be based.
A recent review of the mammalian fauna recovered from the White Narrows local
fauna was provided by Reynolds and Lindsay (1999) who suggested that this
depositional unit represents a transition from the late Miocene/earliest Pliocene
Hemphillian Land Mammal Age to the Pliocene Blancan Land Mammal Age. The
small mammals they reported include the murid rodents Paronychomys cf. P.
lemredfieldi., Copemys cf. C. vasquezi, Peromyscus valensis, Repomys cf. R. gus-
tleyi, Calomys (Bensonomys) cf. C. coffeyi, Calomys (Bensonomys) cf. C. arizo-
nae, Neotoma (Paraneotoma) cf. N. vaughani, and several heteromyid taxa, in-
cluding Dipodomys gidleyi, Oregonomys cf. O. sargenti, and undetermined spe-
cies of Perognathus and Prodipodomys (Reynolds and Lindsay 1999).

The lack of confident species identifications for most of the rodent taxa in the

PLIOCENE HERPETOFAUNA FROM NEVADA 3

fauna renders biochronological age estimates difficult. Most of the genera can be
found in Hemphillian and Blancan deposits and definitive species identifications
are required for refined biochronological age estimates. Of the nine taxa listed by
Reynolds and Lindsay (1999) as being “‘restricted temporally”’ to either the Hem-
phillian or Blancan land mammal ages, only two (Peromyscus valensis and Di-
podomys gidleyi) are definitively identified to species. Peromyscus valensis is
currently known only from the Hemphillian and D. gidleyi only from the Blancan.
In addition, the shrew genus Sorex is represented in the White Narrows local
fauna (possibly by two species; see table 3, p. 473, in Reynolds and Lindsay
1999), and is elsewhere known only from Blancan and younger faunas (Repenning
1967; McKenna and Bell 1997). The locality is either of latest Hemphillian age,
dating between approximately 6.5 and 4.9 Ma, or is earliest Blancan, dating be-
tween approximately 4.9 and 4.3 Ma. The overriding compliment of taxa seems
to imply a Blancan age for the fauna, and is therefore the assumed age for this
report (this is in agreement with the conclusions of Reynolds and Lindsay 1999).

Systematic Paleontology

All specimens are housed in the Section of Geological Sciences at the San
Bernardino County Museum and are catalogued under collection number SBCM
L-2515. Each specimen has a separate catalog number. Terminology for anurans
follows Tihen (1962) and Sanchiz (1998). Iguanian familial designation follows
Frost and Etheridge (1989).

Class AMPHIBIA Linnaeus, 1758
Subclass Lissamphibia Haeckel, 1866
Order Anura Rafinesque, 1815
Family Bufonidae Gray, 1825
Genus Bufo Laurenti, 1768
Bufo boreas/canorus/exsul group

Material.—Left ilia 570-571, 2720-2729; right ilia 572, 2730-2734.

Identification.—The dorsal protuberance is relatively high (varies from high to
medium-low on the fossils), but the anterior and posterior edges of the protuber-
ance are even with the top of the dorsal prominence (the protuberance does not
stand out from the prominence). A distinct, projecting protuberance occurs on the
living B. cognatus, B. microscaphus, B. retiformis, and B. woodhousei and on the
extinct B. hibbardi and B. pliocompactilis (Wilson 1968; Taylor 1941A) implying
that our specimens do not belong to any of these species. The extinct B. suspectus
has a prominence with the posterior slope steeper than the anterior slope; it was
assumed by Tihen (1962) to belong to the B. valliceps species group and by Estes
and Tihen (1964) to belong to the B. americanus species group. The specimens
listed above have a dorsal prominence similar in size to that described for B.
suspectus, but do not exhibit the steeper posterior slope. The range of individual
variation in this character needs to be thoroughly examined for all North American
representatives of Bufo.

The ventral acetabulur expansion is not flared out and flattened as on B. punc-
tatus, or anteriorly rounded as on B. debilis (young and adult specimens). Spec-
imen 571 is not similar in size or in robustness to B. holmani (Parmley 1992),
nor does it have the medially-directed crest on the dorsal surface near the middle

4 SOUTHERN CALIFORNIA ACADEMY OF SCIENCES

Figure 1. Herpetofaunal specimens from the Blancan White Narrows local fauna, Clark County,
Nevada. A, left ilium of Bufo boreas/canorus/exsul group, SBCM L2515-571; B, right ilium of Bufo
suspectus, SBCM L2515-2718; C, right maxilla fragment of Phrynosomatidae indet., SBCM L2515-
602; D, right dentary fragment of Phrynosomatidae indet., SBCM L2515-603; and E, right spleniod-
entary fragment, SBCM L2515-595. Scale bars = 1 mm.

of the shaft as is characteristic of B. hibbardi (Taylor 1941A). The prominence
and morphology of the protuberance on 571 is identical to living B. boreas spec-
imens with an svl of approximately 30 mm. Because the ilia listed above exhibit
characters most similar to those found in the Bufo boreas species group, we refer
our specimens to the B. boreas/canorus/exsul group. As indicated above, the
White Narrows adult specimens are always small, svl approximately 26 to 40
mm, and in this character resemble more the living toads B. exsul and B. canorus
and not the larger B. boreas. Today Bufo exsul and B. canorus do not live near

PLIOCENE HERPETOFAUNA FROM NEVADA 5

the Moapa Valley region; B. boreas is known from the Muddy River drainage
(Stebbins 1985; Hovingh 1997).

Remarks.—Specimen 571 (Figure 1A) is the most complete of the ilia from
White Narrows local fauna and is used here as representative of all the specimens
referred to this group. The ilium is complete except for the extreme anterior end
of the shaft. The overall size of most specimens is that of a toad with a svl (snout-
vent length) from 26 to 30 mm (2720 is equal in size to modern toads of svl
approximately 40 mm).

Bufo suspectus Tihen, 1962

Material.—Left ilia 2716—2717; right ilia 2718-2719.

Identification.—The low dorsal prominence of the ilium, with the posterior
slope steeper than the anterior, and the position of the dorsal protuberance some-
what posterior to the midpoint of the base of the prominence are characteristic
for the species. The four ilia listed above all show these features (Figure 1B).

Remarks.—Bufo suspectus is a small species of toad originally described from
the Blancan Fox Canyon Locality in Kansas (Tihen 1962). Additional material
(consisting of a frontoparietal and two ilia) was subsequently recovered from the
Miocene Valentine Formation of Nebraska, but was named a distinct species (B.
valentinensis) on the basis of the supposed geographic and temporal improbability
that a species from the Pliocene of Kansas could be the same as a Miocene species
of Nebraska (Estes and Tihen 1964). Subsequent reports of “B. valentinensis”’
(e.g., Holman 1970, 1973; Chantell 1971; Parmley 1992) continued this practice,
but Sanchiz (1998) recently synonymized the two species under B. suspectus,
which we endorse.

Bufo sp.

Material.—Angulosplenial 563, 2735-2737; right ilium 573; humerus 564—
565, 2738-2743.

Identification.—These specimens were not preserved well enough to permit a
more refined identification.

Remarks.—All specimens are from adults of small species of Bufo that appear
similar in size to living species with svl of approximately 25 to 45 mm.

Class REPTILIA Laurenti, 1768
Order Squamata Oppel, 1811
Family Phrynosomatidae Fitzinger, 1843

Material.—Right maxilla fragment 602; right dentary fragment 603.

Identification.—The fragmentary nature of this material prevents identification
beyond the family level. We compared the specimens with modern skeletal ma-
terial of Callisaurus, Cophosaurus, Holbrookia, Petrosaurus, Phrynosoma, Sce-
loporus, Uma, Urosaurus, and Uta. We were unable to detect any derived char-
acters that would permit definitive allocation to any of these taxa, but in their
overall size and morphology, the specimens most closely resemble modern spec-
imens of various species in the genus Sceloporus.

The difficulties in identifying isolated skeletal elements of Sceloporus species
were discussed by Etheridge (1964) and Larsen and Tanner (1974). The fossils
were compared with modern skeletal material from S. clarkii, S. graciosus, S.

6 SOUTHERN CALIFORNIA ACADEMY OF SCIENCES

Jarrovii, S. magister, S. occidentalis, S. olivaceous, S. orcutti, S. poinsettii, S.
scalaris, S. undulatus, and S. virgatus. Our comparisons failed to reveal any di-
agnostic features of anterior maxillae or dentaries in extant species, but the fossils
are different in some respects from certain species. The teeth are not the relatively
heavy, transversely compressed trilobate teeth typical of the extinct S. robustus
(Twente 1952). The fossils are larger and more robust than modern specimens of
S. graciosus, S. scalaris, and most S. virgatus, S. undulatus, and S. occidentalis.
The fossil specimens differ from the living S. clarkii and S. orcutti in that they
lack the more pointed, slightly recurved anterior teeth often seen in these two
living species. The fossil teeth do not show any trend toward being trilobate and
wide, as in modern S. magister, however, the robust nature of the anterior portion
of the fossil dentary, and the appearance of the dental shelf and meckel’s groove
are most similar to that species.

Remarks.—The maxilla is a fragmented (3.4 mm long) anterior portion with
two blunt conical teeth (Figure 1C). The anterior dentary fragment (3.5 mm long)
contains four blunt, conical teeth (Figure 1D).

Family Xantusiidae Baird, 1858
Xantusia Baird, 1858

Material.—L maxilla 591; R spleniodentary 595; R spleniodentary fragment
592, 594, 2744; L spleniodentaries 599-600; L spleniodentary fragments 598, 601.

Identification.—Specimen 595 (Figure 1E) is described here and is represen-
tative of the Xantusia material from the White Narrows. Specimen 595 is a right
spleniodentary with three complete teeth preserved at mid-dentary. The teeth are
unicuspate, are of a uniform width at the base and gently taper at the crown. The
anterior 10% of the spleniodentary is missing. The dental gutter is well developed.

These fossil specimens are readily identifiable as xantusiids. The White Nar-
rows focal fauna specimens are small, of relatively slight build, and have closely
spaced, simple teeth that lack lateral cusps. The splenial appears to be fused with
the dentary in all specimens, and does not extend posteriorly beyond the apex of
the coronoid in specimens where this character can be evaluated. A pronounced
dental gutter is present in all of the spleniodentaries, but there is a varying degree
of development in this feature. In all specimens, however, the dental gutter is
markedly more developed than in any modern specimens of Xantusia examined
(Figure 1E).

The small size, slight build, and simple, conical, unstriated teeth of the fossils
distinguish them from Klauberina riversiana and from the Paleogene genus Pa-
laeoxantusia. The dentary teeth of Lepidophyma have lingually-directed cusps
that superficially resemble, in dorsal view, a mammalian tribosphenic tooth, a
feature distinctly lacking in the White Narrows specimens. The limited availability
of skeletal material of Cricosaura typica makes adequate comparisons impossible
at this time, but MCZ 10454 has much more delicately constructed jaw elements
than any of the specimens from the White Narrows local fauna. The splenio-
dentary of X. henshawi is longer, more gracile, and has more teeth on average
than do the fossil specimens. The fossil specimens are most similar to Xantusia
vigilis, but are more robust and are slightly longer than the corresponding bones
of that species.

A detailed description of an extinct form of Xantusia from the Anza-Borrego

PLIOCENE HERPETOFAUNA FROM NEVADA 7

Desert in California was provided by Norell (1989). The preserved material shows
characteristic plesiomorphic features for the genus, but lacks apomorphies. The
plesiomorphic nature of the fossils recovered from Anza-Borrego led Norell to
describe Xantusia downsi* as a new metaspecies (see Gauthier et al. 1988 for
explanation of the use of ‘**’’ for metaspecies). The White Narrows Xantusia
specimens are similar to those described by Norell in that they are all character-
ized by small size, the plesiomorphic presence of a dental gutter, and the syna-
pomorphic reduction of tricuspid teeth. Morphologically, the specimens cannot be
distinguished from X. downsi*, or from numerous other (unpublished) plesiom-
orphic xantusiids ranging in age from Barstovian (middle Miocene) to early Ir-
vingtonian (early Pleistocene; CJB, pers. obs.). Given the uncertain relationships
among plesiomorphic xantusiids, we choose not to identify our material as X.
downsi* and simply refer the specimens to Xantusia.

Family Colubridae Oppel 1811
Subfamily Colubrinae Oppel 1811

Material.—Trunk vertebra 618.

Identification.—The specimen conforms to the diagnosis provided by Holman
(1979) for colubrine trunk vertebrae. It lacks the hypapophyses characteristic of
anterior trunk vertebrae (and those of natricines) and the subcentral paramedian
lymphatic fossae characteristic of posterior trunk vertebrae (LaDuke 1991). In
overall morphology and proportions, it most closely resembles trunk vertebrae of
the ‘racers’ Coluber and Masticophis. Auffenberg (1963) provided measurements
to distinguish mid-trunk vertebrae of Coluber and Masticophis in the eastern U.S.,
but LaDuke (1991) noted geographical variation in Auffenberg’s characters. Due
to the somewhat poor preservation of this specimen, generic determination is not
attempted. Numerous highly fragmented specimens of snake vertebrae were also
recovered but are not identifiable.

Discussion and Conclusions

As demonstrated above, the overriding compliment of mammalian taxa seems
to imply a Blancan age for the fauna. It appears that the White Narrows local
fauna is early Blancan in age (~4.9-4.3 Ma), but probably post-dates the early
Blancan Panaca Formation from the nearby Meadow Valley (which dates to about
4.95 Ma; Lindsay et al. 1999; Mou 1999; Reynolds and Lindsay 1999) and pre-
dates the well-known Blancan faunas (e.g., Hagerman) of the Glenns Ferry For-
mation, southern Idaho (see review in Mead et al. 1998).

Vertebrate Faunas

The termination of the Hemphilliian Land Mammal Age in the earliest Pliocene
is marked by the extinction of most of the typical mammalian species of the late
Hemphillian, including taxa with long Miocene histories. The late Hemphillian
mammalian faunas suggest that the process of change was taking place at different
rates in different geographic regions of North America (Tedford et al. 1987). The
accelerating pace of mammalian immigration from Hemphillian into Pleistocene
time reflects the availability of dispersal routes into North America and, possibly
most importantly, an increase in environmental instability.

The herpetofauna of North America became essentially modern at the familial

8 SOUTHERN CALIFORNIA ACADEMY OF SCIENCES

level during the Miocene (Holman 1995). Many modern families and genera of
anurans make their first appearance in North America during the Miocene, in-
cluding Bufo, Rana, Pelobatidae, and Hylidae. Many families of lizards occur,
including Iguanidae (sensu lato), Scincidae, Teiidae, Anguidae, Helodermatidae,
Xantusiidae, and Rhineuridae. Snakes are represented by five families, including
Aniliidae, Boidae, Colubridae, Elapidae, and Viperidae (Holman 1995). These
families (except Aniliidae) persist in North America into the Pliocene and through
to the Recent. Although Pliocene herpetofaunal records are rare in North America,
those available indicate a basically modern fauna (Estes and Baez 1985; Parmley
and Holman 1995; Holman 1995).

The majority of the published herpetofaunas of Neogene age from Nevada are
late Pleistocene (Rancholabrean) or Holocene in age (Banta 1966; Mead and Bell
1994). At present, our knowledge of late Tertiary herpetofaunas from Nevada is
extremely limited. The White Narrows local fauna and deposits located farther
north at Panaca, Nevada (Lindsay et al. 1999; Mou 1996, 1997, 1999) appear to
be the only sites of this age being studied in the region today. Scaphiopus alex-
anderi was reported from sediments in the Esmeralda Formation of Miocene age
(Zweifel 1956) and an undescribed turtle from the same formation was listed by
MacDonald and Pelletier (1958). Miopelodytes gilmorei, a pelodytid anuran, was
described from the middle Miocene of Elko County, Nevada (Taylor 1941B).
From localities farther north and west of the White Narrows local fauna, Rana
Johnsoni and R. plax were described from sediments that appear to be of Clar-
endonian to Hemphillian age (upper Miocene; La Rivers 1953, 1966), and an
undescribed Clarendonian turtle is included in the Chalk Spring Locality fauna
of Elko County (MacDonald and Pelletier 1958). An unidentified snake was re-
corded from the late Miocene Thousand Creek fauna by MacDonald and Pelletier
(1958). A single specimen of snake previously identified as Coluber/Masticophis
was recovered from Hemphillian sediments in the Truckee Formation of west-
central Nevada (Ruben 1971).

The herpetofauna from the White Narrows is not taxonomically diverse. An-
urans and a xantusid lizard dominate the fauna. The anurans are expected given
the reconstruction of lake, riparian, and oak-juniper (?) open woodland commu-
nities nearby (Axelrod 1991; Thompson 1991). The anuran taxa recovered are
expected in the region, although species identifications are not precise for most
specimens. The recovery of bufonid anurans in the Bufo borea/canorus/exsul
group might be predicted based on the Recent forms found in the region today
(Hovingh 1997), however, this record represents a temporal range extension back
to the early Pliocene.

The presence of plesiomorphic Xantusia in the White Narrows local fauna is
significant for a number of reasons. These specimens represent the northernmost
fossil record of the genus reported to date. Norell (1989) reported similar ple-
siomorphic xantusiids from late Pliocene and early Pleistocene sediments in Anza-
Borrego Desert, San Diego County, California. Norell also mentioned that poten-
tially similar forms were present in the Barstow Formation and in Clarendonian
age sediments of the Dove Springs Formation of California. Whistler and Burbank
(1992) list the Dove Springs Formation material as Xantusia sp., and this material
resembles (in its plesiomorphy) X. downsi*. We confirm the presence of plesiom-
orphic Xantusia specimens in at least seven Barstovian deposits in California

PLIOCENE HERPETOFAUNA FROM NEVADA e

(UCMP localities V5501, V6447, V6449, V6463, V65145, V65147, V6604; also
SBCM locality 1.130.37, possibly equivalent to UCMP V65147). Fossil material
identified as “‘Iguanidae or Xantusiidae”’ from the early Miocene Boron Local
Fauna in San Bernardino County, California (Whistler 1984) cannot be defini-
tively referred to either taxon at this time; we examined the material and it is too
fragmentary to be informative. The geographic and temporal distribution of these
fossils raises interesting questions regarding the propriety of allocating geograph-
ically and temporally distinct fossils to the same metaspecies. Resolution of this
taxonimic problem, and of the systematic position of the fossils in question is
beyond the scope of this paper, but will be addressed at a later date.

It would appear from the related data presented above that the basin holding
White Narrows sediments contained a lake, with a chemistry permitting the de-
position of marl (Schmidt et al. 1996). Climate was probably still subhumid, but
a cooling and aridification trend was occurring. Based on assumed reconstructions
from the paleobotanical records, this lake might have been surrounded by a mosaic
of oak-juniper woodland, possibly other deciduous trees and shrubs, and a riparian
community along the lake margins in stream courses. A subhumid climate around
a lake with surrounding riparian and open woodland communities would seem
ideal for a much more diverse local herpetofauna than was actually recovered.
Certainly the lake environment supported a diverse fauna; according to Reynolds
and Lindsay (1999) the sediments contained (in addition to the mammals dis-
cussed above) remains of perch and sucker fish, gastropods, and ostracods. The
low taxonomic diversity is probably due to sampling bias. Additional stratigraph-
ic, paleomagnetic, and paleontologic work is required to better understand the
herpetofaunal changes that took place during the Pliocene and immediately prior
to the glacial/interglacial phases of the Quaternary.

Acknowledgements

Sue Beard, George Billingsley, Ernie Duebendorfer, Joel Pederson, Dwight
Schmidt, and Van S. Williams provided helpful information about the Muddy
Creek and White Narrows formations. Eric Scott and Scott Springer helped with
locality information for the SBCM material. We thank Jacques Gauthier for in-
sightful discussions about xantusiid lizard evolution. G.E. Swartz provided helpful
comments on an earlier version of this report. Figures were prepared by Leigh
Anne McConnaughey, for whose patience we are most grateful. We thank Kathy
Springer and Betsy Slemmer (SBCM) for assistance with the loan of herpetolog-
ical remains from the White Narrows local fauna.

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Accepted for publication 24 May 2000.

Bull. Southern California Acad. Sci.
100(1), 2001, pp. 12—23
© Southern California Academy of Sciences, 2001

An Evolutionary Classification and Checklist of Amphibians and
Reptiles on the Pacific Islands of Baja California, México

L. Lee Grismer

Department of Biology, La Sierra University, Riverside, California 92515-8247

Abstract.—The herpetofauna of the Pacific islands of Baja California is evaluated
in light of an evolutionary species concept. Ten subspecies were relegated to
synonyms of their peninsular counterparts and three subspecies were elevated to
species status.

Resumen.—tLa herpetofauna de las islas del Pacifico de Baja California esta re-
visada basada en el concepto evolutivo. Este resulté en la relegacion de 10 su-
bespecies al sin6dnimo a sus contrapartes peninsulares y la elevaci6n de tres su-
bespecies al nivel de especie.

The Pacific coast of Baja California is fringed with a number of islands and
small archipelagos. Most are young, relatively small, landbridge islands but others
are older and continental or oceanic in origin (Grismer 1993). The herpetofauna
of these islands as a whole has received little attention except for the publication
of a number of checklists (Bostic 1975; Grismer 1993; Savage 1967; Van Den-
burgh 1905; Van Denburgh and Slevin 1914; Wilcox 1980; Zweifel 1958) and a
biogeographical study of the northern islands (Wilcox 1980). This herpetofauna
has never been evaluated taxonomically as a faunal unit.

Subsequent to the latest checklist of this herpetofauna (Grismer 1993), a num-
ber of additions (Wong 1997), deletions (Grismer and Hollingsworth 1996; Wong
1997), errors (Aguirre et al. 1999) and/or taxonomic changes (Grismer 1994a,
1999b; Grismer and McGuire 1996; Grismer and Hollingsworth in press; McGuire
1996; Smith et al. 1998; Wong and Grismer in prep.) have been published (Table
1). Additionally, this fauna has never been analyzed in the context of an evolu-
tionary species concept (ESC) as has recently been done for the herpetofauna of
the islands in the Gulf of California (Grismer 1999a,b). Grismer (1999b) noted
that in the Gulf of California, classifications based on a biological species concept
(Mayr 1969) had remained unstable for a number of years. This was because the
recognition of insular populations as species or subspecies was largely founded
on subjective interpretations of degrees of differentiation even though the data
sets being interpreted had remained unchanged. Grismer (1999b) proposed to
reduce this subjectivity by employing an ESC (Simpson 1961; Wiley 1978; Frost
and Hillis 1990), in which only discretely diagnosable (1.e., no overlap in character
state variation) lineages were recognized as species and the subspecies category
was abandoned (see Grismer, 1999b for discussion). The subspecies category was
not used because its operational duality (i.e., usage for both diagnosable insular
populations and portions of continuous continental populations) often misrepre-
sents history. The ESC proved most useful when evaluating insular populations
because it divorced decisions of taxonomic rank from subjective interpretations

HERPETOFAUNA FROM PACIFIC ISLANDS OF BAJA CALIFORNIA 13

Table 1. Summary of proposed taxonomic changes used herein. Referenced changes are those that
occurred subsequent to Grismer (1993).

Taxonomy of Grismer (1993) Newly proposed taxonomy

Caudata

Plethodontidae
Batrachoseps pacificus major B. major (Wake and Jockusch 2000)
Squamata (Lizards)

Crotaphytidae
Gambelia wislizenii copei G. copei (McGuire 1996)

Phrynosomatidae
Sceloporus magister monserratensis S. zosteromus (Grismer and McGuire 1996)
Uta stellata U. stansburiana (Grismer 1999a; Upton and Murphy

1997)

Gekkonidae
Phyllodactylus xanti zweifeli P. xanti

Teiidae
Cnemidophorus tigris multiscutatus C. tigris
Cnemidophorus tigris vividus C. tigris

Anguidae
Elgaria paucicarinata cedrosensis E. cedrosensis (Grismer and Hollingsworth in prep.)
Elgaria multicarinata ignava E. multicarinata
Elgaria multicarinata nana E. nana
Squamata (Snakes)

Colubridae
Chilomeniscus cinctus C. stramineus (Wong and Grismer in prep.)
Diadophis punctatus anthonyi D. punctatus
Hypsiglena torquata baueri H. torquata
Hypsiglena torquata martinensis H. torquata
Lampropeltis zonata herrerae L. herrerae
Masticophis flagellum fuliginosus M. fuliginosus (Grismer 1994a)
Pituophis melanoleucus coronalis P. catenifer
Pituophis melanoleucus fuliginatus P. catenifer
Pituophis vertebralis insulanus P. insulanus (Grismer 1994a)
Crotalus viridis caliginis C. caliginis
Crotalus exsul exsul C. ruber (Smith et al. 1998)

of reproductive compatibility based on degree of differentiation. In instances
where subspecies merely delimit the geographic distribution of selected character
states within a continuous continental population, there is no evidence that the
subspecies represent independent lineages and thus, should not be recognized in
a formal taxonomy. This is because the organisms manifesting these character
states merely form a co-extensive integrating section of a continuously distributed
species. Therefore, it is philosophically illogical and operationally counterproduc-
tive to consider arbitrarily defined sections of continuous populations and allo-
patric diagnosable entities as equivalent phenomenological systems even though
both have been traditionally given the rank of subspecies.

It is proposed here that a classification based on the application of the ESC
rather than the biological species concept will be more consistent with historical
processes because it discourages the recognition of taxa that are not demonstrable
evolutionary lineages. Thus, an evolutionary classification is less likely to be
misleading to evolutionary biologists working to discover patterns, processes, and/

14 SOUTHERN CALIFORNIA ACADEMY OF SCIENCES

or adaptations (Brooks and McLennan 1991). Such an interpretation of the Pacific
island herpetofauna is warranted.

Species Accounts

The following are discussions of those taxa whose reevaluation under the ESC
resulted in changes in their taxonomy. Also treated are published distributional
errors not corrected elsewhere in the literature. A summary of the proposed tax-
onomic changes presented herein and taxonomic changes published subsequent
to Grismer (1993) are listed in Table 1. Table 2 lists the species and the islands
on which they occur and Appendix I lists the islands and the species that inhabit
them. The location of the islands is illustrated in Figure 1.

Caudata
Plethodontidae
Batrachoseps major

Bostic (1975) reported Batrachoseps major from Isla San Martin. The specimen
was purported to be collected in the late 1970s by Tom Cozens, then a student
at San Diego State University (Cozens, pers. comm., 1980). The disposition of
the specimen remains unknown.

Anura
Ranidae
Rana pipiens complex

A single specimen of the Rana pipiens complex (Los Angeles County Museum
[LACM] 91380) was collected from Isla Sur of Islas de Los Coronados on 20
June 1959. No other individuals have been reported. Because there is no per-
manent water on this island, this specimen is considered a single introduction.
Interestingly, three tadpoles (LACM 91381) of the same complex were collected
from Punta Banda south of Ensenada opposite Islas Todos Santos on 29 March
1952. No additional specimens from this locality have been reported. Perhaps,
during the early fifties, an attempt was made to establish these frogs for com-
mercial purposes.

Squamata (Lizards)
Phrynosomatidae
Urosaurus nigricaudus

In a genetic study of Urosaurus nigricaudus from Baja California, Aguirre et
al. (1999) included what they believed to be a specimen U. nigricaudus from Isla
de Cedros (voucher number 1861 of R. W. Murphy). This species, however, has
never been reported from Isla de Cedros nor are there any museum records listing
its presence despite the numerous collections made from this island in the last 45
years. It is also absent from the adjacent Vizcaino Peninsula of Baja California
(Grismer et al. 1994) to which Isla de Cedros was most recently connected. This
record is therefore considered erroneous. The specimen in question, if indeed from
Isla de Cedros, is most likely Uta stansburiana. This may account for the some
of the problems it posed within their data set (Aguirre et al. 1999).

HERPETOFAUNA FROM PACIFIC ISLANDS OF BAJA CALIFORNIA 15

Gekkonidae
Phyllodactylus xanti zweifeli

Dixon (1964) described Phyllodactylus xanti zweifeli from islas Magdalena and
Santa Margarita on the basis of having a higher number of scales across the snout
between the third supralabials (19-22, n = 18) as compared to peninsular P. xanti
(14-21, n = 105) as well as having a lower number of scales across the venter
(26-33, n = 18 vs. 31-41, n = 105). However, because the ranges of variation
in these counts overlaps with those of peninsular populations, P. x. zweifeli is not
discretely diagnosable and is recognized here as P. xanti.

Teiidae
Cnemidophorus tigris

Cnemidophorus tigris occurs on six islands along the Pacific coast of Baja
California (Grismer 1993; Grismer and Hollingsworth 1996). Cope (1892) pro-
posed the name C. multiscutatus for the whiptail lizards of Isla de Cedros. Van
Denburgh (1894) proposed the name C. stejnegeri for populations ranging from
Los Angeles, California, southward to near Laguna San Ignacio (see Smith 1946).
Subsequent to their descriptions, these two species went through a multitude of
taxonomic rearrangements, terminating with Burger (1950) who, without com-
ment, placed both populations under the name C. t. multiscutatus. Zweifel (1958)
noted that lizards from coastal southern California were very different in striping
pattern and coloration from lizards of Isla de Cedros. He stated that it probably
was not “‘proper to refer the two populations to the same subspecies.’’ I have
observed living individuals from islas de Cedros and Natividad and found them
to be less distinctly striped than lizards from southern California populations but
they do form a cline with populations from the adjacent Vizcaino Peninsula. This
is most notable in the dark blotching of the gular and temporal regions where it
is prominent in the Vizcaino Peninsula whiptails, less so in lizards from Isla
Natividad, and even less so in lizards from Isla de Cedros. Clinal patterns have
been observed in other reptiles through these regions as well (Grismer et al. 1994).
Therefore, C. t. multiscutatus is not discretely diagnosable and is recognized here
as C. tigris.

Walker (1981) proposed the name Cnemidophorus tigris vividus for the whiptail
lizards of islas Norte and Sur of Islas de Los Coronados. He compared a series
of lizards from Isla Sur to C. tigris of Isla de Cedros, a population from over 500
km to the south, rather than the presumable source population of C. tigris from
the adjacent peninsula less than 10 km away. Grismer (1994b) noted that the Islas
de Los Coronados populations and those from the adjacent mainland overlap in
the number of granules around the body (80-100, n = 11 vs. 92-116, n = 15,
respectively), granules between the occiput and rump (167—204, n = 11 vs. 192—
231, nm = 15), number of femoral pores (32—40, n = 11 vs. 36—43, n = 15), and
the number of subdigital lamellae on the fourth toe (27-32, n = 11 vs. 29-32, n
= 15). The striping pattern in lizards of the Islas de Los Coronados populations
tends to be more vivid but it is not distinct from some individuals of adjacent
peninsular populations. Therefore, the Islas de Los Coronados populations are
considered here as C. tigris.

SOUTHERN CALIFORNIA ACADEMY OF SCIENCES

Table 2. Checklist of the herpetofauna of the Pacific islands of Baja California, México. Asterisks
following taxa indicate insular endemics.

Taxon

CAUDATA

Plethodontidae
Aneides lugubris
Batrachoseps major

ANURA
Bufonidae
Bufo punctatus
Hylidae
Hyla regilla
SQUAMATA (Lizards)
Crotaphytidae
Gambelia copeii
Iguanidae
Dipsosaurus dorsalis
Phrynosomatidae
Callisaurus draconoides
Phrynosoma coronatum
Sceloporus occidentalis
Sceloporus zosteromus
Urosaurus nigricaudus
Uta stansburiana

Eublepharidae

Coleonyx variegatus
Gekkonidae

Phyllodactylus xanti
Teiidae

Cnemidophorus hyperythrus

Cnemidophorus tigris

Scincidae
Eumeces skiltonianus

Anguidae
Anniella geronimensis
Anniella pulchra
Elgaria cedrosensis
Elgaria multicarinata
Elgaria nana*
SQUAMATA (Snakes)
Leptotyphlopidae
Leptotyphlops humilis
Pythonidae
Lichanura trivirgata
Colubridae
Chilomeniscus stramineus
Diadophis punctatus

Insular locale

Los Coronados (Isla Norte)
Los Coronados (all islands), Isla San Martin, Todos Santos (Isla
Sur)

Santa Margarita

Cedros

Cedros, Magdalena, Santa Margarita
Magdalena, Santa Margarita

Santa Margarita

Cedros

Cedros, Todos Santos (Isla Sur)

Cedros, Magdalena, Santa Margarita

Magdalena, Santa Margarita

Asuncion, Cedros, Las Brozas, Las Piedras, Los Coronados (all
islands), Magdalena, Natividad, Pata, San Benito, San Geroni-
mo, San Martin, San Roque, Santa Margarita, Todos Santos
(Isla Sur)

Cedros, Santa Margarita

Magdalena, Santa Margarita

Cedros, Los Coronados (islas Norte and Sur), Magdalena, Nativi-

dad, Santa Margarita

Los Coronados (islas Norte and Sur), Todos Santos (islas Norte
and Sur)

San Gerénimo

Los Coronados (islas Norte and Sur), Todos Santos (Isla Sur)
Cedros

San Martin

Los Coronados (islas Norte and Sur)

Cedros
Cedros, Natividad

Cedros, Magdalena
Todos Santos (Isla Sur), San Martin

HERPETOFAUNA FROM PACIFIC ISLANDS OF BAJA CALIFORNIA

Table 2. Continued.

Taxon Insular locale

Eridiphas slevini Santa Margarita

Hypsiglena torquata Cedros, Los Coronados (all islands), San Martin

Lampropeltis herrerae* Todos Santos (Isla Sur)

Masticophis fuliginosus Magdalena, Santa Margarita

Pituophis catenifer Los Coronados (Isla Sur), San Martin

Pituophis insulanus* Cedros

Pituophis vertebralis Magdalena, Santa Margarita

Salvadora hexalepis San Ger6énimo, Todos Santos (islas Norte and Sur)
Viperidae

Crotalus caliginis* Los Coronados (Isla Sur)

Crotalus enyo Magdalena, Santa Margarita

Crotalus mitchellii Santa Margarita

Crotalus ruber Cedros, Santa Margarita

Islas de Los

iy we ,

Islas Todos Santos

Isla San Martin

Isla San Gerénimo

Islas San Benito ——__y ,,

Isla de Cedros uit

Laguna Ojo de
Isla Natividad Liebre &

Isla Asuncién

Isla San Roque

Isla Santa Margarita

Fig. 1. Location of islands along the Pacific coast of Baja California, México.

18 SOUTHERN CALIFORNIA ACADEMY OF SCIENCES

Anguidae
Elgaria multicarinata

Fitch (1934) separated Elgaria multicarinata nana of islas Norte and Sur of
Islas de Los Coronados from E. m. webbi of San Diego County, California by its
smaller size, weak keeling, having fewer transverse ventral scale rows, and subtle
differences in the head and body color pattern. However, only adult body size
discretely differentiates these two populations, and according to Fitch (1934), “‘no
overlapping size could be shown among the 49 adult specimens from Los Co-
ronados Islands and 35 from San Diego County.’’ Average SVL for E. m. nana
was 93.3 mm with a maximum SVL of 114 mm and for E. m. webbi from San
Diego County, average SVL was 135 mm with a maximum of 166 mm (Fitch
1938). Fitch (1938) was aware that body size differences could be the result of
an ecological effect imposed by an insular environment rather than a genetically
based difference as has been proposed by more recent authors (e.g. Petron and
Case 1997 and citations therein). However, Fitch (1938) concluded that the body
size differences have a genetic basis, noting ontogenetic changes and sexual di-
morphism in E. m. webbi-specifically, that the largest individuals have relatively
thicker, more heavily keeled scales, and in males, much wider temporal regions.
Fitch (1938) pointed out that the largest individuals of E. m. nana showed these
characters which were indicative of their advanced age even though they were
smaller than the small adults of E. m. webbi. Additionally, Zweifel (1952) ob-
served a 79 mm SVL female E. m. nana copulating, and Burrage (1965) indicated
that the hatchling size range of the Islas de Los Coronados population is 32-35
mm SVL, essentially the same as that of hatchling E. m. webbi (30-36 mm) from
San Diego County, California. This strongly suggests that adulthood, and its ac-
companied morphological changes, is reached at a much smaller SVL in E. m.
nana than in E. m. webbi. Based on this, E. m. nana is recognized here as a
distinct species, E. nana.

Van Denburgh (1898) described Elgaria multicarinata ignava from Isla San
Martin as an endemic subspecies characterized by its heavy keeling and darkened
dorsal pattern. Fitch (1938), however, noted that an increase in the degree of
keeling was a trend that developed in all of the southernmost populations of E.
m. webbi and did not accord it taxonomic status. Its overall dark color pattern is
likely a result of substrate matching, being that it inhabits dark, rocky volcanic
habitats. A similar color pattern is found in populations from the volcanic areas
of the adjacent peninsular coastline west of San Quintin. Therefore, there are no
discretely diagnostic characteristics unique to this population and thus, it is rec-
ognized here as E. multicarinata.

Squamata (Snakes)
Colubridae
Diadophis punctatus

Van Denburgh and Slevin (1923) proposed the name Diadophis punctatus an-
thonyi for the population on Isla Sur of Islas Todos Santos. This population was
diagnosed as having a more robust body (Blanchard 1942) and an obscure neck
ring with poorly defined edges (Van Denburgh and Slevin 1923). It is difficult to
interpret from Blanchard (1942) how he determined that D. p. anthonyi was “‘larg-

HERPETOFAUNA FROM PACIFIC ISLANDS OF BAJA CALIFORNIA 19

er and stouter-bodied”’ than adjacent populations of D. punctatus because all mea-
surements he gave fall within the range of D. punctatus from the adjacent pen-
insula. Additionally, many specimens from northern Baja California and southern
California have a poorly defined neck ring as well. Therefore, this population
lacks discretely diagnostic characters and is considered as D. punctatus.

Hypsiglena torquata

Zweifel (1958) described Hypsiglena torquata baueri from Isla de Cedros on
the basis of a number of subtle character state trends of dorsal blotching, nuchal
blotching, and the lateral striping on the head. In a review of these snakes, Tanner
(1966), noting that these character states overlapped with those occurring in ad-
jacent peninsular populations of H. torquata, could not differentiate this subspe-
cies. Based on this, H. t. baueri is recognized here as H. torquata.

Tanner and Banta (1962) described Hypsiglena torquata martinensis on the
basis of a single female differentiated from all other Baja California populations
in having 54 subcaudals, two loreal scales, and a dorsal scale row formula of 23-
21-19-17. Moquard (1899) demonstrated that central peninsular populations of H.
torquata had 47-58 subcaudal scales and I have observed specimens from the
vicinity of Bahia de Los Angeles with two loreal scales. The diagnostic value of
the scale row formula is uninterpretable. Tanner and Banta (1962:24) state that
“In martinensis, ...the first fourth of the body has the increase to 23 rows and
nearly half have 22 rows. This formula is more nearly the standard pattern for
Hypsiglena, that is, the greatest number of rows from the nape to near mid-body
and then one or more reductions before the vent.’’ Therefore, these characters do
not discretely diagnose H. t. martinensis and it is considered here a synonym of
H. torquata. .

Lampropeltis zonata

Van Denburgh and Slevin (1923) described Lampropeltis zonata herrerae from
Isla Sur of Islas Todos Santos. In a revision of L. zonata, Zweifel (1952) diag-
nosed L. z. herrerae from all other L. zonata by having a combination of no red
in the color pattern and the posterior margin of the first white band being anterior
to the angle of jaw. This population is often considered as lacking red bands (e.g.,
Rodriguez-Robles et al. 1999: Fig. 4). However, homologous bands do occur in
the anterior portion of the body but are unique in that they have become white
or sometimes brownish. Hayes (1975) demonstrated that L. z. herrerae had a
significantly higher mean number of ventral scales (218.3, 216—220, n = 10)
compared to L. zonata from the adjacent peninsula (210.4, 207-216, n = 6) and
that their ranges only slightly overlapped. Additionally, he showed that the SVL
of L. z. herrerae averaged over 50 mm larger than the SVLs of southern L. zonata.
This character state is considered here to be unique because it is the result of an
increase in the number and the overall size of the body vertebrae (Hayes 1975).
Based on these characteristics, Hayes (1975) recommended that L. z. herrerae be
elevated to species status. Using mtDNA, Rodriguez-Robles et al. (1999) dem-
onstrated that L. z. herrerae is an exclusive population most closely related to
individuals of L. zonata from the Sierra San Pedro Martir. Based on the above
(excluding ventral scale counts), I elect to follow Hayes (1975) and recognize L.
z. herrerae as a full species L. herrerae.

20 SOUTHERN CALIFORNIA ACADEMY OF SCIENCES

Pituophis catenifer

Klauber (1946) described Pituophis catenifer coronalis from Isla Sur of Isla de
Los Coronados on the basis of four specimens. He diagnosed this population as
usually having suboculars, frequent abnormalities in the head plates, and fewer
number of dorsal blotches. Additionally, he detailed subtle differences from ad-
jacent continental populations of P. catenifer in the color pattern of the head.
Klauber (1946) also noted, however, that none of these characters discretely sep-
arated P. c. coronalis from many other subspecies of P. catenifer and therefore,
this population is recognized here as P. catenifer.

Klauber (1946) described and differentiated Pituophis catenifer fuliginatus from
Isla San Martin from peninsular P. catenifer on the basis of having a darker color
pattern, large amounts of black spotting on the head, a lower average number of
body blotches (62.6, 55-70, n = 15 vs. 75.5, 57-90, n = 52), usually a single
instead of two preoculars, a high frequency of aberrant prefrontals, and paired
dark subcaudal streaks. Klauber (1946) noted that the overall darkness of the
population was probably related to substrate matching and I have observed sim-
ilarly colored individuals from the volcanic regions west of San Quintin in coastal
areas adjacent to Isla San Martin. None of the scale characters discretely separates
P. c. fuliginatus from adjacent peninsular populations and subcaudal streaking
also appears in other P. catenifer from Baja California (Klauber 1946). Therefore,
this population is recognized here as P. catenifer.

Crotalus viridis

Klauber (1949) described Crotalus viridis caliginis from Isla Sur of Islas de
Los Coronados. Although he could find no differences in color pattern or squa-
mation between it and the adjacent peninsular populations of C. viridis, he did
note significant differences in body proportions and SVL. Klauber (1949) noted
that C. v. caliginis would not grow to the size of an average adult C. v. helleri
of the adjacent peninsula. The largest specimen he measured was 674 mm total
length and he notes that C. v. helleri regularly reach 1100 mm in length. Also,
the rattles of C. v. caliginis reach parallelism at a width of 10—11 mm whereas
in C. v. helleri, parallelism is reached at 15-17 mm (parallelism happens when
adulthood is reached). Finally, specimens of C. v. caliginis of the same size as
C. v. helleri have disproportionally smaller heads (Klauber, 1938). Klauber (1949)
noted that a 1100 mm C. v. helleri ‘““would have 5 times the bulk” of a 650 mm
C. v. caliginis. Based on these data, C. v. caliginis is considered here to be a
distinct species, C. caliginis.

Acknowledgments

For comments on the manuscript and/or discussions of species concepts I thank
B. Hollingsworth, H. Wong, and E. Mellink. I wish to thank K. Beaman for
assistance with Rana records of the Los Angeles County Museum.

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Accepted for publication 1 March 2000

Appendix I

Checklists of the herpetofauna of the islands along the Pacific coast of Baja California, México.
Asterisked taxa are insular endemics.

Isla Asuncion. Uta stansburiana.

Isla de Cedros. Hyla regilla, Gambelia copei, Phrynosoma coronatum, Sceloporus zosteromus, Sce-
loporus occidentalis, Uta stansburiana, Coleonyx variegatus, Cnemidophorus tigris, Elgaria cedro-
sensis*, Leptotyphlops humilis, Lichanura trivirgata, Chilomeniscus stramenius, Hypsiglena torquata,
Pituophis insulanus*, Crotalus ruber.

Isla Las Brozas. (Within Laguna Ojo de Liebre). Uta stansburiana.

Isla Las Piedras. (Within Laguna Ojo de Liebre). Uta stansburiana.

HERPETOFAUNA FROM PACIFIC ISLANDS OF BAJA CALIFORNIA 23

Isla Magdalena. Dipsosaurus dorsalis, Gambelia copei, Sceloporus zosteromus, Urosaurus nigri-
caudus, Uta stansburiana, Phyllodactylus xanti, Cnemidophorus hyperythrus, Cnemidophorus tigris,
Chilominescus stramenius, Masticophis fuliginosus, Pituophis vertebralis, Crotalus enyo.

Isla Natividad. Uta stansburiana, Cnemidophorus tigris, Lichanura trivirgata.

Isla Pata. (Within Laguna Ojo de Liebre). Uta stansburiana.

Isla San Geronimo. Uta stansburiana, Anniella geronimensis, Salvadora hexalepis.

Isla San Martin. Batrachoseps major, Uta stansburiana, Elgaria multicarinata, Diadophis punctatus,
Hypsiglena torquata, Pituophis catenifer.

Isla San Roque. Uta stansburiana.

Isla Santa Margarita. Bufo punctatus, Callisaurus draconoides, Dipsosaurus dorsalis, Gambelia
copei, Sceloporus zosteromus, Urosaurus nigricaudus, Uta stansburiana, Coleonyx variegatus, Phyl-
lodactylus xanti, Cnemidophorus hyperythrus, Cnemidophorus tigris, Eridiphas slevini, Masticophis
fuliginosus, Pituophis vertebralis. Crotalus enyo, Crotalus mitchellii, Crotalus ruber.

Islas de Los Coronados. (Three major islands). Aneides lugubris (Isla Norte), Batrachoseps major,
Uta stansburiana, Eumeces skiltonianus (islas Norte and Sur), Cnemidophorus tigris (islas Norte and
Sur), Elgaria nana* (islas Norte and Sur), Anniella pulchra (islas Norte and Sur), Hypsiglena torquata,
Pituophis catenifer (Isla Sur), Crotalus caliginis* (Isla Sur).

Islas San Benito. (Three islands). Uta stansburiana.

3Islas Todos Santos. (Two islands). Batrachoseps major, Sceloporus occidentalis, Uta stansburiana
(islas Norte and Sur), Eumeces skiltonianus (islas Norte and Sur), Anniella pulchra, Diadophis punc-
tatus, Lampropeltis herrerae*, Salvadora hexalepis.

! Includes all three major islands (islas Sur, Norte, Medio) unless noted otherwise. Isla Medio
consists of two small islets: a larger southern islet and a smaller northern islet. No records are known
from the latter.

2 Includes all three islands.

3 Presence on Isla Sur only unless indicated

Bull. Southern California Acad. Sci.
100(1), 2001, pp. 24—35
© Southern California Academy of Sciences, 2001

Spot Pattern of Girella nigricans, the California Opaleye: Variation
among Cohorts and Climate Periods

Jana L. D. Davis

Scripps Institution of Oceanography, University of California at San Diego,
9500 Gilman Drive 0208, San Diego, California, 92093-0208

Abstract.—Girella nigricans (California opaleye) exhibits variability in dorso-
lateral spot pattern. Southern California opaleye usually have one pair of white
spots; however, fish with additional spots are frequently observed. Additional
spots are thought to result from gene flow with the six-spotted Gulf of California
Girella simplicidens. In the present study, the proportion of fish with extra spots
was compared among and within nine G. nigricans cohorts settling from 1997 to
1999. This proportion was variable among the nine cohorts. When analyzed by
climate regime, cohorts settling during the 1997—98 El Nino event had signifi-
cantly higher proportions of multi-spotted fish than “‘normal’’ and La Nifia co-
horts. Within five of nine cohorts, the proportion of fish with additional spots
significantly increased through time during the study, suggesting that survivorship
of multi-spotted fish was greater than that of two-spotted fish during the juvenile
stage. The easily identifiable spot polymorphism of Girella nigricans provides a
useful tool by which to study hybridization between two marine fishes and track
changes in gene flow and gene expression over time.

The distribution of nearshore marine populations is often partly determined by
abiotic factors. Gradients in temperature, for example, are important on several
spatial scales, from meter-scale intertidal zonation (Nakamura 1976) to latitudinal
distribution on the kilometer-scale (Morris 1960). Changes in temperature on dif-
ferent temporal scales can affect species’ distributions as well. The daily temper-
ature cycle plays a role in meter-scale cross-shore movements of fish (Gibson et
al. 1998), seasonal temperature changes force vertical habitat shifts in motile
intertidal species (Zander et al. 1999), and temperature variation on scales longer
than a year shapes alongshore distribution of nearshore populations (Barry et al.
1995). Over a 60-year period during which water temperature increased by
0.75°C, Barry et al. (1995) found increases in abundance of southern species and
decreases in northern species at a California rocky intertidal site, suggestive of
range shifts to the north.

Interannual temperature cycles on scales shorter than 60 years, such as that
driven by the El Nifio Southern Oscillation (ENSO), may also influence species
ranges. During warm El Nifio events, a rise in water temperature results in shifts
of many species to higher latitudes (Arntz and Tarazona 1990). A similar range
shift might be expected for hybrid zones where reproductive isolation of species
is incomplete. One such zone occurs in Baja California in the region of overlap
between Girella nigricans (California opaleye) and Girella simplicidens (Gulf
opaleye). Girella nigricans occurs mainly from Cabo San Lucas, Baja California
to San Francisco and has one pair of lateral white spots flanking its dorsal fin

SPOT PATTERN VARIATION IN CALIFORNIA OPALEYE 2D

(Thomson et al. 1979). Girella simplicidens occurs in the Gulf of California to
Cabo San Lucas and has three or four pairs of white spots (Thomson et al. 1979;
Robins et al. 1991). Although listed as separate species based on dentition, body
shape, and spot number, this status may not be warranted morphologically or
genetically (Orton and Buth 1984), and genetic exchange between the two groups
produces individuals with three, four, and five spots in various lateral arrange-
ments (see Orton et al. 1987).

The forces driving hybridization between marine fish species are poorly un-
derstood (Rao and Lakshmi 1999). Reports of marine fish hybrids are much rarer
than those of freshwater fish hybrids, due to both a lower tendency of marine fish
to hybridize as well as mistaken classification of hybrids as distinct species (Hubbs
1955; Rao and Lakshmi 1999). Possible conditions favorable to marine hybrid-
ization include outnumbering of one closely related species by another, intergra-
dation in the parental species’ habitats, and environmental disturbances (Rao and
Lakshmi 1999). The relative contribution of these conditions to specific hybrid-
ization cases, like that of G. nigricans and G. simplicidens, have not been ade-
quately addressed (Rao and Lakshmi 1999). Questions pertaining to the location
of the G. nigricans-G. simplicidens hybrid zone, the validity of species-level dis-
tinction, the frequency of interbreeding, the fertility of the hybrid offspring, and
hybrid variability among others, remain and warrant further study.

One Girella hybrid study has addressed the relationship between latitude and
the number of three-, four-, five-, and six-spotted fish (referred to hereafter as
“‘multi-spotted”’’) within the G. nigricans range (Orton et al. 1987). Lower pro-
portions of multi-spotted fish were found at three southern California sites than
at Miller’s Landing, Baja California. The presence of such a gradient was attri-
buted to a higher level of genetic exchange between G. nigricans and G. simpli-
cidens at southern latitudes closer to G. simplicidens’ range (Orton et al. 1987).
If El Nino and other warm water events cause species’ ranges to shift to higher
latitudes, this gradient of multi-spotted opaleye abundance might also be expected
to shift to higher latitudes. At fixed points in California, which are north of the
peak region of genetic exchange between the two Girella groups, such a range
shift might be observed as local increases in the proportion of multi-spotted in-
dividuals.

The purpose of the present study was to address the temporal variability in
opaleye spot pattern in San Diego, California. Specific goals were to (1) test
whether the frequency of spot patterns varied among cohorts recruiting at different
times, (2) determine whether spot pattern differed among climate regimes in
which the cohorts settled (El Nifio, “‘normal,’’ or La Nifia), and (3) determine
whether the proportion of multi-spotted individuals within a cohort changed over
time, indicating differential survivorship.

Methods

Opaleye and their spot patterns were sampled at two sites in San Diego, Cal-
ifornia, USA: False Point, in La Jolla (117.3°W, 32.8°N), and Dike Rock, 500 m
north of the SIO Pier in the Scripps Coastal Reserve (117.3°W, 32.9°N). After a
two- to three-month planktonic larval stage, opaleye generally occupy tidepools
for one or two years or until they reach 75 mm total length (Norris 1963; Stevens
et al. 1989). Juvenile opaleye are most frequently found in middle to high inter-

26 SOUTHERN CALIFORNIA ACADEMY OF SCIENCES

tidal pools from 30—90 cm above mean lower low water (MLLW) in San Diego
(Davis 2000b). After their intertidal stage, they abandon the intertidal zone in
favor of subtidal areas.

Opaleye at False Point were collected from a set of 55 tidepools ranging from
6 cm below MLLW to 107 cm above MLLW. Each tidepool was bailed or si-
phoned to permit collection of all fish present. Rocks were removed, and each
pool was thoroughly searched. Opaleye were collected, their total lengths (TL)
and standard lengths (SL) were measured in mm, and the number of spots on
each side was recorded. The pool was then refilled, and the fishes were returned.
About 4 to 8 days were needed to sample all 55 tidepools. Data were collected
during 12 sampling periods: May 1997, August 1997, November 1997, February
1998, May 1998, June 1998, August 1998, October 1998, November 1998, Feb-
ruary 1999, March 1999, and August 1999. In August 1999, spot patterns were
measured only for opaleye collected from the largest False Point tidepool.

At Dike Rock, opaleye spot pattern was scored in one large tidepool (52 cm
above MLLW) from May through October of three years: 1997, 1998, and 1999.
This study pool, used by Norris (1963) for behavioral observations of opaleye, is
the largest permanent tidepool in the reserve, measuring 4.5 m long, 1.5 m wide,
and about 40 cm maximum depth. Opaleye in the pool were collected with min-
now traps one to three times per week on average during each May-to-October
period, a period that included most opaleye recruitment and therefore highest
abundances. From May 25—August 4, 1997, one 40 cm minnow trap with 2 mm
mesh and openings of 2.8 cm was deployed for 60 min on each sampling day.
On all dates after August 4, 1997, a second trap, with 6 mm mesh and 4 cm
Openings, was added. The traps were baited with canned cat food and placed in
fixed locations in the tidepool. All opaleye collected were measured (TL and SL),
their spot pattern was identified, and they were released back into the pool.

Minnow traps were used only at Dike Rock because its pool, much larger than
the False Point pools, harbored more opaleye than the False Point pools. At False
Point, traps did not capture enough individuals for analysis. In addition, traps
were easier to use than the method of draining pools, permitting more frequent
sampling at Dike Rock.

Opaleye cohorts were identified from size-frequency histograms and from the
arrival of prejuveniles to the study areas. Prejuveniles, characterized by silvery
sides, green dorsal surfaces, and the absence of spots, transform into juveniles
within a few days of settlement (Stevens et al. 1989). During this transformation
period, they turn an olive color and attain their characteristic spots, which are
fixed in number during an individual’s lifetime (Orton et al. 1987). In general,
prejuveniles supplying each cohort identified in the study arrived over an ap-
proximately two-week period, followed by a period of absence of prejuveniles.
Each cohort was identified at or within a month of setthement, with the exception
of one cohort that settled during winter 1998 at Dike Rock, a period when fish
were not sampled at this site. Settlement period for this winter cohort was esti-
mated based on the mean size of its fish (64 mm TL) when sampling began in
May 1998. For all summer cohorts at Dike Rock, setthement period was deter-
mined by the arrival of prejuveniles. Settlement period for each False Point cohort
was estimated from periodic (approximately every 2—3 months) size-frequency
histograms and when possible, the presence of prejuveniles. Cohorts were fol-

SPOT PATTERN VARIATION IN CALIFORNIA OPALEYE pe |

lowed through time at False Point until they left the intertidal zone and followed
at Dike Rock either until they left the intertidal zone or until the end of October
of their settlement year.

The proportion of multi-spotted opaleye (Py) per weekly period was calculated
as:

Py = Ny/CNz — Np;)

where Ny is the number of fish with more than two spots collected during a 7-
day period, N; is the number of total fish collected, and N,, is the number of
prejuveniles (fish with undeveloped spots). Py was calculated over a weekly pe-
riod instead of daily because the percentage of multi-spotted fish was generally
on the order of 5—10%, and on some occasions fewer than 10 fish were caught
per day. Therefore, daily data were combined on weekly intervals to avoid zero
values and artificially high values driven by low sample size. At False Point, spot
proportions were calculated for each cohort using N,,, N;, and Np, summed across
all 55 study pools. No pool was sampled more than once, but because from three
to six days were needed to sample all 55 pools, it is possible that fish moved
between pools from day to day resulting in some fish being resampled. At Dike
Rock, Py was calculated for all fish within a cohort caught within a 7-day period.
Because data were always collected from the same pool, it is likely that many of
the same fish were caught day after day. However, the frequency of recaptures
was not expected to be different for two-spotted and multi-spotted fish at either
site. Therefore, although the data are not independent, they are not expected to
be biased with regard to the hypotheses. For statistical analyses, these values were
subjected to arcsin square root transformation.

To determine whether cohorts settling during different climate periods (‘“‘nor-
mal,’’ El Nino, or La Nifia) had different P,, values, each cohort was assigned to
a climate period based on temperature and sea level data measured at Scripps
Pier. According to temperature and sea level anomalies, the El Nifio period began
in late summer 1997 and continued through about May of 1998. The La Nifia
period was in its early stages in August 1998 and continued through the end of
the study (Lynn et al. 1998).

To address the question of whether the cohorts had significantly different values
of Py, a one-way analysis of variance (ANOVA) was used to test the difference
in average weekly spot proportions among all nine cohorts. Normality of the data
was examined using Lilliefors test of residuals (p > 0.05). ANOVAs were also
used to test whether P,, was different among cohorts within each of the three
climate periods. To determine whether spot proportion was different among cli-
mate periods, an ANOVA was used with average weekly spot proportion for each
cohort within a climate period as replicates. A nested ANOVA with cohort nested
within climate period would have provided the most appropriate test to address
these questions. However, because different numbers of cohorts were measured
during the three climate periods, a nested design was not possible.

To address the question of whether spot proportion changed within cohorts over
time, regression analysis was used. In these models, weekly P,, was the dependent
variable and time served as the independent variable. To determine whether the
proportion of three-spotted fish (P;) was greater than the proportion of four-spotted
fish (P,) within cohorts, a paired t-test was used.

28 SOUTHERN CALIFORNIA ACADEMY OF SCIENCES

Table 1. Settlement and size of the nine study cohorts: Cohorts are identified by site (DR = Dike
Rock and FP = False Point) and are named by season of settlement (sum = summer, win = winter),
the last two digits of the year in which they settled, and their order if more than one cohort settled
during a season (1 = first to settle, 2 = second to settle). Dates of settlement and climate type at time
of settlement (NORM = normal, EN = El Nino, and LN = La Nina) are listed. The time period over
which each cohort was followed and average total length (mm) of fishes at the start and end of that
time period are presented.

Glimnaes Sampling dates Avg. fish size

Site Cohort Settlement type Start End Start End

DR sum 97 1~— mid-Jun—end-Jun 1997 NORM _ Jun 8 97 Oct 14 97 28.0) 81a
DR sum 97 2- mid-Jul—end-Jul 1997 NORM _ Jul 9 97 Oct 13.97 30.0 48.4

FP. ssuim-97 Jun—Jul 1997 NORM _— Jun 20 97 May 15 98 . 23.5... 730
DR win 98 Jan or Feb 1998 EN May 25 98 Nov 6 98 64.4 94.0
FP win 98 Feb 1998 EN Feb 15°98 © May 299 33.7" SO.0
DR = sum 98 1~— mid-Jun—end-Jun 1998 NORM _ Jun 8 98 Nov 6 98 29°35 ~ COS
DR sum 98 2 mid-Aug—end-Aug 1998 LN Aug 1998 Nov 6 98 24.8 46.2
FP sum 98 Aug 1998 LN Aug 1 98 Aug 20 99 32.0 74.6
DR , . sum,99 mid-Jul—end-Aug 1999 LN Jul 11 99 Oct 26 99 30.6 49.8
Results

During the study, 4012 spot number and configuration scores were taken on
post-prejuvenile Girella: 1569 at Dike Rock in 1997, 1335 at Dike Rock in 1998,
493 at Dike Rock in 1999, and 615 at False Point from May 1997 to August
1999. As in Orton et al. (1987), most individuals were two-spotted. Of the multi-
spotted fish captures, there were 203 scores of three-spotted fish, 118 scores of
four-spotted fish, 7 scores of five-spotted fish, and 2 scores of six-spotted fish

From opaleye size frequencies at the two sites, nine cohorts were identified
throughout the study period: three at False Point and six at Dike Rock (Table 1).
At False Point, cohorts settled in summer 1997, winter 1998, and summer 1998.
The summer 1997 cohort was actually produced by two recruitment events, one
occurring in late June 1997 and one in late July. However, although they were
distinct during August 1997, they were not identifiable in subsequent sampling
months and therefore were combined into one cohort for analysis.

At Dike Rock, two cohorts settled in summer 1997 (Figure 1), three were
identified from summer 1998, and one cohort settled in summer 1999. One 1998
cohort was greater than 60 mm TL in May of that year, and therefore it likely
settled at about the same time as the winter 1998 False Point cohort. The other
two 1998 cohorts settled during the summer. Although cohorts that appeared at
the same time at the two sites were possibly part of a large scale “‘meta-cohort,”’
they were considered separate cohorts in the present study. Because some cohorts
settled at different times than others, and because cohorts probably abandon their
tidepool nursery areas at different times, not all cohorts were followed over the
same size ranges (Table 1).

The proportion of multi-spotted fish (P,,) varied among the nine cohorts (AN-
OVA: F,7, = 5.12, p< 0.001) (Figure 2). However, within the El Nifio and La
Nifia climate periods, P,, was not significantly variable among cohorts (ANOVA:
El Nifio, F,,, = 2.18, p = 0.168; La Nifia, F,,, = 0.50, p = 0.612). Py of the
four normal cohorts was variable (F;3, = 6.42, p = 0.001); however, for the

SPOT PATTERN VARIATION IN CALIFORNIA OPALEYE 29

Table 2. Regression analyses of the number of multi-spotted fish within a cohort versus time.
Cohorts are identified and named as in Table 1. The number of total spot measurements of fish within
each cohort, as well as the number of weeks for which spot data were taken, are listed.

No. No.
Site Cohort measurements weeks Slope i p-value
DR sum 97 1 841 11 #S0cX 10% 0.43 0.028
DR sum 97 2 728 12 tae Xx 1052 G32 0.055
EP sum 97 196 =) =03°x 10° 0.04 0.749
DR win 98 176 8 +2iA x 10 0.70 0.010
FP win 98 179 > +4.4 x 10° 0.26 0.380
DR sum 98 1 938 14 OT xX. 10 0.64 <0.001
DR sum 98 2 221 9 +8.8 X 10°? 0.27 0.156
FP sum 98 240 6 ee Ors 0.80 0.016
DR sum 99 493 11 +59" 103 0.26 0.111

‘“‘normal’’ cohort that settled during the period between El Nifo and La Nifia
(June 1998), El Nino conditions prevailed during most of its larval stage. Without
this cohort, which had a relatively high average weekly P,, (11.8%), the pre-E]
Nino cohorts did not exhibit variation in weekly Py (F..5 = 1.34, p = 0.281).

Mean weekly proportion of multi-spotted fish in a cohort was significantly
different among climate periods (normal, El Nino, and La Nina) (ANOVA: F,.,
= 6.47, p = 0.032; Figure 2). Cohorts recruiting during the El Nifio period had
higher mean values of P,, (mean of mean P,, = 20.4%) than those recruiting
during the normal periods (6.7%) (a posteriori Fisher’s LSD; p = 0.009) and the
La Nifia period (7.8%) (a posteriori Fisher’s LSD; p = 0.013). Spot proportions
of the normal and La Nifia cohorts were not significantly different from each
other (p = 0.886).

P,, tended to increase over time within cohorts (Figure 3). This increase was
significant in 5 cohorts: 1997 summer 1, 1997 summer 2, 1998 winter, and 1998
summer 1 cohorts at Dike Rock, and the summer 1998 cohort at False Point
(Table 2). Within cohorts, the proportion of three-spotted fish was greater than
the proportion of four-spotted fish (Table 3). Two-spotted fish were most abundant,
followed by three-spotted fish, then by four-spotted fish.

Discussion

Hundreds of three- and four-spotted and several five-spotted Girella individuals
were observed in San Diego from 1997 to 1999. However, only two Girella
individuals with six spots, individuals that may have been genetically “‘pure”’ G.
simplicidens, were observed. The rarity of juvenile G. simplicidens suggests that
adult G. simplicidens were not common in the San Diego area. Therefore, multi-
spotted fish in the present study were probably not the result of G. nigricans-G.
simplicidens hybridization occurring within the San Diego region. Instead, high
numbers of fish with three and four spots suggests either that 1) hybrid larvae
were transported north, or 2) alleles or series of alleles coding for extra spots
were present in San Diego populations. The present study does not permit rejec-
tion of either hypothesis; however, results of the present study do indicate that
processes controlling presence of multiple-spotted fish are variable over time. The
frequency of multi-spotted fish varied temporally, both among cohorts and within

30 SOUTHERN CALIFORNIA ACADEMY OF SCIENCES

A. Jul 26-29 1997 prejuvenile
[_] transformed

$22 = (26,28) (32,34] (38,40] (44,46] (50,52] (56,58] (62,64] (68,70] >74

Number of individuals

$22 = (26,28] (32,34] (38,40] (44,46] (50,52] (56,58] (62,64] (68,70] >74

Size categories (mm TL)

Figure 1. An example of opaleye cohorts distinguishable by size-frequency histograms. Two co-
horts settled at Dike Rock during the summer of 1997. The two cohorts A) from July 26 to July 29,
1997, at the end of the settlement period for the smallest cohort, and B) from August 18 to August
21, after three weeks of growth. A few prejuveniles were still contributing to the younger cohort, but
most juveniles had already settled.

cohorts. Cohorts recruiting during the E] Nifio period had higher spot-proportions
than those recruiting during non-El Nifio periods. Within cohorts, regardless of
climate period, the proportion of multi-spotted fish increased over time.
Among-cohort variability.—Increases in the proportion of multi-spotted Girella
(P,,) among cohorts recruiting during the El] Nifio period could have resulted from
several processes. Environmental disturbance tends to promote marine fish hy-
bridization (Rao and Lakshmi 1999), and the 1997—98 El Nino event may have
served as a natural disturbance inducing more interbreeding of G. nigricans and
G. simplicidens in the southern hybrid zone. Northward transport of hybrid larvae
to San Diego might have increased during El Nino due to changes in currents.
Opaleye larvae are neustonic, usually found up to 110 km from shore (Stevens
et al. 1989), and are subjected to surface transport by the southward offshore
California Current and the northward inshore California Countercurrent. During
the 1997—98 El Nifio event, the California Current moved offshore and the Cal-
ifornia Countercurrent increased in velocity (Norton et al. 1985; Lynn et al. 1998).
As a result, the inshore band of northward transport widened, encompassing a
greater width of the cross-shore opaleye larval distribution, and the northward
transport of anomalously warm water increased (Lynn et al. 1998), presumably
along with associated larvae. Hybrid larvae transported north may also have ex-
perienced increased survivorship. If hybrids are intermediate between G. nigricans

SPOT PATTERN VARIATION IN CALIFORNIA OPALEYE aa

Table 3. Comparison of the proportion of opaleye with three spots (P;) and four spots (P,) in each
cohort. Cohorts are identified as in Table 1. A paired f-test indicates that P, is greater than P, within
cohort (n = 9, t = 2.40, p = 0.034).

Site Cohort Ps P,

DR sum 97 1 0.045 0.024
DR sum 97 2 0.044 0.031
FP sum 97 0.038 0.006
DR win 98 0.060 0.089
FP win 98 0.165 0.096
DR sum 98 1 0.065 0.053
DR sum 98 2 0.057 0.021
FP sum 98 0.035 0.029
DR sum 99 0.061 0.030

and G. simplicidens in temperature-related characters, as they are in spot number,
then opaleye with a southern, warm-water G. simplicidens ancestor might survive
better in warmer El] Nino years than colder years.

The multi-spotted fish collected in San Diego may not be hybrid offspring, but
instead may reflect a polymorphism for spot number within the San Diego pop-
ulation. In this case, the variable Py among cohorts may have resulted from
temperature-sensitive expression of genes controlling spot number. Although spot
number is not a plastic trait after post-settlement development (Orton et al. 1987),
conditions during the larval stage may dictate the number of spots that are to
develop. Alternatively, larvae with additional-spot alleles may experience differ-
ent survivorship during different environmental conditions, leading to recruiting
cohorts with different spot proportions. If fish with additional spots are charac-
terized by other southern traits, such as higher warm-water affinity, then anom-
alously warm E] Nifio events might lead to cohorts with higher Py. However, in
the present study, the response of spot proportion to temperature was not consis-
tent in two ways. First, the two El Nifio cohorts recruited during the winter of
1998, which although anomalously warm, was still cooler than the usual summer
season of recruitment. The fact that these El Nino cohorts were in addition the
only two winter cohorts also complicates the comparison among these and the
summer-recruiting normal and La Nino cohorts. Second, La Nifia temperature was
about 1—2°C cooler than long-term (1966-1994) average temperatures (Davis
2000a), but spot proportions of fish recruiting during early (summer 1998) and
late (Summer 1999) La Nifia conditions were not lower than “‘normal’’ period
spot proportions (Figure 2).

Within-cohort variability.—The within-cohort variability of Py observed in the
present study is opposite to that expected based on Orton et al. (1987)’s exami-
nation of fish size and spot proportion. In the present study, the proportion of
multi-spotted fish within most cohorts increased over time as fish grew larger
(Figure 3). At one of Orton et al. (1987)’s sites, the proportion of multi-spotted
fish was lower in 1-3 year-old fish (>60 mm SL or > about 75 mm TL) than in
young-of-the-year fish (30—60 mm SL or about 37-75 mm TL), suggesting that
survivorship of fish with extra spots was lower than that of two-spotted fish.

Results of the present study were not consistent with this suggestion. Two
explanations may account for the discrepancy. First, Orton et al. (1987) studied

oz SOUTHERN CALIFORNIA ACADEMY OF SCIENCES

0.35
a Normal
O25
0.2
a> 0.15

0.054
= eee Fy

IABY
PP Oy WR Se ck AC aa ke
BG nik Ge Ber Oy oe camel
ho ean capi eee. (Ze niesten 60 bee
Rue! alitehicdettial™ iy caidas Le
Sateen ee (Fd cna oN «ae adie
= ee
of S| wa ree) FW

cohort

Figure 2. Average weekly proportion of multi spotted opaleye (P,,) + 1 SE (back-transformed)
among nine opaleye cohorts sampled at Dike Rock (DR) and False Point (FP) during normal, El Nino,
and La Nifia climate periods. Cohorts are named by season, year, order of settlement, and site as in
Table 1.

fish from 30—120+ mm SL (about 37—150+ mm TL), and grouped 30—60 mm
SL (about 37—75 mm TL) fish for size comparisons. In the present study, most
cohorts were not followed beyond 75 mm TL, so the two studies examined slight-
ly different ranges of G. nigricans’ life history. The proportion of multi-spotted
fish may increase during opaleye’s intertidal phase (<75 mm TL, Stevens et al.
1989), as indicated by the present study, then decrease after the intertidal phase,
as suggested by Orton et al. (1987). Second, in Orton et al. (1987), large and
small fish were collected at the same time, so comparisons were made across
cohorts. The present study shows that different cohorts can have significantly
different proportions of multi-spotted fish. As a result, across-cohort comparisons
may not adequately address survivorship or selection issues. Therefore, variability
in spot proportion among size classes at a particular time in Orton et al. (1987)
might not have been the result of differences in survivorship of multi-spotted fish
as a cohort aged, but may reflect variability among cohorts.

The increased frequency of multi-spotted fish over time in most of the cohorts
in the present study indicates that within the size range of 30 to 75 mm TL, over
the course of several months, the survivorship of multi-spotted fish is higher than
that of two-spotted fish. Intertidal opaleye generally occupy middle and upper
tidepool habitats (Davis 2000b), which can reach temperatures during spring and
summer daytime low tides that are above their preferred temperature of 27—28°C

SPOT PATTERN VARIATION IN CALIFORNIA OPALEYE 33

A. m@ DR97suml1 0 DR97sum2 @ FP97sum
*K

SS Set Pa him dient Nee Faas Namah cee aR tas VEE.

Jun 20 1997 Nov 7 1997 Mar 27 1998

B. e@ DR98win o FP98win

Feb 20 1998 Jul 10 1998 Nov 28 1998

Weekly proportion of multi-spotted opaleye (P,,)

C. a DR98suml A DR98sum2 YW FP98sum Yy DR9IIsum

Jul 10 1998 Nov 28 1998 Apr 161999 Sep 3 1999

Date

Figure 3. Weekly proportions of multi-spotted opaleye (P,,) over time of each of the nine False
Point (FP) and Dike Rock (DR) cohorts. Cohorts are named as in Table 1. A) Cohorts that recruited
in the summer of 1997; B) cohorts that recruited in the winter of 1998; C) cohorts that recruited in
summer 1998 and summer 1999. Dotted lines and solid lines indicate regression lines for cohorts from
FP and DR, respectively. Asterisks indicate regression lines with slopes significantly different from
zero. See Table 2 for r? and p-values.

34 SOUTHERN CALIFORNIA ACADEMY OF SCIENCES

(Norris 1963) and close to their lethal maximum temperature (Douderoff 1942).
If the presence of additional spots is associated with warm-water adaptations,
multi-spotted fish might cope with high temperatures better than two-spotted fish
during the intertidal life-history phase. Survivorship of multi-spotted fish in size
classes larger than 75 mm TL might then decrease after this intertidal phase during
the colder subtidal phase, perhaps explaining why Orton et al. (1987) observed
lower proportions of multi-spotted fish in larger size classes.

Conclusion.—The presence of a visible, easily measured hybrid intermediate trait
potentially associated with temperature affinity, like dorsal spot pattern in G.
nigricans, provides an ideal tool with which to measure effects of climate change
on gene flow and genetic expression within populations. Further studies are need-
ed to explicitly address selection and survivorship questions. Genetic analysis
could establish whether G. nigricans and G. simplicidens are distinct species and
also whether spot number is associated with other warm-water southern or cold-
water northern traits. If these are two species, collections over a latitudinal range
in southern Baja and the Gulf of California could establish whether stabile hybrid
Girella populations exist, where the boundaries of the Girella hybrid zone are,
and the extent to which the two species share genetic information. Tagging studies
in which individuals are followed through time would address survivorship ques-
tions based on fewer assumptions than cohort analysis. Such information would
contribute both to the understanding of influences on hybridization in marine
fishes and the sensitivity of hybridization to climate change. Management plans
of Girella recreational and commercial fisheries would also benefit from infor-
mation about species identities and hybridization.

Acknowledgments

The field assistance of Doug MacIntyre, Edward Vowles, Andrew Juhl, Erin
Hubbard, Nicole Dederick, and Julie Frost is greatly appreciated. Thanks to Lisa
Levin, Trevor Price, Dave Checkley, Phil Hastings, Paul Dayton, Paul Smith, and
Clint Winant for offering comments on the manuscript. Support was provided by
the Department of Defense National Science and Engineering Graduate Fellow-
ship, the J. M. Hepps Graduate Fellowship, Sigma Delta Epsilon Graduate Women
in Science, and the Mildred Mathias, Sigma Xi, and PADI Foundations.

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Accepted for publication 19 June 2000.

Bull. Southern California Acad. Sci.
100(1), 2001, pp. 36—43
© Southern California Academy of Sciences, 2001

Diversity of Parasitic Cuscuta and their Host Plant Species in a
Larrea-Atriplex Ecotone

Simon A. Lei

Department of Biology, Community College of Southern Nevada,
6375 West Charleston Boulevard, WDB, Las Vegas, NV 89146-1139

Abstract.—The distribution of four species of parasitic dodder (Cuscuta spp.) on
a variety of host plant species was quantitatively investigated in a creosote bush-
saltbush (Larrea tridentata-Atriplex spp.) ecotone in the Amargosa Valley of
southern Nevada. Species of Cuscuta did not parasitize all of their potential host
plants equally. Although white bursage (Ambrosia dumosa) was the most abun-
dant species in the community, Cuscuta showed the highest frequency of infes-
tation on Larrea. Cuscuta biomass was greatest in Larrea, possibly because of
Larrea’s large above-ground canopy. Among the host species, Larrea plants ex-
hibited the highest mortality from parasitism. Annuals, biennials, and herbaceous
perennials exhibited little or no infestation by Cuscuta species. Host plants with
heavy infestation showed a significant reduction in survival and flowering success
compared to host plants with light or no infestation. Although a generalist in their
parasitic nature on a variety of host plant species, different Cuscuta species dem-
onstrate specialized opportunistic behavior in their degree of selection and pref-
erence for specific individual host species irrespective to host abundance. Two of
the primary factors for which different Cuscuta species selected their respective
hosts were host morphology (lifeform) and phenology (developmental stage).

Parasitism occurs when an association exists between two species that benefits
the parasitic organism at the expense of its host organism. The host constitutes a
living microhabitat for the parasite. The monotypic family Cuscutaceae has a
cosmopolitan occurrence, represented solely by one genus Cuscuta (dodder), with
many species native to North America (Kuijt 1969). This family is often included
as a subfamily of Convolvulaceae, but differs in its parasitic life-form (Kuyt
1969). Species of Cuscuta are among the best known of the higher vascular plant
parasites because of their extraordinary appearance and behavior (Kuijt 1969).

Multiple species of Cuscuta are known to occur in southern Nevada (Cronquist
1984), with different Cuscuta species parasitizing different xerophytic and halo-
phytic hosts. Cuscuta salina is known to primarily parasitize halophytes, such as
four-winged saltbush (Atriplex canescens), shadscale (A. confertifolia), and iodine
bush (Allenrolfea occidentalis) (Kearney and Peebles 1951). Cuscuta californica
occurs frequently on white bursage (Ambrosia dumosa) (Beauchamp 1986). Two
common host plant species of Cuscuta denticulata are creosote bush (Larrea
tridentata) and cheesebush (Hymenoclea salsola) (Beauchamp 1986). Hosts of
Cuscuta campestris are mostly herbaceous, including composites and grasses
(Munz 1974). In an area with multiple species of Cuscuta, identifications of these
parasites are distinguished primarily by their geographical location, floral mor-

PARASITISM OF CUSCUTA ON LARREA-ATRIPLEX COMMUNITY 37

phological characteristics, and by their host plant species (Wesley Niles, personal
communication).

Seeds of Cuscuta spp. germinate near the soil surface, and may develop a small
root system which sustains the plant until the stem reaches a suitable host plant.
Many species of Cuscuta lack chlorophyll and do not photosynthesize (Belzer
1984). Cuscuta spp. have only scale-like vestigial leaves, depending solely on
exploitation of resources from their hosts for growth, survival, and regulation of
their environment (Whitson 1987). The orange-colored, spaghetti-like parasitic
threads function as runners, allowing an individual to move from host to host, as
well as to densely infest a single host (Kelly et al. 1988). Upon attachment to a
host, a Cuscuta plant becomes entirely parasitic, with subsequent degeneration of
its terrestrial root system (Kelly 1992), and the resource acquisition is entirely
above-ground. A stem of Cuscuta spp. infests its host by coiling around the host
stem or leaf and sending haustoria into the host’s vascular system (Kelly 1992).
Soon after the first haustorial contacts have been made, the radicle dies and all
contact with the soil is irrevocably lost (Kuit 1969).

The objective of this study was to examine the distribution of four Cuscuta
species on 11 host plant species in the Amargosa Valley of southern Nevada.
Specifically, woody and subwoody plant species were identified and assessed for
1) Cuscuta biomass and relative percent cover of host covered by Cuscuta as a
measure of the degree of infestation; 2) flowering success between the infested
and uninfested host plants; and 3) condition (living or dead) of each infested host
individual.

Materials and Methods
Study Site

Field studies were conducted during Spring 1998 in the Amargosa Valley
(roughly 36°50’ N, 116°05’ W) of southern Nevada where multiple species of
Cuscuta were present. The woody vegetation zone (elevation 760 m) was domi-
nated by Larrea-Atriplex spp., with numerous individuals of Ambrosia and a few
individuals of Hymenoclea, seepweed (Suaeda torreyana), and Allenrolfea. A low
abundance of annual and perennial herbaceous species was also present, including
milkvetch (Astragalus spp.), desert marigold (Baileya pleniradiata), bugseed (Di-
coria canescens), desert globemallow (Sphaeralcea ambigua), and fluff grass (Er-
ioneuron pluchellum).

The Amargosa Valley was selected on the basis of an abundant infestation of
Cuscuta species in a relatively homogeneous habitat with a variety of host plant
species. This area thus provides an assessment of host specialization in four Cus-
cuta species (C. california, C. campestris, C. denticulata, and C. salina) without
having the effects of significantly different environmental variables inherent with
the selection of separate geographic study sites.

Field Surveys

Two hectares northeast of U.S. Highway 95 were selected in the Amargosa
Valley. Within these two hectares, all plant species were identified, but only
woody species abundance (number of individuals) were determined. The amount
of host canopies covered with green leaves and covered with their respective
Cuscuta species, along with the flowering success of host plants were visually

38 SOUTHERN CALIFORNIA ACADEMY OF SCIENCES

Table 1. Four species of Cuscuta parasitizing 11 host species in a Larrea-Atriplex ecotone in the
Amargosa Valley of southern Nevada. Lifeforms (S = Shrub, Ss = subshrub, A = Annual, B =
Biennial, and HP = Herbaceous Perennial) of host plants are shown. Names of host and parasitic
species are arranged alphabetically.

Parastic species Host species Lifeform
Cuscuta californica Ambrosia dumosa S
C. campestris Baileya pleniradiata iP

Chaenactis fremontii A
Oryzopsis hymenoides HP
C. denticulata Hymenoclea salsola S
Larrea tridentata S
Sphaeralcea ambigua HP
C. salina Allenrolfea occidentalis S
Atriplex canescens S
Atriplex confertifolia S
Suaeda torreyana Ss

estimated in 10-% point increments (Lei 1999a, b, and c). Host plants that lacked
flower or fruit production and without green leaves on branches were assumed
dead. The condition of seven woody and subwoody (suffrutescent) species cov-
ered with parasites was recorded as either live (1) or dead (QO). All parasitic stems
were collected from all woody and suffrutescent host plants with infestations, and
were oven-dried at 45°C for 72 hours in a biology laboratory at the Community
College of Southern Nevada (CCSN) to determine biomass accumulation of Cus-
cuta.

Statistical Analyses

One-way Analysis of Variance (ANOVA), followed by Tukey’s multiple com-
parison test were used to detect differences in Cuscuta biomass among host spe-
cies, and to compare means of Cuscuta biomass when a significant infestation
effect was detected, respectively (Analytical Software 1994). The ANOVA was
also employed to detect survival and flowering success between infested and
uninfested host individuals. Mean values were presented with standard errors, and
statistical significance was determined at p = 0.05.

Results

Four species of Cuscuta were found to primarily parasitize seven woody and
subwoody species, as well as two annual and two herbaceous perennial species
within the study area (Table 1). Hosts of C. campestris were herbaceous plants,
including Baileya and Indian ricegrass (Oryziopsis hymenoides), while hosts of
C. denticulata were woody plants, such as Hymenoclea and Larrea (Table 1).
Herbaceous plants that were rarely infested with parasites included the annuals
Baileya and Chaenactis fremontii, as well as the perennials Oryzopsis and Sphaer-
alcea (Table 2). Conversely, fiddleneck (Amsinckia tessellata), Astragalus spp.,
grama grass (Bouteloua barbata), Dicoria, and Erioneuron revealed no infestation
at all (Table 2).

The percentage of host canopies covered by multiple species of Cuscuta varied
significantly among the host types (Table 1; Fig. 1). Although Ambrosia was the

PARASITISM OF CUSCUTA ON LARREA-ATRIPLEX COMMUNITY 39

Table 2. Percentage of host canopies (mean + S.E.) (annuals, biennials, and herbaceous perennials)
covered by multiple species of Cuscuta in a Larrea-Atriplex ecotone in the Amargosa Valley of
southern Nevada. Species of Cuscuta generally exhibited little or no infestation on herbaceous host
plants. Host species names are arranged alphabetically and their lifeforms are shown below. Symbols
of host plant lifeforms are explained in Table 1.

Host species Lifeform % cover of Cuscuta spp.

Amsinckia tessellata A Not infested
Aristida glauca HP Not infested
Astragalus spp. HP Not infested
Baileya pleniradiata A OF 54.3

Bouteloua barbata A Not infested
Bromus rubens A Not infested
Chaenactis fremontii A 10.2 + 2.4

Cirsium neomexicanum B Not infested
Cryptantha spp. A Not infested
Dicoria canescens A Not infested
Erioneuron pluchellum HP Not infested
Malacothrix glabrata A Not infested
Muhlenbergia porteri HP Not infested
Oryzopsis hymenoides HP eo ea ies

Sphaeralcea ambigua HP C.$-= ot

Sporobolus cryptandrus HP Not infested

most abundant host species, it had a low frequency of C. california infestation.
Larrea plants were less abundant than Ambrosia, yet had the highest frequency
of C. denticulata infestation (Fig. 1). A significant difference was detected be-
tween Larrea and Hymenoclea in percentage of host canopy cover infested by C.
denticulata (P < 0.05; Fig. 1).

Biomass accumulation of Cuscuta species also varied significantly (P = 0.001)
among the infested host plant species (Fig. 2). Larrea plants had the greatest
mean percentage covered by C. denticulata, and had the greatest mean C. denti-
culata biomass because of the large above-ground canopy (Fig. 2). Atriplex spp.
also exhibited abundant C. salina biomass on their canopies, whereas other woody
taxa contained a relatively low parasitic biomass (Fig. 2). From casual observa-
tions, more parasitic biomass was found in the center than around the periphery
of shrub canopies. Within the same perennial shrub species, Cuscuta revealed the
greatest biomass on individual plants that were more vigorous with a rapid growth
rate. Host plants not infested with parasites showed a significantly (P = 0.01;
data not shown) greater percentage of green leaves and active flowering than host
plants infested with parasites. Hosts with heavy infestation exhibited a significant
(P <= 0.01; data not shown) reduction in green leaves and flowering success com-
pared to hosts with light or no infestation.

Condition (survival) of woody and subwoody hosts infested with Cuscuta spe-
cies was observed. Larrea and Atriplex spp. displayed a greater degree of infes-
tation by C. denticulata and C. salina, respectively, based on percent cover and
biomass than the more abundant Ambrosia (Figs. 1-2). Among the woody and
subwoody plants, Larrea had the highest, while Allenrolfea had the lowest number
of dead hosts (Fig. 3). Although most host plants were alive, several dead hosts
including Atriplex spp., Larrea, Ambrosia, and Hymenoclea with live parasites

40 SOUTHERN CALIFORNIA ACADEMY OF SCIENCES

90 Ti r Seat oa

a a

30 ab e
b be b
20
‘s
Lo
O at

AMDU ALOC ATCA ATCO HYSA LATR SUTO

ithe

mas ik

MEAN HOST CANOPY COVERED. BY: CUSCUTA (%)

AOSTISPECIES

Fig. 1. Percentage of host canopies (mean + S.E.) covered by multiple species of Cuscuta on the
seven woody and subwoody host species in a Larrea-Atriplex ecotone in the Amargosa Valley of
southern Nevada. Only host species infested with Cuscuta were computed. Narrow vertical bars denote
standard errors of the means. Different letters at the top of columns indicate significant differences at
p = 0.05 using Tukey’s Multiple Comparison Test. Host species abbreviations: Allenrolfea occidentalis
(ALOC), Ambrosia dumosa (AMDU), Atriplex canescens (ATCA), Atriplex confertifolia (ATCO),
Hymenoclea salsola (HYSA), Larrea tridentata (LATR), and Suaeda torreyana (SUTO).

were found (Fig. 3). Despite being considered alive, some nearly dead hosts were
also found in all seven woody and subwoody species. Within the same host spe-
cies, significantly greater (P = 0.05; data not shown) infestation by parasites were
observed on individual hosts with greater height and canopy size.

Discussion

In general, Larrea plants were the most preferred host, followed by Atriplex
spp. for the growth of parasites. This study supports the theory that Cuscuta spp.
are not a strict generalist in the sense that they do not equally infest all available
host types in proportion to host abundance. My data reinforces Kelly et al. (1988)
study, suggesting that Cuscuta species are selective consumers with multiple spe-
cies of Cuscuta parasitizing different species of host plants. Although Ambrosia
was the most abundant species, Larrea exhibited the highest mortality from par-
asitism in this study.

Kelly (1992) found that Cuscuta species made morphological changes gauged
towards expected resource (water and nutrient) gain from the host. Species of
Cuscuta exhibit behavior in which they grow away from host plants with low
nutrient availability and rapidly coiled around host plants with high nutritional
value (Kelly 1992). Rejection of a potential host indicates that a parasitic plant

PARASITISM OF CUSCUTA ON LARREA-ATRIPLEX COMMUNITY 4]

a =
aa a
Oo
Oo 2
<l
=
O
(@ a)
6
—
=)
C)
Y)
3)
a vei
Pa
=i
LJ
=
0

AMDU ALOC ATCA ATCO HYSA LATR SUTO

DOSE ele S

Fig. 2. Biomass of Cuscuta species (mean + S.E.) on the seven woody and subwoody host species
in a Larrea-Atriplex ecotone in the Amargosa Valley of southern Nevada. Only host species infested
with Cuscuta were computed. Narrow vertical bars denote standard errors of the means. Different
letters at the top of columns indicate significant differences at p = 0.05 using Tukey’s Multiple
Comparison Test. Host species abbreviations are explained in Figure 1.

may strategically take the risk of forfeiting the initial host for the chance of
acquiring better resources from another host later (Kelly 1992).

There are several potential explanations for the dispersal of Cuscuta seeds.
First, the seeds of Cuscuta species appear to be dispersed haphazardly; animals
as dispersal agents are probably rare and unimportant (Kuit 1969). Second, some
Cuscuta seeds may fall to the ground and germinate there. Third, seeds of Cuscuta
may be transported by wind or water to new hosts (Kuijt 1969). Fourth, the reason
why some Cuscuta species infested more than others is not completely known. It
may be a maternal influence when C. denticulata seedlings from plants grown on
Larrea select Larrea more often than Cuscuta spp. seedlings from other host
species. Consequently, the emerging C. denticulata seedlings would grow directly
and lead to a more vigorous growth on the Larrea plants. Although a number of
annual and perennial herbaceous species were not infested by parasites, these
species were potential hosts because they were present in the community.

Biomass accumulation of Cuscuta species differed significantly among host
species. Woody perennials showed the greatest Cuscuta biomass, whereas annuals,
biennials, and herbaceous perennials exhibited minimal or no infestations in this
study. A limited Cuscuta infection success on biennials and herbaceous perennial
hosts is related to host morphology (lifeform) since the presence of scattered
vascular bundles in grasses may not be amenable to resource exploitation by
Cuscuta species (Kelly and others 1988). Additionally, host phenology (devel-

42 SOUTHERN CALIFORNIA ACADEMY OF SCIENCES

100 aaah. oats keene r me
GM Live
Y/] Dead
80 + 4
|
Y) |
e |
a
80+
Y)
ee
O
na
a 0 a
=
=
Za
20 + e
0 iy LZ)

AMDU ALCO ATCA ATCO HYSA LATR SUTO
MOS? SPECIES

Fig. 3. Condition (live or dead) of the seven woody and subwoody host species infested with
Cuscuta species in a Larrea-Atriplex ecotone in the Amargosa Valley of southern Nevada. Host species
abbreviations are explained in Figure 1.

opmental stage) is also likely to determine the biomass and abundance of Cuscuta
species. Mature or long-lived plants generally have a greater canopy size com-
pared with juvenile or short-lived plants. Within the same host species, a relatively
large host canopy size would indicate a greater surface area available on second-
ary branches for successful colonization and establishment of Cuscuta species. In
this study, Cuscuta accumulated more tissue or biomass on those hosts that grew
better and faster, presumably due to higher moisture content and nutritional value.
Not all xerophytic plants functioned equally as hosts for multiple species of Cus-
cuta in this study. Although water and nutrient availability were not quantitatively
examined, infection of parasite on the host, as demonstrated by the higher prob-
ability of infestation on Larrea and Atriplex spp. in comparison to Ambrosia, may
be attributed to proportionally different water and nutrient uptake by these host
plant species, or to different characteristics of the hosts and/or parasitic species.

Host morphology and phenology were two main factors that partially deter-
mined which species of Cuscuta parasitizing which species of host plants. Within
the same host species in this study, species of Cuscuta tended to select individual
hosts with greater height and canopy size. Seedlings appear to grow toward a
source of high nutrient and, to a lesser extent, moisture (Kuijt 1969). Host mor-
phology and phenology may be strongly associated with the availability of water
and nutrients. Host preference in multiple species of Cuscuta are still not fully
understood. Further research, including water and nutrient status of existing and

PARASITISM OF CUSCUTA ON LARREA-ATRIPLEX COMMUNITY 43

potential host plants, at various geographical locations, are required to improve
our understanding regarding the host preference in parasitic Cuscuta plants.

Acknowledgments

Valuable field assistance provided by Steven Lei, David Valenzuela, and She-
vaun Valenzuela was gratefully acknowledged. Helpful comments by David Char-
let greatly improved the manuscript. The Department of Biology at the Com-
munity College of Southern Nevada (CCSN) provided logistical support.

Literature Cited

Analytical Software. 1994. Statistix 4.1, an interactive statistical analysis program for microcomputers.
Analytical Software, St. Paul, Minnesota. 329 pp.

Beauchamp, R. M. 1986. A Flora of San Diego County, California. Sweetwater River Press, National
City, California. 241 pp.

Belzer, T. J. 1984. Road side plants of southern California. Mountain Press Publishing Company,
Missoula, Montana. 158 pp.

Cronquist, A. 1984. Intermountain Flora: Vascular Plants of the Intermountain West, The New York
Botanical Garden, New York.

Kearney, T. H. and R. H. Peebles. 1951. The Flora of Arizona. University of California Press, Berkeley,
California.

Kelly, C. K., D. L. Venable, and K. Zimmer. 1988. Host specialization in Cuscuta costariensis: an
assessment of host use relative to host availability. Oikos 53:315-320.

Kelly, C. K. 1992. Resource choice in Cuscuta europaea. Proc. Nat. Acad. Sci. 89:12194—-12197.

Kuit, J. 1969. The Biology of Parasitic Flowering Plants. University of California Press, Berkeley,
California. 246 pp.

Lei, S. A. 1999a. Host-parasite relationship between Utah juniper and juniper mistletoe in the Spring
Mountains of southern Nevada. Pages 99-104 in Proceedings: Ecology and management of
pinyon-juniper communities within the interior west. USDA Forest Service, Rocky Mountain
Research Station, Ogden, Utah.

. 1999b. Phenological events and litterfall dynamics of blackbrush in southern Nevada. Pages

113—118 in Proceedings: Shrubland ecotones. USDA Forest Service, Rocky Mountain Research

Station, Ogden, Utah.

. 1999c. Effects of severe drought on biodiversity and productivity in a creosote bush-black-
brush ecotone of southern Nevada. Pages 217—221 in Proceedings: Shrubland ecotones. USDA
Forest Service, Rocky Mountain Research Station, Ogden, Utah.

Munz, P. A. 1974. A Flora of Southern California. University of California Press, Berkeley, California.
1086 pp.

Whitson, T. D. 1987. The Weeds and Poisonous Plants of Wyoming and Utah. Cooperative Extension
Service, Laramie, Wyoming.

Accepted For Publication 19 June 2000

Bull. Southern California Acad. Sci.
100(1), 2001, pp. 44-50
© Southern California Academy of Sciences, 2001

Persistence of the Nematode, Oswaldocruzia pifiens (Molineidae),

in the Pacific Treefrog, Hyla regilla (Hylidae), from California

Stephen R. Goldberg! and Charles R. Bursey?

'Department of Biology, Whittier College, Whittier, California 90608
?Department of Biology, Pennsylvania State University, Shenango Campus,
147 Shenango Avenue, Sharon, Pennsylvania 16146

Abstract.—Miulti-year samples of Hyla regilla from three California counties (Los
Angeles, Orange, Riverside) as well as single-year samples from three additional
California counties (Humboldt, Imperial, Santa Clara) were examined for hel-
minths. Gravid individuals of one species of cestode, Distoichometra bufonis and
two species of nematodes, Oswaldocruzia pipiens and Rhabdias ranae were
found. Metacercariae of two species of trematodes, Alaria sp. and Clinostomum
sp. and larvae of one nematode species, Physaloptera sp. were also found. Of the
helminths found in the multi-year samples, only O. pipiens was persistent; how-
ever, it was not stable.

Although many amphibians species have been recorded as hosts for helminth
parasites (Prudhoe and Bray 1982; Baker 1987), the majority of this work has
concentrated on faunistic surveys typically based upon collections taken during a
single season. A general conclusion drawn from these studies is that helminth
communities of anurans are depauperate and isolationist in character (Barton
1997). However, two measures of helminth communities developed by Meffe and
Minckley (1987) are not addressed in these single season collections: persistence,
a measure of presence or absence of a species over time, and stability, a qualitative
measure based upon the relative constancy of species abundances over time. These
measures can only be addressed with long-term studies; unfortunately, there are
few published accounts of long-term variation (biennial or greater) in helminth
infracommunities of anurans. In Poland, Grossman and Sandner (1953), in Russia,
Markov and Rogoza (1949, 1953), and in England, Lees (1962) published data
on seasonal variation in the prevalence of helminths of Rana temporaria. Also
from Poland, Kuc and Sulgostowska (1988) published data collected from Rana
ridibunda over a period of four years.

The Pacific treefrog, Hyla regilla (Baird and Girard 1852), is a small anuran
that occurs from British Columbia to the tip of Baja California Sur, México and
east to western Montana and eastern Nevada (Stebbins 1985). Pacific treefrogs
prefer low plant growth near water and frequent a variety of habitats from sea
level to elevations of 3540 m including grassland, chaparral, woodland, forest,
desert oasis and farmland (Stebbins 1985). There are seven reports of helminths
from northern populations of this frog (Millzner 1924; Douglas 1958; Lehmann
1965; Macy 1960; Efford and Tsumura 1969; Brooks 1976, Johnson et al. 1999)
and one report from southern California (Koller and Gaudin 1977).

Multi-year collections of H. regilla from three California counties (Los An-
geles, Orange, Riverside) as well as single season collections from three California

HELMINTHS OF THE PACIFIC TREEFROG 45

Table 1. Number (N), SVL, and collection dates of Hyla regilla from California counties with
number infected by and prevalence (%) of anuran parasites.

Distoicho- Oswaldo- Rhab-

SVL HISD metra cruzia dias

County N range (mm) Collection dates bufonis pipiens ranae
Humboldt 3 39 + 1.5, 38-41 1997, Aug —- — —
Santa Clara 18 34 + 4.1, 21-40 1998, Jan—May DAL) 54h) oo
Imperial 2 31 + 1.4, 30-32 1959, Mar — 2 (100) -—
Los Angeles 14 30 + 4.3, 19-35 1943, Mar — F271) a
2 30133 00,130 1944, Mar — — ——
1 25 1963, Mar — — —=
17 30 + 3.7, 25-36 1971, Jan—Apr — 7 (41) —
2 34 + 5.0, 30-37 1972, Apr — 2 (100) a
Orange 12 35 + 5.0, 30-48 1957, Feb—Mar — — —
10 33 + 4.8, 27-43 1958, Feb —- -
5 33 + 7.2, 24-41 1961, Feb — 1 (20) —
4 37 + 5.0, 30-41 1962, Mar — — —
8 33 + 4.4,29-40 1963, Feb — — as
pd 32 + 1.4, 31-33 1964, Feb — — as
2 34 + 5.7, 30-38 1965, May—Jun — — —~
8 36 + 2.6, 32-39 1966, Mar — ras —

2 34 + 5.0, 31-38 1967, Mar—May — 1 (50) 1 (50)
8 29 & 3.3-. 24-35, 11972, Feb — i ¢is) —
Riverside ] 35 1965, June --- 1 (100) —
1 24 1967, May — — ==

S 2 3.0, 121—St 1969, July — 2 (67) f G3)
1 18 1972, Aug —- A —

counties (Humboldt, Imperial, Santa Clara) were examined for helminths. The
purpose of this paper is to evaluate persistence and stability of helminths harbored
by H. regilla from California.

Materials and Methods

One hundred twenty-eight H. regilla (mean + 1 SD snout-vent length [SVL]
= 32 mm + 5 SD, range 18—48 mm) from 6 counties in California were examined
(collection data by year is given in Table 1). There were 47 female (SVL = 33
mm + 6 SD, range = 18—43 mm) and 81 male (SVL = 32 mm + 4 SD, range
= 19-48 mm) frogs in the total sample. All frogs had been fixed in 10% formalin
and preserved in 50% ethanol. The body cavity of each frog was opened by a
longitudinal incision and the gastrointestinal tract was removed and slit longitu-
dinally. The esophagus, stomach, small intestine, large intestine, lung, urinary
bladder, coelom and liver were searched with a dissecting microscope for hel-
minths. Helminths were placed in a drop of undiluted glycerol on a glass slide
and allowed to clear for study with a compound microscope. Nematodes were
identified from these slides. Cestodes and trematodes were stained in hematoxylin
and mounted in balsam for identification. Where applicable, difference in preva-
lence between male and female frogs was examined by the chi-square test (x7),
numbers of helminths per male and female hosts were evaluated by the Kruskal
Wallis test, and correlation analysis (7) was used to relate intensity of infection
to age (as estimated by SVL).

46 SOUTHERN CALIFORNIA ACADEMY OF SCIENCES

Results

Gravid individuals of one species of cestode, Distoichometra bufonis Dickey
1921; and two species of nematodes, Oswaldocruzia pipiens Walton 1929, and
Rhabdias ranae Walton 1929 were found. Metacercariae of two species of trem-
atodes, Alaria sp. and Clinostomum sp., and larvae of one species of nematode,
Physaloptera sp., were also found. Only Oswaldocruzia pipiens was found to be
persistent (Table 1). Number, prevalence (number of infected hosts divided by
number of hosts examined), and abundance (number of individuals of a parasite
species divided by the number of hosts examined) for each helminth species by
locality are given in Table 2. Voucher specimens were placed in vials of 70%
ethanol and deposited in the U.S. National Parasite Collection (USNPC): Alaria
sp. (mesocercaria), 88611; Clinostomum sp. (metacercaria), 88612; Distoichom-
etra bufonis, 88614; Oswaldocruzia pipiens, 88615; Rhabdias ranae, 88609; Phy-
saloptera sp. (larvae), 88610.

Thirty four frogs (27%) were found to harbor 157 helminths (x = 5 + 5 SD
per infected frog). Of these, 29 were larvae of helminth species not capable of
completing their life cycles in anurans. Mean helminth species richness for in-
fected frogs was 1.0 + 0.2 SD, range = 1-2 species. Eighteen of 81 male frogs
(22%) harbored 59 helminths; 16 of 47 female frogs (34%) harbored 98 helminths.
Prevalence of helminth infection (x? = 2.13, 1 df, P > 0.05) as well as number
of helminths harbored per host (Kruskal Wallis test = 2.6, 1 df, P > 0.05) was
not significantly different between male and female frogs. Thirty three frogs
(26%) harbored a single species of helminth; 1 frog (1%) harbored 2 species. The
smallest infected frog was 26 mm SVL. There was no correlation between number
of helminths and SVL (r = 0.002, p > 0.05). Inspection of Table 2 will show
that in no two localities did H. regilla harbor the same combination of helminth
species and that the helminths preferred specific host locations. This is the first
report of metacercariae of Clinostomum sp. and larvae of Physaloptera sp. in
Ayla regilla.

Discussion

Barton (1997) described anuran helminth communities as depauperate and iso-
lationist. Depauperate is used in the sense that few helminth species are found in
a host species from a particular locality. Table 2 supports the use of depauperate
to describe helminth communities harbored by H. regilla. Isolationist is used in
the sense that helminth density is low, helminth species are unaffected by one
another and some niches are absent. Table 2 also supports the use of isolationist
to describe helminth communities of H. regilla. In addition, none of the helminth
species found in this study was unique to H. regilla. Of the six helminth species
present, Alaria sp., Clinostomum sp., and Physaloptera sp. are incapable of com-
pleting their life cycles in anurans. Species of Alaria utilize mammals as final
hosts and species of Clinostomum utilize birds as final hosts; metacercariae of
both are commonly found in frogs (Smyth and Smyth 1980). Larvae, but no
adults, of Physaloptera sp. have been reported from anurans (Anderson 1992).
Distoichometra bufonis and Rhabdias ranae are common parasites of anurans
(Brooks 1976; Baker 1987). Oswaldocruzia pipiens has been reported from frogs,
toads, salamanders, lizards and turtles (Baker 1987). The term generalist should

HELMINTHS OF THE PACIFIC TREEFROG

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48 SOUTHERN CALIFORNIA ACADEMY OF SCIENCES

Table 3. Reports of Distoichometra bufonis, Oswaldocruzia pipiens and Rhabdias ranae from
California by County.

Helminth

Host County Prevalence (%) Reference
Distoichometra bufonis

Bufo boreas Los Angeles 19/255 (7) Koller and Gaudin 1977

Rhabdias ranae

Hyla regilla

Los Angeles

28/232 (12)

Los Angeles 4/69 (6) Goldberg et al. 1999
Hyla regilla Los Angeles 2IZAZ (1) Koller and Gaudin 1977
Santa Clara 2/18 (11) this study
Oswaldocruzia pipiens
Bufo boreas Butte not stated Ingles 1936
Kern not stated Ingles 1936
Los Angeles 119/255 (47) Koller and Gaudin 1977
Los Angeles 10/30 (33) Goldberg et al. 1999
Riverside 1/11 (9) Goldberg et al. 1999
San Diego not stated Ingles 1936
Ayla regilla Imperial 2/2 (100) this study
Los Angeles 161/232 (69) Koller and Gaudin 1977
Los Angeles 12/36 (33) this study
Orange 4/61 (7) this study
Riverside 3/6 (50) this study
Santa Clara 3/18 (17) this study
Rana aurora Butte not stated Ingles 1936
Kern not stated Ingles 1936
San Diego not stated Ingles 1936
Aneides lugubris not stated 21/31 (68) Goldberg et al. 1998
Elgaria multicarinata Los Angeles 2/96 (2) Goldberg and Bursey 1990

Koller and Gaudin 1977

Orange 1/61 (2) this study

Riverside 1/6 (17) this study
Rana boylii not stated not stated Ingles 1936

Marin/Sonoma ZY (TS) Lehmann 1965

also be used as a descriptor of the helminth communities of H. regilla (Table 2).
Thus, in each county studied, H. regilla harbors a depauperate, isolationist com-
munity composed of generalist helminths.

More importantly, data from Los Angeles and Orange Counties (Table 1) sug-
gest that none of these species of helminths maintains a stable population in H.
regilla and that only O. pipiens is persistent, present some years with widely
differing prevalences and absent other years. Several questions arise, namely, is
absence of a helminth species an artifact of sample size, is H. regilla an atypical
host, and do stable populations of these helminths exist in these localities? The
first question cannot be answered by the data examined; it could only be deter-
mined by a long-term study utilizing a large number of hosts. Others have reported
these helminths from H. regilla (Table 3), thus H. regilla is a suitable host. The
life cycle of D. bufonis is unknown but Joyeux (1927) regards the life history of
nematotaeniid cestodes to be direct, that is, without an intermediate host; infection
of a new host occurs through ingestion of cestode eggs. Both O. pipiens and R.
ranae have direct life cycles and infection occurs by integumental penetration
(Anderson 1992). These three helminths are generalists in that they are capable

HELMINTHS OF THE PACIFIC TREEFROG 49

of infecting a number of hosts (Brooks 1976; Baker 1987). Table 3 lists California
records of these three species; however, long-term studies are not available to test
stability in these hosts. The advantage to generalist helminths is that a particular
host is unimportant; infection in a particular host may fluctuate (Table 3), but the
helminth population maintains an overall density.

The conclusion that we draw is that a generalist helminth population may vary
drastically within a particular host over time, but within its population of hosts,
the helminth species is persistent and most likely stable.

Acknowledgments

We thank R. L. Bezy for the opportunity to examine H. regilla from the Natural
History Museum of Los Angeles County (Imperial, Los Angeles, Orange, Riv-
erside Counties) and P. T. J. Johnson for treefrogs from Humboldt and Santa Clara
Counties.

Literature Cited

Anderson, R. C. 1992. Nematode Parasites of Vertebrates: Their Development and Transmission. CAB
International, Wallingford, Oxon, U.K. xii + 578 pp.

Baker, M. R. 1987. Synopsis of the Nematoda parasitic in amphibians and reptiles. Occas. Pap. Biol.,
Mem. Univ. Newfoundland, 11:1—325.

Barton, D. P. 1997. Why are amphibian helminth communities depauperate? Mem. Mus. Vict., 56:
581-586.

Brooks, D. R. 1976. Parasites of amphibians of the Great Plains. Part 2. Platyhelminths of amphibians
in Nebraska. Bull. Univ. Nebraska St. Mus., 10:65—92.

Douglas, L. T. 1958. The taxonomy of nematotaeniid cestodes. J. Parasitol., 44:261—273.

Efford, I. E., and K. Tsumura. 1969. Observations on the biology of the trematode Megalodiscus
microphagus in amphibians from Marion Lake, British Columbia. Amer. Midl. Nat. 82:197—
203.

Goldberg, S. R., and C. R. Bursey. 1990. Helminths of the San Diego alligator lizard, (Gerrhonotus
multicarinatus webbi) (Anguidae). J. Wild. Dis., 26:297—298.

: , and H. Cheam. 1998. Composition and structure of helminth communities of the

salamanders, Aneides lugubris, Batrachoseps nigriventris, Ensatina eschscholtzii (Plethodonti-

dae), and Taricha torosa (Salamandridae) from California. J. Parasitol., 84:248—251.

, ——., and S. Hernandez. 1999. Helminths of the western toad, Bufo boreas (Bufonidae)
from southern California. Bull. S. Cal. Acad. Sci., 98: 39-44.

Grossman, T., and H. Sandner. 1953. Helmintofauna plaz6w Bialowieskiego Parku Narodowego. Acta
Parasitol. Polonica, 1:345—352.

Ingles, L. G. 1936. Worm parasites of California amphibia. Trans. Amer. Microsc. Soc., 55:73—92.

Johnson, P. T. J., K. B. Lunde, E. G. Ritchie, and A. E. Launer. 1999. The effect of trematode infection
on amphibian limb development and survivorship. Science 284:802—804.

Joyeux, C. 1927. Recherches sur la faune helminthologique Algérienne (cestodes et trématodes).
Archs. Inst. Pasteur Alger., 5:509-528.

Koller, R. L., and A. J. Gaudin. 1977. An analysis of helminth infections in Bufo boreas (Amphibia:
Bufonidae) and Hyla regilla (Amphibia: Hylidae) in southern California. Southwest. Nat., 21:
503-509.

Kuc, I., and T. Sulgostowska. 1988. Helminth fauna of Rana ridibunda Pallas, 1771 from Goclawski
Canal in Warszawa (Poland). Acta Parasitol. Polonica, 33:101—105.

Lees, E. 1962. The incidence of helminth parasites in a particular frog population. Parasitology, 52:
95-102.

Lehmann, D. L. 1965. Intestinal parasites of northwestern amphibians. Yearbook Amer. Philosoph.
Soc. pp 284-285.

Macy, R. W. 1960. On the life cycle of Megalodiscus microphagus Ingles (Trematoda: Paramphisto-
matidae). J. Parasitol., 46:662.

50 SOUTHERN CALIFORNIA ACADEMY OF SCIENCES

Markov, G. S., and M. L. Rogoza. 1949. Parasitic fauna of male and female grass frogs. C. R. Acad.
Sci. U.R.S.S. 65:417—420. [in Russian].

, and . 1953. Seasonal and microzonal differences in the parasitic fauna of grass frogs.
C.R. Academy of Sciences U.R.S.S. 91:169-—172. [in Russian].

Meffe, G. K., and W. L. Minckley. 1987. Persistence and stability of fish and invertebrate assemblages
in a repeatedly disturbed Sonoran Desert stream. Am. Midl. Nat., 117:177-191.

Millzner, R. 1924. A larval acanthocephalid, Centrorhynchus californicus sp. nov., from the mesentery
of Hyla regilla. Univ. Calif. Publ. Zool., 26:225—227.

Prudhoe, S., and R. A. Bray. 1982. Platyhelminth parasites of the Amphibia. British Museum (Natural
History) and Oxford University Press, Oxford, 217 pp. + 4 microfiche.

Smyth, J. D., and M. M. Smyth. 1980. Frogs as host-parasite systems I. The Macmillan Press Ltd.,
London, ix + 112 pp.

Stebbins, R. C. 1985. A field guide to western reptiles and amphibians. Houghton Mifflin Company,
Boston, xiv + 336 pp.

Accepted for publication 13 January 2000.

Bull. Southern California Acad. Sci.
100(1), 2001, pp. 51-58
© Southern California Academy of Sciences, 2001

Cercarial Emergence from Rediae in California Snail Tissues

Mark Armitage, M.S.

Azusa Pacific University, P.O. Box 7000/Mary Hill 101, Azusa,
California 91702-7000, 626-815-6000, X5519, marmitage @ apunet.apu.edu

Abstract.—Rediae from Cerithidea californica snails collected at Point Mugu,
CA, yield pleurolophocercous, furcocercous, and xiphidio cercariae. Pleuroloph-
ocercous and xiphidio cercariae emerge one at a time from rediae and never tail
first. Furcocercous cercariae, on the other hand emerge in multiple numbers and
either tail or head first. The pleurolophocercous cercariae collected in this study
probably represent either Ascocotyle sexidigita, or A. (Phagicola) diminuta, both
of which have been excysted from metacercarial cysts in Fundulus parvipinnis
collected at the same site.

Previous authors have described California cercariae which differ from those
found at the Point Mugu site. Maxon and Pequegnat (1949) reported that C.
californica collected from mud flats at upper Newport Bay (CA) yielded 7 dif-
ferent types of cercariae when isolated in incubated finger bowls, including pleu-
rolophocercous (single tail with fin folds), furcocercous (forked tail), and xiphidio
(single tail, no fin folds) cercariae which were also found in this study. These
authors described one furcocercous, two pleurolophocercous, and three echinos-
tome cercariae, all of which had oral spines or other characteristics unlike those
encountered in this study at Point Mugu. Martin (1950a), described the cercariae
of Euhaplorchis californiensis shed by C. californica at Playa del Rey, CA as a
parapleurolophocercous type with an oral sucker surrounded by a crown “‘having
four or five short spines in its dorsal part.’ Martin (1950b) reported cercariae of
Parastictodora hancocki, also shed by Cerithidea, as having three rows of 5—6
spines. Additionally, Martin (1951) described Pygidiopsoides spindalis adults ex-
perimentally derived from the feeding of infected F. parvipinnis specimens to cats
and newly hatched chicks, but did not describe the cercariae from this trematode
until later (Martin 1964), when he reported that the cercariae, also shed from
Cerithidea had ‘‘oral suckers[s]. . . surrounded by a ring of fourteen large spines.”’
Martin made no descriptions of cercariae in a study of seasonal infections of
Cerithidea over a one-year period (1955), but Martin (1972) did provide an an-
notated key to the cercariae that develop in Cerithidea from Southern California.
Finally, Font, et al. (1984) described the cercaria of a sibling species of A. sexi-
digita, named A. gemina from Louisiana and Mississippi, (although A. gemina
cercariae do not infect F. parvipinnis). There were also morphological differences
between cercariae of A. gemina which had spines and bristles and those cercariae
studied here which did not have any of the spines and bristles described by these
other authors.

Materials and Methods

Fifty Cerithidea californica were hand-collected from the exposed mud flats at
low tide at the Laguna Road bridge over the western Mugu lagoon area of the

52, SOUTHERN CALIFORNIA ACADEMY OF SCIENCES

Point Mugu Naval Air Weapons Station, CA, in May 1999. Algae were also taken
from the site. Snails were isolated in 4” fingerbowls in 12% saline under bright
fiber optic illuminators for a period of 36 hours with small quantities of algae.
Light cycle illumination was on ten hours per day, followed by a fourteen-hour
period of darkness. Snails that yielded cercariae after 36 hours were placed in
fresh saline and free swimming cercariae were removed by pipette into fixative.
Those snails which did not produce cercariae were placed into fingerbowls for
further observation, and were reisolated if cercariae began to emerge. After a
week, snails known to yield cercariae were sacrificed by crushing and the tissues,
as well as individual cercariae and rediae, were fixed in 2% glutaraldehyde, buff-
ered in .2M sodium cacodylate, postfixed in 2% osmium, and rinsed in water.
These were then dehydrated through a graded series of acetone. Cercariae and
snail tissue for SEM were air dried, affixed to stubs, coated in gold for 90 seconds,
and imaged and photographed on a Jeol SEM at 15 Kv.

Results

Both large and small rediae were observed at times infecting the same Cerith-
idea digestive gland tissues. Most often, however, snails contained only large or
only small rediae (FIG 2, 7). Thirty one percent of the collected snails when
crushed, yielded rediae in large numbers, infecting only the digestive organs.
Four distinct cercariae were shed.

1) One very small xiphidio cercaria, which came out in small numbers, did not
dehydrate well and was unsuitable for processing in electron microscopy.

2) The pleurolophocercous cercariae were birthed singly, always head first from
rediae which were 275ym thick, 700.m long, and which had unusually large,
thickly collared birth pores (FIG 2,3,4). The cercariae have a well-developed oral
sucker and a massive ventral sucker ringed by a muscular annulus. Additionally,
paired sets of papillae appear on the surface of the cercarial tegument, distal to
the oral sucker (FIG 9). A large range in shape and length variability exists in
live cercariae (FIG 10), therefore, anatomical features in fixed worms must be
considered in light of possible fixation artifacts, including the possible loss of
bristles and spines. Although they do have eyespots, no spines were observed on
any of the pleurolophocercous cercariae, therefore it is possible that these may
represent the larval stage of either Ascocotyle sexidigita or of A. (Phagicola)
diminuta, both of which have been excysted previously from naturally occurring
infections in F. parvipinnis at the same site (Armitage 1997, 1999).

3) The furcocercous cercariae were birthed from rediae that were 804m by
450m and had a single smaller pore (FIG 7), and either came out head or tail
first, but were mostly birthed in multiples (FIG 5,6,7). The cercariae came out in
such large numbers that the water in the 4” bowls became a milky white after 10
hours in light. These cercariae do not correspond to any of the descriptions in the
literature, as they have an almost cylindrical body shape, no eyespots, and no
collar spines.

4) A few furcocercous types resembling those described by Maxon and Pe-
quegnat (1949) were observed (FIG 11), but there were not enough specimens
for electron microscopy.

That only 4 types of cercariae were isolated from the site fits well with data
previously reported showing the presence of Pygidiopsoides spindalis, Ascocotyle

CERCARIAL EMERGENCE IN CERITHIDEA 53

Fig. 1. Thin section, pleurolophocercous rediae from Cerithidea. Note two mature cercariae (ar-
rows). Scale bar = 100um. Fig. 2. SEM micrograph, pleurolophocercous rediae from Cerithidea.
Note closed birthpore. Scale bar = 125ym. A = acetabulum, B = birthpore, C = cercariae, O = oral
sucker, P = papillae, R = rediae, T = tail

SOUTHERN CALIFORNIA ACADEMY OF SCIENCES

SEM micrograph, pleurolophocercous rediae from Cerithidea. Only one cercaria is birthed

Fig..9,
at a time. Scale bar

80m. Fig. 4. SEM Micrograph, pleurolophocercous rediae from Cerithidea.

30m.

Note annular ring around birthpore (arrows). Scale bar

CERCARIAL EMERGENCE IN CERITHIDEA aD

Fig. 5. SEM Micrograph, furcocercous rediae from Cerithidea. Multiple cercariae emerge simul-
taneously. Scale bar = 65ym. Fig. 6. SEM Micrograph, furcocercous rediae from Cerithidea. Note
thick, muscular tail. Scale bar = 45ym.

56 SOUTHERN CALIFORNIA ACADEMY OF SCIENCES

fo ee = Na et

ened:
‘ [a

Fig. 7. SEM Micrograph, furcocercous rediae from Cerithidea. Often, these cercariae are birthed
tail first. Note tail fins (arrows). Scale bar = 50yum. Fig. 8. Light Micrograph, furcocercous cercariae.
Note length of tail relative to body. Scale bar = 80pm.

CERCARIAL EMERGENCE IN CERITHIDEA

Fig. 9. SEM Micrograph, pleurolophocercous cercaria. Note massive acetabulum and papillae.
Scale bar = 20um. Fig. 10. Light Micrograph, pleurolophocercous cercariae, whole mount. Active

worms stretch and compress in to a variety of shapes. Scale bar = 5Ou.m. Fig. 11.
furcocercous cercariae. Scale bar = 35yum.

Light Micrograph,

58 SOUTHERN CALIFORNIA ACADEMY OF SCIENCES

(Phagicola) diminuta, and Ascocotyle sexidigita encysted in fish which also in-
habit the same site (Armitage 1997, 1999). It cannot be discounted, however, that
spines and bristles may have been lost in these specimens due to fixation artifact.

Literature Cited

Armitage, M. 1997 The euryhaline cottid fish, Leptocottus armatus (Girard), second intermediate host
of the trematode Ascocotyle (P.) diminuta. Bull. So. Calif. Acad. Sci. 96(3):112—-116.

1999. The euryhaline gobiid fish, Gillichthys mirabilis Cooper 1864, second intermediate host
of the trematode, Pygidiopsoides spindalis Martin 1951. Bull. So. Calif. Acad. Sci. 98(2):75-—
79.

Font, W. F, R. Heard and R. Overstreet. 1984. Life cycle of Ascocotyle gemina, n.sp., a sibling species
of A. sexidigita (Digenea: Heterophyidae). Trans. Am. Micro. Soc. 103(4):392—407.

Martin, W. E. 1950a. Euhaplorchis californiensis N.G., N.Sp., Heterophyidae, Trematoda, with notes
on its life-cycle. Trans. Am. Micro. Soc. 59(2):194—209.

1950b. Parastictodora hancocki, N.G., N.Sp., (Trematoda: Heterophyidae), with observations

on its life-cycle. J. Parasit. 36(4):360—370.

1951. Pygidiopsoides spindalis, N.G., N.Sp., (Trematoda: Heterophyidae), and its second in-

termediate host. J. Parasit. 37(3):297—300.

1955. Seasonal infections of the snail, Cerithidea californica Haldeman, with larval trema-

todes. Essays Nat. Sci. Honor of Capt. A. Hancock, 203—210. USC Press.

1964. Life cycle of Pygidiopsoides spindalis Martin, 1951 (Heterophyidae: Trematoda). Trans.

Am. Micro. Soc. 83:270—272.

1972. An annotated key to the cercariae that develop in the snail Cerithidea californica. Bull.
So. Calif. Acad. Sci. 71(1):39—43.

Maxon, M. G., and W. Pequegnat. 1949. Cercariae from upper Newport bay. J. Ent. Zool. 41:30—56.

Accepted for publication 19 June 2000.

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CONTENTS

Pliocene Amphibians and Reptiles from Clark County, Nevada. Jim I. Mead
and Christopher J. Bell

An Evolutionary Classification and Checklist of Amphibians and Reptiles on
the Pacific Islands of Baja California, México. L. Lee Grismer

Spot Pattern of Girella nigricans, the California Opaleye: Variation among
Cohorts and Climate Periods. Jana L. D. Davis

Diversity of Parasitic Cuscuta and their Host Plant Species in a Larrea-Atriplex
Ecotone. Simon A. Lei

Persistence of the Nematode, Oswaldocruzia pipiens (Molineidae), in the
Pacific Treefrog, Hyla regilla (Hylidae), from California. Stephen R.
Goldberg and Charles KR. Gursey ee

Cercarial Emergence from Rediae in California Snail Tissues. Mark Armitage

COVER: Light Micrograph, furcocercous cercariae from Cerithidea. Mark Armitage.

ISSN 0038-3872

SOUTHERN CALIFORNIA ACADEMY OF SCIENCES

BOLLETIN

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BCAS-A100(2) 59-128 (2001)
SL Le i

Southern California Academy of Sciences
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Date of this issue 11 September 2001

This paper meets the requirements of ANSI/NISO Z39.48-1992 (Permanence of Paper).

Bull. Southern California Acad. Sci.
100(2), 2001, pp. 59-73
© Southern California Academy of Sciences, 2001

A Fossil Blue Marlin (Makaira nigricans Lacepéde) from the
Middle Facies of the Trinidad Formation (Upper Miocene to Upper
Pliocene), San Jose del Cabo Basin, Baja California Sur, México

Harry L. Fierstine,’ Shelton P. Applegate,* Gerardo Gonzalez-Barba,?
Tobias Schwennicke’, and Luis Espinosa-Arrubarrena?

Biological Sciences Department, California Polytechnic State University,
San Luis Obispo, CA 93407, U.S.A.
2Instituto de Geologia, Universidad Nacional Aut6noma de México,
Ciudad Universitaria, México, D.F., 04510, México
Departamento de Geologia Marina, A.I. de Ciencias del Mar,
Universidad Aut6noma de Baja California Sur, Apartado Postal #19B,
La Paz, Baja California Sur, 23080, México

Abstract.—A large fossil skull and several rostra of Makaira nigricans Lacépéde,
1802 (Perciformes: Istiophoridae), as well as some less diagnostic istiophorid
remains, have been recovered from the middle facies of the Trinidad Formation
near Rancho Algodones, San José del Cabo Basin, Baja California Sur, México.
These are the only billfish specimens known from fossiliferous deposits located
between southern California and Panama. Based on published accounts of the
presence of nannofossils and planktonic foraminifera, and additional field work,
we conclude that the age of the study area is late Miocene to late Pliocene. Based
on the habitat preferences of recent M. nigricans and on the type of sediments,
we conclude that the middle facies of the Trinidad Formation was deposited far
offshore at a water depth of at least 100 m in a bottom environment that was
poorly oxygenated and without currents.

The blue marlin, Makaira nigricans Lacépéde, 1802, is an important commer-
cial and recreational fish species that inhabits the tropical and temperate Atlantic,
Indian, and Pacific oceans favoring depths of over 100 m and temperatures of
approximately 24°C (Nakamura 1983, 1985). Blue marlin are usually distributed
from about 45°N latitude to 35°S latitude in the Pacific Ocean (Nakamura 1983),
although in the far Eastern Pacific blue marlin generally range only from 23°N
to 3°S (Rivas 1975). Makaira nigricans is occasionally observed off southern
California, but only during periods of anomalously high sea surface temperatures
(National Marine Fisheries Service [The Southwest Fisheries Science Center’s
1996 Billfish Newsletter], unpublished).

Fossil remains of blue marlin or blue marlin-like fish (e.g., Makaira sp., cf. M.
nigricans) are reported from the middle Miocene of Belgium, from the late Mio-
cene of Panama, southern California and Virginia, and from the early Pliocene of
North Carolina (Fierstine 1998, 1999, 2001). Discovery of a large skull and sev-
eral rostra of M. nigricans, as well as some less diagnostic istiophorid remains,
in the middle facies of the Trinidad Formation (late Miocene to late Pliocene) in
the San José del Cabo Basin, Baja California Sur, México, offers the first oppor-
tunity to examine billfish specimens from fossil deposits located between southern

60 SOUTHERN CALIFORNIA ACADEMY OF SCIENCES

California and Panama and to discuss the paleoecology of the Trinidad Formation
based on the habitat preference of a still extant bony fish. Interpretations of the
stratigraphy, ages and depositional environments of the rocks near Rancho Los
Algodones are equivocal (Espinosa-Arrubarrena 1979; McCloy 1984; Martinez-
Gutiérrez and Sethi 1997) and we offer our own conclusions based on additional
field work and information from recent publications.

Materials and Methods

The materials and methods used in this study, particularly for the rostrum, have
been described fully in Fierstine and Voigt (1996) and Fierstine (1998, 1999,
2001), but some of it is repeated here for convenience. Approximately 160 whole
and partial skeletons of Recent specimens representing seven species of the family
Istiophoridae were examined and used for comparisons with the fossil material.
The museum number, geological age, and locality are given in the text for each
fossil specimen that was used as comparative material.

Anatomical abbreviations: A, articular; DE, dentary; LA, lacrimal; LE, lateral
ethmoid; M, maxillary; NA, nasal; NC, nutrient canal; PD, predentary; PM, pre-
maxilla; PN, prenasal; S, sclerotic; + denotes extinct taxon.

Institutional abbreviations: IGM, Instituto de Geologia, Ciudad Universitaria,
Universidad Nacional Aut6noma de México, D.E, México; LACM, Natural His-
tory Museum of Los Angeles County, Los Angeles, California, U.S.A.

Characters and their definitions for each bone or structure are as follows:

Rostrum.—Fierstine (1998, 1999) and Fierstine and Voigt (1996) emphasized
two regions of the rostrum in Recent specimens (Fig. 1): 0.5L, or one-half the
distance between the distal tip and the orbital margin of the lateral ethmoid bone
(L); and 0.25L, or one-fourth the distance between the distal tip and the orbital
margin of the lateral ethmoid bone. Six morphometric characters were studied in
each region (Fig. 1): depth (D) and width (W) of rostrum; height (H) and width
(N) of the left nutrient canal (as seen in cross-section); distance (IC) between the
right and left nutrient canals (as seen in cross-section); and distance (DD) of the
left nutrient canal from the dorsal surface of the rostrum (as seen in cross-section).
Characters studied without reference to region were: distribution of denticles on
the dorsal surface of the rostrum measured from the distal tip (DZ); length from
distal tip where denticles are absent from the ventral mid-line (DVS); length from
the distal tip to the distal extremity of the prenasal (P); length from tip where
fused premaxillae divide into separate bones (VSPM); and presence or absence
of denticles on the prenasal.

In the fossil specimens from San José del Cabo (Figs. 2—3; Table 1); the exact
position of 0.5L or 0.25L was unknown and cross-sections were studied at broken
end(s) or from computer tomography images. No transverse cuts were made of
the specimens. Using the techniques of Fierstine and Crimmen (1996) and Fier-
stine (2001), a cross-section was estimated to be at 0.5L if the prenasal bone was
large, and at 0.25L if the prenasal bone was tiny or absent. Because of the frag-
mentary nature of the fossil rostra, DZ was the only character available to study
in each estimated region.

Predentary.—Fierstine (1998, 2001) studied three morphometric characters in
Recent and fossil specimens: length along the ventral mid-line (PL), width across
the widest expanse of the denticulated surface (PW), and depth perpendicular to

FOSSIL BLUE MARLIN FROM BAJA CALIFORNIA SUR 61

Fig. 1. Makaira nigricans Lacépéde. A. Skull, left lateral view. Drawing is a composite of two
Recent specimens (LACM 25491 and 46023-1). B. Enlarged cross-section of generalized istiophorid
rostrum at one-half bill length (0.5L). C. Enlarged cross-section of generalized istiophorid rostrum at
(0.25L). See text for definition of abbreviations (modified from Fierstine, 1999:fig. 3 and Fierstine and
Voigt, 1996:fig. 2).

62 SOUTHERN CALIFORNIA ACADEMY OF SCIENCES

Fig. 2. Makaira nigricans Lacépéde, upper Miocene-late Pliocene, middle facies of the Trinidad
Formation, San José del Cabo Basin, Baja California Sur, México. A. Proximal rostrum (IGM 7888),
left lateral view. B. Partial skull (GM 7889), left lateral view. Dotted lines indicate probable attach-
ment of A with B. C. Partial rostrum (IGM 7884), posterior view. D. Lateral view of C. E. Partial
rostrum (IGM 7893), anterior view. E Lateral view of E IGM 7893). Scale bar equals 5 cm (A, B),
2 cm (D), and 1 cm (C, E, and F).

FOSSIL BLUE MARLIN FROM BAJA CALIFORNIA SUR 63

F ane Es

Fig. 3. Istiophorid billfish fossils, upper Miocene-late Pliocene, middle facies of the Trinidad
Formation, San José del Cabo Basin, Baja California Sur, México. A. Istiophoridae gen. and sp. indet.,
partial predentary, dorsal view (IGM 7887). B. Istiophoridae gen. and sp. indet., partial predentary,
dorsal view (IGM 7885). C. Istiophoridae gen. and sp. indet., partial ?dorsal pterygiophore (IGM
7894), anterior view. E. Makaira sp., cf. M. nigricans Lacépéde, partial rostrum, posterior view (IGM
7883). E Lateral view of E (IGM 7883). Scale bar equals 1 cm (A—E) or 2 cm (F).

SOUTHERN CALIFORNIA ACADEMY OF SCIENCES

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FOSSIL BLUE MARLIN FROM BAJA CALIFORNIA SUR 65

the long axis from PW to the ventral surface of the bone (PD). The San José del
Cabo specimens (Fig. 3) were too fragmentary to obtain any of the three mor-
phometric characters.

Skull.—Although there are published descriptions available of a typical or spe-
cific istiophorid skull (Gregory and Conrad 1937; Schultz 1987; Davie 1990),
there are no comparative osteological studies that are useful in determining the
species represented by the partial skull from the San José del Cabo Basin (Fig.
2B). Nakamura (1983, 1985) compared complete neurocrania of Recent istio-
phorid species and found generic differences in overall proportions. Fierstine
(1998, 2001) found specific differences among three isolated skull bones (articular,
maxilla, and parasphenoid) of Recent and fossil istiophorids, but those features
are not preserved in the fossils from the San José del Cabo Basin. Identification
of the skull is based on overall size and its possible attachment to one of the
rostra (IGM 7888).

Pterygiophore.—Potthoff et al. (1986:672, fig. 14) described the development
of pterygiophores in the anal and dorsal fins of istiophorids, but we are not aware
of any published morphological accounts of individual pterygiophores in the adult
Istiophoridae. Identification of the partial pterygiophore (IGM 7894) from San
José del Cabo Basin (Fig. 3) is based on comparison with pterygiophores in the
dorsal and anal fins of three Recent istiophorids, LACM 46023-1 (M. nigricans),
LACM 25509 (M. indica), and LACM 25499 (T. angustirostris).

Regional Geology

The Buena Vista-San José del Cabo Basin is located near the southern end of
the Baja California Peninsula between the Sierra La Laguna and Sierra La Trin-
idad mountain ranges (Fig. 4). Both ranges are composed of crystalline and meta-
morphic rocks. Based on evidence from fission-track thermochronology, Fletcher
et al. (2000) suggested that the uplift of the Sierra La Laguna Mountains along
the San José del Cabo fault started approximately 10—12 Ma. The basin covers
approximately 2,000 km? and contains both terrestrial and marine strata that range
in age from early middle Miocene to Recent (McCloy 1984; Martinez-Gutiérrez
and Sethi 1997). Martinez-Gutiérrez and Sethi (1997) considered the basin to have
formed in association with the opening of the Gulf of California and formation
of the Baja California Peninsula, and proposed a general model for its evolution.
The sedimentary rocks of the basin filling are mainly dipping to the southwest or
west, and for this reason the oldest sedimentary rocks are exposed along the
eastern margin of the basin, becoming younger to the southwest and west. The
presence of faults complicates this general picture.

The Calera Formation (Fig. 5) is the oldest sedimentary and non-marine unit
in the basin (Martinez-Gutiérrez and Sethi 1997), and is composed of sandstones
and conglomerates deposited in an alluvial fan environment. Its age is uncertain
due to the lack of fossils, but McCloy (1984) assigned an age of no younger than
middle Miocene, and Martinez-Gutiérrez and Sethi (1997) considered the beds to
be middle Miocene to late Miocene, an age range that essentially agrees with the
fission-track data of Fletcher et al. (2000), if the basin began to fill with deposits
soon after uplift of the Sierra La Laguna Mountains. The superposed Trinidad
Formation (Fig. 5) was deposited in a nearshore to basinal marine setting during
the middle Miocene to upper Pliocene (see discussion below). The marine Refugio

66 SOUTHERN CALIFORNIA ACADEMY OF SCIENCES

109°40'
GULF OF
CALIFORNIA

109°30'

GULF
OF
X, CALIFORNIA

23°40'

PACIFIC SANTIAGO

OCEAN

23°10'

SAN JOSE
DEL CABO,

Fig. 4. Map of southern Baja California Sur, México (B.C.S.), indicating collection localities for
istiophorid billfish in the middle facies of the Trinidad Formation (upper Miocene-late Pliocene), San
José del Cabo Basin. (modified from Martinez-Gutiérrez and Sethi, 1997:figs. 1,2).

Formation (Fig. 5) overlies the Trinidad Formation and the contact between them
is transitional as well as erosional (Martinez-Gutiérrez and Sethi 1997). The Re-
fugio Formation is composed of siltstones, sandstones, and limestones. Many
sandstones are cross-bedded and fossiliferous, indicating nearshore depositional
settings. McCloy (1984) suggested a late Pliocene age for the Refugio Formation,
whereas Smith (1991) and Martinez-Gutiérrez and Sethi (1997) considered it to
be early Pliocene.

The Trinidad Formation

The Trinidad Formation is the oldest marine stratigraphic unit in the Buena
Vista-San José del Cabo basin. McCloy (1984) estimated its thickness to be be-
tween 700 and 1000 m, whereas Martinez-Gutiérrez and Sethi (1997) estimated
its thickness at 400 m. McCloy (1984) informally divided the formation into four
lithologic subunits (A to D). Subunit A is generally a sequence that grades upward
from course to fine and is composed of cross-bedded or planar-bedded sandstone,
siltstones, and fissile and laminated shales. These beds may have alternating tan
to buff siltstones and gray shales with sandstone intercalations. Fossils (mainly
mollusks) are common and McCloy (1984) interpreted the unit as inner to outer

FOSSIL BLUE MARLIN FROM BAJA CALIFORNIA SUR 67

shelf deposits. Subunit A is well-exposed around Rancho Lengua de Buey (N 23°
20.318’, W 109° 33.910’). Subunit B, a succession of sandstone, siltstone, and
alternating beds of sandstone and mudstone, is related to an outermost shelf to
upper shelf depositional environment. Sedimentary structures (graded beds, cross-
bedding) indicate traction and downslope transport of sandy sediments (McCloy
1984). We found outcrops of this unit at Rancho El Bosque (N 23° 20.53’, W
109° 36.378’). Subunit C is a succession of mudstones, diatomaceous shales, and
diatomite that displays a transitional or marked rhythmic cyclicity often with fine
laminae. McCloy (1984) and Carrefio (1992) found massive diatomites in the
central part of the basin, and McCloy (1984) proposed that they were deposited
in a partially aerated to anoxic environment. We found good outcrops of subunit
C in Cafiada del Enmedio. Subunit D consists of greenish, laminated, non-bio-
turbated, clayey siltstones that grade upward into massive to cross-bedded bio-
turbated, fossiliferous sandstones. McCloy (1984) suggested these sediments were
deposited in an outer shelf environment. Subunit D is well-exposed near Rancho
La Calabaza (N 23° 20.71’, W 109° 38.252’).

Martinez-Gutiérrez and Sethi (1997) subdivided the Trinidad Formation into
three vertically stacked lithofacies. The basal facies is approximately equivalent
to McCloy’s (1984) subunit A and was interpreted as representing nearshore to
lagoonal, brackish-marine deposits. The middle facies is equivalent to McCloy’s
subunits B and C, and was interpreted as having been deposited in “‘shelf depths
slightly greater than that of normal wave base”? (Martinez-Gutiérrez and Sethi
1997). We believe the middle facies was deposited in much deeper water that was
influenced initially by turbidity currents (subunit B). The presence of non-biotur-
bated diatomaceous sediments in subunit C indicates a low sedimentation rate in
a basinal setting. The upper facies corresponds to McCloy’s (1984) subunit D,
and Martinez-Gutiérrez and Sethi (1997) suggested that it was deposited in a high
energy, shallow marine depositional environment, an interpretation that is consis-
tent with our observations.

The Trinidad Formation has been assigned different ages. McCloy (1984) con-
sidered it to span middle? Miocene to late Pliocene. She gave a late Pliocene age
for subunit C based on microfossils. Carrefio (1992) demonstrated an uppermost
?Miocene/early Pliocene to middle Pliocene age for beds exposed near the town
of Santiago that approximately correspond to McCloy’s subunits B and C. How-
ever, according to Berggren et al. (1995), the microfossils reported by Carrefio
extend into the late Pliocene. In contrast, Martinez-Gutiérrez and Sethi (1997)
suggested an age from late Miocene to early Pliocene, but did not present new
evidence for their conclusion. In conclusion, the total stratigraphic range for the
Trinidad Formation probably spans from middle Miocene to upper Pliocene.

The billfish fossils described herein were recovered from several localities.
Locality IGM 95 (N 23° 20.400’, W 109° 36.931’): is located in a westward
dipping sequence, known informally as La Angostura, that is exposed west of
Rancho El Bosque (Fig. 4). It consists of 40 m of diatomaceous mudstone and
clayey siltstone that probably correspond to McCloy’s (1984) subunit C. In the
upper part of the outcrop there are abundant large, yellow-weathering limestone
concretions that contain the billfish fossils that we report here.

Locality IGM 240 (N 23° 20.550’, W 109° 39.537’) is located in a westward
dipping sequence that is exposed in Cafiada del Enmedio (Fig. 4). A 55 m thick

68 SOUTHERN CALIFORNIA ACADEMY OF SCIENCES

stratigraphic section contains diatomaceous mudstone at its base and is transitional
upward to clayey siltstone and then to siltstone at the top. These beds mark the
transition between McCloy’s (1984) subunits C and D. The upper part of this
stratigraphic section has yellow-weathering concretions some of which contain
remains of fossil billfish similar to those collected at locality IG 95.

Other fossil localities are located in the area around Rancho Algodones (N 23°
13.200’, W 109° 38.450’) (Fig. 4). Locality IGM 92 (Los Algodones) includes
exposures distributed southwest of the ranch. Locality IGM 93 (Los Dientes Gran-
des) is situated about 1 km southwest of the ranch, and corresponds to locality
BCS-7 of Espinosa-Arrubarrena (1979). Barnes (1998) reported that locality IGM
92 has yielded the remains of mysticete and odontocete whales, and locality IGM
93 has yielded mysticete whales and a possible odobenine walrus. The rocks
exposed in this region have been reported as Refugio Formation (formerly called
Salada Formation) by Espinosa-Arrubarrena (1979), Espinosa-Arrubarrena and
Applegate (1981), and Barnes (1998), but for reasons given below, we now be-
lieve they are part of the Trinidad Formation. The geologic map of Martinez-
Gutiérrez and Sethi (1997:figs. 2, 11) only shows the Refugio Formation in this
region although a stratigraphic section made near the ranch includes the Trinidad
Formation in its lower part. In our field work we noted that the strata in this area
generally dip 10—20°W. There are no major faults. The ranch rests on beds of the
lower or lower middle Trinidad Formation and lithologic features exposed near
the ranch fit subunit B of McCloy (1984). Topographically higher areas are partly
covered by Pleistocene terrace deposits that earlier workers might have confused
with the Refugio Formation. East of the Rancho Algodones the Trinidad For-
mation disconformably overlies granitic basement rocks. The gradational contact
with the superposed Refugio Formation is well exposed 2 km to the west and
southwest of the ranch and, because of the striking lithologic differences between
the two formations, the Refugio and Trinidad Formations are easily separated in
the field. The general lithology of the Trinidad Formation, dominated by greenish
shale and siltstone, agrees with differences noted in the more northerly areas.
However, we did not observe the diatomites that are typically found in the middle
part of the formation.

Espinosa-Arrubarrena (1979) and Espinosa-Arrubarrena and Applegate (1981)
suggested a late Pliocene age for the selachian fauna of locality IGM 92 (Los
Algodones) based on the stratigraphic ranges of the shark species, and a similarity
between the invertebrate fauna that was collected at Espinosa-Arrubarrena’s lo-
cality BCS-43 and faunas in the Imperial Formation in California and the San
Marcos Formation near Santa Rosalia, Baja California. However, the Imperial
Formation is now thought to range from the late Miocene to late Pliocene in age
(McDougall et al. 1999) and the San Marcos Formation is now known to be late
Miocene based on radiometric data (Smith, 1991). The selachian fauna by itself
offers little help in determining the exact age of the Trinidad Formation in the
Los Algodones area because it includes species that range from the late Miocene
and Pliocene to Recent (Espinosa-Arrubarrena 1979; Espinosa-Arrubarrena and
Applegate 1981:table 1).

In conclusion, the fossils described below came from the middle to upper part
of the Trinidad Formation, probably corresponding to McCloy’s (1984) subunits
B and C. We can not give a precise age, but believe the age for these subunits

FOSSIL BLUE MARLIN FROM BAJA CALIFORNIA SUR 69

in our study area to be late Miocene to late Pliocene. The specimens probably
settled to the bottom in a poorly oxygenated environment that lacked bottom
currents.

Systematic Paleontology
Class Actinopterygii (sensu Nelson, 1994)
Division Teleostei (sensu Nelson, 1994)

Order Perciformes (sensu Johnson and Patterson, 1993)
Suborder Scombroidei (sensu Carpenter et al., 1995)
Family Istiophoridae (sensu Robins and deSylva, 1960)
Istiophoridae, genus and species indet.

Figs. 3A—D

Specimens.—Locality IGM 92: numerous fragments of a large rostrum, unca-
talogued; partial pterygiophore (?dorsal fin), IGM 7894. Locality IGM 95: three
predentaries, IGM 7885-7887; two median fin spine fragments, IGM 7890-7891;
pectoral fin spine fragment, IGM 7892. IGM 240: distal rostral fragments, un-
catalogued.

Discussion.—These bones are too fragmentary to be positively identified to
genus, however, the rostra, pterygiophore, fin spines, and two predentaries are
from fish of large size, a factor that favors their identification as belonging to the
genus Makaira or Tetrapturus audax, and not to the genus [stiophorus nor to T.
albidus, T. angustirostris, T. belone, or T. pfluegeri. The pterygiophore is a distal
fragment. Its shield-like shape, the stellate pattern on its anterior and posterior
surfaces for articulation with the pterygiophore anterior and posterior to it, and
the broad articular surface for the fin spine, are characteristic features of a pter-
ygiophore from the anterior part of the dorsal or anal fin in the Istiophoridae. It
is similar in morphology to the pterygiophore that supports the 3rd or 4th dorsal
spine, but because of a lack of comparative skeletal material, we can not eliminate
the possibility it supported an anal spine. The uncatalogued specimens from lo-
calities IGM 92 and IGM 240 were examined by one of us (HLF) in 1984, but
subsequently were discarded, lost, or misplaced before they could be accessioned
by IGM.

Genus Makaira Lacépéde, 1802
Makaira sp., cf. M. nigricans Lacépéde, 1802
Figures 3E, F

Specimens.—Locality IGM 95: distal rostrum, IGM 7883.

Discussion.—Although two ratios (D/W and DD/D) fall only within the ob-
served range of values computed for M. nigricans and not within the range of
any other Recent istiophorid (Table 1), the rostrum was not positively identified
as belonging to M. nigricans. The dorsal surface of the rostrum was completely
covered with denticles, yielding a very large DZ/W value, a feature unknown in
any Recent or fossil M. nigricans (Fierstine 1999: Tables 2, 3).

Makaira nigricans Lacépéde, 1802
Figures 2A—F
Specimens.—Locality IGM 93: distal rostrum, IGM 7893. Locality IG 95: two
distal rostra, IGM 7882, 7884; proximal rostrum, IGM 7888; partial skull, IGM
7889.

70 SOUTHERN CALIFORNIA ACADEMY OF SCIENCES

Los Barriles

Formation
Refugio
Formation
Y
|
Y
eo
—
yy
IGM 92, 93
Trinidad IGM 95
Formation IGM 240

3S)

O| >
N | &
ols
cif bls
|
S)

Miocene

Calera
Formation

Granitic
basement

Fig. 5. Stratigraphic column of beds near Rancho Algodones, San José del Cabo Basin, Baja
California Sur, México.

Discussion.—All ratios (Table 1) computed for the above rostra are within the
range of values observed for Recent M. nigricans with one exception, ratio [C/
W for IGM 7888. Specimen IGM 7888 was identified as belonging to M. nigri-
cans for two reasons: 1) ratio IC/W is not within the observed range of values
of any fossil or Recent istiophorid, but is closest to the value of Recent ™M.
nigricans (Fierstine 1999: Tables 2, 3), and 2) ratio DD/D is only within the

FOSSIL BLUE MARLIN FROM BAJA CALIFORNIA SUR #8

observed range of Recent M. nigricans. The partial skull (IGM 7889) has no
osteological feature that is diagnostic of M. nigricans, however, its identification
is based on our belief that both rostrum IGM 7888 and the skull are from the
same individual. The skull and rostrum belong to a similar-sized fish and both
were encased in a sandy matrix that contained small veins of calcite.

The partial skull is a fully articulated unit from mid-orbit to the base of the
rostrum and it has an overall length of 308 mm and a posterior width of 245 mm.
The left side is more complete than the right side. The neurocranium contains the
anterior-most part of the frontals, lateral ethmoids, nasals, and posterior parts of
the prenasals. The olfactory foramen of the lateral ethmoid is visible in the nasal
fossa. The thin portion of the frontals that covers the pineal apparatus (Rivas
1953) on the mid-dorsal surface of the skull is not preserved and the pineal fossa
is exposed. The left orbit contains the anterior half of the sclerotic.

The maxillary segment contains its anterior articulation with the prenasal, dor-
sal articulation with the lacrimal, and ventral articulation with the premaxilla. The
lower jaw contains the entire articular-dentary suture. Denticles are visible on
both the dentary and premaxilla.

Both the dorsal-ventral diameter (115 mm) of the sclerotic (IGM 7889) and the
width of the skull (IGM 7889) across the lateral ethmoids (248 mm) are approx-
imately 1.4 times greater than similar measurements of a 181 kg Recent M. ni-
gricans (LACM 46023-1). Assuming that IGM 7889 came from a specimen with
a length (tip of bill to fork of caudal fin) that was 1.4 times longer than LACM
46023-1 (3280 mm), then the skull (GM 7889) and rostrum (IGM 7888) probably
are remains of a fish larger than 500 kg, based on the length-weight curve pub-
lished in Strasburg (1969). Individuals of Recent M. nigricans that are larger than
160 kg are always females (Hopper 1986:60).

Discussion and Conclusions

The presence of M. nigricans in a marine upper Miocene or Pliocene deposit
in Baja California Sur is not surprising because it has been the most common
billfish identified in Neogene deposits bordering the eastern North Pacific Ocean
from southern California to Panama (Fierstine and Applegate 1968; Fierstine and
Welton 1988; Fierstine, 1999), and it is commonly caught off Cabo San Lucas,
Baja California Sur today. What is surprising is that no species of billfish other
than M. nigricans has been positively identified in fossil deposits bordering the
eastern North Pacific even though other Recent istiophorids (especially /. platyp-
terus and M. indica, and T. audax) now inhabit the same waters at least during
part of the year [Gottfried (1982) identified /. platypterus in the upper Pliocene
San Diego Formation based on a fragmentary vertebra, but after examination of
the specimen we believe it should be identified as Istiophoridae genus and species
indeterminate]. Perhaps the absence of other istiophorids as fossils in the eastern
North Pacific realm is due in part to our inability to accurately identify billfish
from partial remains. Identifications are based primarily on comparing rostral
fragments with complete rostra from Recent fish where emphasis is placed on
cross-sectional morphology at 0.25L and 0.5L, two areas that must be estimated
in fossil fragments. Fierstine and Voigt (1996) noted another limitation in their
statistical study of rostra of Recent billfish; the lack of large-sized M. nigricans
and M. indica. Species identifications of Recent billfish from vertebrae and other

2 SOUTHERN CALIFORNIA ACADEMY OF SCIENCES

bones are based on small sample sizes as well (Fierstine 1998, 2001) and in most
cases have not proven to be diagnostic (except for the predentary).

As noted above, Martinez-Gutiérrez and Sethi (1997) concluded that the middle
facies (subunits B and C) of the Trinidad Formation were deposited in “shelf
depths slightly greater than normal wave base’’, but that we concluded that the
middle facies was deposited in much deeper water based on type of sediments.
Because M. nigricans favors depths of over 100 m (Nakamura 1983, 1985), its
presence in the Trinidad Formation supports a greater water depth and more open-
sea environment, assuming that fossil and Recent blue marlin have similar eco-
logical preferences. Two of the specimens, a predentary (IGM 7885) and a rostral
fragment (IGM 7893), are badly eroded (possibly by stomach acid) and may have
been transported into the San José del Cabo Basin as stomach contents of a more
shallow-dwelling animal.

Acknowledgments

We thank M. del Carmen Perrilliat (IGM) and R. Feeney (LACM) for loan of
specimens, ES. Vernacchia (San Luis Diagnostic Center) for computer tomogra-
phy (CT) images at minimal cost, and L.G. Barnes (LACM) for references and
sage advice. Figure 3 was modified from an illustration by C. Bloomer. A. Fier-
stine provided encouragement throughout the study.

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controlling phototactic movements. Bull. Marine Sci. of the Gulf and Caribbean, 3(3):168—180.

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1-16 in Proceedings of the International Billfish Symposium Kailua-Kona, Hawaii, 9-12 Au-
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turus pfluegeri, based on western North Atlantic specimens. Bull. Marine Sci. of the Gulf and
Caribbean, 10:383-—413.

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Annalen Naturhistorisches Museum Wien, Serie A, fur Mineralogie und Petrographie, Geologie
und Paladontologie, Anthropologie, und Prahistories, 89:95—202.

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Accepted for publication 28 January 2001.

Bull. Southern California Acad. Sci.
100(2), 2001, pp. 74-85
© Southern California Academy of Sciences, 2001

Contributions to the Life History of Adult Pacific Lamprey
(Lampetra tridentata) in the Santa Clara River Of Southern
California

Shawn D. Chase
Sonoma County Water Agency, P.O. Box 11628, Santa Rosa, CA 9540]

Abstract.—Data on the relative abundance, seasonal timing, and size at entry into
freshwater of upstream migrants were collected on a population of Pacific lamprey
inhabiting the Santa Clara River. In addition, spent lamprey were also collected
and provided information on the length, decrease in body length between entry
into freshwater and spawning the following year, and the potential timing of
spawning.

The number of Pacific lamprey counted in the fish ladder has ranged from 20
in 1997 to 908 in 1994 and was at least partially related to the length of time
that the ladder was open. The upstream migration is regulated by streamflow, and
has begun as early as mid December, and as late as mid March in the Santa Clara
River. The entire lamprey migration period was sampled only once during the
1995 season and the upstream migration spanned an approximately three month
period (late January through early May). Peak lamprey migration occurred in
March of most years. Pacific lamprey captured in the upstream ladder averaged
between 593 and 610 mm in length between 1994 and 1997 (range 485—800 mm).

Adult Pacific lamprey in the Santa Clara River apparently spend approximately
one year in freshwater prior to spawning. During this time, lamprey do not feed.
The average length of spent Pacific lamprey collected in the downstream trap
ranged from 427 mm in 1995 to 446 mm in 1997 (overall range 355 to 610 mm).
Based on the capture of spent Pacific lamprey in the downstream trap, spawning
likely begins by late January in most years, and spawning may continue into
April.

Anadromus Pacific lamprey (Lampetra tridentata) inhabit coastal rivers and
streams from northern Baja California (Rio Santo Domingo) (Ruiz-Campos et al.
1997) to Alaska (Unalaska) (Moyle 1976). Although this species has received
some attention from researchers in Canada (e.g., Beamish 1980), very little is
known about the life history of Pacific lamprey in California rivers. An oppor-
tunity to collect information on adult life history of Pacific lamprey in southern
California occurred during a study designed to monitor the performance of fish
passage facilities at the Vern Freeman Diversion on the Santa Clara River. The
Vern Freeman Diversion is operated by the United Water Conservation District
(UWCD), which diverts water at Saticoy, approximately 16.8 kilometers inland
from the Pacific Ocean. In 1991, the UWCD constructed the Freeman Diversion
Improvement Project to improve the existing diversion. This action was taken at
the direction of the State Water Resources Control Board to combat seawater
intrusion in the Oxnard Coastal Plain aquifers. This intrusion results from over-
draft of groundwater to supply water for irrigation, industry, and municipal uses.

PACIFIC LAMPREY IN THE SANTA CLARA RIVER 5 fa

\ SPECIAL PROJECTS FISHERIES \GENERAL \SANTA_CLARA-RIVER

VICINITY MAP
MOT 10 SCALE

Pyramid Dam

Bouquet
Reservoir

Castaic
Reservoir

Santo Paula
Creek

FILLMORE

Piru Creek
Diversion

USACE FLOOD
CONTROL PROJECT

Freeman
Diversion

FIGURE 1: MAP OF SANTA CLARA RIVER BASIN

The improvements consist primarily of a permanent concrete riverbed stabilization
structure and diversion. These were necessary for the UWCD to maintain its
ability to divert water to groundwater recharge basins in the Oxnard Plain Forebay
Basin. Historical in-river aggregate mining destabilized and degraded the Santa
Clara River bed, which had lowered approximately 22 feet opposite the diversion
headworks since 1928, when diversions began. The down cutting of the riverbed
also contributed to repeated failures of the previous sand dike diversion structure.
The permanent concrete structure, completed in 1991, has halted headcutting,
stabilized the riverbed both upstream and downstream of the project, and im-
proved the ability of UWCD to divert streamflow to groundwater recharge basins.
The Freeman Diversion includes a two-entrance denil fish ladder, a fish screen,
and by-pass facilities to provide anadromous fish passage upstream and down-
stream of the diversion facility.

Background

The Santa Clara River drains portions of Los Angeles and Ventura counties in
southern California (Figure 1). The mainstem Santa Clara River flows through a
narrow alluvial valley onto a coastal plain and is fed by several tributaries that
flow out of local mountains. The major tributaries are Santa Paula, Sespe and
Piru creeks. Streamflow is typical of most southern California rivers—extremely
low to intermittent flow in its lower reaches during the dry summer and fall

76 SOUTHERN CALIFORNIA ACADEMY OF SCIENCES

months, with high peak flows during winter storms. During the low flow period,
a sand bar forms at the mouth of the Santa Clara River estuary forming an
intermittent barrier to fish migration to or from the ocean. Fish also are prevented
from migrating through the lower Santa Clara River until sufficient rainfall pro-
vides adequate streamflow to allow for passage.

The upper mainstem Santa Clara River provides habitat for several native spe-
cies, including steelhead (Oncorhynchus mykiss), unarmored threespine stickle-
back (Gasterosteus aculeatus williamsoni), partially armored threespine stickle-
back (G. a. microcephalus), as well as the introduced Santa Ana sucker (Catos-
tomus santaanae) and arroyo chub (Gila orcutti) (Bell 1978; Swift et al. 1993).
The lower Santa Clara River (in the vicinity of the Vern Freeman Diversion
Facility) serves primarily as a migration corridor for steelhead and lamprey (Puck-
ett and Villa 1985). Spawning and rearing habitat for steelhead and Pacific lam-
prey are located primarily in upstream tributaries, such as Sespe Creek (Puckett
and Villa 1985).

Methods

This study was designed to monitor the upstream (adult) and downstream
(smolt) migrations of steelhead through the fish ladder and fish by-pass facility
at the Vern Freeman Diversion (ENTRIX 1991). In 1991, a temporary trap and
fyke net was placed in the ladder during a high flow event to monitor fish move-
ment upstream through the diversion facility. In 1993, a semi-permanent fish trap
was installed in the fish ladder. Under agreement with the California Department
of Fish and Game, U. S. Fish and Wildlife Service and the U. S. Army Corp of
Engineers (USACE), the fish ladder will be operated throughout the upstream
migration period in the Santa Clara River at the Vern Freeman Diversion provided
certain criteria were met (detailed in the USACE Section 404 Permit). The ladder
may be closed 48 hours after streamflow (above the diversion) has declined below
415 cfs. The diversion facility is not operated under extremely high streamflow
conditions and when turbidity levels exceed approximately 2,000 NTU’s. The
ladder is also closed temporarily when sand is flushed from the mouth of the
diversion intake. The downstream by-pass facility is operated as long as there is
continuous flow to the ocean. When flow is discontinuous, smolts are collected
in a trap and transported to the estuary/ocean for release, depending upon the
condition (open or closed) of the estuary’s mouth.

Upstream Trap

A denil-type fish ladder provides access for upstream migrating fish around the
diversion structure. During periods of high streamflow, a relatively high velocity
current is required to attract upstream migrating steelhead into the fish ladder.
The water surface elevation inside the fish ladder (at the downstream fish en-
trance) is maintained such that the head created by this elevational difference
results in a mean water velocity flowing out of the fish ladder at a calculated
eight feet per second.

The trap was serviced every morning that the ladder was in operation. During
servicing, the fish ladder was drained by closing the upstream gates and debris
and sand that collected around the trap were removed. The fish trap was checked

PACIFIC LAMPREY IN THE SANTA CLARA RIVER FI

during this time. In addition, the rest of the fish ladder was surveyed for fish
stranded between the baffles as a result of the dewatering of the fish ladder.

Pacific lamprey collected in the ladder were counted and measured to the near-
est centimeter, total length (TL). Photographs were taken of representative indi-
viduals. Lamprey were then released upstream of the trap to continue their up-
stream migration.

In 1994 and 1995, a marking study was conducted to determine if adult Pacific
lamprey required more than one 24-hour period to ascend the fish ladder. In each
year, 100 adult lamprey were marked with a hole-punch in the dorsal fin and
released back into the ladder where they were originally found. The number of
lamprey with hole-punched dorsal fins were recorded on the day following the
marking event.

Downstream Trap

Adult lamprey were collected in the downstream trap and in the diversion canal,
upstream of the fish screens. Lamprey collected in the downstream trap were
counted, measured, and released into the fish by-pass facility (essentially a pipe
leading back to the river downstream of the diversion facility). The diversion’s
intake is located near the outlet of the fish ladder. Therefore, it was possible for
upstream migrating lamprey to be swept back into the diversion and into the
downstream trap (however, the occurrence of upstream migrants in the down-
stream trap was extremely low). Upstream migrants and spent Pacific lamprey
were distinguished based on the presence or absence of abrasions and lesions.
Pacific lamprey were classified as spent adults if they were covered with abrasions
(assumed to be the result of constructing redds). Lamprey lacking abrasions were
classified as upstream migrants that were swept back into the diversion canal.

Results
Timing of Upstream Migration

Since streamflow in the Santa Clara River is intermittent during the long dry
summer period, streamflow conditions suitable for upstream migration are solely
dependent on winter rains. The length of time that anadromous fish have to mi-
grate through the lower Santa Clara River is controlled by the timing and intensity
of rainfall, and by the operations rules for the fish ladder and diversion.

Rainfall varied greatly in the project area during the years sampled. Rainfall
data have been collected in Santa Paula (located approximately 10 miles east of
the diversion) since 1890. Since 1890, annual rainfall in the basin has ranged
from 6.42 to 38.11 inches, averaging 17.28 inches. Between 1994 and 1997,
annual rainfall totals have ranged from 13.39 to 35.34 inches. The length of time
that streamflow conditions suitable for upstream migration existed ranged from
29 days in 1996 to 137 days in 1995.

In 1994, rainfall totaled 13.39 inches (65 percent exceedance). The sand bar at
the mouth of the river likely first breached on 7 February, and streamflow con-
ditions suitable for upstream migration existed in the lower river until 9 April (62
days) (Table 1, Figure 2). Upstream migrating Pacific lamprey were observed in
the ladder from 17 February through 9 April, when the ladder was closed ac-
cording to 404 Permit conditions. The number of lamprey observed in the ladder
was relatively low during the first four weeks that the ladder was operated (61

78 SOUTHERN CALIFORNIA ACADEMY OF SCIENCES

Table 1. Probable date of breaching of the stream mouth and recording of first lamprey in ladder.

No. of days
Probable date Date first lamprey Last day lamprey ladder
Year sand bar breached in ladder recorded operated
1994 7 February 17 February 9 April! 50
1995 2 January 18 January 18 May 137
1996 20 February 25 February 25 March! 23
1997 24 December? 16 December 18 February! 45

' Ladder likely closed prior to the end of the upstream migration period.
* Sand bar breached briefly in October, November, and early December for a few days at a time
prior to the 24 December breaching event.

total by March 15). On March 16, 142 lamprey were counted in the ladder, the
highest single daily total during the study. During the last two weeks of March,
676 adult lamprey were counted. A total of 908 adult Pacific lamprey were ob-
served in the ladder during 1994 (Table 2).

In 1995, rainfall totaled 35.34 inches (4 percent exceedance). The sand bar at
the mouth of the river likely first breached on 2 January, and suitable streamflow
conditions for upstream migration existed in the lower river through 20 May (137
days). Pacific lamprey were observed in the ladder from 18 January through 18

eeeemcses
January
9 | 10 2] 15 17 205] 2h 22 230 p 24, | eas
De PD ee
—|— rrr = =
eo ee

ike
Oe CE YN A CC ME

December

February

RARARAR MES UABDAIE SOOT LTR OL AR ARNEIIR SEED Be PI
oa

Fig. 2. Dates that the Upstream fish ladder was in operation, 1994—1997.

PACIFIC LAMPREY IN THE SANTA CLARA RIVER 72

Table 2. Weekly counts of adult Pacific lamprey caught in the upstream migrant trap, 1991-1997.

Week
Month ending 1991! 199323 19944 1995 1996° 1997’

December iW —_— a — — — 2
24 — — — — — 1

January 7 — -— — 0 = 0)
14 — — 6) —- 0

21 — — 1 — l

28 — — 2. — 0

February -: — 88 0) 95 — O
cr? —— 0) 74 — 1

18 — 1 35 oa 7

aS — 19 16 14 8

March 4 — 318 ml 24 85 —
Ly “= (ij 2 19 —

18 — 283 4 36 oe

Zs -— 240 20 155 oo

April 1 74 48 201 20 — —
8 — 133 34 — —

15 —~ 13 9 — oo

22 —- — 9 — —

29 -- —_ § a a

May 6 — 11 — 13 — —
13 ao — 8 —_ —

20 —— — 2. — —

Za — — — — —

June 4 — — — a= —
ti — — — —- —

Total 74 465 908 368 309 20

' Ladder operated from 26 March to 2 April, 1991.

? Ladder operated from 17 February to 17 May, 1993.

> Daily lamprey counts were visually estimated on some days during 1993 (e.g., “15 to 20 lamprey
in ladder today’’), on these days the lower value was used to estimate abundance, and the numbers
were combined into monthly totals only.

+ Ladder operated from 4 February through 9 April, 1994.

> Ladder operated from 6 January through 20 May, 1995.

7 Includes leap year day (8 day period).

May (Table 1). Prior to 31 January, three lamprey were observed in the ladder.
Approximately 46 percent of the Pacific lamprey run occurred during the first two
weeks of February. The lamprey migration remained fairly constant through the
second week in April. In 1995, 368 adult Pacific lamprey were observed in the
ladder (Table 2).

In 1996, rainfall totaled 13.90 inches (59 percent exceedance). Significant rain-
fall during this year did not fall in southern California until February, and the
sand bar at the mouth of the river likely first breached on 20 February. Adult
Pacific lamprey were first observed in the ladder on 25 February. Suitable flow
conditions for upstream migration existed in the lower river from 25 February
through 5 March, and again from 14 March through 25 March (29 days) (the
ladder was closed between 6 March and 13 March). Weekly counts of lamprey

80 SOUTHERN CALIFORNIA ACADEMY OF SCIENCES

Table 3. Minimum, maximum and average lengths (mm) of upstream migrating Pacific lamprey,
1994-1996.

Year Minimum length Maximum length Average length N
1994 yao 700 610 71
1995 485 750 610 254
1996 490 675 604 pi ys
1997 She 800 395 19

peaked during the last week that the ladder was open. A total of 309 adult Pacific
lamprey were observed in the ladder during 1996.

In 1997, rainfall totaled 19.64 inches (31 percent exceedance), falling primarily
during December and January. The sand bar at the mouth of the river likely first
breached in October for a short time-period, and again in November and early
December. The sand bar breached again on 24 December with suitable flow con-
ditions for upstream migration existed in the lower river until 18 February (57
days). Adults were observed in the fish ladder from 16 December, after one of
the brief breaching events, and a few lamprey were counted in the ladder through
18 February, when the ladder was closed. Although suitable streamflow conditions
were present to allow for upstream migration during December and January, only
four lamprey were observed in the ladder during this time. A total of 20 adult
Pacific lamprey were observed in the ladder during 1997 (Table 2).

Counts

Counts of Pacific lamprey in the ladder represent a minimum number of mi-
grating adults since the trap probably does not hinder upstream movement. Mark-
ing studies conducted in 1994 and 1995 found that the majority (92 and 93 per-
cent, respectively) of the lamprey were able to negotiate the fish ladder in less
than 24 hours. The number of adult Pacific lamprey recorded in the ladder an-
nually has ranged from 20 (1997) to 908 (1994). However, the entire run was
censused only once, in 1995, when 371 adult lamprey were counted (Table 2). In
1993, sampling began after lamprey were first observed in the ladder, when 465
adult lamprey were counted.

Length of Adults at Time of Entry into the River

The upstream migrating lamprey ranged in total length (TL) from 485 to 800
mm (Table 3). The average length of upstream migrating Pacific lamprey has been
nearly constant. Pacific lamprey averaged 610 mm TL in 1994 and 1995, 604
mm TL in 1996, and 593 mm TL in 1997.

Likely Time of Spawning

Adult lamprey in a variety of conditions ranging from dead to apparently
healthy and vigorous have been captured in the downstream trap. The majority
of these lamprey were covered with abrasions, and were assumed to have recently
spawned. Timing of spent lamprey appearing in the downstream trap is related to
the onset of spawning and very likely streamflow in spawning tributary(s) and in
the Santa Clara River. It is not known how long after spawning that lamprey
weaken to the point where they begin to drift downstream, or how long it takes

PACIFIC LAMPREY IN THE SANTA CLARA RIVER 81

Table 4. Weekly summary of adult Pacific lamprey caught in the downstream migrant trap, 1994—
1996.

Month Ending 1994! 19952 1996? 19972

January vi — 0) _ —

N
(o.2)
|

February 4

March 4

N
N
oN oo oo ©

—
OP WNNANOWON ON NK CO

April 1 13

—
CoRR DOOFRFR KY NOK WNT OC OC

May 6

N
\O
Sy SS
OW —
N

June 3 —

July 1 as

—_
~
|
OSooCoeooOWONnNWN
|
|

—
—"
ie)
N
&
—
|

Total 70

' Downstream trap closed on 25 May, 1994.
* Downstream trap closed on 27 July, 1995.
> Downstream trap closed on 3 May, 1996.

* Downstream trap closed on 29 April, 1997.

Table 5. Number, seasonal timing, and lengths of Pacific lamprey captured in the downstream trap
between 1994 and 1996.

Average
Year Number First observed Last observed Range length
1994 25 10 March 21 May 390-479 44]
1995 103 4 February 11 June 355-510 427
1996 54 17 February 29 April 355-615 438

1997 16 10 February 8 April 411-492 446

82 SOUTHERN CALIFORNIA ACADEMY OF SCIENCES

Number
=
(=)

250 300 350 400 450 500 550 600 650 700 750 _ 800
Total Length (mm)

f= Downstream (j Upstream

Fig. 3. Length-frequency of Pacific lamprey collected in the upstream and downstream fish by-
pass facilities, 1994-1997 data combined.

them to drift from spawning tributaries down to the diversion dam. Spent lamprey
have been collected from 4 February to 11 June (Tables 4 and 5). Spent lamprey
occurrence in the downstream trap peaked in late March and early April during
1994 and 1996 and in May during 1995 (Table 4). Based on the capture of spent
lamprey in the trap, spawning begins in late January and may continue through
at least May in some years. Peak spawning probably occurred between February
and April.

Length of Pacific Lamprey Collected in the Downstream Trap

Pacific lamprey collected in the downstream trap ranged in length between 355
and 615 mm TL between 1994 and 1997 (Table 5). Similar to lamprey collected
in the upstream trap, the average length of lamprey collected in the downstream
trap remained relatively constant between years, ranging from 427 to 446 mm TL
between 1994 and 1997.

Decrease in Body Length Between Entry into Freshwater and After Spawning

Pacific lamprey collected in the upstream trap were considerably larger com-
pared to lamprey collected in the downstream trap within the same year (Figure
3). I hypothesize that the lamprey collected in the downstream trap are members
of the previous year’s upstream migration as has been previously described by
Beamish (1980). If this hypothesis is correct, then Pacific lamprey in the Santa

Table 6. A comparison of total body lengths of adult Pacific lamprey at the time of upstream
migration and after spawning the following year.

Average Difference Percentage
length (mm) Range (mm) (mm) decrease
Pre-spawn length in 1994 610 485-750
Post spawn length in 1995 427 355-508 183 30.0
Pre-spawn length in 1995 610 485-750
Post spawn length in 1996 437 355-615 173 28.2
Pre-spawn length in 1996 604 490-675

Post spawn length in 1997 446 411-492 158 26.2

PACIFIC LAMPREY IN THE SANTA CLARA RIVER 83

Clara River decreased in body length, on average, between 26.2 and 30.0 percent
of their body length between entry into freshwater and spawning (Table 6). The
alternative hypothesis that the lamprey captured in the downstream trap are mem-
bers of that year’s spawning migration would require that the observed decrease
in body length would have occurred over a relatively short (one to three month)
period.

Discussion
Timing of Upstream Migration

Migration in the Santa Clara River is regulated by streamflow, and adult lam-
prey have been observed in the ladder for the first time as early as mid-December
in 1997 and as a late as the last week in March in 1991, depending on the timing
of winter rains. Adult lamprey are not thought to range far from their natal streams
during the marine phase of their life history (Moyle 1976). Lamprey have been
collected in the fish ladder (approximately 16.8 kilometers inland) as early as six
days after the probable breaching date of the lagoon mouth, and as late as 16
days after the lagoon breached. However, the number of adult lamprey captured
in the ladder have typically remained low during the first two weeks of the run.

In California, Pacific lamprey have been reported to migrate upstream between
April and late July (Moyle 1976; Wang 1986), although in the Trinity River in
northern California, Moffett and Smith (1950, cited by Moyle 1976) reported
upstream migration by adult lamprey in August and September. In the Santa Clara
River, upstream migrating Pacific lamprey were observed from mid-December
through mid-May between 1994 and 1997. However, the peak run generally oc-
curred between February and the first week of April. The adult Pacific lamprey
upstream migration period spanned an approximately four-month period (mid-
January though mid-May) in 1995, the only year to date that the entire lamprey
spawning migration was sampled. However, 87.3 percent of the run was observed
in the ladder between February and the first week of April. Very few Pacific
lamprey were observed in the ladder prior to February in any year. For example,
in 1997, although suitable streamflows for migration were present from late De-
cember through January, five lamprey were observed in the ladder during this
time. The upstream migration period extended into the first week of May in 1993
and the third week in May in 1995. The apparent earlier timing of upstream
migration in the Santa Clara River, compared to more northern river systems, is
likely an adaptation to the rainfall pattern in southern California, where the ma-
jority of the precipitation, and thus suitable streamflow conditions, occur between
January and March.

The number of Pacific lamprey counted in the fish ladder has ranged from a
low of 20 in 1997 to 908 in 1994. The numbers of lamprey counted at the Vern
Freeman Diversion represent a minimum number; the true number of lamprey
returning to the river is undoubtedly higher. Pacific lamprey can pass through the
ladder unhindered. Thus an unknown number of adult lamprey could migrate
through the fish ladder without being detected. A test using a mark-recapture
technique demonstrated that slightly more than 90 percent of the lamprey could
pass through the ladder in less than 24 hours.

84 SOUTHERN CALIFORNIA ACADEMY OF SCIENCES

Size at Time of Upstream Migration

Upstream migrating lamprey collected in the fish ladder ranged from 485 to
800 mm TL, averaging approximately 606 mm TL between 1994 and 1997. Pa-
cific lamprey in the Santa Clara River are comparable in length to those collected
in Canada. In Canada, upstream migrating lamprey ranged in length between 130
and 720 mm TL in six populations reported by Beamish (1980). These populations
could be divided into two size ranges based on length; a “‘small’’ population
averaging between 260 and 290 mm in length (ranging between 130 and 510 mm
in length for three populations combined), and a “‘large’”’ group averaging between
600 and 640 mm TL (ranging between 550 and 720 mm in length for three
populations combined) (Beamish 1980).

Pacific lamprey do not feed after reentering freshwater during their spawning
migration (Hardisty and Potter 1971; Whyte et al. 1993). Energy reserves are
used for migrating to natal spawning areas and gonadal development. During this
period of starvation, Pacific lamprey decrease in length and weight (Hardisty and
Potter 1993). Pacific lamprey have been kept alive under laboratory conditions
for up to two years without eating (Whyte et al. 1993). A similar decrease in
body length was observed in lamprey in the Santa Clara River. Between 1994
and 1997, Pacific lamprey collected in the downstream trap averaged 427 and
446 mm TL, compared to Pacific lamprey captured in the upstream trap which
averaged 593 and 610 mm TL. Hardisty and Potter (1993) and Beamish (1980)
have reported that lamprey may remain in fresh water for approximately one year
prior to spawning. Based on the differences in the average size of Pacific lamprey
collected in the upstream and downstream traps, combined with the peak occur-
rences of lamprey in the two facilities, it appears that Pacific lamprey in the Santa
Clara River hold over in fresh water for one year prior to spawning. If the smaller
lamprey captured in the downstream trap are members of the previous years
spawning migration, then adult lamprey decreased, on average, between 26.2 and
30.0 percent of their body length between entering freshwater and spawning the
following year. Since peak abundance of lamprey in the upstream and downstream
fish passage facilities occurred at approximately the same time (between late Feb-
ruary and early May), the observed difference in body length would have had to
occurred over an approximately one to two month period for the lamprey collected
in the downstream trap to have been part of that years upstream migration. In
addition, in 1996, the first lamprey was observed in the downstream fish by-pass
facility on 17 February, although the mouth of the lagoon was first breached on
or about 19 February. A similar decrease in body length was reported for Pacific
lamprey inhabiting rivers in British Columbia. Beamish (1980) reported that Pa-
cific lamprey decreased in length at least 20 percent between the time of entry
into freshwater and the on-set of spawning. However, the lamprey in Beamish’s
study had been in freshwater for an unknown period of time, and thus the actual
length at time of entry was unknown.

Pacific lamprey have been reported to die after spawning (Hardisty and Potter
1971), although, Michaels (1980, 1984) reported that some lamprey survived to
spawn again a second time. Some of the spent lamprey captured in the down-
stream trap were still alive at the time of capture. It is not known if any were

PACIFIC LAMPREY IN THE SANTA CLARA RIVER 85

able to successfully readapt to a saltwater existence and survive to spawn a second
time.

Based on the capture of spent lamprey in the downstream trap in 1995 between
4 February and 11 June, it appears that spawning may begin as early as January
and may continue into at least May. In 1996, a relatively dry year, spent lamprey
were captured in the downstream trap between 17 February and 28 April.

This time period suggests that Pacific lamprey spawn earlier in the Santa Clara
River compared to more northern rivers, where spawning has been reported to
occur between April and July (e.g. Moyle 1976, Beemish, 1980, Wang 1986). As
with the earlier timing of upstream migration, the earlier spawning period for
Santa Clara River lamprey is likely an adaptation to the timing of precipitation
in southern California.

Acknowledgments

The United Water Conservation District provided the funding for this study.
John Dickenson, UWCD Project Engineer, allowed and encouraged the collection
of data outside the scope of the 404 permit requirements. Wayne Lifton contrib-
uted significantly to the development of the original study plan and in the editing
of the annual reports that formed the basis of this report. John Southwick collected
and measured most of the lamprey for this study, and without his dilengent efforts,
this study would not have been possible. The Author also wishes to thank Drs.
Richard Beamish, Peter Moyle, and Camm Swift for their thoughtful review of
this paper. Their comments and insights are greatly appreciated.

Literature Cited

Beamish, R. J. 1980. Adult biology of the river lamprey (Lampetra ayresi) and the Pacific lamprey
(Lampetra tridentata) from the Pacific coast of Canada. Canadian Journal of Fish and Aquatic
Sciences. 37:1906—1923.

Bell, M. A. 1978. Fishes of the Santa Clara River System, southern California. Contributions in
Science. Natural History Museum of Los Angeles. 295:1—20.

ENTRIX Inc., 1991. Vern Freeman Diversion Project fishery mitigation monitoring study plan to
address 404 permit special condition B. Prepared for the United Water Conservation District.
15 pp.

Hardisty, M. W. and I. C. Potter. 1971. The General Biology of Adult Lampreys. /n Hardisty and
Potter, eds. The Biology of Lampreys. Volume 1. Academic Press London.

Michael, J. H., Jr. 1980. Repeat spawning of Pacific lamprey. California Fish and Game. 66(3): 186—
187.

Michael, J. H., Jr. 1982. Additional notes on the repeat spawning by Pacific lamprey. California Fish
and Game. 66(3): 186—187.

Moffett, J. W. and S. H. Smith. 1950. Biological investigations of fisheries resources of Trinity River,
California. USFWS Spec. Sci. Rep. Fisheries 12:71 pp.

Moyle, P. B. 1976. Inland fishes of California. University of California Press, Berkeley. 405 pp.

Puckett, L. K. and N. A. Villa. 1985. Lower Santa Clara River Steelhead Study: Final Report. De-
partment of Fish and Game. 31 pp.

Ruiz-Campos, G., S. Contreras-Balderas, M. L. Lozano-Vilano, S. Gonzales-Guzman, and J Alaniz-
Garcia. 1997. Distributional status of the continental fishes of the northwester Baja California,
Mexico. 1996 Desert Fishes Council Proceedings.

Wang, J. C. S. 1986. Fishes of the Sacramento-San Joaquin Estuary and adjacent waters, California:
a guide to the early life histories. Prepared for the Interagency Ecology Study Program for the
Sacramento-San Joaquin Estuary. Technical report 9.

Whyte, J. N., R. J. Beamish, N. G. Ginther, and C.-E. Neville. 1993. Nutritional condition of the
Pacific lamprey (Lampetra tridentata) deprived of food for periods of up to two years.

Accepted for publication 17 September 2000.

Bull. Southern California Acad. Sci.
100(2), 2001, pp. 86-95
© Southern California Academy of Sciences, 2001

Combined Effects of Drought and Phoradendron juniperinum
Infestation Severity on Fruit Characteristics of P. juntperinum and
its Funtperus osteosperma Hosts

Simon A. Le!

Department of Biology, WDB, Community College of Southern Nevada,
6375 West Charleston Boulevard, Las Vegas, Nevada 89146-1139

Abstract.—The interactive effects of severe drought and severity of Phoradendron
Juniperinum (juniper mistletoe) infestation on fruit characteristics of parasitic P.
Juniperinum and its Juniperus osteosperma (Utah juniper) host trees were ex-
amined in Pine Creek of the Red Rock Canyon National Conservation Area in
southern Nevada. A severe drought, characterized by extremely low precipitation
and above average air temperatures, started in January and persisted through mid-
July 1997. Significant interactions were detected between drought and parasite
severity for fruit production, fruit water content, diameter, thickness, dry mass as
well as seed length and seed dry mass of P. juniperinum. Similarly, significant
ineractions were found between drought and parasite severity for fruit and seed
characteristics of J. osteosperma hosts. There was also evidence for significant
correlations between the drought* parasite severity combination and all of the
fruit traits measured in both hosts and parasites, and evidence for more positive
correlations with parasites as the severity of drought increased in Pine Creek.

Phoradendron juniperinum (juniper mistletoe) are autotrophic hemiparasites in-
habiting branches of higher vascular plants (Kuijt 1969; and Calder and Bernardt
1983). These parasites are photosynthetic but show some physiological depen-
dence on a host plant, and use the xylem sap of the host to provide water and
mineral nutrients (Calder and Bernhardt 1983). Phoradendron juniperinum are
parasitic on woody plant species that are sparsely distributed in southern Nevada.
These parasites commonly grow on Juniperus osteosperma (Utah juniper) and
other gymnosperm hosts (Munz 1974). The final outcome is a net gain in P.
Juniperinum foliage, which occupies more and more of the host canopy as the
infection intensifies through time (Calder and Bernhardt 1983).

Drought refers to a period with low precipitation in which the water content
of the soil greatly reduces and the plants suffer from lack of water. The warm
Mojave Desert of southern Nevada is permanently arid, with annual precipitation
amounts of less than 105 mm (NOAA, Las Vegas and vicinity). Precipitation
variability is a major factor in the occurrence of drought. Southern Nevada ex-
perienced an extreme drought during the first six months of 1997, with precipi-
tation falling well below the monthly averages (NOAA, Las Vegas and vicinity).
Moreover, the severity of the drought increased with decreasing elevation. Infes-
tation of P. juniperinum greatly reduces host growth and the ability to survive
drought and insect outbreak (Calder and Bernhardt 1983), particularly in juvenile
host trees. Damage to host plants is largely caused by a combination of environ-
mental and Phoradendron-induced water and nutrient (physiological) stress (Hol-

DROUGHT EFFECTS ON FRUIT IN JUNIPER AND MISTLETOE 87

linger 1983; Glatzel 1983; Schulze and Ehleringer 1984; Schulze et al. 1984;
Ehleringer et al. 1986). From casual observations, the fruit production and other
fruit traits of P. juniperinum and its J. osteosperma hosts appeared to be greatly
reduced by drought in southern Nevada.

The biology of P. juniperinum and its J. osteosperma host trees is well docu-
mented (Kuijt 1969; Calder and Bernhardt 1983; Schulze and Ehleringer 1984;
Ehleringer et al. 1986; Dawson et al. 1990). Juniperus osteosperma hosts serve
as both habitat and resource (water and nutrients) for parasitic P. juniperinum.
Yet, possible interactions and correlations between drought and severity of P.
Juniperinum infestation in determining the fruit characteristics of both J. osteos-
perma hosts and P. juniperinum have not been documented. Two hypotheses were
made prior to data collection. First, effects of drought or effects of P. juniperinum
infestation would adversely impact various fruit characteristics of both J. osteos-
perma hosts and parasitic P. juniperinum plants. Second, there would be inter-
actions and correlations between the drought* parasite severity combination and
fruit traits of both hosts and parasites, and more positive correlations with the
parasites. These two hypotheses were tested by a combination of field and labo-
ratory measurements of various fruit traits with appropriate statistical analyses.

Materials and Methods
Study Site and Field Surveys

Pine Creek of the Red Rock National Conservation Area (36°05’ N, 115°40’
W; elevation 1,400 m) in the Spring Mountains was selected on the basis of P.
Juniperinum—J. osteosperma interactions during summers of 1997 and 1998. Win-
ters and springs of 1997 and 1998 represented drought and non-drought periods,
respectively (Fig. 1). Precipitation was 75.8 % lower during the first six months
of the 1997 drought compared to 1998. The drought was ended by above average
monsoonal rainfalls in July and September of 1997. Well above average rainfalls
associated with an El Nino Southern Oscillation (ENSO) event occurred in Winter
and early Spring of 1998 (Fig. 1). Mean monthly air temperatures varied consid-
erably during the first six month of drought (1997) and non-drought (1998) pe-
riods (Fig. 2).

A total of 85 J. osteosperma trees was found in Pine Creek, and these trees
were surveyed for the presence of parasites. Thirty (30) of 85 trees were not
infested by parasites. All 55 host trees infested with P. juniperinum were similar
in size. From casual observations, various levels of P. juniperinum infestation
were evident, and localized influences of P. juniperinum on its J. osteosperma
hosts were conspicuous. The 55 P. juniperinum-infested trees were categorized
into three levels (light, moderate, and heavy) of infestation. Light, moderate, and
heavy infestation implied under 20, between 20 and 40, and over 40 P. juniper-
inum individuals per J. osteosperma tree, respectively.

Field and laboratory measurements of fruit characteristics were conducted
twice: once in the drought and once in the non-drought period. Because some
fruits of both host and parasitic plants may persist from one year to the next, all
fruits were collected when counting. Fruits of the same plants were collected in
early August of 1997 and 1998 to ensure comparability. Brightly colored flagging
tapes were used to tag canopies of host and parasitic plants for ease of visuali-

MEAN MONTHLY PRECIPITATION (mm)

Fig. 1.

230

SOUTHERN CALIFORNIA ACADEMY OF SCIENCES

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O 1998
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Comparison of mean monthly precipitation among the 1997 (drought), 1998 (non-drought),

and 1936-1998 (average) years (NOAA, Red Rock Canyon, elevation 1,400 m).

MEAN MONTHLY AIR TEMPERATURE (C)

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Fig. 2. Comparison of mean monthly air temperature among the 1997 (drought), 1998 (non-
drought), and 1936-1998 (average) years (NOAA, Red Rock Canyon, elevation 1,400 m).

DROUGHT EFFECTS ON FRUIT IN JUNIPER AND MISTLETOE 89

Table 1. Two-way ANOVA results of the effects of year, severity of infestation, and their inter-
actions on various fruit characteristics of P. juniperinum. df = 1 for year; df = 2 for parasite severity
and for year*parasite severity combination. Significance levels: *: P = 0.05; **: P = 0.01; ***: P<
0.001; ns: non-significant.

Year Parasite severity Year* severity

Fruit trait PF P r P F P
Production 29536 0.0034** 126.88 0.00738" 403.23 O:00027**
% water content 608.22 0.0016** 543.00 G00Ls** 97.56 0.0019"
Diameter 144.27 0.0012** 82.45 O0022+* 176.58 0.0000***
Thickness 6.00 0.0917ns 10.50 0.0424* 20.00 0.004 1**
Dry mass 13.36 0.0354* fs 0.0655ns 13.90 COOL +
Seed length 2.54 0.2152ns 4.80 0.1151ns 7a 0.0338*
Seed dry mass 75.00 0.0032** 10.00 0.0452* 72.50 O0027*

zation in the subsequent year. Fruit production was determined by counting the
number of berries from individual J. osteosperma and P. juniperinum canopies
during the peak or near peak fruit production. A total of 100 berries was randomly
selected in each infection level of hosts and parasites to measure fruit dry mass,
size (diameter and thickness), water content, as well as seed length and dry mass.
Host trees included individuals with three levels parasitic infections, as well as
individuals without any visible parasites (control) on trunks and branches.

Statistical Analyses

Two-way analysis of variance (ANOVA; Analytical Software 1994) was per-
formed on fruit characteristics of parasitic P. junierinum, with year (drought and
non-drought) and parasite severity (light, moderate, and heavy) as main effects.
Similarly, two-way ANOVA was also performed on fruit characteristics of J.
osteosperma, with year and parasite severity (control, light, moderate, and heavy)
as main effects. In order to assess host and parasite plant responses to changes
in weather condition, linear regression analysis was used to correlate fruit char-
acteristics with year, parasite severity, and year* severity combination. Fruit water
content was expressed in percentages. Mean values of fruit production and fruit
water content were presented with standard errors, and statistical significance was
determined at P < 0.05.

Results

Significant interactions (P <= 0.05; Table 1, Figs. 3 and 4) were detected be-
tween year and severity of P. juniperinum infestation for all measured fruit char-
acteristics of P. juniperinum. Between periods of high and low precipitation, sig-
nificant differences (P = 0.05) were observed in fruit production (Fig. 3), fruit
water content (Fig. 4), fruit diameter, fruit dry mass, as well as seed dry mass
(Tables 1 and 3). Fruit production, fruit water content, diameter, thickness, as well
as seed dry mass were also found to be significantly different (P = 0.05) among
the three levels of infestation (Tables 1 and 3).

Significant correlations were also detected between all P. juniperinum fruit
traits and year* parasite severity combination. Seed length was significantly cor-
related with year (P <= 0.05; Table 2). Fruit thickness and dry mass were signif-
icantly correlated with parasite severity (P = 0.05; Table 2).

90 SOUTHERN CALIFORNIA ACADEMY OF SCIENCES

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WEATHER CONDITION

Fig. 3. Fruit production (Mean + SE, n = 100 per treatment) of P. juniperinum growing on J.
osteosperma hosts with three levels of infections in Pine creek of southern Nevada. Narrow vertical
bars denote standard errors of the means. Within the same weather condition, columns labeled with
different letters are significantly different at P = 0.05.

Significant interactions (P = 0.05; Table 4, Figs. 5 and 6) were observed be-
tween year and severity of infestation for all measured fruit traits of J. osteo-
sperma hosts. Between the two years, significant differences were detected in fruit
production (Fig. 5), fruit water content (Fig. 6), along with seed length and dry
mass (Tables 4 and 6). Fruit production, fruit water content, and seed dry mass
were found to be significantly different (P = 0.05) among the three levels of
infestation.

Significant correlations were also seen between host fruit traits and year* par-
asite severity combination. Seed dry mass was significantly (P = 0.05; Table 5)

Table 2. Correlation coefficient (R’) for the relationship between P. juniperinum fruit characteristics
and year, severity of infestation, as well as year*severity combination. Significance levels: *: P =
0:05; **; P= 0.01: +** P< 0.001 ns: nonsignmiicant.

Fruit trait Year Parasite severity Year* severity
Production 0.54 ns 0.46 ns U.99 Fee
% water content 0.36 ns 0.63 ns Os =
Diameter 0.64 ns 0.24 ns 0.88 *
Thickness O/17-fis 0.71 0.88 *
Dry mass 0.02 ns 0:86:4* O87
Seed length Oi 2as 0.21 ns 0:93.55

Seed dry mass 0.49 ns 0.46 ns O93 +

DROUGHT EFFECTS ON FRUIT IN JUNIPER AND MISTLETOE 91

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Fig. 4. Fruit water content (Mean + SE, n = 100 per treatment) of P. juniperinum growing on J.
osteosperma hosts with three levels of infections in Pine creek of southern Nevada. Narrow vertical
bars denote standard errors of the means. Within the same weather condition, columns labeled with
different letters are significantly different at P = 0.05.

correlated with year. However, all fruit traits other than seed dry mass were sig-
nificantly (P = 0.05; Table 4) correlated with parasite severity.

Discussion

Fruit characteristics of P. juniperinum on hosts with three levels of infestation,
as well as of uninfested J. osteosperma hosts and hosts with three levels of P.
Juniperinum infestation were compared during drought and non-drought periods.
The interactive effects of severe drought and heavy parasitism significantly re-
duced the fruit production and other fruit traits of both hosts and parasites in Pine
Creek of the Red Rock National Conservation Area in southern Nevada.

Table 3. Fruit characteristics of P. juniperinum growing on J. osteosperma hosts with three levels
of P. juniperinum infections in Pine Creek of southern Nevada (n = 100 per fruit or seed character-
istic).

Weather Infection Diameter Thickness Dry mass Seed length Seed dry mass

condition status (mm) (mm) (mg) (mm) (mg)
Drought Light 4.4 3.6 24.7 3.4 11.4
Moderate 4.4 Bo 23.4 3.3 10.2

Heavy 4.2 3.3 22.6 31 10.0

Non-drought Light 4.6 ao 29 3.6 12.4
Moderate 4.5 35 23.2 3.6 jG es)

Heavy 4.5 a) yp a 2 ae) 11.1

92 SOUTHERN CALIFORNIA ACADEMY OF SCIENCES

Table 4. Two-way ANOVA results of the effects of year, severity of infestation, and their inter-
actions on various fruit characteristics of J. osteosperma. df = 1 for year; df = 3 for parasite severity
and for year*parasite severity combination. Significance levels: *: P = 0.05; **: P = 0.01; ***: Ps
0.001; ns: non-significant.

Year Parasite severity Year*severity
Fruit trait F P F P F r
Production 132.54 0.0014** 48.70 0.0048** 235.16 0.0000***
% water content 100.72 0.0016** 570.05 0.0081>=* 67.38 0.0002***
Diameter 12.00 0.0742ns 2.95 0.300ns 11.42 G.0393*
Thickness 3.00 0.2254ns 6.33 0.1364ns 10.73 0.0429*
Dry mass 0.44 0.5743ns 13.25 0.0702ns 10.21 0.0458*
Seed length 27.00 O203551* 4.33 0.1875ns 19.69 0.0188*
Seed dry mass 165.14 0.0060** 86.14 0.0HMS* 26.67 0.0123*

Weather extremes are an important environmental factor that may lower the
reproductive success, particularly the fruit characteristics of P. juniperium and its
J. osteosperma host trees. Insufficient precipitation and considerably above av-
erage air temperatures over a period of six months in 1997 may have been an
example of such an extreme. The well below average seasonal precipitation and
above average air temperatures from January to mid-July 1997 period likely re-
sulted in low soil water content and high soil temperatures. Such severe drought
conditions would result in substantial host and parasitic plant water stress. This
severe drought was followed by above average monsoonal rainfalls in July and
September (NOAA, Red Rock Canyon).

Parasites that heavily infested their hosts also experienced a significant reduc-
tion in fruit production and other fruit traits relative to parasites that lightly in-
fested their hosts. In this study, J. osteosperma trees were susceptible to P. jun-
iperinum in the sense that establishment occurred over time. Significant relation-
ships between parasite severity and fruit characteristics are probably the normal
pattern as a consequence of parasitism, regardless of drought. The reduction in
fruit production and other fruit characteristics would occur long before the ex-
treme drought in 1997. In general, these relationships between the severity of
infestation and fruit characteristics became more prominent under drought stress.
No comparative fruit characteristic data are available since the responses of P.

Table 5. Correlation coefficient (R*) for the relationship between J. osteosperma fruit characteristics
and year, severity of infestation, as well as year*severity combination. Significance levels: *: P =
0.05; **: P < 0.01; ***: P < 0.001; ns: non-significant.

Fruit trait Year Parasite severity Year* severity
Production 0.47 ns O32F% 0:98 45=
% water content 0.37 ns 0.60 * 0:96 “<4
Diameter 0.37 ns 0762 > ei
Thickness 0.15 ns O74 O.89F*
Dry mass 0.35 ns 0:50 * 0:85
Seed length 0.12 ns 0.62 * 0.74 *

Seed dry mass 0.69 * 0.27 ns OT et

DROUGHT EFFECTS ON FRUIT IN JUNIPER AND MISTLETOE $5

Table 6. Fruit characteristics of uninfected J. osteosperma hosts (control) and hosts with three
levels of P. juniperinum infections in Pine Creek of southern Nevada (n = 100 per fruit or seed
characteristic).

Weather Infection Diameter Thickness Dry mass Seed length Seed dry mass
condition status (mm) (mm) (g) (mm) (g)
Drought Control 92 hs 2.4 ips, i!
Light 8.8 ike: 2.4 Tet 1.0
Moderate 8.4 Pe: px) fe 0.9
Heavy 8.1 (83) ZA 6.0 0.9
Non-drought Control oN 7.4 2:0 8.3 1
Light 23 7.4 ZS 8.1 | ee
Moderate 9.0 Ges PRE 7.6 LZ
Heavy 8.8 7 ol 2.4 74 Lal

jJuniperinum and its J. osteosperma hosts to drought were not previously inves-
tigated.

Phoradendron juniperinum are autotrophic hemiparasites (Kuijt 1969; Calder
and Bernhardt 1983; Lei 1999), but must acquire water and mineral nutrients
from its J. osteosperma host plant through direct xylem connections (Ehleringer
et al. 1986). In general, Phoradendron species compete aggressively with their
hosts for water and nutrients (Calder and Bernhardt 1983). A combination of
severe drought and heavy P. juniperinum infestation would impose a substantial

700
5 :
Light :
600
WM Moderate Dt aa
= VSO y
= : XO
) Peseeeoend
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xx eee
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Or Sees
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etetatete’
a Soe
% Sotetetats
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KES b ,
Sexetatoces
Za Bocececonest bs <4
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etonececeee, by
P5509 Ks a
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Satetetete’ Rx re,
és BS 55505 b> a
oP? 2G Sere cece
os k>
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— eetetetee®, PRN
= secacecenece
ee seees
252525 etetacetens
RX
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Saseterete Seeeseses
| ae ?
Toc Seeerenee Reecere ~ =
be lopoceconece, SN.
% joconocecene, \
ee etatecetete. ‘
eetateeetet etetetetete
PSeeoe5 Reseceteren: Se
joven q bexexociced \
px q ee KxOd
ROS2 “4 ROT
bose 4 SRK
Rocegecece: \ / / Be eee
J eeeceneeee, oe bees
O <7 Z 16 Mat ZS RSR
Drought Non—drought

WEATHER CONDITION

Fig. 5. Fruit production (Mean + SE, n = 85) of uninfested J. osteosperma hosts (control) and
hosts with three levels of P. juniperinum infections in Pine creek of southern Nevada. Narrow vertical
bars denote standard errors of the means. Within the same weather condition, columns labeled with
different letters are significantly different at P = 0.05.

94 SOUTHERN CALIFORNIA ACADEMY OF SCIENCES

Non—drought
WEATHER CONDITION

Fig. 6. Fruit water content (Mean + SE, n = 85) of uninfested J. osteosperma hosts (control) and
hosts with three levels of P. juniperinum infections in Pine creek of southern Nevada. Narrow vertical
bars denote standard errors of the means. Within the same weather condition, columns labeled with
different letters are significantly different at P = 0.05.

physiological stress on its J. osteosperma hosts. Within a single, heavily-infested
host under normal (non-drought) conditions, parasites experience intraspecific in-
teractions, especially density-dependent exploitation and interference competition
(Smith 1996). In this study, some P. juniperinum individuals had a significantly
lower fruit production than others. Occasional severe or prolonged droughts are
likely to increase the intensity of intraspecific competition. Consequently, the
overall reproductive success, including fruit characteristics, of P. juniperinum
would be constrained by resource and space within the host. In this study, drought
appeared to have a more detrimental effect on P. juniperinum than on its hosts
because some established P. juniperinum individuals on heavily parasitized trees
exhibited a substantially lower fruit production.

Uninfested or lightly infested /. osteosperma trees appeared to be tolerant to
water and heat (drought) stress, and were capable of abundant fruit production in
periodically stressful desert environment. Nevertheless, J. osteosperma hosts with
severe infestation are likely to experience a limited reproductive success during
periods of drought. Juniperus osteosperma trees are already under considerable
infestation stress, and the additional stress of drought weakens host trees enough
to limit their reproductive success. Drought stress accentuates or accelerates the
detrimental effects of P. juniperinum infestation. Juniperus osteosperma trees with
severe infestation would gradually decline in fruit characteristics compared to
similar trees with no infestation. This decline would occur over many years, if
not several decades. Aridity is a permanent feature in the warm Mojave Desert

DROUGHT EFFECTS ON FRUIT IN JUNIPER AND MISTLETOE 95

of southern Nevada. Drought, however, is a temporary feature, occurring when
precipitation falls below normal. Results of this study suggest that combined ef-
fects of heavy parasitism and occasional severe droughts can significantly limit
certain aspects of reproductive success, particularly fruit characteristics, of both
parasitic P. juniperinum and its J. osteosperma host plants.

Acknowledgments

Sincere appreciation is expressed to Steven Lei, David Valenzuela, and Shevaun
Valenzuela for providing valuable field and laboratory assistance. Appreciation is
also expressed to the Department of Biology of the Community College of South-
ern Nevada (CCSN) for providing logistical support.

Literature Cited

Analytical Software 1994. Statistix 4.1, an interactive statistical program for microcomputers. Ana-
lytical Software, Tallahassee, Florida.

Calder, M. and P. Bernhardt. 1983. The biology of mistletoes. Academic Press, New York.

Dawson, T. E., J. R. Ehleringer, and J. D. Marshall. 1990. Sex-ratio and reproductive variation in the
mistletoe Phoradendron juniperinum (Viscaceae). Amer. J. Botany 77:585—589.

Ehleringer, J. R., C. S. Cook, and L. L. Tieszen. 1986. Comparative water use and nitrogen relation-
ships in a mistletoe and its host. Oecologia 68:279—284.

Glatzel, G. 1983. Mineral nutrition and water relations of hemiparasitic mistletoes: a question of
partitioning experiments with Loranthus europaeus on Quercus petraea and Q. robur. Oecol-
ogia 56:193-201.

Hollinger, D. Y. 1983. Photosynthesis and water relations of the mistletoe, Phoradendron villosum,
and its host, the California valley oak, Quercus lobata. Oecologia 60:396—400.

Kuijt, J. 1969. The biology of parasitic flowering plants. University of California Press, Berkeley,
California.

Lei, S. A. 1999. Host-parasite relationship between Utah juniper and juniper mistletoe in the Spring
Mountains of southern Nevada. Pages 99-104 in Proceedings: Ecology and management of
pinyon-juniper communities within the interior west. USDA Forest Service, Rocky Mountain
Research Station, Ogden, Utah.

Munz, P. A. 1974. A flora of Southern California. University of California Press, Berkeley, California.

National Oceanic and Atmospheric Administration (NOAA). 1998. Local climatological data: annual
summary with comparable data, Las Vegas, Nevada. National Climatic Data Center, Ashville,
North Carolina.

Schulze, E. D. and J. R. Ehleringer. 1984. The effect of nitrogen supply and water-use efficiency of
xylem-tapping mistletoes. Planta 162:268—275.

Schulze, E. D., N. C. Turner, and G. Glatzel. 1984. Carbon, water and nutrient relations of two
mistletoes and their hosts: a hypothesis. Plant, Cell and Environment 7:293—299.

Smith, R. L. 1996. Ecology and Field Biology (Sth ed.). Harper Collins College Publishers, Inc., New
York.

Accepted for publication 19 June 2000.

Bull. Southern California Acad. Sci.
100(2), 2001, pp. 96-99
© Southern California Academy of Sciences, 2001

Spatial Distribution of Blackbrush (Coleogyne ramosissima Torr.)
Populations in the Mojave Desert

Simon A. Lei

Department of Biology, WDB, Community College of Southern Nevada,
6375 West Charleston Boulevard, Las Vegas, Nevada 89146-1139

The pattern of spatial distribution of a plant population is a fundamental char-
acteristic of that population, but it is a feature that is extremely difficult to describe
in precise and meaningful terms (Clark and Evans 1954). At the local level, even
in a relatively homogeneous environment, individuals in a single plant population
can be distributed randomly, clumped together, or in highly regular patterns (Cun-
ningham and Saigo 1999).

Blackbrush (Coleogyne ramosissima Torr.) shrubs are established primarily
along the Colorado River drainage and several adjacent enclosed basins of the
Great Basin-Mojave Desert transition (Bowns and West 1976). Coleogyne ra-
mosissima shrubs are a common vegetation type in mid-elevations of the Mojave
Desert, with creosote bush-white bursage (Larrea tridentata-Ambrosia dumosa)
shrublands occurring on valley floors and lower desert mountain slopes and with
pinyon pine-Utah juniper (Pinus monophylla-Juniperus osteosperma) woodlands
occurring at higher mountain slopes (Lei 1995).

Some ecological aspects of C. ramosissima and its shrublands have been doc-
umented (Beatley 1974 and 1976; Bowns 1973; Bowns and West 1976; Bradley
1964; Brown 1982; Callison and Brotherson 1985; Korthuis 1988; Lei 1995,
1999a, b; Lei and Walker 1995, 1997a, b; and Pendleton et al. 1995 and 1999).
However, C. ramosissima was selected as a representative species for such a study
because the spatial distribution of individuals and populations within the C. ra-
mosissima shrublands in isolated mountain ranges in the Mojave Desert has not
been quantatively investigated. From casual observations, the spatial distribution
of C. ramosissima individuals and populations appears to be clumped throughout
the Mojave Desert. This hypothesis was tested by field measurements with ap-
propriate statistical analysis.

Field studies were conducted at fully developed C. ramosissima shrublands
throughout the Mojave Desert during July 2000. The five study sites were located
in the Spring and Newberry Mountains of southern Nevada, the Clark Mountain
of southeastern California, the Virgin Mountains of northwestern Arizona, and
the Mormon Range of southwestern Utah (Table 1). Elevation varied considerably,
ranging from 1,250 m in the Mormon Range to 1,450 m in the Spring Mountains.
These five sites were fairly representative of C. ramosissima populations, and
formed nearly monospecific blackbrush vegetation zones in the Mojave Desert.
Each of the five sites represented an isolated mountain range for C. ramosissima
population.

The weather pattern of the Mojave Desert is characterized by wide-ranging
daily air temperatures, high year-round air temperatures, extremely high potential
evaporation, little cloud cover, low relatively humidity, low annual precipitation

BLACKBRUSH SPATIAL DISTRIBUTION pi

Table 1. Geographical characteristics of the five C. ramosissima study sites. Location, as well as
approximate latitude (N), longitude (W), and elevation (m) are shown. Mountain ranges are arranged
alphabetically in the Mojave Desert.

Location County, State Latitude Longitude Elevation
Clark Mountain San Bernadinom, CA 35°05! 1 Fs 1300
Mormon Range Washington, UT 3720" 114°00' 1250
Newberry Mountains Clark, NV a 20° 114°50' 1300
Spring Mountains Clark, NV 55 50 LESS5" 1450
Virgin Mountains Mohave, AZ 36°50’ 114°00' 1300

(Lei 1999b). The Mojave Desert resembles the Mediterranean-type climate char-
acterized by hot, dry summers and cool, wet winters. Episodic monsoonal winds
and thunderstorms occur during summer seasons. Winter rainfalls, although vary-
ing considerably from year to year, contribute to most of the total annual precip-
itation (Lei 1999b). The terrain consists of rocky slopes and alluvial fans dissected
by dry wash channels. Soil profiles are poorly developed, and soils are composed
primarily of weathered granite and limestone bedrock. Organic decomposition and
soil formation are slow due to the arid nature of the region (Lei 1999b).

Within each site, the spatial distribution of C. ramosissima population was ex-
amined on a 10-ha plot. The nearest neighbor method was used to determine whether
shrubs of the same species are distributed at random, are clumped, or are regular
(Barbour et al. 1987). At each site, 100 random points were distributed evenly among
the four parallel transects located on the 10-ha plot. Intervals between two parallel
transects are 20 m apart. However, intervals between two points within a transect
were randomly selected to avoid biased field measurements. The distance measured
was from the center of individual C. ramosissima located closest to the random point
to the center of its nearest C. ramosissima neighbor.

One-way Analysis of Variance (ANOVA), followed by Tukey’s Multiple Com-
parison Test (Analytical Software 1994) was used to detect differences among dis-
tances between one C. ramosissima to its nearest C. ramosissima neighbor, and to
compare site means when a significant distance effect was detected, respectively.
Mean distance values were presented with standard errors, and statistical significance
was determined at P <= 0.05.

The ratio of the observed mean distance to the expected mean distance (R-value)
served as a measure of departure from randomness (Clark and Evans 1954). The
nearest neighbor method (Clark and Evans 1954) was used to determine whether the
C. ramosissima populations were randomly distributed within the C. ramosissima
shrublands. The significant difference in the value of R for C. ramosissima popula-
tions was tested with the c value of 1.96, representing the 5 % level of significance
for a two-tailed test (Clark and Evans 1954; McClave and Dietrich 1991).

Mean distances between C. ramosissima and its nearest C. ramosissima neighbor
were significantly different (P = 0.05; Table 2) among the five isolated mountain
ranges in the Mojave Desert. The mean distances ranged from 210 cm in the Mormon
Range in southwestern Utah to 275 cm in the Clark Mountains of southeastern
California.

Coleogyne ramosissima populations among the five isolated mountains ranges
were strongly aggregated, ranging from 0.13 in the Mormon Range to 0.17 in the

98 SOUTHERN CALIFORNIA ACADEMY OF SCIENCES

Table 2. Distance (mean + SE) and R-values from one individual C. ramosissima to its nearest C.
ramosissima neighbor in five isolated mountain ranges of the Mojave Desert (N = 100 per mountain
range). Mean values followed by different letters indicate significant differences at P = 0.05 using
Tukey’s Multiple Comparison Test.

Location Mean distance (cm) R-value
Clark Mountain 2A 2 BA Ta 0.17
Mormon Range 210 + 19.4 b 0.13
Newberry Mountains Zo 2 2255 Oe 0.16
Spring Mountains 239 + 28.4 ab 0.15
Virgin Mountains 247 + 11.2 ab 0.16

Clark Mountains (Table 2). When examining the spatial distribution of C. ramosis-
sima populations, there was a tightly clustering of mean values of distance from one
C. ramosissima plant to another and for R-values. For the spatial distribution in this
study, R < 1.0, indicating a significant departure from random expectation in the
direction of aggregated spacing by the c test. According to the distance to nearest
neighbor as a measure of spatial distribution in plant populations, R = 0 in a max-
imum aggregation, since all of the individuals occupy the same locus and the distance
to nearest neighbor is therefore 0. In contrast, R = 2.1491 in a maximum uniformity,
since individuals will be distributed as evenly and widely as possible in a hexagonal
pattern (Clark and Evans 1954). The ratio of observed to expected mean distance to
nearest neighbor provides a measure of the degree to which the distributional pattern
of the observed population deviates from random expectation (Clark and Evans
1954).

The distance from one individual plant to another provides a variable for the
measurement of spacing that obviates the use of quadrats, and, therefore, eliminates
the effect of quadrat size (Goodall 1953). The measure of spacing in this study is a
measure of the degree to which the distribution of individuals in C. ramosissima
populations at given areas departs from that of a random distribution. Thus, random-
ness is a spatial concept, intimately dependent upon the boundaries of the space
chosen by the investigator (Clark and Evans 1954). In this study, all five C. ramo-
sissima populations on isolated mountains ranges clearly departed from random ex-
pectation with a high degree of significance as the distance to nearest neighbor is
concerned. Although significant differences in mean distances were detected, only a
slight difference in the degree of aggregation was found among the five C. ramosis-
sima populations in the Mojave Desert.

Acknowledgments

I gratefully acknowledge Steven Lei, David Valenzuela, and Shevaun Valen-
zuela for valuable field assistance. Steven Lei assisted with statistical analysis and
provided helpful comments on earlier versions of this manuscript.

Literature Cited

Analytical Software. 1994. Statistix 4.1, an interactive statistical program for microcomputers. Ana-
lytical Software, St Paul, Minnesota.

Barbour, M. G., J. H. Burk, and W. D. Pitts. 1987. Terrestrial plant ecology, Second Edition. The
Benjamin/Cummings Publishing Company, Inc., Menlo Park, California.

BLACKBRUSH SPATIAL DISTRIBUTION wer

Beatley, J. 1974. Effects of rainfall and temperature on the distribution and behavior of Larrea di-
varicata (creosote-bush) in the Mojave Desert of Nevada. Ecology 55:245-—261.

Beatley, J. 1976. Vascular plants of the Nevada Test Site and Central-southern Nevada: ecologcial and
geographical distributions. National Technical Information Service, United States Department
of Commerce, Springfield, Virginia.

Bowns, J. 1973. An autecological study of blackbrush (Coleogyne ramosissima Torr.) in southern
Utah. Unpublished dissertation, Utah State University, Logan, Utah.

Bowns, J. and N. West. 1976. Blackbrush (Coleogyne ramosissima Torr.) on southern Utah rangelands.
Department of Range Science, Utah State University. Utah Agricultural Experiment Station,
Research Report 27.

Bradley, W. G. 1964. The Vegetation of the Desert Game Range with special reference to the desert
bighorn. Trans. Desert Bighorn Council 8:43—67.

Brown, D. 1982. Biotic communities of the American Southwest: United States and Mexico. The
University of Arizona for the Boyce Thompson Southwestern Arboretum, Tucson, Arizona.

Callison, J. and J. Brotherson. 1985. Habitat relationship of the blackbrush community (Coleogyne
ramosissima) of southern Utah. The Great Basin Naturalist 45:321—326.

Clark, P. J. and EK C. Evans. 1954. Distance to nearest neighbor as a measure of spatial relationships
in populations. Ecology 35:155—162.

Cunningham, W. P. and B. W. Saigo. 1999. Environmental Science, Fifth edition. WCB McGraw-Hill,
Boston, Massachusettes.

Goodall, D. W. 1953. Objective methods for the classification of vegetation. I. The use of positive
interspecific correlation. Australian Journal of Botany 1:39—63.

Korthuis, S. 1988. Coleogyne ramosissima. In: Fischer, William C., Compiler. The Fire Effects Infor-
mation System (Data base). Missoula, Montana: U.S. Department of Agriculture, Forest Service,
Intermountain Research Station, Intermountain Fire Sciences Laboratory. Magnetic tape reels;
9 track; 1600 bpi, ASCII with common LISP present.

Lei, S. A. 1995. A gradient analysis of blackbrush (Coleogyne ramosissima Torr.) communities in
southern Nevada. Unpublished thesis. University of Nevada, Las Vegas, Nevada.

Lei, S. A. and L. R. Walker 1995. Composition and distribution of blackbrush (Coleogyne ramosis-
sima) Torr. communities in southern Nevada. p. 191—195, in E. D. McArthur, J. S. Haley, and
D. K. Mann, compilers. Proceedings: wildland shrub and arid land restoration symposium,
General Technical Report INT-GTR-315, Ogden, UT: U.S. Department of Agriculture, Forest
Service, Intermountain Research Station.

Lei, S. A. and L. R. Walker 1997a. Classification and ordination of Coleogyne communities in southern
Nevada. The Great Basin Naturalist 57:155—162.

Lei, S. A. and L. R. Walker 1997b. Biotic and abiotic factors influence the distribution of Coleogyne
communities in southern Nevada. The Great Basin Naturalist 57:163-—171.

Lei, S. A. 1999a. Phenological events and litterfall dynamics of blackbrush in southern Nevada. p.
113-118 in E. D. McArthur, W. K. Ostler, and C. L. Wambolt, compilers. Proceedings: Shrub-
land Ecotones, Proceedings RMRS-P-11. Ogden, UT: U.S. Department of Agriculture, Forest
Service, Rocky Mountain Research Station.

Lei, S. A. 1999b. Ecological anatomy of seven xerophytic shrub species in southern Nevada. p. 206—
211 in E. D. McArthur, W. K. Ostler, and C. L. Wambolt, compilers. Proceedings: Shrubland
Ecotones, Proceedings RMRS-P-11. Ogden, UT: U.S. Department of Agriculture, Forest Ser-
vice, Rocky Mountain Research Station.

McClave, J. T. and FE H. Dietrich. 1991. Statistics, Fifth Edition. Dellen Publishing company, San
Francisco, California.

Pendleton, B. K., S. E. Meyer, and R. L. Pendleton. 1995. Blackbrush biology: insights after three
years of a long-term study. p. 223-227, in E. D. McArthur, J. S. Haley, and D. K. Mann,
compilers. Proceedings: wildland shrub and arid land restoration symposium, General Technical
Report INT-GTR-315, Ogden, UT: U.S. Department of Agriculture, Forest Service, Intermoun-
tain Research Station.

Pendleton, R. L., B. K. Pendlton, and S. D. Warren. 1999. Response of blackbrush seedlings to
inoculation with arbuscular mycorrhizal fungi. p. 245-251 in E. D. McArthur, W. K. Ostler,
and C. L. Wambolt, compilers. Proceedings: Shrubland Ecotones, Proceedings RMRS-P-11.
Ogden, UT: U.S. Department of Agriculture, Forest Service, Rocky Mountain Research Station.

Accepted for publication 28 January 2001.

Bull. Southern California Acad. Sci.
100(2), 2001, pp. 100-108
© Southern California Academy of Sciences, 2001

Postfire Seed Bank and Soil Conditions in a Blackbrush
(Coleogyne ramosissima Torr.) Shrubland

Simon A. Lei

Department of Biology, Community College of Southern Nevada,
6375 West Charleston Boulevard, WDB, Las Vegas, NV 89146-1139

Abstract.—Ten-year postfire seed bank and soil conditions were quantitatively
investigated in a blackbrush (Coleogyne ramosissima) shrubland in Sandy Valley
of southern Nevada. A severe, lightning-induced fire occurred in June 1987, cre-
ating a nearly barren landscape. Seed density of woody species at the soil surface
and in the top 3 cm of soil was significantly lower in burned areas compared to
adjacent unburned areas. However, within the burned areas, no significant differ-
ences were detected in seed density of woody species. Although seed transport
from adjacent unburned areas out onto the burns was minimal, evidence of limited
long-distance dispersal of C. ramosissima seeds was found. Soil moisture and
organic matter decreased significantly, whereas soil pH, soil temperature, bulk
density, and compaction increased significantly in burned areas compared to un-
burned areas. Nevertheless, soil salinity did not differ significantly after burning.
Limited long-distance dispersal, extremely low soil seed densities, as well as
adverse weather and impoverished edaphic conditions were some of the primary
obstacles to reestablishment of C. ramosissima plants and their shrublands.

Fire and its impact on soil seed bank and soil conditions have been of interest
to many ecologists, especially in major shrublands of the desert Southwest. Fires
occur frequently at elevations above 1,650 m in the Mojave Desert woodlands
because the cool, semiarid climate results in a substantial accumulation of fuel
(Humphrey 1974). However, fires are less frequent at mid- and lower elevations
(below 1,650 m) of the Mojave Desert shrublands primarily due to limited bio-
mass and vegetation cover, wide spacing between shrubs, and insufficient accu-
mulation of flammable material (Brown and Minnich 1986). Blackbrush (Coleo-
gyne ramosissima) shrublands are located at mid-elevations. Shrub species in C.
ramosissima communities have a low recovery rate years after fire, and are subject
to long-standing changes in the structure and species composition in southeastern
California (Minnich 1995) and southern Nevada (Lei 2000). Fire greatly reduces
woody vegetation over an extensive area, thus exacerbating re-establishment by
requiring long-range seed dispersal from widely scattered unburned individuals
that provide local seed sources (Minnich 1995).

Coleogyne ramosissima produce seeds that usually fall near the parent plants
(Lei, personal observations). Coleogyne ramosissima plants are capable of long-
range seed dispersal by wind, water (downslope movement), or fauna (Brown and
Minnich 1986; Minnich 1995). Evidence of long-range wind, water, or fauna
dispersal from adjacent unburned areas to burned areas was found since a few
seeds were observed on the surface near the center of large burned areas in
southern Nevada (Lei, personal observations).

100

POSTFIRE SOIL SEED DENSITIES AND SOIL CONDITIONS 101

A seed bank is an aggregation of ungerminated seeds potentially capable of
replacing adult plants through time (Leck et al. 1989). The potential for replacing
adult plants is essential. If seeds get permanently buried too deeply, they can be
considered lost from the desert seed bank, as they would not be involved in
germination, granivory, redistribution or other processes that directly relate to seed
bank dynamics (Leck et al. 1989). Seeds of desert shrubs generally cannot emerge
from below 4 cm (Leck et al. 1989). However, seeds in desert soils are distributed
mostly near the surface; approximately 80 to 90 % of seeds are found in the upper
2 cm of soil (Reichman 1975). Coleogyne ramosissima vegetation zones do not
form long-term or permanent desert seed banks, and reestablishment of C. ra-
mosissima may also depend on rodents transporting seed from the adjacent un-
burned areas out onto the burns, a small possibility for large disturbances (Pen-
dleton et al. 1995). Coleogyne ramosissima seeds are buried by rodents to a few
centimeters in depth; these seeds may germinate from rodent caches after aban-
donment (Bowns 1973; Bowns and West 1976).

Following a severe fire, soil organic matter and percent pore space decrease
significantly. On the contrary, fire significantly increases soil pH, temperature,
compaction, and bulk density in C. ramosissima shrublands of southern Nevada
(Lei 2000).

Fire has been responsible for altering and severely damaging C. ramosissima
vegetation zones in southern Nevada (Lei 2000). Coleogyne ramosissima stands
do not recover from fire disturbance, and much acreage of this vegetation type is
being lost due to an increase in fire frequency (Lei 2000). The time required for
a complete postfire recovery of vegetation is still unknown in C. ramosissima
shrublands in southern Nevada and throughout its range. Postfire woody vegeta-
tion recovery in the C. ramosissima shrublands has been documented (Beatley
1974, 1975 and 1980; Callison et al. 1985; Korthuis 1988; Lei 2000; and Minnich
1995). However, the possible effects of fire on seed density of woody plants
remain poorly understood. The objectives of this article were to quantitatively
evaluate soil parameters, along with the presence and seed density of woody
species ten years after burning in Sandy Valley of southern Nevada.

Materials and Methods
Study Site

The study was conducted during summer 1998 in Sandy Valley, along State
Highway 160, located on the lower west-facing slopes of the Spring Mountains
(approximately 36°00'N, 115°40’W; 1,350 to 1,400 m in elevation) in southern
Nevada. Coleogyne ramosissima forms a nearly monospecific vegetation zone at
mid-elevations, with only a scattered distribution of other shrub species (Lei and
Walker 1997; Lei 2000).

Burned and unburned areas were once similar in species composition, vegeta-
tion cover, community structure, soil, geology, and geomorphic surfaces (Tim
Rash, Personal Communication). Burned and unburned areas were separated by
a two-lane highway, forming two distinct landscapes. The fire was started in June
1987 by lightning from a summer monsoonal thunderstorm, and burned approx-
imately 4,000 ha from the upper C. ramosissima elevational boundary through
the upper portions of the creosote bush-white bursage (Larrea tridentata-Ambro-

102 SOUTHERN CALIFORNIA ACADEMY OF SCIENCES

sia dumosa) zone. This extensive fire provided an opportunity to examine postfire
seed density of woody species, as well as edaphic characteristics of a C. ramo-
sissima shrubland.

Fire History

Sandy Valley is under the jurisdiction of the Las Vegas District of the Bureau
of Land Management (BLM). Fire data were obtained from fire reports and atlases
of the BLM, which provided the most reliable source of C. ramosissima fire
history available in Sandy Valley. Topographic maps and aerial photographs were
used to determine fire boundaries and to map the extent of burns. The burn
margins and scars in the C. ramosissima vegetation zone were often visible and
identifiable based on the presence or absence of the dominant plant species.

Seed and Soil Collections

Seeds of woody species and their corresponding soil samples were collected
from five, | m? plots randomly situated along each of 20, 150 m transects situated
in both burned and unburned areas. Transects were oriented parallel to, and at
least 50 m from, the edge of the road. In burned areas, 75 plots were located at
the burn-edge (8 m from the edge of the burn scar), one-quarter of the distance
to the burn-center (300 m from the burn-edge), and in the center of the burn (600
m from the burn-edge). In unburned areas, five transects were located 100 m from
the burn-edge.

Soils were sampled from the entire | m? plots to a depth of 3 cm. After removal
of surface rocks and litter, soils were collected from both inter-plant gaps and
directly under existing plant canopies in order to measure the full range of the
seed bank and heterogeneity of soil characteristics. Soils collected from open
spaces and under plant canopies were then pooled per plot after thorough mixing.
Seeds on ground surface were observed using a magnifying glass. Each soil sam-
ple was sifted through a l-mm sieve to search for seeds. Numbers of seeds of
woody species were individually counted in the field. Density was expressed as
number of seeds per 1 m*. Sieved and oven-dried soils were retained for labo-
ratory analyses at the Community College of Southern Nevada (CCSN).

Soil Analyses and Measurements

In the field, soil temperatures at the surface and at a depth of 3-cm were
recorded with a soil thermometer located at the central point within each of the
100 plots. Soil temperatures were recorded from mid-morning hours to minimize
diurnal soil temperature variation due to sun angle. Soil temperatures were re-
corded simultaneously with soil moisture and sample collection to ensure com-
parability. Soil compaction was estimated using a penetrometer that was inserted
into the soil after removing stony surface pavements. Percent pore space was
determined using the following equation: Pore space = 100 — (D,/D, - 100),
where D, is the bulk density of the soil and D, is the average particle density,
usually about 2.65 g/cc (Hausenbuiller 1972; Davidson and Fox 1974).

In the laboratory, the fresh soil samples were weighed, dried in a 65°C oven
until they reached a constant mass, and reweighed to determine gravimetric water
content. Soil bulk density was assessed by dividing dry mass by volume. Soil pH
was determined on a saturation paste acquired by mixing equal volumes of dry

POSTFIRE SOIL SEED DENSITIES AND SOIL CONDITIONS 103

Table 1. Mean seed density of wood plants (no./m’*; N = 100 plots) at the ground surface in burned
and adjacent unburned areas of the C. ramosissima vegetation zone in Sandy Valley. Within burned
areas, seed density is shown at three distances from the fire-edge. Mean values in rows followed by
different letters are significantly different at P = 0.05.

Burned area

Plant species Unburned area 8 m 300 m 600 m
Coleogyne ramosissima 0.14 a 0.07 b 0.06 b 0.04 b
Encelia virginensis 0.17 a 0.09 b 0.07 b 0.07 b
Gutierrezia sarothrae 0.24 a OTS’ b O12 0.11 b
Lycium andersonii 0.04 a Ob Ob Ob
Menodora spinescens 0.05 a Ob Ob Ob
Thamnosma montana 0.07 a Ob Ob Ob
Yucca brevifolia 0.04 a Ob Ob Ob

soil saturated with deionized water (McLean 1982). Total organic matter was
obtained for samples that were pre-dried at 65°C for 72 h, followed by mass loss
on ignition at 550°C for 4 h (Black 1965). Soil salinity (total soluble salts) was
acquired by an electrical conductivity bridge, using a slurry consisting of equal
parts of soil to distilled water paste (Rhoades 1982).

Statistical Analyses

One-way analysis of variance (ANOVA; Analytical Software 1994) was used
to compare means of seed densities, as well as to compare corresponding soil
attributes between burned and unburned areas in the C. ramosissima vegetation
zone. ANOVA was also used to detect differences among burned areas only.
Burned areas were subdivided into three distances from the fire edge. Tukey’s
multiple comparison test (Analytical Software 1994) was then performed to com-
pare means when a significant fire effect was detected between burned and un-
burned areas, as well as among burned areas only. Student t-tests (Analytical
Software 1994) were conducted to compare soil temperatures between the soil
surface and at 3-cm depth in burned and unburned areas. Mean values are pre-
sented with standard errors, and P-values less than or equal to (S) 0.05 are re-
ported as statistically significant.

Results and Discussion
Seed Densities

For all woody species evaluated, soil seed density was significantly lower (p
= 0.05; Tables 1 and 2) in burned compared to unburned areas in Sandy Valley
of southern Nevada. Specifically, Gutierrezia sarothrae density was highest in
both treatments at both soil surface and 3 cm depths (0.14 and 0.10 seeds/m/,
respectively), followed by Encelia virginensis density at the surface (0.17 seeds/
m? in unburned and 0.08/m? in burned areas) and Coleogyne ramosissima at 3
cm depths (0.10/m? in unburned and 0.02/m? burned areas).

Within burned or unburned areas, seed density of C. ramosissima, E. virginen-
sis, G. sarothrae, Lycium andersonii, and Menodora spinescens was significantly
higher (P = 0.01) on the surface of soil (Table 1) than under 3 cm of soil (Table
2). A number of seeds were found deeper than 3 cm below the soil surface in

104 SOUTHERN CALIFORNIA ACADEMY OF SCIENCES

Table 2. Mean seed density of woody plants (no./m?; N = 100 plots) at the top 3 cm of soil in
burned and adjacent unburned areas of the C. ramosissima vegetation zone in Sandy Valley. Within
burned areas, seed density is shown at three distances from the fire-edge. Mean values in rows followed
by different letters are significantly different at P = 0.05.

Burned area

Plant species Unburned area 8 m 300 m 600 m
Coleogyne ramosissima 0.10 a 0.03 b 0.02 b 0.02 b
Encelia virginensis 0.09 a 0.04 b 0.04 b 0.03 b
Gutierrezia sarothrae 0.17 a 0.07 b 0.05 b 0.05 b
Lycium andersonii 0) 0 0 0
Menodora spinescens 0) 0) 0) 0
Thamnosma montana 0.05 a Ob Ob Ob
Yucca brevifolia 0) 0 0 0

unburned areas (Lei, personal observation), presumably due to animals (rodents)
placing them in caches and, to a lesser extent, wind-blown sand burying seeds
several centimers beneath the soil under shrub canopies through time.

No significant differences were found at various distances within burned areas
in this study. In addition to long-distance seed dispersal, scattered surviving in-
dividuals of woody plants on unburned “‘fire islands’’ throughout the burns would
provide local seed source through time (Minnich 1995). Nevertheless, no such
‘‘fire islands’’ existed in this study because all woody plants were eradicated by
fire, and therefore, woody seeds found on the surface in burned areas depended
on long-distance dispersal.

Seed banks of the warm deserts are composed primarily of annual species;
perennial species do not form persistent seed banks (Leck et al. 1989). Shrubs in
warm deserts have a minimal dependence on seed banks for regeneration and
protection against climatic uncertainty or other environmental stochascity (Leck
et al. 1989). Their strategy is to produce a few seeds almost every year, most of
which do not persist in the seed bank (Boyd and Brum 1983). Examination of
habitat differences within the C. ramosissima shrubland in Sandy Valley indicates
that seed bank dynamics are governed by local plant distributions and local flow-
ering and fruiting events. Soil seed densities do not correlate well with plant
densities in time or space (Leck et al. 1989). In this study, the significantly fewer
number of seeds in burned areas suggests that C. ramosissima shrubland will
require a long period of time to return to pre-burn conditions following fire dis-
turbance.

Soil Properties

Edaphic factors appeared to be critical for seed germination of C. ramosissima
and associated woody taxa in Sandy Valley. Soil physical and chemical charac-
teristics were significantly altered ten years after burning. However, no significant
differences were detected at various distances within extensive burned areas. With
the exception of soil salinity (0.3 in unburned and 0.4 in burned areas; Table 4),
all soil parameters measured differed significantly between burned and unburned
areas ten years after burning.

Burned areas had significantly higher (p = 0.05; Table 4) soil temperatures

POSTFIRE SOIL SEED DENSITIES AND SOIL CONDITIONS 105

(39.7 to 40.7°C) at or near the surface than unburned areas (37.5°C). Soil tem-
peratures at the surface and at 3-cm depth were significantly higher in burned
than unburned areas in southern Nevada (Lei 2000). Conversely, soil moisture
was significantly higher in unburned (1.1 %) than in burned (0.6 to 0.8 %; Table
4) areas. Depending on fuel accumulation rates, burning should be expected to
have a long-term effect on soil moisture and soil temperature, at least in the
mineral horizon. Surface litter allows for both water retention (reduced evapo-
transpiration) and cooling (shades the mineral soil also affecting evaporation).
Surface litter affects soil moisture and soil temperature long after burning only
further emphasizes the long-term effect of fire on C. ramosissima vegetation
zones.

Soil pH was higher (P <= 0.05; Table 4) in burned than in unburned areas of
the C. ramosissima vegetation zone. Soil pH increased significantly from 7.7 in
unburned to 8.1 in burned areas at the C. ramosissima zone (Table 4). Fire tends
to increase pH, making soils more basic. The hydrogen ion concentration decreas-
es after incineration, and raising the soil pH is usually significant in the upper 10
cm (Scotter, 1963; Raison 1979; Wright and Bailey 1982).

Percent pore space was significantly lower (P <= 0.05; Table 4) in burned
(45.7 to 47.1 %) compared to unburned (50.2 %) areas. Desert soils of southern
Nevada are relatively high in sand and gravel. Sandy soils typically have a pore
space of 35 to 50 % (Davidson and Fox 1974), which is in agreement with this
study. The decrease in percent pore space may also reflect the reduction in soil
organic matter (4.1 % without burn; 1.9 to 2.0 % with burn). Organic matter is
generally clay-sized, which has a substantially smaller pore space than sand and
silt. Organic matter also decreases bulk density of the soil because it is less dense
(lighter) than a corresponding volume of mineral soil (Barbour et al. 1987), which
is consistent with this study, indicating that soil bulk density increased signifi-
cantly (Table 4) in burned areas. The carbon content is inversely correlated with
the bulk density of the soil (Barbour et al. 1987). In this study, the increase in
soil bulk density of burned areas, along with the decrease in pore space, would
most likely increase water-holding capacity, particularly at depth. On the soil
surface, however, this water may fall within the evaporation zone and, thus, be
subject to evaporative losses.

The increase in soil compaction with burning (+0.8 to +1.2 kg/cm’; Table 4)
is also consistent with the increase in bulk density and decrease in pore space.
The more compact the soil, the less likely that evaporation will occur. Gravimetric
water in small pore spaces is very tightly held against evaporative and plant-
uptake losses. Yet, the increase in soil compaction in burned areas may inhibit
root growth of woody taxa that are adapted to a looser soil condition (Davidson
and Fox, 1974).

Weather Conditions

Southern Nevada experienced several episodes of drought in recent years (Table
3), resulting in widespread plant water stress. Droughts in southern Nevada are
unpredictable in terms of their duration and timing. Rainfall variability is a major
factor in the occurrence of drought. Most recently, a major drought began in
summer 1995, and reached its greatest intensity during the first six months of
1997. According to weather records between 1987 and 1997, only three consec-

106 SOUTHERN CALIFORNIA ACADEMY OF SCIENCES

Table 3. Mean annual precipitation (mm) and air temperature (C°) from 1988 through 1997. Official
postfire weather data (NOAA, Las Vegas) were obtained from the McCarran Airport in Las Vegas,
near Sandy Valley. Individual annual precipitation and air temperature values (1988-1997) are com-
pared with the overall mean annual precipitation and air temperature values (1936—1997), respectively.
The overall mean annual precipitation is approximately 100 mm, and mean air temperature is 19.2°C.

Year Precip. (mm) % diff. from mean Air temp. (°C) % diff. from mean
1988 SS 26 19.9 3.6
1989 33:6 — 60.4 20.4 +6.1
1990 95,3 —4.8 19.7 Me
199] 103.1 + a1 19.5 aa oP
1992 250.9 +86.0 20.1 +4.6
1993 128.3 +24.8 19.7 +2.6
1994 65.0 —42.4 20.6 +7.0
1995 93.7 =6.5 20.6 +70
1996 AO, 1 == 2 20.7 +s
1997 92.2 =e Fe 20.3 +3.6

utive years, from 1991 through 1993, revealed above average rainfall in Sandy
Valley. Mean annual air temperatures, on the contrary, did not vary considerably,
ranging from 0.3 to 1.5 °C only (Table 3). Mean annual precipitation revealed a
considerably greater fluctuation than mean annual air temperatures from 1988
through 1997. Although 1991—1993 had above average rainfall, mean annual air
temperatures from the 1988—1997 period were consistently higher than mean an-
nual air temperatures from the 1936—1997 period (Table 3).

Rainfall must be adequate during the winter and early spring to trigger seed
germination, and during the spring and early summer to support seedling estab-
lishment in shrublands of the Mojave Desert (Beatley 1974). Coleogyne ramosis-
sima plants do not produce large fruit crops and abundant seeds in successive
years even if rainfall is adequate (Pendleton et al. 1995). Similarly, low seed
production may also apply to the associated woody taxa in the C. ramosissima
shrubland despite favorable weather conditions occurring in some years. In this

Table 4. Soil physical and chemical characteristics (mean + SE; n = 100 plots) at adjacent un-
burned areas and at various distances within burned areas in the C. ramosissima vegetation zone of
Sandy Valley in July 1998. Within burned areas, seed density is shown at three distances from the
fire edge. Soil samples were collected from the top 3 cm. Pore space and soil organic matter were
expressed in percentages. Mean values in rows followed by different letters are significantly different
ate, = 0:05.

Burned area

Factor Unburned area 8 m 300 m 600 m

Temperature (0 cm) 37.5.2 Odie a 39] 30.22. 40.7 + 0.25.b 40.2 + 0.28 b

(3 cm) 36.4 + 0.15 a 39.1 = O15 39.4 + 0.18 b 38.8 + 0.17 b
Moisture (%) Li Gals 0.7 + 0.04 b 0:6.=-0:05°5 0.8 + 0.07 b
pH T.F + O04 a 8:0" O02"D S105 8.0 20S 6
Bulk density (g/cm+*) 1.3° +0108 ‘a 1.4 + 0.05 b 1.4 + 0.07 b 1.4 + 0.06 b
Compaction (kg/cm?) 4.2)%,0,25 a 5:0) O.27ib 5.3 = 0.29'b 5.4 = 0:32 b
Pore space (%) 20.2. 2% 3eRSng 46.0 + 3.24 b 47.1 + 4.34 b 45.7 + 4.22.b
Organic matter (%) 4.1 + 0.35.a 2.0 + 0.20 b 2.33%. 0.24-b LO = 021 5
Salinity (mmho/cm) 0.3 + 0.04 a 0.4 + 0.05 a 0.4 + 0.03 a 0.4 + 0.04 a

POSTFIRE SOIL SEED DENSITIES AND SOIL CONDITIONS 107

study, a combination of sharply contrasting mean annual precipitation and above
average air temperatures following fire disturbance may partially explain the low
soil seed densities and delayed seed germination of C. ramosissima and associated
woody taxa.

Ecological Implications

The severe, lightning-induced fire in June 1987 created a unique set of postfire
seed bank and edaphic conditions in Sandy Valley of southern Nevada. Fire
caused a long-term removal of C. ramosissima and associated woody taxa. In
addition to limited active dispersal mechanisms, extremely low soil seed densities,
and adverse weather conditions, significant alterations in soil attributes following
fire disturbance no longer favor the development of a seed bank for enhancing
seed germination and seedling establishment of woody taxa. The lack of signifi-
cant differences in seed density of woody species at various distances within the
burned area seems to indicate an extremely slow recovery. Desert perennials are
generally protected against environmental stochascity by a long life rather than
by a persistent seed bank. However, the greater seed bank of G. sarothrae and
E. virginensis may be a factor in their more successful response after fire distur-
bance. Coleogyne ramosissima plants may have an unusual method of seed bank
development such as rodent caches. Ecological succession is stalled in the C.
ramosissima vegetation zone. Whether a long recovery time reflects historic con-
ditions of a dynamic ecosystem consisting of a diversity of different seral com-
munities or whether it is simply an artifact of human intervention, a complete
recovery time is yet to be determined. This study, however, provides one more
part of the ultimate determination.

Acknowledgments

The valuable field assistance of Steven Lei, David Valenzuela, and Shevaun
Valenzuela was gratefully acknowledged. Tim Rash of the Bureau of Land Man-
agement (BLM) provided valuable fire records and provided stimulating discus-
sions. Critical review by David Charlet and an anonymous reviewer greatly im-
proved the manuscript. The Department of Biology at the Community College of
Southern Nevada (CCSN) provided logistical support.

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Boyd, R.S. and G.D. Brum. 1983. Postdispersal reproductive biology of a Mojave desert population
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Leck, M.A., V.T. Parker, and R.L. Simpson. 1989. Ecology of soil seed banks. Academic Press, Inc.,
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Accepted for publication 28 January 2001.

Bull. Southern California Acad. Sci.
100(2), 2001, pp. 109-116
© Southern California Academy of Sciences, 2001

Helminths of Six Species of Colubrid Snakes from
Southern California

Stephen R. Goldberg! and Charles R. Bursey?

‘Department of Biology, Whittier College, Whittier, California 90608
*Department of Biology, Pennsylvania State University, Shenango Campus,
Sharon, Pennsylvania 16146

Abstract.—Six species of colubrid snakes from California were examined for
helminths: Arizona elegans, Chionactis occipitalis, Masticophis flagellum, Mas-
ticophis lateralis, Phyllorhynchus decurtatus and Rhinocheilus lecontei. One spe-
cies of Trematoda, Paralechriorchis syntomentera, two species of Cestoda, Ooch-
oristica osheroffi and Mesocestoides sp. (tetrathyridia), four species of Nematoda,
Physaloptera abjecta, Spauligodon goldbergi, Thubunaea iguanae, and Physa-
loptera sp. (larvae) and one species of Acanthocephala represented by cystacanths
(Oligacanthorhynchidae), were found. Nine new host records are reported.

Although 38 species of snakes are recorded for California (Brown 1997), few
have been examined for helminths. There are reports of helminths for Crotalus
cerastes, C. ruber, C. viridis, Rhinocheilus lecontei, and Thamnophis elegans
collected in California (Voge 1953; Alexander and Alexander 1957; Mankau and
Widmer 1977; Widmer and Specht 1992; Bursey et al. 1995; Goldberg et al.
1998). The purpose of this study was to examine 6 species of colubrid snakes
from California for helminths: the glossy snake, Arizona elegans; western shoy-
elnose snake, Chionactis occipitalis; coachwhip, Masticophis flagellum; striped
racer, Masticophis lateralis; spotted leafnose snake, Phyllorhynchus decurtatus;
and longnose snake, Rhinocheilus lecontei. Geographic ranges for these snakes
are in Stebbins (1985). Of these 6 species, only Masticophis flagellum (from
Georgia, Texas) has been examined for helminths (Harwood 1932; Reiber et al.
1940; Schad 1962; Conn and McAllister 1990).

Materials and Methods

One hundred fifty-nine individuals of six colubrid snake species: Arizona ele-
gans (n = 43, mean snout-vent length [SVL] = 589 mm + 205 SD, range =
238-930 mm), Chionactis occipitalis (n = 31, SVL = 258 mm + 20 SD, range
= 222-300 mm), Masticophis flagellum (n = 12, SVL = 861 mm + 118 SD,
range = 697-1104 mm), Masticophis lateralis (n = 14, SVL = 765 mm + 136
SD, range = 520—963 mm), Phyllorhynchus decurtatus (n = 26, SVL = 357 mm
+ 47 SD, range = 242—469 mm), and Rhinocheilus lecontei (n = 33, SVL =
590 mm + 93 SD, range = 362—743 mm) were borrowed from the herpetology
collection of the Natural History Museum of Los Angeles County (LACM), Los
Angeles, California (accession numbers, Appendix 1). Eleven of 14 Masticophis
lateralis (79%) were from the San Gabriel Mountains (34°18'N, 117°50’W) Los
Angeles County, 3 (21%) were from the Puente Hills (34°01'N, 117°57’W) Los
Angeles County, California. All individuals of the other five species were from

109

110 SOUTHERN CALIFORNIA ACADEMY OF SCIENCES

desert areas in the Coachella Valley (33°50'N, 116°20’'W) of Riverside County,
California. Snakes were collected from 1951 to 1975.

The body cavity was opened by a longitudinal incision from vent to throat and
the gastrointestinal tract was excised by cutting across the esophagus and rectum.
The esophagus, stomach, and small and large intestines were slit longitudinally
and examined under a dissecting microscope. Nematodes were examined and
identified after clearing in a drop of concentrated glycerol. Trematodes, cestodes
and acanthocephalans were regressively stained in hematoxylin and studied as
whole-mounts in Canada balsam. Voucher helminths were deposited in the United
States National Parasite Collection, (USNPC) Beltsville, Maryland (Appendix 2).

Results

One species of Trematoda, Paralechriorchis syntomentera (Sumwalt 1926)
Bryd and Denton 1938; two species of Cestoda, Oochoristica osheroffi Meggitt
1934 and Mesocestoides sp. (as tetrathyridia); four species of Nematoda, Physa-
loptera abjecta Leidy 1856, Spauligodon goldbergi Bursey and McAllister 1996,
Thubunea iguanae Telford 1965, Physaloptera sp. (third stage larvae); and one
species of Acanthocephala represented by oligacanthorhynchid (proboscis short,
globular; hooks in six spiral rows) cystacanths were found. Number of helminths,
prevalence (infected snakes of a species divided by snake sample size expressed
as a percentage), mean intensity (mean number of helminths per infected snake)
and infection sites within the host are given in Table 1. Nine new host records
are reported. Arizona elegans and Masticophis lateralis harbored five helminth
species each; Chionactis occipitalis and Rhinocheilus lecontei harbored three;
Masticophis flagellum harbored two and Phyllorhynchus decurtatus harbored one
helminth species. Helminth community characteristics are given in Table 2.

Discussion

Arizona elegans, Chionactis occipitalis, Masticophis flagellum, Phyllorhynchus
decurtatus and Rhinocheilus lecontei are sympatric in southern California and are
found in dry, relatively open areas supporting chaparral, creosote bush, mesquite
and sagebrush (Behler and King 1979). Masticophis lateralis prefers chaparral,
open hardwood-pine forest in the mountains and is especially common around
water (Behler and King 1979).

All helminths found in this study have been previously reported from snakes.
Paralechriorchis syntomentera was originally described as Zeugorchis syntomen-
tera by Sumwalt (1926) from the mouth cavity of Thamnophis sirtalis collected
on San Juan Island, San Juan County, Washington. Byrd and Denton (1938) erect-
ed the genus Paralechriorchis for it and two closely related species. The life
history of P. syntomentera was described by Ingles (1933) who experimentally
infected young Thamnophis ordinoides collected at Berkeley, Alameda County,
California through the ingestion of infected amphibians. Fantham and Porter
(1954) have also reported Thamnophis ordinoides of Quebec, Canada to harbor
P. syntomentera. Masticophis lateralis is a new host record.

Oochoristica osheroffi was originally described from Pituophis melanoleucus
collected in Nebraska by Meggitt (1934). Alexander and Alexander (1957) de-
scribed Oochoristica crotalicola from Crotalus cerastes and C. viridis of Cali-
fornia; however, this cestode was synonymised with O. osheroffi by Widmer

111

HELMINTHS OF CALIFORNIA SNAKES

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HELMINTHS OF CALIFORNIA SNAKES Ld i

(1966). Oochoristica osheroffi has been reported in Crotalus viridis from Colo-
rado and New Mexico (Widmer and Olsen 1967; Pfaffenberger et al. 1989). Ar-
izona elegans and Masticophis lateralis represent new host records.

Tetrathyridia of Mesocestoides sp. are frequently found in snakes; McAllister
et al. (1991) have summarized world occurrences. Tetrathyridia have been pre-
viously found in Masticophis flagellum from Texas by Conn and McAllister
(1990) and from Crotalus atrox, C. lepidus, C. molossus, C. pricei, C. ruber, C.
scutulatus, C. tigris, C. viridis and Thamnophis elegans from California (Voge
1953; Mankau and Widmer 1977; Widmer and Specht 1992; Bolette 1997a,
1997b; Goldberg and Bursey 1999). This is the first report of tetrathyridia in
Arizona elegans, Masticophis lateralis and Rhinocheilus lecontei. Bolette (1997a)
believed rattlesnakes serve as paratenic hosts.

Physaloptera abjecta was originally described from Masticophis flagellum (=
Psammophis flagelliformis) from Pennsylvania by Leidy (1856). The identity of
this snake is uncertain as M. flagellum does not occur in Pennsylvania (Conant
and Collins 1998). Physaloptera variegata Reiber, Byrd and Parker 1940, de-
scribed from a Coluber constrictor collected in Florida, was synonymized with
P. abjecta by Morgan (1941). It has been reported from Masticophis flagellum of
Georgia (Reiber et al. 1940) as well as the colubrids Coluber constrictor, Het-
erodon platirhinos, Lampropeltis getula, Opheodrys (= Liopeltis) vernalis and
Thamnophis sirtalis from Georgia, Florida or Wisconsin and the anguid lizard,
Ophisaurus ventralis from Georgia (Reiber et al. 1940; Morgan 1941; Mawson
1956). Arizona elegans is a new host record; California is a new locality record.

Spauligodon goldbergi was described from the ground snake, Sonora semian-
nulata, from Texas by Bursey and McAllister (1996). This is the second report
of Spauligodon goldbergi. Chionactis occipitalis represents a new host record;
California is a new locality record.

Thubunaea iguanae was originally described from the phrynosomatid lizard,
Sceloporus magister, from Riverside County, California and was present in a
variety of lizards collected by Telford (1965). Arizona elegans, Chionactis occip-
italis, Masticophis flagellum and Rhinocheilus lecontei represent new host records.
A related species, Thubunaea cnemidophorus, has been reported from Crotalus
cerastes, C. mitchellii and C. scutulatus of southern Nevada (Babero and Em-
merson 1974).

Third stage larvae of Physaloptera sp. were present in each of the species
examined in this study and have also been reported in M. flagellum from Texas
by Conn and McAllister (1990). The majority of the 16 species of Physaloptera
from North America listed by Morgan (1941) have mammalian hosts. All species
of Physaloptera require an insect intermediate host (Anderson 2000) and could
be expected in any insectivore. Amphibians and reptiles harboring larvae of Phy-
saloptera sp. but no adults are summarized in Goldberg et al. (1993). Because
these larvae were found mainly in the intestine of the snakes examined, we believe
they are a by-product of diet and will be passed in feces without further devel-
opment. This is the first report of physalopteran larvae in A. elegans, C. occipi-
talis, M. lateralis, P. decurtatus and R. lecontei.

Oligacanthorhynchid cystacanths of acanthocephalans have previously been re-
ported in Rhinocheilus lecontei from Riverside County, California as well as Ar-
izona, Texas and Mexico (Goldberg et al. 1998). In addition, Bolette (1997b)

114 SOUTHERN CALIFORNIA ACADEMY OF SCIENCES

reported oligacanthorhynchid cystacanths in Rhinocheilus lecontei collected in
Arizona and provided a list of cystacanths from nine additional snake species.
This is the first report of cystacanths in Masticophis lateralis.

The helminths found in this study fall into two categories: those requiring
intermediate hosts, namely Paralechriorchis syntomentera, Oochoristica osheroffi,
Physaloptera abjecta, Thubunaea iguanae, and the acanthocephalans; and those
infecting directly by egg ingestion, namely Mesocestoides sp. and Spauligodon
goldbergi. In all cases, it is an oral route of infection.

There is some dietary overlap in these snakes: Arizona elegans feeds mainly
on lizards and rodents with a few birds and snakes; Chionactis occipitalis eats
insects, spiders, scorpions and centipedes; Masticophis flagellum feeds on small
mammals, birds, lizards, snakes, insects and carrion; Masticophis lateralis eats
frogs, lizards, snakes, small mammals, birds and insects; Phyllorhynchus decur-
tatus feeds on small lizards and their eggs; Rhinocheilus lecontei feeds almost
exclusively on lizards (Stebbins 1985; Rodriguez-Robles et al. 1999). Widmer
and Olsen (1967) suggested that helminth infections can be transmitted to snakes
when snakes eat infected arthropods or when they eat prey which has recently
fed on infected arthropods. Likewise, ingestion of prey infected by a species of
Mesocestoides or by Spauligodon goldbergi could introduce feces containing eggs
of these species into a snake host with subsequent development of an infection.

Examination of other California snakes will be needed before helminth com-
munities can be described and assigned. However, it is of interest to note that
only Masticophis lateralis which is especially common in areas with water (Behler
and King 1979) harbored Paralechriorchis syntomentera, a helminth requiring
amphibians as intermediate hosts. All sympatric desert snakes eating lizards har-
bored Thubunaea iguanae. All six species contained third-stage larvae of Phy-
saloptera sp., more likely a by-product of diet than potential infection. One desert
snake species, Arizona elegans, and the non-desert species, Masticophis lateralis,
harbored Oochoristica osheroffi, typically a parasite of rattlesnakes.

Acknowledgments

We thank David A. Kizirian (Natural History Museum of Los Angeles County)
for permission to examine snakes and Cheryl Wong and Megan E. Lahti for
assistance with dissections.

Literature Cited

Alexander, C. G., and E. P. Alexander. 19°57. Oochoristica crotalicola, a new anoplocephalid cestode
from California rattlesnakes. J. Parasitol. 43:365—366.

Anderson, R. C. 2000. Nematode parasites of vertebrates: Their development and transmission., 2nd
edition, CABI Publishing, CAB International, Wallingford, Oxon, United Kingdom, xx + 650
Pp.

Babero, B. B., and E H. Emmerson. 1974. Thubunaea cnemidophorus in Nevada rattlesnakes. J.
Parasitol. 60:595.

Behler, J. L., and EF W. King. 1979. The Audubon Society field guide to North American reptiles and
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Bolette, D. P. 1997a. First record of Pachysentis canicola (Acanthocephala: Oligacanthorhynchida)
and the occurrence of Mesocestoides sp. tetrathyridia (Cestoidea: Cyclophyllidea) in the western
diamondback rattlesnake, Crotalus atrox (Serpentes: Viperidae). J. Parasitol. 83:751—752.

. 1997b. Oligacanthorhynchid cystacanths (Acanthocephala) in a long-nosed snake, Rhinoch-

HELMINTHS OF CALIFORNIA SNAKES 115

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(Viperidae) from Maricopa County, Arizona. Southwest. Nat. 42:232—236.

Brown, P. R. 1997. A field guide to snakes of California. Gulf Publishing Company, Houston, Texas,
Vint, + 215 pp.

Bursey, C. R., S. R. Goldberg, and S. M. Secor. 1995. Hexametra boddaertii (Nematoda: Ascaridae)
in the sidewinder, Crotalus cerastes (Crotalidae), from California. J. Helm. Soc. Wash. 62:78—
80.

Bursey, C. R., and C. T. McAllister. 1996. Spauligodon goldbergi sp. n. (Nematoda: Pharyngodonidae)
and other parasites of Sonora semiannulata (Serpentes: Colubridae) from New Mexico and
Texas. J. Helm. Soc. Wash. 63:62—65.

Byrd, E. E., and J. EK Denton. 1938. New trematodes of the subfamily Reniferinae, with a discussion
of the systematics of the genera and species assigned to the subfamily group. J. Parasitol. 24:
379-401.

Conant, R., and J. T. Collins. 1998. A field guide to reptiles and amphibians: Eastern and central
North America, third edition, Houghton Mifflin Company, Boston, xviii + 616 pp.

Conn, D. B., and C. T. McAllister. 1990. An aberrant acephalic metacestode and other parasites of
Masticophis flagellum (Reptilia: Serpentes) from Texas. J. Helminthol. Soc. Wash. 57:140—145.

Fantham, H. B., and A. Porter. 1954. The endoparasites of some North American snakes and their
effects on the Ophidia. Proc. Zool. Soc. London 123:867—898.

Goldberg, S. R., and C. R. Bursey. 1999. Crotalus lepidus (Rock Rattlesnake), Crotalus molossus
(Blacktail rattlesnake), Crotalus pricei (Twin-spotted rattlesnake), Crotalus tigris (Tiger rattle-
snake). Endoparasites. Herpetol. Rev. 30:44—45.

Goldberg, S. R., C. R. Bursey, and H. J. Holshuh. 1998. Prevalence and distribution of cystacanths
of an oligacanthorhynchid acanthocephalan from the longnose snake, Rhinocheilus lecontei
(Colubridae), in southwestern North America. J. Helminthol. Soc. Wash. 65:262—265.

Goldberg, S. R., C. R. Bursey, and R. Tawil. 1993. Gastrointestinal helminths of the western brush
lizard, Urosaurus graciosus graciosus (Phrynosomatidae). Bull. Southern Calif. Acad. Sci. 92:
43-51.

Harwood, P. D. 1932. The helminths parasitic in the amphibia and reptilia of Houston, Texas, and
vicinity. Proc. U.S. Natl. Mus. 81:1—76.

Ingles, L. G. 1933. Studies on the structure and life-history of Zeugorchis syntomentera Sumwalt, a
trematode from the snake Thamnophis ordinoides from California. Univ. Calif. Publ. Zool. 39:
163-178.

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Acad. Nat. Sci. Philadelphia 42—58.

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tetrathyridia in southern California reptiles with notes on the pathology in the Crotalidae. Jap.
J. Parasitol. 26:256—259.

Mawson, P. M. 1956. Physaloptera variegata Reiber, Byrd and Parker, 1940 from three species of
reptiles. Can. J. Zool. 34:75—76.

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for Mesocestoides sp. tetrathyridia (Cestoidea: Cyclophyllidea), with a summary of the genus
from snakes of the world. J. Parasitol. 77:329-—331.

Meggitt, E J. 1934. On some tapeworms from the bullsnake (Pityopis sayi), with remarks on the
species of the genus Oochoristica (Cestoda). J. Parasitol. 20:181-189.

Morgan, B. B. 1941. A summary of the Physalopterinae (Nematoda) of North America. Proc. Helm.
Soc. Wash. 8:28-—30.

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talus viridis viridis) and gopher snakes (Pituophis melanoleucus sayi) from the eastern high
plains of New Mexico. J. Wild. Dis. 25:305—306.

Reiber, R. J., E. E. Byrd, and M. V. Parker. 1940. Certain new and already known nematodes from
Amphibia and Reptilia. Lloydia 3:125—144.

Rodriguez-Robles, J. A., C. J. Bell, and H. W. Greene. 1999. Food habits of the glossy snake, Arizona
elegans, with comparisons to the diet of sympatric long-nosed snakes, Rhinocheilus lecontei.
J. Herp. 33:87—92.

Schad, G. A. 1962. Studies on the genus Kalicephalus (Nematoda: Diaphanocephalidae) II. a taxo-
nomic revision of the genus Kalicephalus Molin, 1861. Can. J. Zool. 40:1035—1165.

116 SOUTHERN CALIFORNIA ACADEMY OF SCIENCES

Stebbins, R. C. 1985. A field guide to western reptiles and amphibians. Houghton Mifflin Co., Boston,
xiv + 336 pp.

Sumwalt, M. 1926. Trematode infestation of the snakes of San Juan Island, Puget Sound. Washington
University Studies 13:73-101.

Telford, S. R., Jr. 1965. A new species of Thubunaea (Nematoda: Spiruroidea) from California lizards.
Jap. J. Exp. Med. 35:111-114.

Voge, M. 1953. New host records for Mesocestoides (Cestoda: Cyclophyllidea) in California. Am.
Midl. Nat. 49:249—251.

Widmer, E. A. 1966. Synonymy of Oochoristica crotalicola Alexander and Alexander, 1957. Bull.
Wild. Dis. Assoc. 2:82—84.

Widmer, E. A., and O. W. Olsen. 1967. The life history of Oochoristica osheroffi Meggitt, 1934
(Cyclophyllidea: Anoplocephalidae). J. Parasitol. 53:343—-349.

Widmer, E. A., and H. D. Specht. 1992. Isolation of asexually proliferative tetrathyridia (MVesocestoides
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Accepted for publication 19 September 2000.

Appendix 1

Museum numbers (LACM) from the Natural History Museum of Los Angeles County for six species
of colubrid snakes from California.

Arizona elegans (n = 43) 102030—102035, 102037—102063, 102101—102107, 102109-102111.
Chionactis occipitalis (n = 31) 42410, 52292, 52300, 52301, 52306, 52311, 52325, 52327, 52344,
52354, 52361, 52369, 52373, 52378, 52379, 52387-52389, 52401, 52405, 52425, 52430, 63625,
102757—102760, 102762, 102768, 122099, 122100.

Masticophis flagellum (n = 12) 103136, 103138, 103149, 103150, 103153, 103164, 103165,
103172, 103174, 103176, 103178, 103182.

Masticophis lateralis (n = 14) 027794, 027795, 027797, 052540, 052542, 075211, 111203, 111204,
111207, 111210, 111213, 111215, 111216, 111218.

Phyllorhynchus decurtatus (n = 26) 102868, 102874, 102904, 102910, 102913, 102921—102923,
102925-—102930, 102934, 102935, 102937, 102939, 102943, 102949-102951, 115876, 115877,
133896,. 133897.

Rhinocheilus lecontei (n = 33) 102622, 102624, 102627, 102630—102632, 102634, 102636, 102638,
102639, 102641—102643, 102645—-102647, 102655, 102656, 102660—102667, 102669, 102672-
102677.

Appendix 2

Helminths deposited in the United States National Parasite Collection (USNPC) for six species of
colubrid snakes from California.

Arizona elegans: Oochoristica osheroffi (90583); Mesocestoides sp. (90425); Physaloptera abjecta
(90426); Thubunaea iguanae (90427); Physaloptera sp. (90428). Chionactis occipitalis: Spauligodon
goldbergi (90429); Thubunaea iguanae (90430); Physaloptera sp. (90431). Masticophis flagellum:
Thubunaea iguanae (90432); Physaloptera sp. (90433).

Masticophis lateralis: Paralechriorchis syntomentera (90434); Oochoristica osheroffi (90435); Me-
socestoides sp. (90436); Physaloptera sp. (90437); oligacanthorhynchid cystacanths (90438).

Phyllorhynchus decurtatus: Physaloptera sp. (90439). Rhinocheilus lecontei: Mesocestoides sp.
(90441); Thubunaea iguanae (90440); Physaloptera sp. (90442).

Bull. Southern California Acad. Sci.
100(2), 2001, pp. 117-122
© Southern California Academy of Sciences, 2001

Helminths of the California Treefrog, Hyla cadaverina (Hylidae),

from Southern California

Stephen R. Goldberg’ and Charles R. Bursey?

‘Department of Biology, Whittier College, Whittier, California 90608
*Department of Biology, Pennsylvania State University, Shenango Campus,
Sharon, Pennsylvania 16146

Abstract.—Ninety-one California treefrogs, Hyla cadaverina, from three counties
in southern California (Los Angeles, Orange, Riverside) were examined for hel-
minths. The trematode, Langeronia burseyi, and metacercariae of Alaria sp., Fi-
bricola sp., and Gorgoderina sp.; the cestode, Distoichometra bufonis, and two
species of nematodes, Rhabdias ranae and larvae of Physaloptera sp., were found.
Helminth distribution patterns were found to be patchy; no two counties exhibited
the same combination of helminth species.

The California treefrog, Hyla cadaverina Cope 1866, is known from the moun-
tains of southern California to northern Baja California from elevations near sea
level to around 2290 m (Stebbins 1985). To our knowledge, there is one report
(Dailey and Goldberg 2000) of helminths from this species. The purpose of this
paper is to analyze helminth infracommunities of H. cadaverina from the northern
portion of its range: Los Angeles County, Orange County and Riverside County,
California.

Materials and Methods

Ninety-one H. cadaverina (Los Angeles County: N = 34, snout-vent length
[SVL] = 32 mm + 4 SD, range = 25—41 mm, collected 1963-1965; Orange
County: N = 39, SVL = 37 mm + 5 SD, range = 17—45 mm, collected 1960—
1972; Riverside County: N = 18, SVL = 28 mm + 6 SD, range = 21—42 mm,
collected 1964-1971) were borrowed from the Natural History Museum of Los
Angeles County (LACM) and examined for helminths (accession numbers in ap-
pendix). The body cavity of each treefrog was opened by a longitudinal incision
and the gastrointestinal tract was removed and slit longitudinally. The esophagus,
stomach, small intestine, large intestine as well as lungs, urinary bladder, coelom
and liver were searched for helminths with a dissecting microscope. Nematodes
were placed in a drop of undiluted glycerol on a glass slide and allowed to clear
for study with a compound microscope. Nematodes were identified from these
slides. Trematodes and cestodes were stained in hematoxylin and mounted in
balsam for identification. Numbers of individuals for each species of helminth
were recorded for each host. Prevalence (the percentage of infected frogs), mean
intensity (the mean number of helminths per infected frog), abundance (the num-
ber of individuals of a helminth species divided by the number of hosts examined)
and species richness (the number of helminth species per infected frog) were
determined. Prevalences of infection for male and female frogs were compared
by the chi-square test (x7), numbers of helminths per male and female hosts were

| Be

118 SOUTHERN CALIFORNIA ACADEMY OF SCIENCES

evaluated by the Kruskal-Wallis test and correlation analysis (7) was used to relate
intensity of infection to age of host (as estimated by SVL). A discussion of
measures of analyses for community structure can be found in Brower et al.
(1998). Of these, measures selected for evaluation of the component helminth
community structure were species richness, Simpson dominance, and Simpson
diversity. For evaluation of helminth infracommunity structure, mean number of
helminth individuals per host, mean number of helminth species per host and
Brillouin’s index were used. For community similarity, the Jaccard coefficient,
percentage of similarity, and Morisita’s index were used.

Results and Discussion

Gravid individuals of one species of trematode, (Langeronia burseyi Dailey
and Goldberg 2000); one species of cestode, (Distoichometra bufonis Dickey
1921); and one species of nematode, (Rhabdias ranae Walton 1929), were found.
Metacercariae of three species of trematodes, (Alaria sp., Fibricola sp. and Gor-
goderina sp.), and larvae of one species of nematode, (Physaloptera sp.), were
found. Voucher specimens were placed in vials of 70% ethanol and deposited in
the United States National Parasite Collection (Appendix).

Twenty-eight treefrogs (31%) were found to harbor 590 helminths (X = 21 +
42 SD per infected treefrog), of which 469 (79%) were larvae of species not
capable of completing their life cycles in anurans. These include Alaria sp., Fi-
bricola sp. and Physaloptera sp., (see Smyth and Smyth 1980; Goldberg et al.
1993). Mean helminth species richness for infected treefrogs was 1.2 + 0.5 SD
(range = 1-3 species). Seventeen of 53 male treefrogs (32%) harbored 354 hel-
minths; 11 of 38 female treefrogs (29%) harbored 236 helminths. Neither prev-
alence of helminth infection nor number of helminths per host was significantly
different between male and female treefrogs (x? = 0.10, 1 df, P > 0.05; Kruskal
Wallis test = 0.43, P > 0.05, respectively). Twenty-four treefrogs (26%) harbored
a single species of helminth; 3 (3%) harbored 2 species; and 1 individual (1%)
harbored three species. The smallest infected frog measured 22 mm SVL; there
was a positive correlation between number of helminths (all species combined)
and SVL (r = 0.34, P = 0.080). Number, prevalence and mean intensity of
helminths by county are given in Table 1.

Similarity characteristics of the helminth component communities are summa-
rized in Table 2. The Jaccard coefficient is based upon species presence in a
community and ranges from O (no species found in both communities) to 1.0 (all
species found in both communities). Morisita’s index considers the number of
species, the number of individuals, as well as the proportion of the total repre-
sented by each species and ranges from 0% (no similarity) to 1.0 (identical).
Percentage of similarity is based upon species abundance and ranges from 0%
(no species found in both communities) to 100% (same species found in both
communities at similar abundances). No two counties exhibited the same com-
binations of helminth species. In this study (Table 1), the helminth communities
from Los Angeles County and Orange County are shown to have two species in
common, the helminth communities from Los Angeles County and Riverside
County have one species in common; however, helminth communities from
Orange County and Riverside County have no species in common.

Infracommunity structure is presented in Table 3. Brillouin’s index is used in

iwi

HELMINTHS OF CALIFORNIA TREEFROG

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epo]eUldly,
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a SS eescca=_=_— 0:05 —
“BrUsIOFTe)

uoyINos WoIJ AyUNOD Kq YULAaAvpDI IAF] WoIF syUTUUTAY JO (GS [| F JW) Aysuoqur ueow pur ‘(g) sougeaoid ‘(N)) SYUTWUTSY JO JoquINU ‘sa}yIs UONOAJUT *[ IqQRI.

120 SOUTHERN CALIFORNIA ACADEMY OF SCIENCES

Table 2. Jaccard coefficient, Morisita’s index and percentage of similarity for helminth communities
of Hyla cadaverina by county from southern California.

Orange County Riverside County

Jaccard coefficient

Los Angeles County 0.40 0.17

Orange County 0)
Morisita’s index

Los Angeles County 0.61 0.01

Orange County 0
Percentage of similarity

Los Angeles County 48.8 0.50

Orange County 0)

a relative fashion to determine which species assemblages are more or less diverse
than others and is based upon relative abundance with larger values indicating
evenness of distribution across species. Simpson diversity is based upon abun-
dance with larger values indicating evenness of distribution of individuals across
species. Simpson dominance is also based upon abundance with larger values
indicating aggregation of most individuals into one or a few species. Based upon
Brillouin’s index, the helminth infrapopulation collected in Orange County has
the most even distribution. Simpson diversity index indicates that Los Angeles
County and Riverside County have similar diversities and are less diverse than
the infracommunity in Orange County. Likewise, most helminths in the infracom-
munities of Los Angeles County and Riverside County belong to one species
(Simpson dominance index).

Except for Langeronia burseyi which is presently known only from H. cadav-

Table 3. Diversity characteristics of the helminth infracommunities for Hyla cadaverina by county
from southern California.

Los Angeles Orange Riverside

Characteristics County County County
No. treefrogs examined 34 39 18
Mean SVL + SD, range (mm) 32 +4 a7 = 5 28 = 6
No. treefrogs infected 11 4 12
Prevalence (as %) 32 10 67
No. helminths 374 179 37
Mean intensity + SD 33.9 + 45:6 44.7 + 78.8 3.1 BRA
Mean abundance + SD 11.0. 29.8 4.6 + 26.1 2h
Mean species richness + SD | Ree | Ff 13.205 it = ee
No. helminth species 4 3 3
Proportion with O helminth species 0.67 0.89 0:33
Proportion with 1 helminth species 0.24 0.08 0.61
Proportion with 2 helminth species 0.06 0.03 0.06
Proportion with 3 helminth species 0.03 0.00 0.00
Proportion with 4 helminth species 0.00 — ==
No. helminths species maturing in anurans Z 1 1
Brillouin’s index 0.31 0.37 0.12
Simpson diversity (D,) 0.49 0:55 0.49

Simpson dominance (d,) 0.51 0.45 0.51

HELMINTHS OF CALIFORNIA TREEFROG 121

erina collected in Orange County (Dailey and Goldberg 2000), none of the hel-
minth species found in this study was unique to H. cadaverina. However, this is
the first record of H. cadaverina as a host for D. bufonis and R. ranae as well as
the first report of Alaria sp., Fibricola sp., Gorgoderina sp., and Physaloptera
sp. in H. cadaverina. Species of Alaria and Fibricola utilize mammals as final
hosts, species of Gorgoderina utilize anurans as final hosts; metacercariae of all
3 species are commonly found in frogs (Smyth and Smyth 1980). Distoichometra
bufonis is a common parasite of anurans (Brooks 1976) as is R. ranae (see Baker
1987). Larvae of Physaloptera spp., usually parasites of lizards and mammals,
have been reported from anurans (Anderson 2000).

Of the 7 helminth species found in this study, 4 species are capable of com-
pleting their life cycles in anurans. Individuals of Gorgoderina require bivalve
intermediate hosts and aquatic insects or tadpoles serve as second intermediate
hosts (Smyth and Smyth 1980). When infected tadpoles or insect larvae are eaten
by frogs, excystment takes place in the stomach and migration to the kidneys and
bladder occurs (Smyth and Smyth 1980). We cannot speculate whether the Gor-
goderina metacercariae found in the present study would have migrated to the
kidneys or bladder to complete development or if H. cadaverina was acting as a
paratenic (transport) host. The life cycle of L. burseyi is unknown but other le-
cithodendriid trematodes have been shown to utilize snails as intermediate hosts
(Schell 1970). Likewise, the life cycle of D. bufonis is unknown, but Joyeux
(1927) regards the life cycle of nematotaeniid cestodes to be direct, i.e., without
an intermediate host and infection of a new host occurs through ingestion of
cestode eggs. Rhabdias ranae has a direct life cycle and infection occurs by
integumental penetration (Anderson 2000). Of the non-anuran parasites, species
of Physaloptera utilize insect intermediate hosts and adults occur mainly in stom-
achs of reptiles, birds and mammals (Anderson 2000); larvae might be expected
in any insectivorous host. Miracidia of Alaria sp. (definitive host = carnivore)
and Fibricola sp. (definitive host = mouse, raccoon) utilize snails as intermediate
hosts (Smyth and Smyth 1980). Cercariae of both Alaria sp. and Fibricola sp.
may penetrate the skin of either tadpoles or frogs (Hayden 1969; Pearson 1961).

It would be of interest to know which helminth species infect sympatric anurans
and whether there is recruitment of helminths from one locality to another. Pe-
riodic visits to water are the most likely time for infection by L. burseyi, Alaria
sp., Fibricola sp., Gorgoderina sp. and R. ranae. Distribution patterns of definitive
hosts, as well as intermediate hosts, may help explain the presence or absence of
these helminths in the localities examined. Feeding behavior would be a more
important consideration for infection by D. bufonis and Physaloptera sp. Presence
of these helminths in H. cadaverina is, no doubt, the result of patchy distribution
of the particular helminth species.

Acknowledgment

We thank David A. Kizirian (Natural History Museum of Los Angeles County)
for permission to examine H. cadaverina.

Literature Cited

Anderson, R. C. 2000. Nematode parasites of vertebrates: Their development and transmission. 2nd
edition. CABI Publishing, CAB International, Wallingford, Oxon, U.K. 650 pp.

122 SOUTHERN CALIFORNIA ACADEMY OF SCIENCES

Baker, M. R. 1987. Synopsis of the Nematoda parasitic in amphibians and reptiles. Mem. Univ.
Newfoundland, Occas. Pap. Biol., 11:1—325.

Brooks, D. R. 1976. Parasites of amphibians of the Great Plains. Part 2. Platyhelminths of amphibians
in Nebraska. Bull. Univ. Nebraska St. Mus., 10:65—92.

Brower, J. E., J. H. Zar, and C. N. von Ende. 1998. Field and laboratory methods for general ecology,
4th edition. McGraw-Hill, Boston, Massachusetts. xi + 273 pp.

Dailey, M. D., and S. R. Goldberg. 2000. Langeronia burseyi sp. n. (Trematoda: Lecithodendriidae)
from the California treefrog, Hyla cadaverina (Anura: Hylidae), with revision of the genus
Langeronia Caballero and Bravo-Hollis, 1949. Comp. Parasitol., 67:165—168.

Goldberg, S. R., C. R. Bursey and R. Tawil. 1993. Gastrointestinal helminths of the western brush
lizard, Urosaurus graciosus graciosus (Phrynosomatidae). Bull. So. Calif. Acad. Sci., 92:
43-51.

Hayden, D. W. 1969. Alariasis in a dog. J. Amer. Vet. Med. Assoc., 155:889-891.

Joyeux, C. 1927. Recherches sur la faune helminthologique Algérienne (cestodes et trématodes). Arch.
de I’Institut Pasteur d’ Algérie, 5:509—528.

Pearson, J. C. 1961. Observations on the morphology and life cycle of Neodiplostomum intermedium
(Trematoda: Diplostomatidae). Parasitology, 51:133—172.

Schell, S. C. 1970. How to know the trematodes. W. C. Brown Co., Dubuque, Iowa, vii + 355 pp.

Smyth, J. D., and M. M. Smyth. 1980. Frogs as host-parasite systems I. The MacMillan Press, Ltd.,
London, ix + 112 pp.

Stebbins, R. C. 1985. A field guide to western reptiles and amphibians. Houghton Mifflin Company,
Boston, xiv + 336 pp.

Accepted for publication 21 December 2000.

Appendix

Hyla cadaverina borrowed from the Natural History Museum of Los Angeles County (LACM) by
California County. Los Angeles County: 12263, 12265-12273, 12275-12280, 12283-12285, 12287—
12294, 114170—-114176; Orange County: 88837, 88854, 88881, 88882, 88894, 88895, 88905, 88907,
88918, 88921, 88923, 88927, 88930-88933, 88935, 88937, 88941, 88942, 88946, 88953-88956,
88958-88960, 88962-88969, 114182—114184; Riverside County: 114185, 114187—114198, 114200—
114204. Helminths from Hyla cadaverina deposited in the United States Parasite Collection, USNPC,
Beltsville, Maryland: Langeronia burseyi 90644; Alaria sp. 90645; Fibricola sp. 90646; Gorgoderina
sp. 90647; Distoichometra bufonis 90648; Rhabdias ranae 90649; Physaloptera sp. 90650.

Bull. Southern California Acad. Sci.
100(2), 2001, pp. 123—127
© Southern California Academy of Sciences, 2001

A New North Pacific Heterochone Transferred from Aphrocallistes
(Porifera: Hexactinellida)

Henry M. Reiswig

Redpath Museum and Department of Biology, McGill University,
859 Sherbrooke St. W., Montreal, Quebec, Canada H3A 2K6
email: cxhr@musica.mcgill.ca

Abstract.—A hexactinellid sponge specimen from southern California, determined
as a member of the genus Heterochone, was found to be conspecific with Aphro-
callistes beatrix incognitus, a form previously described from the Okhotsk Sea
by Koltun (1967). The taxon is redescribed and reassigned as a new combination,
Heterochone incognitus (Koltun). It represents an addition to the North American
Pacific fauna. The simple zoological diagnosis of Heterochone is: Aphrocallistidae
with atrialia as pinular hexactins.

The deep-water marine fauna of the Pacific Coast of North America is poorly
known primarily owing to avoidance of the region by the major oceanographic
expeditions of the late 1900’s. During an ongoing survey of California collections
by myself and coworkers, with the aim of producing an updated guide to the
Porifera of California, we encountered a hexactinellid sponge from southern Cal-
ifornia unknown to the region (last summarized by de Laubenfels 1932). The
specimen is the third and, although imperfect, the best preserved specimen of a
species known to date as Aphrocallistes beatrix incognitus; it has been recorded
only from the Okhotsk Sea, eastern Russia (Koltun 1967). The severely damaged
condition of the earlier specimens is likely cause for the original incorrect generic
assignment, which is here resolved and corrected.

Materials and Methods

The specimen was obtained on loan from the Benthic Invertebrate Collection
of Scripps Institute of Oceanography, La Jolla, California (SIO). After photo-
graphing the specimen, small pieces of dermal and atrial surfaces were whole-
mounted in Canada balsam for light microscopy and digested in hot nitric acid
for spicule cleaning. Cleaned spicules were either mounted directly in balsam on
slides or retained on nitrocellulose filters which were cleared and mounted on
slides. Spicules and body apertures were measured by microscope-coupled digi-
tizer. Spicule drawings were made directly from video-captured images. Data in
text are given as: minimum-mean-maximum of 25 measurements.

Systematics
Class Hexactinellida Schmidt, 1870
Subclass Hexasterophora Schulze, 1886
Order Hexactinosa Schrammen, 1903
Family Aphrocallistidae Gray, 1867
Genus Heterochone lima, 1927

Diagnosis.—Aphrocallistidae with atrialia as pinular hexactins.
Type species.—Chonelasma calyx Schulze, 1886

123

124 SOUTHERN CALIFORNIA ACADEMY OF SCIENCES

Fig. 1. Heterochone incognitus specimen SIO P 592. A, presumed lower (right) and upper (left)
surfaces of the lobate fragment, with bases of two funnels indicated by asterisks and intact portion of
funnel wall indicated by arrowheads. B, dermal surface with intact pinule lattice covering entire
surface, including entrances to diarhysial channels. C, atrial surface with open, uncovered apertures
of diarhysial channels.

Remarks.—Upon his erection of Heterochone, jima (1927) provided an exten-
sive comparison of the new genus with its only sister genus, Aphrocallistes, but
did not provide a diagnosis. Reid (1963), aware of Ijima’s action, characterized
the genus by body form, a strategy perhaps necessary for paleontological use but
insufficient for zoological application. Koltun (1967) was apparently unaware of
ljima’s formation of Heterochone, perhaps because it was mistakenly omitted
from the final list of Ijima’s (1927) publication (Reiswig 1990). The short, new
diagnosis provided here differentiates Heterochone (with hexactine atrialia) from
Aphrocallistes (with diactine atrialia).

A HEXACTINELLID SPONGE NEW TO CALIFORNIA 25

50um

=
&

100um

=
o)
=

100um

50um
50um

Fig. 2. Spicules of Heterochone incognitus specimen SIO P 592. A, dermal pinular hexactin. B,
atrial pinular hexactin. C, small moderately-spined hexactin. D, larger coarsely-spined hexactin. E,
uncinate, entire and magnified segment. E narrow scopule with 4 tines. G, divergent scopule with 6
tines. H, oxyhexactine microsclere. I, two hemioxyhexasters with branching restricted to rays of the

major axis. J, discohexaster.

Heterochone incognitus (Koltun, 1967)
Figs. 1-2, Table 1.

Synonymy.—Aphrocallistes beatrix incognitus Kotun, 1967: 60, Fig. 39.

Holotype.—Zoological Institute, Russian Academy of Science (Leningrad) N
16362 (2 fragments), 148°57’E, 44°41’N, 780m, RV ‘Vitiaz’ stn. 5640 (not ex-
amined).

Material examined.—SIO P 592, in alcohol, 118°53.6'’W, 33°20.4'N. 1165—958
m depth, 11 Dec. 1971, RV “Thomas Washington’, col. Mathews.

Body and framework.—Specimen a massive irregular fragment, 13.4 cm X 6.9
cm X 4.0 cm, as part of basal region without attachment site; dead skeletal frame-

126 SOUTHERN CALIFORNIA ACADEMY OF SCIENCES

Table 1. Spicule measurements of Heterochone incognitus, SIO P 592 with comparison data from
Okhotsk Sea specimens of Koltun, 1967.

Item measured Mean + s.d. Range N Koltun, 1967

Dermal pinule A

pinulus length (wm) 1S" 25 24 88-222 100 120-165

tangential ray length (wm) 1SGy= 22 104—227 100 99-154

proximal ray length (wm) 304 + 155 68-728 100 159-264
Gastral pinule B

pinulus length (wm) 198 + 47 85-280 25 nr.

tangential ray length (jm) LTOLE 37 104—247 2s Ie

proximal ray length (wm) PS. 133 65—193 pls n.r.
Scopule F length (wm) 606 + 84 420-756 25 412—660*
Scopule G length (jm) 257-2 103 369-751 25 412—660*
Hexactin D ray length (wm) 216 + 47 146-341 25 nt.
Hexactin C ray length (wm) L72 = Al 100-278 25 i
Uncinate length (mm) 5.4 + 0.9 3.6—7.1 pits 1.0—4.0

width (jm) 24 5 12-35 50 13-32

Oxyhexactin diameter (zm) O2°>. 16 64-126 25 66-121
Hemioxyhexaster diameter (jm) 100) = 19 65-129 a n.m.
Discohexaster diameter (jm) 28.002, S16 21.2—44.3 25 38

* Scouple types not measrued separately; n.r. = not reported; n.m. = not measured.

work on presumed lower side; 2 major depressions interpreted as bases of mostly
missing funnel-form body extensions on opposite presumed upper side (Fig. 1A);
surface even and compacted but edge of upper funnel with small region of intact
body wall (Fig. 1A, arrows); wall 1 cm thick penetrated by radial diarhyses (skel-
etal channels of dictyonal framework) passing from dermal to atrial surface; der-
mal surface entirely covered by rectangular lattice of loose pinular hexactins of
149-783-235 jm mesh (Fig. 1B); dermal openings of diarhyses 0.44-/.07-1.88
mm diameter and irregulary distributed; atrial surface lined by compact felt of
pinular hexactins not forming a rectangular lattice; atrial apertures of diarhyses
0.27-0.94-1.74 mm diameter, irregularly distributed, uncovered and open (Fig.
1C); dictyonal framework typically aphrocallistid (with diarhyses) with beams
partly smooth and partly sparsly spined, 49-S8-188 «1m in thickness; meshes 3-
and 4-sided, very irregular with sides 183-483-1059 wm.

Spicules.—Spicule form and dimensions are summarized in Fig. 2 and Table
1. Megascleres: Dermal and atrial pinular hexactins (Fig. 2A—B) are similar but
proximal rays of dermal forms have greater length range; parenchymal hexactins
occur in larger coarsly spined form (Fig. 2D) and smaller moderately spined form
(Fig. 2C); scopules with micro-thorned tines occur in 2 forms in both surfaces:
form with 4 tines and small (10°) angular spread (Fig. 2F), and form with 6—8
tines more widely (30°) divergent (Fig. 2G); large uncinates (Fig. 2E) are of form
typical of the family.

Microscleres: Oxyhexactins (Fig. 2H) to hemioxyhexasters (Fig. 21) with
smooth primary rays and micro-rough secondary rays numbering 1-4, often with
branching retricted to one axis; discohexaster (or tylohexasters) with short smooth
primary rays, each bearing 5 rough secondary rays terminating in a small cap
with 4-6 marginal spines (Fig. 2J).

A HEXACTINELLID SPONGE NEW TO CALIFORNIA iA

Remarks.—The specimen, SIO P 592, agrees in spiculation with that described
by Koltun (1967) as Aphrocallistes beatrix incognitus (Table 1; Koltun 1967, Fig.
39). Koltun’s material consisted of 2 small, damaged pieces of sponge, ca. 2.5 X
1.5 cm, plus numerous fragments of washed-out skeletal framework collected
from the Okhotsk Sea. He was able to describe and measure dermal and paren-
chymal spicules but atrial surfaces were too damaged to enable determination of
associated spicules critical to generic placement. Surprisingly he made no state-
ments on framework structure or channelization, features which were available
for assessment and critical for family assignment. His placement of the Okhotsk
material was presumably influenced by the distinctive “‘roller-form’”’ of the he-
mihexasters, a well known feature of Aphrocallistes beatrix, and compromised
by the unavailability of atrial spicules and his lack of awareness of Ijima’s Het-
erochone. With availability of the atrial surface in the southern California speci-
men, and conclusion that the specimen is conspecific with the Okhotsk material,
Kotun’s specimens can now be correctly reassigned as the new combination, Het-
erochone incognitus Koltun. The new form is easily differentiated from other
Heterochone species: H. calyx Schulze has shorter inflated pinulus and spheric
oxyhexasters; H. hamata Schulze has no oxyhexasters; H. tenera Schulze has
microsclere populations that are mainly discohexactins.

Acknowledgments

I thank Spencer Luke and Larry Lovell for making loan material available for
this study, and Prof. V.M. Kotun for providing holotype collection data. Financial
support was provided by the Natural Sciences and Engineering Research Council
of Canada.

Literature Cited

Ijima, I. 1927. The Hexactinellida of the Siboga Expedition. Siboga Exped. Rept. 6:1—383.

Koltun, V.M. 1967. Vitreous sponges of the Northern and Far-Eastern Seas of the USSR. [in Russian]
Opred. Faune S.S.S.R. 94:1-124.

Laubenfels, M.W. de 1932. Marine and fresh water sponges of California. Proc. U.S. Nat. Mus. 81:
1-140.

Reid, R.E.H. 1963. Notes on a classification of the Hexactinosa. J. Paleont. 37:218—231.

Reiswig, H.M. 1990. Correction of Ijima’s (1927) list of recent hexactinellid sponges (Porifera). Proc.
Biol. Soc. Wash. 103:731-—745.

Schulze, EE. 1886. Uber den Bau und das System der Hexactinelliden. Abh. K6nigl. Akad. Wiss.
Berlin (Physik.-Math.) 1886:1—97.

Accepted for publication 22 December 2000.

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INSTRUCTIONS FOR AUTHORS

MANUSCRIPT PREPARATION

An abstract summarizing in concise terms the methods, findings, and implications discussed in the paper must
accompany a feature article. Abstract should not exceed 100 words.

A research note is usually one to six typewritten pages and rarely utilizes subheadings. Consult a recent issue
of the BULLETIN for the format of notes. Abstracts are not used for notes.

The literature cited: Entries for books and articles should take these forms.

McWilliams, K. L. 1970. Insect mimicry. Academic Press, vii + 326 pp.

Holmes, T. Jr., and S. Speak. 1971. Reproductive biology of Myotis lucifugus. J. Mamm., 54:452—-458.

Brattstrom, B. H. 1969. The Condor in California. Pp. 369-382 in Vertebrates of California. (S. E. Payne, ed.),

Univ. California Press, xii + 635 pp.

Tables should not repeat data in figures (line drawings, graphs, or black and white photographs) or contained
in the text. The author must provide numbers and short legends for tables and figures and place reference to each
of them in the text. Each table with legend must be on a separate sheet of paper. All figure legends should be
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(grey) backgrounds. Special handling such as dropout half-tones, special screens, etc., must be requested by and
will be charged to authors. As changes may be required after review, the authors should retain the original
figures in their files until acceptance of the manuscript for publication.

PROCEDURE

CONTENTS

A Fossil Blue Marlin (Makaira nigricans Lacépéde) from the Middle Facies
of the Trinidad Formation (Upper Miocene to Upper Pliocene), San José
del Cabo Basin, Baja California Sur, México. Harry L. Fierstine,
Shelton P. Applegate, Gerardo Gonzalez-Barba, Tobias Schwennicke,
and Luis Espinosa-Arrubarrena

Contributions to the Life History of Adult Pacific Lamprey (Lampetra tri-
dentata) in the Santa Clara River of Southern California. Shawn D.

Combined Effects of Drought and Phoradendrom juniperinum Infestation
Severity on Fruit Characteristics of P juniperinum and its Juniperus
osteosperma Hosts. Simon A. Lei

Spatial Distribution of Blackbrush (Coleogyne ramosissima Torr.)
Populations in the Mojave Desert. Simon A. Lei

Postfire Seed Bank and Soil Conditions in a Blackbrush (Coleogyne ramo-
sissima Torr.) Shrubland. Simon A. Lei

Helminths of Six Species of Colubrid Snakes from Southern California.
Stephen R. Goldberg and Charles R. Bursey

Helminths of the California Treefrog, Hyla cadaverina (Hylidae), from
Southern California. Stephen R. Goldberg and Charles R. Bursey

A New North Pacific Heterochone Transferred from Aphrocallistes (Porifera:
Hexactinellida). Henry M. Reiswig

COVER: Makaira nigricans Lacépéde. Skull Lateral view (see Figure | in Fierstine, et al).

ISSN 0038-3872

fern eRN CALIFORNIA ACADEMY OF - SCIENCES

BULLETIN

Volume 100 Number 3

EL NINO SYMPOSIUM

BCAS-A100(3) 129-252 (2001) DECEMBER 2001

Southern California Academy of Sciences
Founded 6 November 1891, incorporated 17 May 1907

OFFICERS

Daniel Pondella, President
Ralph Appy, Vice-President
Susan E. Yoder, Secretary
Daniel A. Guthrie, Treasurer
Daniel A. Guthrie, Editor
David Huckaby, Past President
Hans Bozler, Past President

BOARD OF DIRECTORS

Susan E. Yoder

Professional Members 2°... 2 Sie ce a Se 2B Ug Se Be ee
Siidcat Wember: 2° SS. Oe eI eee ee i eS ke eS ae OS
Memberships in other categories are available on request.

Fellows: Elected by the Board of Directors for meritorious services.

The Bulletin is published three times each year by the Academy. Manuscripts for publication should
be sent to the appropriate editor as explained in “Instructions for Authors” on the inside back cover
of each number. All other communications should be addressed to the Southern California Academy —
of Sciences in care of the Natural History Museum of Los Angeles County, Exposition Park, Los
Angeles, California 90007-4000.

Date of this issue 10 December 2001

This paper meets the requirements of ANSI/NISO Z39.48-1992 (Permanence of Paper).

SOUTHERN CALIFORNIA ACADEMY
OF SCIENCES

CALL FOR PAPERS
2002 ANNUAL MEETING
June 7-8, 2002
CLAREMONT MCKENNA COLLEGE
CLAREMONT

Contributed Papers & Posters: Both professionals and students are welcome to submit abstracts for
a paper or poster in any area of science. Abstracts are required for all papers, as well as posters, and
must be submitted in the format described below. Maximum poster size is 32 by 40 inches.

Symposia: The following symposia are planned at the present time. If you wish to participate or to
organize any additional symposia, please contact the organizer or the Academy Vice President, Ralph
Appy (310 732 3497) rappy @portla.org. Organizers should have a list of participants and a plan for
reaching the targeted audience.

Virtual Oceans
Organizers: Judy Doino Lemus jdlemus @usc.edu 213-740-1965

Rocky Reef Monitoring
Organizers: Dan Pondella pondella@ oxy.edu (323) 259-2955 and Bob Grove grovers@sce.com
626-302-9735

Conservation Management F
Organizer: Brad Blood BBlood@ sapphosenvironmental.com 626-683-3547 |

CALIFORNIA

ACADEMY OF SCIENCES
High School Science Education

Organizers: Martha and Richard Schwartz SCI/RS@aol.com DEC 2 6 2001

SCCWRP Bight 98 Regional Monitoring

Organizer: Stephen Wiesberg 714 372 9203 stevew@sccwrp.org LIBRARY

Effects of exotic species on Southern California wildlife
Organizers: Dan Guthrie dguthrie @jsd.claremont.edu 909 607 2836 and Andrew Jirik
ajirik@ portla.org

Aerial Particulate Contaminants
Ralph Appy rappy@portla.org 310-732-3497

There will be additional sessions of Invited Papers and Posters and of papers by Junior Academy
members.

Student Awards: Students who elect to participate are eligible for best paper or poster awards in the
following categories. Biology: ecology and evolution, biology: genetics and physiology, physical sci-
ence. A paper by any combination of student and professional co-authors will be considered eligible
provided that it represents work done principally by student(s). In the case of an award to a co-authored
paper, the monetary award and a one year student membership to the Academy will be made to the
first author only.

For further information on posters, abstracts, registration and deadlines, see the Southern California
Academy of Science web page at: www.lam.mus.ca.us/~scas/

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Bull. Southern California Acad. Sci.
100(3), 2001, pp. 129-130
© Southern California Academy of Sciences, 2001

Proceedings of Special Symposium:

New and Rare Fish and Invertebrate Species to California during
the 1997-1998 El Nino
Sponsored by
The Southern California Academy of Sciences
May 20, 2000

Daniel J. Pondella, II' and M. James Allen? Editors

'Vantuna Research Group, Department of Biology, Moore Laboratory of
Zoology, Occidental College, Los Angeles, California 90041
?Southern California Coastal Water Research Project,
Westminster, California 92683

Introduction

By some measures 1997-1998 El Nifio southern oscillation (ENSO) was the
strongest such event of the 20 century and perhaps the strongest of all recorded
history. For most of us, an El Nifo means increased rains in the Southern Cali-
fornia area, due to a disruption of the normal path of the jet stream. In the study
of marine ecology and fisheries biology, El Nifio’s have much more dire conse-
quences. These winter storms can devastate our coastline and are accompanied
by unusually warm and unproductive water. El Nifio’s have been cited as the
cause of the collapse of fishery stocks as well as the demise of our world re-
nowned kelp beds. ENSO events have increased in both frequency and magnitude
for the past two decades, which has intensified our awareness of this global phe-
nomenon. These changes, which we have seen in our coastal ecosystems, have
implications of macroscale changes in oceanography extending far beyond the
Southern California arena. As we sit on the precipice of the 21‘ century, the
staggering ramifications of these new oceanographic conditions trigger questions
of global climate change and we are challenged with the prospects of global
warming.

The Southern California Bight, as a transitional zone between the cold tem-
perate Oregonian fauna to the north and the warm subtropical San Diegan fauna
to the south, is a critical oceanographic realm for studying the effects of such
oceanographic disturbances. As our climate changes, our marine fauna responds
rapidly within this region. It has been noted that organisms distributed to the
south have the ability to migrate or colonize more northern locales during these
anomalously warm periods. But, what is less well known is the long-term fate of
these organisms. When our coastal waters cool, expatriated individuals may not
survive. On the other hand, colonization during these warming events may result
in permanent additions to our fauna, and a shift in the marine ecology of our
region. The strength of the 1997-1998 ENSO was mirrored by an unusually high
occurrence of subtropical organisms along the California coast. Considering that
range extensions during ENSO events have reported for decades, it was our opin-

129

130 SOUTHERN CALIFORNIA ACADEMY OF SCIENCES

ion that the whole new suite of organisms appearing during this period was of
critical importance in aiding our understanding of the macroscale changes that
may be occurring.

Part of the Southern California Academy of Science’s mission is to disseminate
information concerning scientific research in Southern California. We accomplish
this primarily through two venues, our Annual Meeting and the Bulletin. On May
20, 2000 during our Annual Meeting at the University of Southern California we
held a symposium entitled “‘New and Rare Fish and Invertebrate Species to Cal-
ifornia during the 1997-1998 El Nino.’’ We drew on all aspects of our scientific
community to compile the most complete synopsis of the effects of this event on
the biology of macroinvertebrates and fishes. We are pleased that the participants
of this symposium took the time out of their hectic schedules to compose the
following papers and we hope that the following publication will heighten our
awareness of the changes we are observing in our environment.

Bull. Southern California Acad. Sci.
100(3), 2001, pp. 131-136
© Southern California Academy of Sciences, 2001

First Occurrence of Blackspot Wrasse, Decodon melasma Gomon
1974 (Pisces: Labridae) in California

M. James Allen! and Ami K. Groce?

‘Southern California Coastal Water Research Project,
Westminster, California, 92683
2City of San Diego, Metropolitan Wastewater Department, Environmental
Monitoring and Technical Services Division, San Diego, California 92106

Wrasses (family Labridae) are epibenthic, demersal, and water-column fishes
found in coastal warm-temperate and tropical waters, usually near rocky and coral
reefs of the Atlantic, Indian, and Pacific Oceans. Although this is the second
largest family of marine fishes (Nelson 1994), only three species have been re-
ported from California: rock wrasse, Halichoeres semicinctus; sefiorita, Oxyjulis
californica; and California sheephead, Semicossyphus pulcher (Hubbs et al. 1979;
Eschmeyer et al. 1983). This paper reports the first occurrences of a fourth species
of wrasse in California.

Following the 1997-1998 El Nifo, three specimens of a small labrid were
collected in the Southern California Bight (SCB) by 7.6-m wide (headrope) sem-
iballoon otter trawls with 1.2-cm cod-end mesh. The first specimen, 51 mm stan-
dard length (SL), was collected on 2 June 1998 off Dana Point, California (latitude
33°27.80’ N and longitude 117°44.85’ W) at a depth of 60 m. The second spec-
imen (also 51 mm SL) was collected on 25 June, 1998 at a depth of 60 m off
Laguna Beach, California (latitude 33°30.07' N and longitude 117°49.40’ W),.
These fish were collected during a cooperative trawl survey between the Ocean
Institute (Orange County Marine Institute at that time) and the Southern California
Coastal Water Research Project (SCCWRP). Both specimens were identified at
that time by M. J. Allen as the blackspot wrasse, Decodon melasma Gomon 1974.
A third specimen (57 mm SL) was collected on 26 April, 1999 off San Diego,
California (latitude 32°37.54' N and longitude 117°19.37’' W) at a depth of 100
m. It was captured at one of the City of San Diego, Metropolitan Wastewater
Department, Environmental Monitoring and Technical Services’ long-term, fixed-
location trawl monitoring stations. City of San Diego marine biologists brought
this specimen to the attention of R. H. Rosenblatt (Scripps Institution of Ocean-
ography; SIO), who identified it as Decodon melasma. All three specimens have
been catalogued in the SIO Marine Vertebrates Collection: SIO 99-100 (San Di-
ego); SIO 00-77 (Dana Point); and SIO 00-78 (Laguna Beach).

The capture of blackspot wrasse at Laguna Beach, CA represents a range ex-
tension of more than 1,500 km north of its northernmost record (Gomon 1974).
The three specimens are the first records of the species outside of the Gulf of
California north of Cabo San Lucas (latitude 22°45’ N). Based on the new spec-
imens, the current geographic range of black spot wrasse is now from Laguna
Beach, California and the northern Gulf of California to Peru, including Cocos
Islands (Gomon 1974; Allen and Robertson 1994). Its range extends along the
warm-temperate San Diego and Cortez Provinces and the tropical Mexican and

131

132 SOUTHERN CALIFORNIA ACADEMY OF SCIENCES

Table 1. Location and meristic data for blackspot wrasse, Decodon melasma specimens collected
in southern California in 1998 and 1999.

Specimens
Category SIO 00-77 SIO 00-78 SIO 99-100

Collection information

Date 2 Jun 98 25 Jun 98 26 Apr 99

Location Dana Point, CA Laguna Beach, CA San Diego, CA

Latitude N 33°27.80' 33°30.07' 32°37.54'

Longitude W 117°44.85’ 117°49.40' 117°19.37'

Depth (m) 60 60 100
Standard Length (mm) 51 51 ae
Meristic Counts

Dorsal Fin Elements Oe XII, 9 XI, 10

Anal Fin Elements Il, 10 Ill, 10 Ill, 10

Pectoral Fin Rays 17 17 16

Pelvic Fin Elements 5 Ls hes

Lateral line pores 29 29 Scales missing

Gill Rakers 5+9= 14 5+9=14 5+9=14

Panamic Provinces of Briggs (1974). Blackspot wrasse occurs on flat sandy to
soft bottoms, often with some rocky rubble or patch reefs at depths of 40 to 160
m (Gomon 1974), and as such, is characteristic of the middle and outer shelf
zones of Allen and Smith (1988). It occurs in deeper water and on a different
habitat (soft-bottom) than the other California species, which are inner shelf (<30
m) rocky bottom and kelp bed species (Feder et al. 1974).

The three California specimens had similar meristics (Table 1) and color pat-
terns. They had five dusky bars on the back (about two to three scales in width),
extending ventrally from the dorsal fin, across the lateral line, and to the midlateral
body, fading ventrally, with a dark spot on each side of the dorsal caudal peduncle
(Fig. 1). The color of the body was similar to that shown in Allen and Robertson
(1994). The body was pink, fading to white on the abdomen, on the pectoral fin
base, and under the pelvic fins. The nape, top of head, and snout were dusky,
with white on the head below the eye, and on the lower jaw. The head posterior
to the eye was pink extending from there to the dorsal base of the pectoral fin.
The upper lip was yellow posteriorly, around the anterior and ventral rim of the

A.Wubo

Fig. 1. Juvenile (51 mm standard length) blackspot wrasse, Decodon melasma, collected off La-
guna Beach, California, at depth of 60 m on June 25, 1998; SIO 00-78 (drawing by Atsuhiro Kubo).

BLACKSPOT WRASSE IN CALIFORNIA $33

Fig. 2. Adult (140 mm standard length) blackspot wrasse, Decodon melasma (drawing by Atsuhiro
Kubo, based on photograph in Gomon 1974).

eye was yellow, and a yellow line extended posteroventrally from the eye onto
the operculum. There was a yellow spot on the posterior operculum dorsal to this
line, and the preopercular area was yellow. The spinous dorsal fin was dusky on
the dorsal edge, with a black spot on dorsal spines 11 to 13. The anal fin was
yellowish with a white edge, the caudal fin and pelvic fins white, and the pectoral
fin pink. The eyes had black edges dorsally, fading to yellow, then red around
most of the pupil.

The blackspot wrasse has a relatively elongate compressed body (depth 20-32%
of standard length, increasing with size) (Figs. 1 and 2) (Gomon 1974, 1995).
Adults (not yet observed in California) have relatively blunt heads, slightly sub-
terminal mouths (Fig. 2). The body is red dorsally and white below, with head red
dorsally, white ventrally, and with three yellow stripes below the eye. Merisitic
elements have the following ranges (from Gomon 1974, Watson 1996, and new
California specimens): dorsal fin (X-XII,9—10); anal fin (III,9—10); pectoral fin (14—
18); pelvic fins (1,5); branchiostegal rays (6); lateral line scales and pores (28-29);
and gill rakers (S—7+9—12=14-—19). It has caniniform teeth, with two pairs at the
anterior of each jaw enlarged (Gomon 1974, Allen and Robertson 1994).

Characters that distinguish blackspot wrasse from other California labrids are
the following: 1) scaly head with lower limb of preopercle scaly; 2) large scales
(28-29 in lateral line); 3) 10—12 dorsal spines; 4) adult coloration—red with a
black spot dorsolateral on body and yellow eye stripes; and 5) juvenile colora-
tion—pinkish red with up to 6 dusky bars above the lateral line, yellow eye
stripes, and a dark spot on the spinous dorsal fin (Table 2). Blackspot wrasse is
more similar in characteristics to California sheephead than to rock wrasse or
sefiorita. Maximum size of adult blackspot wrasse is 23 cm in length (Gomon
1995).

Blackspot wrasse first occurred in California during the 1997-1998 El Nino
period, as did several other species (Lea and Rosenblatt 2000). It is likely that its
larvae came into the Southern California Bight with the warm water mass from
the south. It is not known if these individuals are the result of long-distance
dispersal from a distant population (1,500 km away) or whether they dispersed
from populations along the outer coast of Baja California, which is less well
sampled. Many shallow-living wrasses transform at a small size (Watson 1996)

134 SOUTHERN CALIFORNIA ACADEMY OF SCIENCES

Table 2. A key to species and life stages of wrasses, family Labridae, of California. Based on
information in Jordan and Evermann (1898), Miller and Lea (1972), Gomon (1974), Eschmeyer et al.
(1983), Allen and Robertson (1994), Nelson (1994), Gomon (1995), Humann (1996), and Watson
(1996).

Characteristics of California Labridae: Mouth protractile; jaw teeth separate, projecting outward; dorsal
fin with 8—14 spines and 9-13 soft rays; anal fin with 3 spines and 9-13 soft rays; caudal fin with
7+7 principal caudal rays; pectoral rays 12—19 soft rays; pelvic fins, 1 spine and 5 soft rays; 6
branchiostegal rays; gill rakers, 5—8 (upper limb) + 9—16 (lower limb) (note, gill raker counts for
Semicossyphus pulcher are 6—7 + 10-11 = 17-19; R. N. Lea, Calif. Dep. Fish Game, pers. comm.);
lateral line scales, 26 to 60; lateral line continuous.

la. Dorsal spines 10—12; sides of head more or less scaly; pink or red coloration on body ..... z

1b. Dorsal spines 8 to 10; head mostly naked; body color yellow to brown (sometimes
BRCCIU) ee fas oe on STE ag eile eS tes Males a ago. mPa Ac ah be al acoom aocale 3

2a. Scales large (28 to 29 in lateral line); lower limb of preopercle scaly; one or more dark
blotches dorsolaterally on sides; yellow eye stripes....... blackspot wrasse, Decodon melasma

a. Single dark spot dorsolaterally on side (Fig. 2); body depth 25-30%; color red; >13 cm
Sat Pra a Ee oo 3 ye aby oe Sots eee Pe Ew SE a adult

b. Five to six dark bars on back (one on dorsal caudal peduncle) (Fig. 1); body depth
about 20—25% of standard length; color pink; <13 cm SL .................. juvenile

2b. Scales small (about 60 in lateral line); lower limb of preopercle naked............
SE ee ee ere ee eae eet ee California sheephead, Semicossphus pulcher

a. Head and tail black, midbody red, chin white; body deep, compressed; >30 cm SL ..
RE Pet yn aT NY NRE an, > See ieat earns reenter is Pie: BOR I 2. terminal phase (male)

b. Fins without spots; body deep, compressed, pinkish with white chin; length 15 to 30
CMY Ee eres es SS ee Ee ies be ee ee ea ee ea aoe 2 eee initial phase (female)

c. Single white stripe on side; black spots on anterior and posterior dorsal fin, dorsolateral
caudal base, anal fin, and pelvic fins; body deep, reddish; <15 cm SL......... juvenile.

3a. Posterior canines well developed on both sides; dorsal spines pungent............
Ee tet ee raee Wy ee nie, aN aE eer) Se Eee rock wrasse, Halichoeres semicinctus

a. Body with black bar behind pectoral fin, back unmarked or with multiple bars; >30 cm
IG te ge ee ON eee RE See ee a ee terminal phase (male)

b. Black flecks generally present on body; length 12 to 30cm SL...... initial phase (female)

c. Body with two white stripes on side of body, and two black spots on dorsal fin; body
elongate conipressed;, yellow, orange, om stecn;,<12 cm SL. 4. Jor Pele eee juvenile

3b. Posterior canines rudimentary; dorsal spines slender, very flexible sefiorita, Oxyjulis californica

a. Body with broad black spot on the caudal fin at base of fin; >2.5 cm SL..........
ee ey pre end, a cro Se er SRO A ng Re ne juvenile and adult
b. Body with a black spot on posterior dorsal and anal fins; length less 2.5 cm........

and may be planktonic as eggs and larvae for about a month. Blackspot wrasse
(a deeper-living species) may transform at a larger size (as do many deeper living
species of other families; Moser 1996). If so, they may spend more time in the
plankton (perhaps to 3 mo), and travel further in the current before settling. As-
suming current velocities of 2 to 10 cm/sec without eddies (based on extreme
values for the California Current; Hickey 1993), eggs and larvae could travel
about 50—250 km in one month or 150—800 km in three months in a north flowing
current. Given that both of these distances fall short of the 1,500 km distance
from Cabo San Lucas, it is likely that the individuals captured in June 1998 in
California came from spawning populations off the coast of northern Baja Cali-
fornia. However, the individual caught in January 1999 (after the El Nifio had

BLACKSPOT WRASSE IN CALIFORNIA 135

subsided) may have been spawned off either southern California or northern Baja
California. The generally tropical distribution of the species and the warm-tem-
perate or cooler environment of the outer coast of Baja California suggests that
the species may have expanded northward along the Baja California coast during
the ocean warming of the past two decades (Smith 1995).

Thus it is likely that the blackspot wrasse had spawning individuals in or near
southern California and was spawning during this period. The two fish captured
in June 1998 (both 51 mm) were probably spawned in spring of 1998 while the
one captured in January 1999 (57 mm) was probably spawned in fall or early
winter of 1998. Blackspot wrasse may spawn from spring through fall as do the
other California labrids (Watson 1996). Adults of the blackspot wrasse appear to
be synchronous hermaphrodites in all but very large individuals (Gomon 1974).
Individuals with two well-developed ovaries and a small testis on the left side
occur at least to 150 mm SL; individuals with just testicular tissue occur from
138 to 200 mm SL (Gomon 1974).

Little is known about the ecology or behavior of this species. However, its
general body morphology as an adult (i.e., elongate compressed, slightly inferior
mouth, caniniform teeth) and behavior of morphologically similar labrids (Hobson
1968) suggests that it may be a solitary species that cruises over the bottom while
foraging on small benthic crustaceans. Blackspot wrasse is a geminate species of
the red hogfish, Decodon puellaris, of the Atlantic, which occupies similar depths
(6—275 m) and habitat on the Atlantic and Caribbean between South Carolina and
northeastern Brazil, and which grows to a similar size (15 cm) (Gomon 1974;
Robins et al. 1986).

The common name ‘blackspot wrasse’ was suggested by its scientific name
melasma (black spot) in reference to the black dorsolateral spot on each side of
the body (Gomon 1974). This name has been used in Allen and Robertson (1994),
Gomon (1995), and Escobar-Fernandez and Siri (1997). Bussing and Lopez
(1994) used ‘blotched hogfish.’ As this species has not yet been included in the
American Fisheries Society Checklist of Common and Scientific Names of Fishes
of the United States and Canada (see Robins et al. 1991), we recommend the
common name “‘blackspot wrasse’”’ as the English common name for this species.
In Spanish, this species has been called “‘lorito marcado”’ (Bussing and Lopez
1994) and “‘sefiorita de mancha negra’? (Gomon 1995, Escobar-Fernandez and
Siri 1997).

Acknowledgments

The authors thank the crew members of the Orange County Marine Institute
(now Ocean Institute), particularly Julie Goodson (now at Channel Islands Na-
tional Marine Sanctuary) and Shelly Moore (Southern California Coastal Water
Research Project) for recognizing the first two specimens as different and sub-
mitting them for identification. We also thank the crew of the City of San Diego
Ocean Monitoring Program (especially Steven Lagos) for recognizing the third
specimen as different. We thank Atsuhiro Kubo for providing the drawings of the
Laguna Beach specimen and of an adult. We also thank Phillip Hastings and H.
J. Walker of Scripps Institution of Oceanography, University of California, San
Diego and Richard Feeney and Jeffrey Siegel of the Natural History Museum of
Los Angeles for collection information on blackspot wrasse.

136 SOUTHERN CALIFORNIA ACADEMY OF SCIENCES

Literature Cited

Allen, G. R., and D. R. Robertson. 1994. Fishes of the tropical eastern Pacific. University of Hawaii
Press; xik 332 pp.

Allen, M. J., and G. B. Smith. 1988. Atlas and zoogeography of common fishes in the Bering Sea
and northeastern Pacific. NOAA Tech. Rep. NMFS 66. iii + 151 pp.

Briggs, J. C. 1974. Marine zoogeography. McGraw-Hill Book Co., 457 pp.

Bussing, W. A., and M. I. Lopez. 1994 (1993 on back cover but printed in Feb 1994). Demersal and
pelagic inshore fishes of the Pacific coast of lower central America. Rev. Biol. Trop., Spec.
Publ., 164 pp.

Eschmeyer, W. N., E. S. Herald, and H. Hammann. 1983. A field guide to Pacific Coast fishes of
North America. Houghton Mifflin Company, xii + 336 pp.

Escobar-Fernandez, R., and M. Siri. 1997. Nombres vernaculos y cientificos de los peces del Pacifico
mexicano. [Vernacular and scientific names of fishes of the Mexican Pacific]. Universidad
Aut6noma de Baja California, Sociedad Ictiol6gica Mexicana, A. C., MX, 102 pp.

Feder, H. M., C. H. Turner, and C. Limbaugh. 1974. Observations on fishes associated with kelp beds
in southern California. Calif. Dep. Fish Game, Fish Bull. 160. 138 pp.

Gomon, M. E 1974. A new Eastern Pacific labrid (Pisces), Decodon melasma, a geminate species of
the western Atlantic D. puellaris. Proc. Biol. Soc. Wash. 87(54):621—629.

Gomon, M. EF 1995. Labridae. Pp. 1201-1225 in Guia FAO para la identificacion de especies para los
fines de la pesca. Pacifico centro-oriental. Vol. III. Vertebrados—Parte 2. (W. Fischer, W. Schnei-
der, C. Sommer, K. E. Carpenter, and V. H. Niem, eds.), United Nations, Food and Agriculture
Administration, xiii + 1,813 pp.

Hickey, B. M. 1993. Physical oceanography. Pp. 19-70 in Ecology of the Southern California Bight.
(M. D. Dailey, D. J. Reish, and J. W. Anderson, eds.), Univ. Calif. Press, xvi + 926 pp.
Hobson, E. S. 1968. Predator behavior of some shore fishes in the Gulf of California. U. S. Dep.

Interior, Fish Wildl. Serv., Bur. Sport Fish. Wildl., Washington, DC. Res. Rep. 73, vi + 92 pp.

Hubbs, C. L., W. I. Follett, and L. J. Dempster. 1979. List of fishes of California. Occas. Pap. Calif.
Acad. Sci. 133. 51 pp.

Humann, P. 1996. Coastal fish identification: California to Alaska. New World Publications, Inc..,
210 pp.

Jordan, D. S., and B. W. Evermann. 1898. The fishes of North and Middle America: a descriptive
catalogue of the species of fish-like vertebrates found in the waters of North America, north of
the isthmus of Panama. Part II. Bull. U. S. Natl. Mus. No. 47: 1241-2183.

Lea, R. N., and R. H. Rosenblatt. 2000. Observations on fishes associated with the 1997-1998 El Nino
of California. Calif. Coop. Oceanic Fish. Inves. Rep. 41: 117-129.

Miller, D. J., and R. N. Lea. 1972 (addendum added 1976). Guide to coastal marine fishes of California.
Calif. Dep. Fish Game, Fish Bull. 157. 249 pp.

Moser, H. G. (ed.), The early stages of fishes in the California Current Region. Coop. Fish. Invest.
Atlas No. 33. Allen Press Inc., Lawrence, KS. xii + 1505 pp.

Nelson, J. S. 1994. Fishes of the world. Third edition. John Wiley & Sons, Inc., xvii + 600 pp.

Robins, C.R., R.M. Bailey, C.E. Bond, J.R. Brooker, E.A. Lachner, R.N. Lea, and W.B. Scott. 1991.
Common and scientific names of fishes from the United States and Canada. 5th edition. Amer-
ican Fisheries Society Special Publications 20. 183 pp.

Robins, C. R., G. C. Ray, J. Douglass, and R. Freund. 1986. A field guide to Atlantic Coast fishes of
North America. Houghton Mifflin Company, xi + 354 pp.

Smith, PE. 1995. A warm decade in the Southern California Bight. California Cooperative Oceanic
Fisheries Investigations Reports 36: 120—126.

Watson, W. 1996. Labridae: Wrasses. Pp. 1088-1103 in The early stages of fishes in the California
Current Region. (H. G. Moser, ed.), Coop. Fish. Invest. Atlas No. 33. Allen Press Inc., xii +
1505 pp.

Accepted for publication 21 December 2000.

Bull. Southern California Acad. Sci.
100(3), 2001, pp. 137-143
© Southern California Academy of Sciences, 2001

First Occurrence of Speckletail Flounder, Engyophrys sanctilaurentii
Jordan & Bollman 1890 (Pisces: Bothidae), in California

M. James Allen! and Ami K. Groce?

Currently there are 29 species of flatfishes representing three families (Parali-
chthyidae, Pleuronectidae, and Cynoglossidae) in California, with an additional
species and family (Pacific lined sole, Achirus mazatlanus; family Achiridae)
reported just below the United States-Mexico International Border (Hubbs et al.
1979; Lea et al. 1989; Lea, in prep.). This paper reports the first occurrence of
the 30th species of flatfish in California and the first occurrence of the family
Bothidae in the state. Seven California species (gulf sanddab, Citharichthys fra-
gilis; Pacific sanddab, Citharichthys sordidus; speckled sanddab, Citharichthys
stigmaeus; longfin sanddab, Citharichthys xanthostigma; bigmouth sole, Hippog-
lossina stomata; California halibut, Paralichthys californicus; and fantail sole,
Xystreurys liolepis) placed in Bothidae in Robins et al. (1991) and earlier refer-
ences have been placed in Paralichthyidae by most recent authoritative references
(Nelson 1994, Hensley 1995b, Moser and Sumida 1996, Eschmeyer 1998).

On August 6, 1998, an unusual flatfish, 80 mm standard length (SL), was
collected north of La Jolla Submarine Canyon, California (latitude 32°53.32’ N
and longitude 117°16.66’ W) at a depth of 63 m in a 7.6-m wide (headrope)
semiballoon otter trawl with 1.2-cm cod-end mesh. It was collected during the
Southern California Bight 1998 Regional Survey (Bight’98), a bight-wide survey
of the mainland and island shelves of southern California coordinated by the
Southern California Coastal Water Research Project. Scientists working for the
City of San Diego, Metropolitan Wastewater Department, Environmental Moni-
toring and Technical Services brought the specimen to the attention of M. J. Allen,
who identified it as a speckletail flounder, Engyophrys sanctilaurentii Jordan &
Bollman 1890. This specimen has been catalogued in the Scripps Institution of
Oceanography (SIO) Marine Vertebrates Collection (SIO 00-81).

Although the speckletail flounder occurs commonly along the southern coast
of Mexico, Central America, and northwestern South America, it had not previ-
ously been caught north of Sebastian Vizcaino Bay, Baja California, Mexico
(Moser and Charter 1996). The capture of the speckletail flounder off La Jolla,
California represents a range extension of 600 km north of its northernmost record
(published and unpublished) and the first record of this species in California.
Based on this specimen, the current geographic range of speckletail flounder is
now from La Jolla, California and the northern Gulf of California (SIO 60-120:
latitude 30°22.3’N, longitude 113°08.0’'W) to Peru (Hensley 1995a). Its range
extends along the warm-temperate San Diego and Cortez Provinces and the trop-
ical Mexican and Panamic Provinces of Briggs (1974). Speckletail flounder occurs

137

138 SOUTHERN CALIFORNIA ACADEMY OF SCIENCES

on mud, sand, gravel, or shell bottoms at depths of 10 m (LACM 32559.004) to
232 m (Hensley 1995a), with most specimens deeper than 40 m, and is thus
characteristic of the middle and outer shelf zones of Allen and Smith (1988).

The specimen has the following characteristics (Fig. 1): left-eyed; small mouth
reaching to the anterior part of the eye; teeth only on the blind side; narrow
interorbital ridge between eyes with a small sharp spine facing posteriorly; dorsal
fin beginning slightly on blind side of head behind posterior nostril; pectoral fins
relatively short; pelvic fins short, asymmetrical with the left having longer base
and on ventral midline about two rays anterior to the right fin on blind side;
rounded caudal fin; high arch in lateral line over the pectoral fin and a short
anterior bifurcating branch; no lateral line on the blind side. The specimen has
the following meristic characteristics: dorsal fin rays—81; anal fin rays—67; pec-
toral rays—11; pelvic fin rays—6; lateral line pores, eyed side—65; and lateral
line pores, blind side—0O. Body scales ctenoid and imbricating. Gill membranes
entirely separate. The coloration olive tan on the eyed side with dark spots on the
body and medial fins: five along each margin of body near dorsal and anal fins;
three along lateral line posterior to arch; six each on dorsal and anal fins; and
posterior edge of caudal fin with four dark blotches (Fig. 1). The blind side dusky
posteriorly and white anteriorly with five curved, dusky bands on anterior body
and head. The anteriormost extends upward and backward from the cheek to
dorsal margin of body, the next arches upward and backward from preopercle,
the third arches backward from the opercle, the fourth (broken) arches upward
and backward from the ventral body margin below the pectoral fin; and the fifth
almost defines a circle behind the gut cavity.

Combining this information with that in the literature (Jordan and Evermann
1898; Norman 1934; Hensley 1995a; Moser and Charter 1996), speckletail floun-
der has the following ranges of meristics: dorsal fin (78-89); anal fin (66—72);
pectoral fins (10—13); pelvic fins (6); caudal fin (17 total); gill rakers (3—4 upper,
6 lower); lateral line pores (64—68 eyed side, no lateral line on blind side); lateral
line scales (59-68). Its maximum reported size is 200 mm total length (Hensley
1995a).

Speckletail flounder is the only California flatfish with the following characters
in combination: left-eyed; small mouth (reaching anterior part of eye); jaw teeth
only on the blind side; a narrow interorbital crest between the eye with a backward
facing spine; dorsal and anal fins separate from caudal fin; rounded caudal fin
with four to five dark blotches; five to six curved dusky bands on blind side of
body; lateral line of eyed side with high arch over the pectoral fin and a short
bifurcating branch anteriorly, and no lateral line on blind side; and asymmetrical
pelvic fins with that of eyed side on ventral midline, having longer base, and
beginning two rays more anteriorly than that of blind side. The curved dusky

—=

Fig. 1. Speckletail flounder, Engyophrys sanctilaurentii, (80 mm SL) collected near La Jolla Can-
yon, California at a depth of 63 m on August 6, 1998 (SIO 00-81): a) Eyed side (scale patches indicate
size of scales on body); and b) blind side (details of medial fin rays are not shown). Drawings by
Atsuhiro Kubo.

139

SPECKLETAIL FLOUNDER IN CALIFORNIA

140 SOUTHERN CALIFORNIA ACADEMY OF SCIENCES

bands on the blind side are faint or obsolete in small individuals (Jordan and
Evermann 1898) and sometimes fade in larger individuals with preservation.

This species was one of a number of species collected for the first time in
California or the Southern California Bight during the 1997-1998 El Nifio (Lea
and Rosenblatt 2000). Speckletail flounder transforms at a length of 27—37 mm,
a size typical of flatfish species spending a longer time in the plankton and settling
on the middle or outer shelf habitats (Richardson and Pearcy 1977; Allen 1982;
Kramer 1991; Charter and Moser 1996; Moser and Charter 1996; Moser and
Sumida 1996). For comparison, eggs and larvae of California halibut are in the
plankton for about one month before settling to the bottom in shallow water at
10 mm SL (Allen 1988). As speckletail flounder transforms at a larger size, it
may be in the plankton for a longer period (perhaps to about three months). If
so, the species could reach southern California from Sebastian Vizcaino Bay
(about 600 km distance) during this period if water currents were about 7.5 cm/
sec, without eddies. Extreme values for the California Current range from 2 to
10 cm/sec (Hickey 1993). Thus it is possible that speckletail flounder spawned
near its reported northern limit could reach southern California during this period.
It is probably more likely the specimen collected was transported north from
spawning in unreported populations further north along the Baja California coast
than its reported range. The generally tropical distribution of the species and the
warm-temperate or cooler environment of the outer coast of Baja California sug-
gests that the species may have expanded northward along the Baja California
coast during the ocean warming of the past two decades (Smith 1995).

Speckletail flounder larvae can be taken year-round (Moser and Charter 1996).
The age of the specimen collected is not known. If the 80 mm SL specimen
collected in southern California represents young of the year, it may have been
spawned in fall of 1998, settling in southern California between fall and early
spring during the middle of the El Nino. If it is older, then its occurrence in
southern California cannot be attributed to the 1997-1998 El Nifo.

Little is known about the ecology or behavior of this species. However, the
general body morphology as an adult (i.e., small mouth with teeth only on blind
side, sharp ridge between the eyes) is quite similar to that of pleuronectid flatfishes
of the genus Pleuronichthys, (Allen 1982). Given its depth range, this species
may be an ecological counterpart of the hornyhead turbot, Pleuronichthys verti-
calis, which occurs off California and the outer coast of Baja California and of
the ocellated turbot, Pleuronichthys ocellatus, which occurs in the northern Gulf
of California (Fitch 1963, Allen 1982). At least among southern California flat-
fishes, the absence of teeth on the eyed-side of the jaws is characteristic of flat-
fishes that extract polychaetes from tubes and clip off clam siphons (Allen 1982).
Other species of small-mouthed flatfishes with jaw teeth only on blind side ap-
parently do not occur along the coast of Mexico south of Baja California nor off
Central America (Norman 1934; Hensley 1995a,b; Sommer 1995). There are,
however, several species of paralichthyids which have reduced tooth development
on jaws on the eyed side (Norman 1934; Hensley 1995b), a morphology that is
somewhat less appropriate for this type of foraging behavior (Allen 1982).

There are a number of nomenclatural problems associated with the names (both
scientific and common) of this species. The genus and species was first described
by Jordan and Bollman (1890). The date of 1889 originally given for this citation

SPECKLETAIL FLOUNDER IN CALIFORNIA 141

(Jordan and Evermann 1898) is incorrect as the signature date of this document
was February 5, 1890 (Hays 1952). The original species name was sancti-lau-
rentii, named for Saint Lawrence, and referring to the gridiron-like markings on
the blind side. Since that time, the name has been variously given in the literature
as sancti-laurentii (Jordan and Bollman 1890; Jordan and Evermann 1898; Nor-
man 1934), sanctilaurentii (Bussing and Lopez 1994; Eschmeyer 1998), or sanc-
tilaurentia (Hensley 1995a; Moser and Charter 1996; Escobar-Fernandez and Siri
1997). The International Code of Zoological Nomenclature (ICZN 1999) indicates
that hyphens should be removed from compound species-group names originally
published with a hyphen (unless the first element is a Latin letter) and both words
should be united. Thus the hyphenated version is not appropriate. Regarding the
correct ending, ‘ii’ is used if the name refers to a male person and ‘ia’ if it refers
to a quality, state of being, or disease (Jaeger 1966). The species was named after
Saint Lawrence, a 3rd century AD deacon of the early Catholic church who was
tortured to death by a Roman prefect on a hot grill, which branded him with
gridiron marks (Kirsch 1910). Thus, ‘ia’ would refer to the condition of having
the gridiron marks similar to those of Saint Lawrence whereas ‘ii’ would refer to
Saint Lawrence, the person who had the gridiron marks. Although Jordan and
Bollman (1890) refer to the gridiron pattern on the fish for justifying the name,
the name they gave was of the person rather than the Latinized version of the
grid-iron condition. Hence, it appears appropriate to maintain the original ending
of the name, with the correct species name (without a hyphen) for this species
being sanctilaurentii.

Published English common names for this species include ‘speckletail flounder’
(Bussing and Lopez 1994); “speckled-tail flounder’ (Hensley 1995a), and “speck-
ledtail flounder’ (Escobar-Martinez and Siri 1997). The American Fisheries So-
ciety Committee on Names of Fishes (Robins et al. 1991) recommends that com-
mon names be simple and with no hyphens, unless it is necessary to avoid mis-
understanding. Although there is precedent for combining plural modifiers with
nouns to form compound modifying words (e.g., ‘spottedtail goosefish’, ‘spotted-
fin tonguefish’, and ‘stripedfin ronquil’) in Robins et al. (1991), there is no pre-
cedent for ‘speckledtail.” ‘Speckle’ when combined with a noun is always treated
as singular (e.g., ‘specklefin midshipman’, ‘specklemouth eelpout’), presumably
due to the generally plural nature of ‘speckle.’ Thus we recommend ‘speckletail
flounder’ as the common name for this species.

Acknowledgments

The authors thank Steven Lagos of the City of San Diego Ocean Monitoring
Program for retaining the specimen for further identification. We thank Atsuhiro
Kubo for providing drawings of the La Jolla specimen. We also thank Phillip
Hastings and H. J. Walker of Scripps Institution of Oceanography, University of
California, San Diego and Richard Feeney and Jeffrey Siegel of the Natural His-
tory Museum of Los Angeles for collection information on speckletail flounder.

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Fisheries Investigations Reports 36:120-—126.

Sommer, C. 1995. Pleuronectidae. Pp. 1381—1385 in Guia FAO para la identificacion de especies para
los fines de la pesca. Pacifico centro-oriental. Vol. III. Vertebrados — Parte 2, (W. Fischer, W.
Schneider, C. Sommer, K. E. Carpenter, and V. H. Niem, eds.), United Nations, Food and
Agriculture Administration, xiii + 1,813.

Accepted for publication 21 December 2000.

Bull. Southern California Acad. Sci.
100(3), 2001, pp. 144-148
© Southern California Academy of Sciences, 2001

First record of the sabertooth blenny, Plagiotremus azaleus, in
California with notes on its distribution along the Pacific coast of
Baja California

Daniel J. Pondella, I! and Matthew T. Craig

Vantuna Research Group, Department of Biology,
Occidental College Los Angeles, California 90041

On 8 January 1998, while performing monthly ichthyological transects in King
Harbor, Redondo Beach, California (latitude 33°50.5’ N, Longitude 118°24.0’ W),
the senior author observed two individual sabertooth blennies, Plagiotremus aza-
leus, along the inside of the outer breakwater and along the Portofino reef at a
depth of 1.5 m (Pondella and Stephens 1994). The water temperatures were 19.8°
and 18.8° C, respectively. Since the initial sighting, sabertooth blennies were not
observed again for another eight months in spite of continual monitoring. After
17 August 1998 they were observed while performing routine transects until 3
February 1999 along the Portofino reef in variable numbers ranging from one to
six (Table 1). These fishes were observed in a temperature range from 13° to 24.5°
C (Table 1). On 18 August 1998, we observed three sabertooth blennies along
the Portofino reef and one was captured using a hand net and deposited at the
Scripps Institute of Oceanography fish collection (SIO98-263) (Fig. 1). The spec-
imen measured 59.8 mm SL and 68.3 mm TL (Table 2).

The previously reported range of the sabertooth blenny was the lower Gulf of
California to Peru and did not include the Pacific coast of Baja California (Thom-
son, et al. 1979; Allen and Robertson 1994; Grove and Lavenberg 1997). The
occurrence of the sabertooth blenny in Santa Monica Bay, represents a substantial
range extension of approximately 1450 km. It is not, however, the only siting of
this blenny outside of its historic range. It was also reported in a serpulid tube at
the center island of Islas Benitos, Baja California, Sur on 5 August 1998 (R. N.
Lea pers. comm.). On 4 November 1998 while diving on a cooperative (between
CICESE, University of Baja California and University of California, Santa Bar-
bara) research trip, Jennifer Casselle observed and subsequently captured a sa-
bertooth blenny at Chester Rock, Punta Eugenia, Baja California, Sur, (Latitude:
27° 52.19” N, Longitude: 115° 2.72” W). On the same expedition another was
observed at Point Augustine, Cedros Island (latitude 28° 4.46” N, longitude 115°
20.50 W) (D. Schroeder pers. comm.). The specimen at Punta Eugenia measured
59.3 mm SL and 70.6 mm TL (SIOO0-4) (Table 2). All characters, counts and
measures for these two fishes are consistent with those values reported for the
sabertooth blenny, considering that this is the only eastern Pacific representative
of this group (Smith-Vaniz 1976), identification was straightforward.

The sabertooth blennies of the tribe Nemophini (Perciformes: Blenniidae) rep-
resent the most specialized group of the combtooth blennies. The tribe is an
intriguing group of marine reef fishes found almost exclusively at tropical and
subtropical latitudes to a depth of 25 m. Unlike most blenniids, the sabertooth
blennies devote much time to hovering above the substrate or actively swimming

144

SABERTOOTH BLENNY IN CALIFORNIA

145

Table 1. Characters, counts and measurements for two specimens of sabertooth blenny, Plagiotre-
mus azaleus, from southern and Baja California. Lengths are given in millimeters.

Characters, counts and measurements SIO98-263 SIOO0-4
Dorsal Fin VHT, 32 VIII, 33
Anal fin i. 27 TE. 26
Pectoral fin 1s 12
Procurrent caudal fin rays 6-8 + 6-8 5-6 + 5-7
Pelvic fins present present
Incisors on upper jaw 30 52
Incisors on lower jaw 54 55
Incisor ratio 1.8 1.7
Shape of dentary incisors blunt blunt
Shape of snout conical conical
Snout pigmentation uniform uniform
Interorbital pores 2 2
Supraorbital pores 2 2
Mandibular pores 2 2

Bony spur on innermost anal fin rays absent absent
Length of outer lobes of caudal fin elongate elongate
Dorsal fin stripe present present
Standard length 59.8 60.6
Total length 68.3 71.6
Preanal length 25.0 aaa
Caudal fin length IA 1s3

in the water column, they have a well-developed swim bladder, which aids in
their semipelagic behavior (Smith-Vaniz 1976). Uncommonly large dentary ca-
nines used primarily in defense and intraspecific competition characterize Plagi-
otremus, one of five Nemophini genera. These thin and wedge shaped canines are
capable of some movement and are apomorphic along with the lack of both
premaxillary canine teeth and a lateral line. With the exception of a single eastern
Pacific species, the sabertooth blenny, the tribe is restricted to the Indo-Pacific
region.

Originally placed in the genus Runula by Jordan and Bollman (1889), the

Table 2. Date, number of individuals, temperature, and location of observation for the sabertooth
blenny, Plagiotremus azaleus, outside of the Gulf of California. OB = outer breakwater, PR = Por-
tofino reefs in King Harbor, Redondo Beach, CA, as described by Pondella and Stephens (1994).

Date No. individuals Location Temperature (°C)
January 8, 1998 Vs (1) OB, (1) PR 19.8, 18.8
August 5, 1998 1 Islas Benitos, Baja Cal. 20.9
August 17, 1998 2 PR 24.5
October 29, 1998 ) PR 16.8
November 4, 1998 3 Punta Eugenia, Baja Cal. 20.0
November, 1998 1 Cedros Island, Baja Cal. 19.0
November 19, 1998 3 PR 1622
December 15, 1998 3 PR 13:8
January 7, 1999 6 PR 14.0
February 3, 1999 3 PR 13.0

146 SOUTHERN CALIFORNIA ACADEMY OF SCIENCES

~ me 006.666 “es "3 Ae, ?

~~,
eeematmnmeinnah tir Fos ret Fe ggg Pe Ae A GA Pe NOE at gh OE

Fig. 1. Left lateral view of the sabertooth blenny, Plagiotremus azaleus, (59.8 mm SL, SIO98-
263) captured in King Harbor, Redondo Beach, California on 18 August 1998. Photograph by Daniel
J. Pondella, II.

holotype (USNM 44299) was collected at Indefatigable Island, Galapagos. Much
confusion has been noted in the nomenclature of this species, primarily due to
the conspicuous color phase shift from a banded juvenile phase to a striped adult
phase. Runula azaleus was placed in Plagiotremus by Smith-Vaniz (1976) based
upon a single apomorphic character described as “‘snout of adults fleshy, conical.”
Smith-Vaniz (1976) included a key to the genera and species of Nemophini and
he did recognize Runula as a subgenus of Plagiotremus as five of the 11 species
of Plagiotremus, including the sabertooth blenny, share the derived snout shape
described above.

SCUBA divers can easily identify the sabertooth blenny and it is especially
striking within the temperate reef community. Distinguished by its elongate body,
cone-shaped snout, and bright yellow and blue stripes, the sabertooth blenny is
easily differentiated from other members of eastern Pacific reef fish communities
with the exception of the initial phase of the Cortez rainbow wrasse, Thallasoma
lucasanum (Perciformes: Labridae). The sabertooth blenny only superficially re-
sembles the Cortez rainbow wrasse, but differs in lacking the characteristic red
underside of the wrasse, being clearly less deep bodied, and having an inferior
mouth (rather than terminal).

While sabertooth blennies are known to aggregate with adult Cortez rainbow
wrasses, they are not an aggressive mimic of the parasite-cleaning behavior of
the juveniles (Hobson 1969). The three types of classical mimicry (Batesian,
Miillerian and aggressive), may be found in Plagiotremus as well as in the allied
blenniid genera Aspidontus, Ecsenius, and Petroscirtes. The classical example of
aggressive mimicry comes from Aspidontus taeniatus, which has both juvenile
and adult color phases similar to the labrid Labroides dimidiatus that establishes
parasite cleaning stations for larger fishes. This allows A. taeniatus protection so
it can approach larger fishes and bite the fins (Randall and Randall 1960). Pla-
giotremus rhynorhynchos also aggressively mimics this symbiotic cleaner wrasse
and will ambush larger fishes on its own biting off pieces of fins, scales and
mucous while they are feeding (Randall et al. 1996). This aggressive behavior is
what has been observed for P. azaleus which is known to strike larger fishes from
below and behind removing dermal material from the startled animal (Hobson
1969). Batesian mimicry may be due to a noxious taste, which has partially been
demonstrated for P. townsendi, making them unpalatable to predators (Springer
and Smith-Vaniz 1972). There is strong resemblance between the P. laudandus
species group and the sympatric species of Meiacanthus, the fangblennies, and
this may be an example of Miillerian mimicry (Smith-Vaniz 1976). Thus, this

SABERTOOTH BLENNY IN CALIFORNIA 147

genus is of considerable intrigue in the study of the behavioral evolution of mim-
icry.

These fishes are diurnal reef species, which shelter within burrows of worm or
mollusk tubes on the reef (Hobson 1965). The individuals captured and observed
at all locations were adults, as the maximum reported length is 102 mm TL
(Hobson 1969; Thomson et al. 1979). Similar to most blennies, the sabertooth
blenny is oviparous and deposits its eggs in a parental guarded nest followed by
a pelagic larval stage (Watson 1996). There is limited larval data available from
the CalCOFI ichthyoplankton surveys, which describe sabertooth blenny larvae
only from the Gulf of California and to the south (Watson 1996; H. Geoffrey
Moser, pers. comm.). The larvae do have similar preflexion (2.1—5.6 mm), post-
flexion (7.2—13.6 mm) and juvenile (26.8—33.0 mm) lengths with respect to the
other California blennies and may have a fairly extended larval period. For the
southern California blennies the larval period for the mussel blenny, Hypsoblen-
nius jenkinsi, was 34—56 days (mean = 44) and 46—79 days (mean = 66) for the
rockpool blenny, H. gilberti (Stephens et al. 1970; Ninos 1984). The mussel blen-
ny matures in the laboratory in 141 days after hatching (Stevens and Moser 1982).
Considering the life history characters of this and confamilial species (an extended
larval period, small size, habitat specificity and early maturity), the northern
movement of this species was undoubtedly facilitated by larval drift during the
very large 1997—98 El Nino Southern Oscillation event (Chavez et al. 1999). The
observance of these fishes over such a wide geographic area and relatively long
temporal period suggests that their presence in the warm temperate fauna of the
San Diegan Province is not anomalous. However the continued success of the
sabertooth blenny in Southern California is unknown.

Acknowledgements

The following research would not have been possible without the assistance of
the following persons: John S. Stephens, Jr. of the Vantuna Research Group;
Robert N. Lea of the Department of Fish and Game; Donna Schroeder, Jennifer
Casselle and Milton Love of the Marine Science Institute, University of Califor-
nia, Santa Barbara; Jorge A. Rosales Casian and Oscar Sosa Nishizaki of CICESE;
H. Geoffrey Moser of the National Marine Fisheries Service; the support of
Wayne Ishimoto and Chevron Products Company; and the curatorial assistance
of Richard H. Rosenblatt, H. J. Walker, and Cindy Klepadlo at the Scripps Institute
of Oceanography.

Literature Cited

Allen, G. R. and D. R. Robertson. 1994. Fishes of the tropical eastern Pacific. University of Hawaii
Press, Honolulu. xix + 332 p.

Chavez, E P, P. G. Strutton, G. E. Friederich, R. A. Feely, G. C. Feldman, D. G. Foley, and M. J.
McPhaden. 1999. Biological and chemical response of the equatiorial Pacific ocean to the 1997—
98 El Nifio. Science. 286:2126—2131.

Grove, J. S. and R. J. Lavenberg. 1997. The fishes of the Galapagos Islands. Stanford University
Press, Stanford, California. xliv + 863 p.

Hobson, E. S. 1965. Diurnal-nocturnal activity of some inshore fishes in the Gulf of California. Copeia
1965(3):291-—302.

. 1969. Possible advantages to the blenny Runula azalea aggregating with the wrasse Thalas-

soma lucasanum in the tropical eastern Pacific. Copeia 1969(1):191-—93.

148 SOUTHERN CALIFORNIA ACADEMY OF SCIENCES

Jordan, D. S. and C. H. Bollman. 1890. Scientific results of explorations by the U. S. Fish Commission
steamer Albatross. No. IV. Descriptions of new species of fishes collected at the Galapagos
Islands and along the coast of the United States of Colombia, 1887-88. Proc. U. S. Natl. Mus.
12(770):149-83.

Ninos, M. 1984. Setthement and metamorphosis in Hypsoblennius (Pisces, Blenniidae). Ph.D. disser-
tation, University of Southern California, Los Angeles, 181 p.

Pondella, D. J., II, and J. S. Stephens, Jr. 1994. Factors affecting the abundance of juvenile fish species
on a temperate artificial reef. Bull. Mar. Sci. 55(2—3):1216—1223.

Randall, J. E., G. R. Allen, and R. C. Steene. 1996. Fishes of the Great Barrier Reef and Coral Sea.
University of Hawaii Press, Honolulu, HI. xx + 557 p.

Randall, J. D. and H. A. Randall. 1960. Examples of mimicry and protective resemblance in tropical
marine fishes. Bull. Mar. Sci. Gulf and Carib. 10(4):444—480.

Smith-Vaniz, W. E 1976. The saber-toothed blennies, tribe Nemophini (Pisces: Blenniidae). Acad. Nat.
Sci. Phila. Monog. 19. 196 p.

Springer, V. G. and W. E Smith-Vaniz. 1972. Mimetic relationships involving fishes of the family
Blenniidae. Smithsonian Contributions to Zoology 112. 36 p., 4 figs., 7 pls.

Stephens, Jr, J. S., R. K. Johnson, G. S. Key, and J. E. McCosker. 1970. The comparative ecology
of three sympatric species of California blennies of the genus Hypsoblennius Gill (Teleostomi,
Blenniidae). Ecological Monographs 40(2):213-—233.

Stevens, E. G. and H. G. Moser. 1982. Observations on the early life history of the mussel blenny,
Hypsoblennius jenkensi, and the bay blenny, Hypsoblennius gentilis, from specimens reared in
the laboratory. Calif. Coop. Ocean. Fish. Inv. Rep. 23:269-—275.

Thomson, D. A., L. T. Findley, and A. N. Kerstitch. 1979. Reef fishes of the Sea of Cortez. John
Wiley and Sons, New York, New York. xvii + 302 p. + 32 pls.

Watson, W. 1996. Blenniidae: combtooth blennies. Pp. 1182-1199 in H. Geoffrey Moser ed., The
Early Stages of Fishes in the California Current Region. California Cooperative Oceanic Fish-
eries Investigations Atlas No. 33., Allen Press, Inc., Lawrence, Kansas. xii + 1505 p.

Accepted for publication 19 June 2000.

Bull. Southern California Acad. Sci.
100(3), 2001, pp. 149-152
© Southern California Academy of Sciences, 2001

Addition of Blacklip Dragonet, Synchiropus atrilabiatus
(Garman, 1899) (Pisces: Callionymidae) to the
California Ichthyofauna

Ami K. Groce,! Richard H. Rosenblatt, and M. James Allen?

‘City of San Diego, Metropolitan Wastewater Department, Environmental
Monitoring and Technical Services Division, San Diego, California 92106
*Scripps Institution of Oceanography, University of California, San Diego,
La Jolla, California, 92093-0208
3Southern California Coastal Water Research Project,
Westminster, California, 92683

Dragonets (family Callionymidae) are small, often colorful, benthic fishes
found in coastal tropical waters of the Atlantic, Indian, and Pacific Oceans, but
primarily in the Indo-West Pacific (Nelson 1994). The systematics of this family
are not well known, with numbers of taxa ranging from 8 genera and 40 species
to 19 genera and 139 species (Grove and Lavenberg 1997). The only dragonet
known from the Eastern Pacific is Synchiropus atrilabiatus (Garman 1899), which
is found primarily off Mexico and Central America (Grove and Lavenberg 1997).

Following the 1997—1998 El Nifio, two specimens of the blacklip dragonet were
collected in the Southern California Bight (SCB) by semiballoon (7.6-m wide
headrope) otter trawls with 1.2-cm cod-end mesh. The first specimen (56 mm SL)
was collected on 23 July 1998 off Santa Catalina Island (latitude 33°17.68'N,
longitude 118°17.00'W) at a depth of 97 m, during the Southern California Bight
1998 Regional Survey (Bight’98), a bight-wide survey of the mainland and island
shelves of southern California. The second specimen (90 mm SL) was collected
on January 19, 1999 off Point Loma, California (latitude 32°37.54'N, longitude
117°19.37'W) at a depth of 100 m. It was captured at one of the City of San
Diego, Metropolitan Wastewater Department, Environmental Monitoring and
Technical Services’ long-term, fixed-location trawl monitoring stations, which has
been sampled quarterly since July 1991. City of San Diego marine biologists
brought this specimen to the attention of the second author (RHR), who identified
it as Synchiropus atrilabiatus. This was the first specimen identified from Cali-
fornia waters although it was the second specimen collected. The third author
(MJA) identified the first-caught specimen later when voucher specimens collected
during the Bight’98 survey were sent to SCCWRP for taxonomic confirmation.
Both specimens had similar meristics (Table 1) and have been catalogued in the
SIO Marine Vertebrates Collection: SIO 99-1 (Point Loma) and SIO 00-79 (Santa
Catalina Island).

The previous published geographic range of this species was from Bahia Mag-
dalena, Baja California Sur, Mexico and the Gulf of California to Talara, Peru,
including Gorda Banks (off Cabo San Lucas, Baja California Sur, Mexico), Cocos
Island, and the Galapagos Islands (Fricke 1981; Cruz-Aguero et al. 1994). The
capture of Synchiropus atrilabiatus at Santa Catalina Island represents a range
extension of 1,250 km north of its northernmost published record at Bahia Mag-

149

150 SOUTHERN CALIFORNIA ACADEMY OF SCIENCES

Table 1. Location and meristic data for Synchiropus atrilabiatus specimens collected in southern
California in 1998 and 1999.

Specimens
Category SIO 00-79 SIO 99-1

Collection Information

Date 23 July 98 19 January 99

Location Santa Catalina Island, CA off Point Loma, CA

Latitude, Longitude 33°17.68' N, 118°17.00’ W 32°37.54' N, 117°19.37' W

Depth (m) 97 100

Standard Length (mm) 56 90
Merisitic Counts

Dorsal Fin Elements IV, 9 IV, 9

Anal Fin Rays 8 8

Pectoral Fin Rays 20 22

Pelvic Fin Elements yd | Hie

Principal Caudal Fin Rays 10 10

dalena, Mexico (latitude 24°35.0’N) (Cruz-Aguero et al. 1994; Love et al. 1996!)
and about 650 km from its previous northernmost unpublished occurrence (i.e.,
Bahia Playa Maria, Baja California, Mex.; latitude 28°52.0'’N, longitude
114°30.0’W; 1 September 1952; SIO 52-60).

Synchiropus atrilabiatus occurs on soft bottoms on the mainland and island
shelf. Benthic individuals range in depth from 12 to 150 m in sand and mud
habitats, and to a lesser degree in coral rubble (Grove and Lavenberg 1997).
Maximum known size of adults is 121 mm (SIO 84-80). This species is oviparous
with planktonic eggs and larvae (Watson 1996). Larvae are taken throughout the
year, with young larvae collected primarily during summer (Watson 1996). Al-
though the species transforms from larva to juvenile at 8.3—12.5 mm (Watson
1996), pelagic juveniles up to 39 mm SL have been taken in midwater (SIO 72-
342), and both larvae and pelagic juveniles have been taken near the surface
offshore to 300 km over water depths of 4,000 m or more (Grove and Lavenberg
1997).

Synchiropus atrilabiatus has a cottiform body with a small mouth (Figure 1)
and superficially resembles a sculpin (family Cottidae). It differs from all sculpins
in having the gill opening reduced to a pore on the dorsal surface behind the head
(Figure 1); sculpins have relatively large lateral gill openings. It is scaleless with
a pointed snout and highly protrusible upper jaws. Characteristics of S. atrilabia-
tus that distinguish it from other callionymids include numerous small dark
blotches on body, a dorsal fin with dark oval blotches between the third and forth
spines, black coloration on the lower half of the anal fin, and a black margin on
the upper jaw (Fricke 1981). Fin element ranges are the following: dorsal fin
(IV,8—9), anal fin (7—8), pectoral fins (18-23), pelvic fins (1,5), principal caudal
rays (5+5), and procurrent caudal rays (2—3 upper, 2 lower). There are 6 bran-
chiostegal rays.

' Love, M. S., L. Thorsteinson, C. W. Mecklenburg, and T. A. Mecklenburg. 1996. A checklist of
marine and estuarine fishes of the North East Pacific, from Alaska to Baja California. National Bio-
logical Service. Located at website http://id-www.ucsd.edu/ lovelab/home.html

BLACKLIP DRAGONET IN CALIFORNIA Lt

Fig. laandb. Blacklip dragonet (Synchiropus atrilabiatus). Top (a) and side view (b) of specimen
from Santa Catalina Island, 56 mm SL; SIO 00-79 (drawing by Atsuhiro Kubo). Arrows indicate
diagnostic gill pore on dorsal surface behind the head.

The appearance of Synchiropus atrilabiatus in the waters of the Southern Cal-
ifornia Bight at the time of collection may be related to the physical oceanographic
conditions associated with the 1997-1998 El Nino. This was just one of many
tropical species collected for the first time in California after the warm water
intrusion that was first detected in Southern California during July and August
1997 (Lea and Rosenblatt 2000). These fishes may have come into the area as
larvae or juveniles with the warm water mass that moved up from the south.
While no ages were determined for the two specimens discussed here, they were
collected at relatively small sizes (56 mm in July 1998 and 90 mm in January
1999) compared to the maximum size of the largest known S. atrilabiatus (121
mm; SIO), as well as the maximum family size (25 to 30 cm; Bussing and Lopez
1994; Grove and Lavenberg 1997). If juveniles are pelagic to about 39 mm (as
indicated by SIO collection data), the first specimen may have settled to the
bottom in spring of 1998. The second specimen may have settled at this time also
and grown to its length at capture in nearly a year’s time; however, the growth
rate of this species is not known.

The common name ‘blacklip dragonet’ was suggested by the second author
(RHR) in reference to its black upper lip and its scientific name atrilabiatus (black
lip). Other English common names for this species include ‘sleepy dragonet’
(Bussing and Lopez 1994) and ‘antler dragonet’ (Grove and Lavenberg 1997); in
Spanish, it is known as ‘gobio vistoso’ (Bussing and Lopez 1994) and ‘dragonito
de asta’ (Grove and Lavenberg 1997). We recommend ‘blacklip dragonet’ as an
English common name for this species as this name has more diagnostic value
than the other common names.

LS2 SOUTHERN CALIFORNIA ACADEMY OF SCIENCES

Acknowledgments

The authors thank Dr. Michael Franklin (Southern California Marine Institute)
and Steven Lagos and Eric Nestler (both of the City of San Diego, Metropolitan
Wastewater Department, Ocean Monitoring Program) for recognizing the first and
second specimens, respectively, as unusual. We thank Atsuhiro Kubo for contrib-
uting the drawings of the Santa Catalina Island specimen. We also thank Richard
Feeney and Jeffery Siegel of the Natural History Museum of Los Angeles for
collection information on Synchiropus atrilabiatus.

Literature Cited

Cruz-Aguero, J. del la, E Galvan-Magana, L. A. Abitia-Cardenas, J. Rodriquez-Romero, and F J.
Gutiemez-Sanchez. 1994. Systematic list of marine fishes from Bahia Magdalena, Baja Cali-
fornia Sur (Mexico). Cienc. Mar. 20:17—31.

Bussing, W. A., and M. I. Lopez S. 1994. Demersal and pelagic inshore fishes of the Pacific Coast of
lower Central America. Special Publication of the Revista de Biologia Tropical, San Jose, Costa
Rica. 164 pp.

Fricke, R. 1981. Revision of the genus Synchiropus: Theses Zoologicae Vol. I. J. Cramer, Braun-
schweig. 194 pp.

Garman, S. 1899. The fishes in Reports on an exploration off the west coasts of Mexico, Central and
South America, and off the Galapagos Islands by the U. S. Fish Commission steamer “‘Alba-
tross” during 1891. No. XXVI. Mem. Mus. Comp. Zool. v. 24. 431 pp. + 85 pl.

Grove, J. S. and R. J. Lavenberg. 1997. The Fishes of the Galapagos Islands. Stanford University
Press. 936 pp.

Lea, R. N. and R. H. Rosenblatt. 2000. Observations on fishes associated with the 1997—1998 El Nifio
off California. CalCOFI Reports Vol 41:117—129.

Nelson, J. S. 1984. Fishes of the World, Third Edition. John Wiley and Sons, Inc. xvii + 600 pp.

Watson, W. 1996. Callionymidae: Dragonets. Pages 1205-1207 in The Early Stages of Fishes in the
California Current Region. Coop. Fish. Invest. Atlas. No. 33 (H. G. Moser, ed.), Allen Press
Inc. 1,505 pp.

Accepted for publication 21 December 2000.

Bull. Southern California Acad. Sci.
100(3), 2001, pp. 153-155
© Southern California Academy of Sciences, 2001

Addition of the Calico Lizardfish, Synodus lacertinus Gilbert, 1890
(Pisces: Synodontidae) to the Ichthyofauna of the Southern
California Bight

Ami K. Groce, Steven L. Lagos, and Eric C. Nestler

City of San Diego, Metropolitan Wastewater Department, Environmental
Monitoring and Technical Services Division, Point Loma, California 92106

Lizardfishes (Synodontidae) are small to moderate-sized fishes with elongate,
cylindrical bodies and large, spiny toothed, lizard-like mouths. They are common
benthic fishes found in the Atlantic, Indian and Pacific Oceans (Nelson 1994).
Synodus is the only genus known from the Eastern Pacific, and is represented by
five species (S. evermanni, S. lacertinus, S. lucioceps, S. sechurae, and S. scitu-
liceps; Allen and Robertson 1994; Grove and Lavenberg 1997). Only one of the
five species, the California lizardfish, S. lucioceps, has previously been reported
from the Southern California Bight (SCB).

On October 9, 1998, a single specimen of the calico lizardfish, Synodus lac-
ertinus, was collected by small (7.6 m wide headrope) semiballoon otter trawl
during a routine survey performed by the City of San Diego’s Marine Biology
Laboratory (Metropolitan Wastewater Department, Environmental Monitoring and
Technical Services Division). The specimen was captured off Playas de Tijuana
(approx. 6 km south of the United States-Mexico boundary) (latitude 32°28.35’
N and longitude 117°10.50’ W) at a depth of 27 m over sandy substrate. The fish
was measured and photographed, then deposited in the Marine Vertebrates Col-
lection, Scripps Institution of Oceanography (SIO 99-28). It measured 129 mm
standard length (SL) and 145 mm total length (TL) and had the following counts:
dorsal fin elements (11), anal fin rays (8), pectoral fin rays (11), pelvic fin elements
(8) and lateral line scales (61). The specimen was identified by R. H. Rosenblatt
as Synodus lacertinus Gilbert, 1890 (Figure 1). The calico lizardfish has also been
referred to as the sauro lizardfish (Cruz-Aguero et al. 1994, Bussing and Laven-
berg 1995), the banded lizardfish (Grove and Lavenberg 1997), and the reef li-
zardfish (Allen and Robertson 1994).

The previous published geographic range of this species was from Bahia Mag-
dalena, Baja California Sur, Mexico (Cruz-Aguero et al. 1994; Love et al. 1996!)
and the Gulf of California to Peru, including the Cocos and the Galapagos Islands
(Bussing and Lavenberg 1995; Grove and Lavenberg 1997). Unpublished occur-
rences of this species farther north than Bahia Magdalena include a specimen
collected in February 1964 at San Pablo Point (latitude 27°13.0’ N; SIO 64-68)
and a photo of S. lacertinus from Islas San Benito (approx latitude 28° N; R. N.
Lea, pers comm.). The capture of S. lacertinus near the United States-Mexico

153

154 SOUTHERN CALIFORNIA ACADEMY OF SCIENCES

Fig. 1. Calico lizardfish (Synodus lacertinus), dorsal aspect. Specimen from off Playas de Tijuana,
129 mm SL; SIO 99-28. Photo taken by Ron Velarde.

boundary represents a range extension of greater than 500 km from these locations
off central Baja California, Mexico.

Characteristics of Synodus lacertinus that distinguish it from other eastern Pa-
cific synodontids include most notably five broad dark bars across the dorsum
(Grove and Lavenberg 1997). These dark bars make S. lacertinus quite distinct
from S. luciosceps, which is the only lizardfish commonly found in the SCB.
Other diagnostic characters include an upper jaw larger than lower jaw, short
snout (especially compared to S. lucioceps), dorsal and caudal fins with a series
of oblique stripes, and a wide head (as broad as long) (Allen and Robertson 1994;
Bussing and Lavenberg 1995; Grove and Lavenberg 1997). Synodus lucioceps is
also quite distinct from S. lacertinus in that it has a diagnostic yellow coloration
on its gill membranes and pelvic fins. The other Eastern Pacific Synodus, S. ev-
ermanni, S. scituliceps, and S. sechurae (as well as S. lucioceps) all have fairly
dull coloration in comparison to S. lacertinus. In addition to differences in col-
oration, these species have different meristics (see Allen and Robertson 1994,
Bussing and Lavenberg 1995, Grove and Lavenberg 1997).

The appearance of Synodus lacertinus in the Southern California Bight may be
related to the physical oceanographic conditions associated with the 1997—1998
El Nifo. This was just one of many tropical species collected for the first time
in the Bight after the warm water intrusion that was first detected in July and
August 1997 (Lea and Rosenblatt 2000). Our fish may have come into the area
with the warm water mass that moved up from the south. Although the size of
this specimen, at 145 mm TL, was very close to its known maximum length of
160 mm TL (Allen and Robertson 1994), it is possible that the fish either moved
into the area with this El Nifio event as an adult, or with a previous event as a
larvae or juvenile.

Acknowledgments

The authors are indebted to R.H. Rosenblatt for identifying this specimen, and
to the curatorial assistance of H.J. Walker, C. Klepadio and P. Hastings at the
Scripps Institution of Oceanography. We would also like to thank R. Feeney and

CALICO LIZARDFISH IN CALIFORNIA 155

J. Siegel of the Natural History Museum of Los Angeles for collection information
on Synodus lacertinus. We would like to acknowledge the critical review and
assistance of M.J. Allen (Southern California Coastal Water Research Project),
and information provided by R.N. Lea (California Department of Fish and Game).

Literature Cited

Allen, G. R. and D. R. Robertson. 1994. Fishes of the Tropical Eastern Pacific. University of Hawaii
Press. 332 pp.

Bussing, W.A., and R.L. Lavenberg. 1995. Synodontidae. Pages 1625-1628 in Guia FAO para la
identificacion de especies para los fines de la pesca Pacifico Centro-Oriental: Volume III, Ver-
tebrados Parte 2. W. Fisher, W., E Krupp, W. Schneider, C. Sommer, K. E. Carpenter, and V.
H. Niem (eds), United Nations Food and Agriculture Organization, Roma, It.

Cruz-Aguero, J. del la, EK Galvan-Magana, L. A. Abitia-Cardenas, J. Rodriquez-Romero, and F J.
Gutiemez-Sanchez. 1994. Systematic list of marine fishes from Bahia Magdalena, Baja Cali-
fornia Sur (Mexico). Cienc. Mar. 20:17-—31.

Gilbert, C. H. 1890. A preliminary report on the fishes collected by the steamer Albatross on the
Pacific Coast of North America during the year 1889, with descriptions of twelve new genera
and ninety-two new species. Proc. U.S. Natl. Mus. V.13 (797):49—126.

Grove, J. S. and R. J. Lavenberg. 1997. The Fishes of the Galapagos Islands. Stanford University
Press, 936 pp.

Lea, R. N. and R. H. Rosenblatt. 2000. Observations on fishes associated with the 1997-1998 El Nino
off California. CalCOFI Reports Vol 41:117-129.

Nelson, J. S. 1994. Fishes of the World, Third Edition. John Wiley and Sons, Inc. xvii + 600 pp.

Accepted for publication 25 January 2001.

Bull. Southern California Acad. Sci.
100(3), 2001, pp. 156-159
© Southern California Academy of Sciences, 2001

First Record of the Pacific Cornetfish, Fistularia corneta Gilbert
and Starks 1904, a New Species to the Southern California Fauna
During the 1997-1998 El Nino

Michael D. Curtis! and Kevin T. Herbinson?2

'MBC Applied Environmental Sciences, Costa Mesa, California 92626
2Southern California Edison Company, Rosemead, California 91770

On 7 May 1998, two small cornetfish (319 and 345 mm total length) were
taken from the cooling water screenwell in front of the circulating water gates at
the former Southern California Edison’s Huntington Beach Generating Station
(now AES Huntington Beach) during a routine fouling control operation. They
were initially thought to be the reef cornetfish, Fistularia commersonii; however,
critical examination indicated that these two specimens are the Pacific cornetfish,
Fistularia corneta Gilbert and Starks 1904, a new addition to the California fauna.

The occurrence of F. corneta at the Huntington Beach Generating Station intake
in Huntington Beach, Orange County, California (33°38.37' N and 117°58.98' W)
represents a range extension of approximately 836 km from its previously listed
northern most record at San Hipolito, Baja California, Mexico (26°58.0' N and
113°58.2' W). On 27 August 1956, 11 specimens of F. corneta, ranging from
111 to 190 mm, were collected from Bahia San Hipolito (from SIO Collection
No. 64—750'). The Huntington Beach specimens, therefore, represent an extension
of approximately 836 km from that location.

The sea floor directly offshore of the Huntington Beach Generating Station is
relatively smooth and sediments are composed of mostly fine-to-medium grained
sand, with isobaths parallel to the coastline. The intake is located about 500 m
offshore on a smooth sandy bottom at a depth of approximately 8 m. Pacific
cornetfish typically are taken over smooth bottoms (Fritzche 1976) and are re-
ferred to as the deepwater cornetfish in the Gulf of California, as they typically
occur in water depths greater than 30 m (Thomson ef al. 1979). Its previous
published range is from the outer coast of Baja California near Bahia San Hipolito
to Peru and the offshore islands (Hildebrand 1946, Thomson et al. 1979). They
are frequently collected in otter trawls.

Cornetfishes (Fistulariidae) have an elongate, depressed body with long tubular
snout, short oblique mouth, minute teeth, single dorsal fin located posterior on
body above anal fin and a forked caudal fin with a long medial filament (Allen
and Robertson 1994) (Figure 1). There are four species in the tropical and sub-
tropical genus of Fistularia. Two of these, the reef cornetfish and the Pacific
cornetfish, are found in the eastern Pacific (Fritzche 1976, Allen and Robertson
1994, Fritzche and Schneider 1995). The Pacific cornetfish differs from the reef
cornetfish by having more dorsal, anal, and pectoral rays, usually 18 to 20, 17 to
18, and 16 to 18, respectively; reef cornetfish have dorsal rays of 15 to 17, anal

'Scripps Institution of Oceanography Marine Invertebrates Fish Collection. 2000. Website:
www-sioadm.ucsd.edu/FM (Fistularia corneta) SIO number 64—750.

156

FIRST RECORD OF PACIFIC CORNETFISH IN SOUTHERN CALIFORNIA 157

interorbital

Fistularia cometa

Fistularia commersonii

Fig. 1. Dorsal views of head and body of Pacific cornetfish (Fistularia corneta) and reef cornetfish
(Fistularia commersoni) (Fig. from Bussing and Lopez 1994).

rays of 14 to 16, and pectoral rays of 13 to 15 (Thomson et al. 1979, Allen and
Robertson 1994). Pacific cornetfish are reported to attain lengths of at least 700
mm, whereas reef cornetfish can grow to be at least 1500 mm in length (Allen
and Robertson 1994, Fritzche and Schneider 1995). Specimens collected at
Huntington Beach had meristics within the range of Pacific cornetfish (Table 1).

A definitive identification was made by looking at the interorbital area of the
head. In Pacific cornetfish there is a wide smooth interorbital space, whereas
longitudinal ridges are found in this same area in reef cornetfish. This is aptly
illustrated in Bussing and Lopez (1994).

As has been documented with past El Nifios, the advent of the El Nifio of
1997-1998 brought new species of fish and invertebrates to the southern Cali-
fornia waters (Wooster and Fluharty 1985, Lea and Rosenblatt 2000). Although
it appears this cornetfish species may have a preference for slightly cooler waters

Table 1. Meristics of the two Huntington Beach specimens of Pacific cornetfish, Fistularia corneta,
LACM 54542-1.

Specimen
1 2
Total Length (mm) End of Filament 345 319
Biomass (g) 20 14
Dorsal, Fin Rays 18 18
Anal, Fin Rays by 17

Pectoral, Fin Rays Wy 18

158 SOUTHERN CALIFORNIA ACADEMY OF SCIENCES

found at depth, it is not unusual to find expatriate fishes from Baja California
attracted to the vicinity of southern California power plant discharges. Ocean
temperatures in the vicinity of the intake were 16.1° C on the day of capture,
several degrees warmer than seasonally normal due to the effects of the El Nifio.
Typically, temperatures are also 4 to 5° C higher within 10 m of the power plant
discharge plume, decreasing rapidly with distance (MBC1975). It is possible that
the two specimens of F. corneta were attracted to the area due to the presence
of warm water at the outfall. Alternatively, because it is known that the intake
and discharge structures act as de facto artificial reefs attracting a variety of
species of fish, the predatory cornetfish may have been present in the immediate
area to forage on fishes associated with the high relief intake and discharge struc-
tures (Helvey and Dom 1981, Helvey and Smith 1985). Whatever their reason
for being in the vicinity, they were inadvertently entrained by the strong inward
flow of water at the intake tunnel and transported through the tunnel to the forebay
of the power plant where they were subsequently impinged and collected.

The two specimens are deposited at the Natural History Museum of Los An-
geles County, (LACM 54542-1).

Acknowledgments

We wish to thank M. J. Allen for his constant enthusiasm, identification of the
two specimens, suggestions of literature, and critical review of the manuscript.
We would also like to thank R.N. Lea and J. Siegel for their support and en-
couragement and critical reviews of the manuscript which have resulted in an
improved paper. In addition, we would like to thank Southern California Edison,
MBC Applied Environmental Sciences, and AES Huntington Beach Generating
Station for supporting these studies.

Literature Cited

Allen, G.R., and D.R. Robertson. 1994. Fishes of the tropical eastern Pacific. University of Hawaii
Pressxix(-: (332ipp:

Bussing, W.A., and M. I. Lopez S. 1994. Demersal and pelagic Inshore fishes of the Pacific coast of
lower Central America: An illustrated guide. Rev. Biol. Trop; Spec. Publ., 164 pp.

Fritzsche, R. A. 1976. A review of the cornetfishes, genus Fistularia (Fistulariidae), with a discussion
of intrageneric relationships and zoogeography. Bull. Mar. Sci., 26(2):196—204.

Fritzsche, R. A., and M. Schneider. 1995. Fistulariidae. Pp. 1104-1105 in Guia FAO para la identi-
ficacion de especies para los fines de la pesca. Pacifico centro-oriental. Vol. Il. Vertebrados—
Parte 1, (W. Fischer, W. Schneider, C. Sommer, K. E. Carpenter, and V. H. Niem, eds.), United
Nations, Food and Agriculture Administration, xiii + 1,813 pp.

Gilbert, C.H., and E.C. Starks. 1904. The fishes of Panama Bay. Mem. Calif. Acad. Sci. v.4. 304 pp.

Helvey, M., and P. Dom. 1981. The fish population associated with an offshore water intake structure.
Bull. So. Calif. Acad. Sci., 80(1):23-31.

Helvey, M., and R.W. Smith. 1985. Influence of habitat structure on the fish assemblage associated
with two cooling-water intake structures in southern California. Bull. Mar. Sci., 37(1):189-199.

Hildebrand, S. FE 1946. A descriptive catalog of the shore fishes of Peru. Smithsonian Institution, U.S.
Nat. Mus., Bulletin 189:150—152.

Lea, R. N., and R. H. Rosenblatt. 2000. Observation on fishes associated with the 1997-1998 El Nino
off California. Calif. Coop. Ocean. Fish. Inves. Rep. 41:1178—129.

Marine Biological Consultants. 1975. The Marine Environment Offshore Huntington Beach Generating
Station Orange County, California. First Quarterly Report, August 1975 Survey. Prepared for
Southern California Edison Company. Mar. Bio. Consul., Costa Mesa, CA. 40 pp. + appendices.

FIRST RECORD OF PACIFIC CORNETFISH IN SOUTHERN CALIFORNIA 159

Thomson, D. A., L.T. Findley, and A.N. Kerstitch. 1979. Reef fishes of the Sea of Cortez. John Whiley
& Sons, Inc., NY., 302 pp.

Wooster, W.S., and D.L. Fluharty 1985. El Nifio North: Nino Effects in the Eastern Subartic Pacific
Ocean. Washington Sea Grant Prog., University of Washington, 312 pp.

Accepted for publication 21 December 2000.

Bull. Southern California Acad. Sci.
100(3), 2001, pp. 160—166
© Southern California Academy of Sciences, 2001

Records of Mexican Barracuda, Sphyraena ensis, and Scalloped
Hammerhead, Sphyrna lewini, from Southern California
Associated with Elevated Water ‘Temperatures

Michael A. Shane

Hubbs-SeaWorld Research Institute, 2595 Ingraham Street, San Diego,
California 92109

During the 1997—98 El Nifo Southern Oscillation (ENSO), abnormally warm
coastal waters occurred off southern California. Based on satellite imagery, the
highest sea surface temperature anomalies recorded in southern California during
this event were between 3 and 4°C. Monthly mean sea surface temperatures,
recorded at the Scripps Institute of Oceanography (SIO) pier between 1916 and
1994, ranged from 14 to 21°C. Monthly mean sea bottom temperatures, also
recorded at the SIO pier at a depth of 5 m between 1926 and 1994, ranged from
14 to 19°C. During previous warm water years, investigators documented changes
in the ichthyofauna along the Pacific Coast (e.g., Hubbs and Schultz 1929; Wal-
ford 1931; Brooks 1987; Lea and Rosenblatt 1992; Lea and Walker 1995). I report
here on two species of fish that were present off southern California correlated
with elevated water temperatures generated by the 1997-1998 ENSO and by an
anthropogenic source.

Sphyraena ensis

On 20 October 1997, multiple mesh gillnets were deployed on the bottom in
a kelp forest north of Oceanside, California (latitude 33°17.65'N, longitude 117°
29.57'W), in an attempt to catch hatchery-reared white seabass, Atractoscion no-
bilis, released by the Ocean Resources Enhancement and Hatchery Program (OR-
EHP). The following morning, an unfamiliar barracuda was retrieved from a net
set at a depth of 14 m. Also on this morning, water samples were collected at
depth at three sites in this area. The average bottom temperature of the water
samples was 19.7°C. Furthermore, there were no other barracudas caught in this
net or in two others set nearby. This fish was later identified by the author as a
Mexican barracuda, Sphyraena ensis (Jordan and Gilbert 1882), and represents
the first record from southern California. On 11 January 1998 another Mexican
barracuda was taken by hook-and-line aboard the sportfishing vessel MV Dolphin
II off La Jolla, California (latitude 32°51.0'N, longitude 117°16.0’W) in a water
depth of 9 m. The sport fisherman also noted that the Mexican barracuda was
schooling with the more common Pacific barracuda, S. argentea. This fish was
turned over to the Marine Vertebrates Collection, Scripps Institution of Ocean-
ography, and identified by R. H. Rosenblatt; it is catalogued as SIO 98-35. Sub-
sequently, the identification of the specimen collected north of Oceanside was
also verified by R. H. Rosenblatt and deposited in the Scripps collection as SIO
98-36. On 22 September 1998, three more Mexican barracuda were caught by
the OREHP assessment program in a gillnet set on the bottom at a water depth
of 4.5 m near La Jolla (latitude 32°48.28'N, longitude 117°16.08'W). These three

160

SPHYRAENA ENSIS AND SPHYRNA LEWINI IN CALIFORNIA 161

Table 1. Morphometric and meristic data for Sphyraena ensis*

Specimen
SIO SIO HSWRI HSWRI HSWRI
98-35 98-36 SE-1 SE-2 SE-3
Standard length (mm) 425.0 470.0 475.0 433.0 426.0
Head from tip of snout 329 50:2 292 30.0 30.0
Depth 14.3 14.8 15:2 Par 32
Orbit Jul 4.7 5.8 5.8 63
Insertion ventral spine from
tip of snout 44.7 a) i 392 BF 39.4
Spinous dorsal from snout 45.6 43.0 42.3 42.0 42.7
Soft dorsal from snout 416.5 w2e1 71.4 FAS IZ
Length of pectoral fin 13.0 10.6° bt 12.4 1S By
Longest dorsal ray 10.6 6.8° Saal 1S 10.5
Longest anal ray 10.0 TP 8.6 10.0 9.3
Number of dorsal rays and
spines 3 Mle e™ LS RN sis es VS OA a ee ee
Number of anal rays and spines ty 1.7 II, 8 II, 8 II, 8
Number of scales 108 110 108 110 108

“Measurements follow those of Gilbert and Starks (1904). Morphometric characters, with the ex-
clusion of standard length, are given in hundreds of standard length.
® Length of fin or ray on the left side of the body is incomplete.

specimens are presently being held at Hubbs-SeaWorld Research Institute. In ad-
dition, there were also several Pacific barracuda caught in the same net. The
bottom water temperature, recorded from a water sample collected at depth on
this morning, was 19.9°C. Counts and measurements for the five Mexican bar-
racuda described above, following Gilbert and Starks (1904), are provided in
Table 1.

During March or April 1998, Scott Aalbers photographed a school of seven
barracuda in the shallow waters off La Jolla. These barracuda looked similar to
the ones he had observed previously in Mexico. Due to the quality of the pho-
tograph, only two of the barracuda can be positively identified as Mexican bar-
racuda. This identification is based on the observation that the pelvic fin, which
is extended downward and away from the body in these two individuals, is at-
tached directly below the posterior tip of the pectoral fin. Additionally, these two
fish, as well as several others in the photograph, also have dark bars on their
sides. Positive identification of the remaining fish in the photograph as Mexican
barracuda could not be made due to the quality of the photograph and because
this species has been previously observed schooling with the Pacific barracuda.

Four species of barracuda (family Sphyraenidae) occur in the eastern Pacific.
Until now, only the Pacific barracuda had been reported to occur in the marine
waters off California (Miller and Lea 1972; Robins et al. 1991la). The Mexican
barracuda, normally found in the Panamic Zoogeographic Province, had a reported
range extending from Baja California, Mexico, including the Gulf of California,
to Chile (Chirichigno 1974; Robins et al. 1991b). This range consists of tropical
and subtropical ocean waters. The recent collection of this species from the warm-
temperate waters of southern California represents a latitudinal range extension
of over 1000 km.

162 SOUTHERN CALIFORNIA ACADEMY OF SCIENCES

Fig. 1. The upper specimen is a Pacific barracuda, Sphyraena argentea, and the lower specimen
is the Mexican barracuda, Sphyraena ensis, caught off Oceanside (SIO 98-36).

Walford (1937) and Sommer (1995) describe several characteristics that can be
used to distinguish the Mexican barracuda from the more common Pacific bar-
racuda (Fig. 1). One of the most distinctive characteristics is the attachment of
the pelvic fin, which in the Mexican barracuda is underneath or slightly forward
of the posterior tip of the pectoral fin. In the Pacific barracuda the pelvic fin is
attached posterior of the pectoral fin. The Mexican barracuda also has numerous
dark bars or chevrons on its side and the maxillary extends to the fore margin of
the eye. The Pacific barracuda lacks dark bars on its side and has a shorter max-
illary. Furthermore, the Mexican barracuda has between 105 and 120 lateral line
scales, while the Pacific barracuda has from 160 to 170 (Jordan and Evermann
1896; Gilbert and Starks 1904; Meek and Hildebrand 1923).

Sphyrna lewini

Three species of hammerhead sharks (family Sphyrnidae) have been recorded
in California waters (Robins et al. 1991la); however, their occurrence is uncom-
mon. In the eastern Pacific, the distribution of hammerhead sharks is generally
restricted to tropical latitudes. The scalloped hammerhead, Sphyrna lewini (Grif-
fith and Smith 1834), can be distinguished from S. tiburo and S. zygaena, the
other two species that have been reported in California, by the presence of four
lobes on the anterior margin of its head (Miller and Lea 1972). The first reported
California records of scalloped hammerhead were caught off Santa Barbara on
28 August 1977 (Fusaro and Anderson 1980). However, Hubbs (1948) mentioned
that in 1926, an unusually warm water year, many hammerheads (Sphyrna sp.)
were caught in southern California. Unfortunately there are no records or mention
of the species of hammerhead shark caught. Seigel (1985) reported three addi-
tional records from California; one of which was a juvenile. The following in-

SPHYRAENA ENSIS AND SPHYRNA LEWINI IN CALIFORNIA 163

formation provided is for 20 additional records from southern California that were
caught before, during, and after the 1997-1998 ENSO event.

In 1996 and 1997 ten scalloped hammerheads were caught in south San Diego
Bay by Mike Irey, a commercial mullet fishermen. These specimens were depos-
ited in the SIO collection and were identified and measured (range 63 to 99 cm
TL; x=73) by R. N. Lea. Nine additional specimens, which were caught in gillnets
set by the OREHP assessment program, were also collected from south San Diego
Bay (latitude 32°37.10’N, longitude 117°06.63'W) between October 1997 and
June 1999. These specimens were identified and measured (range 57 to 164 cm
TL, x=93) by the author. Of these nine specimens, two were deposited in the
SIO collection (SIO 98-39) and two in the fish collection at San Diego State
University (SDSU 98-101).

On all 19 of these specimens, the lower lobe of the caudal fin and the ventral
surface of the pectoral fins had black tips. The female:male sex ratio was roughly
equal (9:10). In North American waters, male scalloped hammerheads are reported
to become sexually mature at about 180 cm TL and females at around 250 cm
TL (Castro 1983; Branstetter 1987). Although none of the specimens reported
here were examined for sexual maturity, it is presumed that they were all im-
mature since the largest individual, a female, was only 164 cm TL.

Seigel (1985) reported the first California record of a juvenile scalloped ham-
merhead, caught on 4 October 1984. This specimen, which was 54.5 cm in total
length and possessed a mid-ventral umbilical scar, was probably less than one
month old. However, the Marine Vertebrates Collection at SIO includes a scal-
loped hammerhead specimen (SIO 81-152) that is 47.3 cm in total length that
was caught by hook and line just north of the SIO pier (latitude 32°52.0'N lon-
gitude 117°15.0’W) on 6 November 1981. This specimen also has an umbilical
scar and is probably less than one month old. In addition to these two pups, five
of the nine specimens caught by the OREHP assessment program had mid-ventral
umbilical scars. They were taken on 6 October 1997 and ranged from 56.5 to
63.1 cm TL (x=61.3 cm) (Fig. 2). The size of scalloped hammerhead pups at
parturition is between 38 and 60 cm TL (x<50 cm) (Clarke 1971; Branstetter
1987; Chen et al. 1988). Clarke (1971) reported growth rates between 0.03 and
0.25 cm day! for scalloped hammerhead pups tagged in the wild or retained in
laboratory ponds. Based on the presence of their umbilical scars and values re-
ported in the literature, the ages of the 5 pups caught in San Diego Bay were
probably between 45 and 94 days old.

The thermal effluent discharged from an electrical generating station at the
southern end of San Diego Bay creates a thermal plume that has been reported
to elevate water temperatures in this area (Chambers and Chambers 1973; Ford
and Chambers 1974). The extent of this thermal plume changes markedly on a
seasonal and tidal basis. This area of the bay is also more estuarine than the
central and outer portions of San Diego Bay. The area is characterized by higher
salinities and elevated water temperatures caused by shallow water depths (<3
m), bottom sediments that are either black or dark gray silty mud which enhance
solar absorption, and poor tidal flushing. Seasonal water temperatures in south
San Diego Bay range from 14 to 24°C outside the thermal effluent plume, while
those influenced by the plume range from 16 to 31°C (Ford and Chambers 1974).
Water temperatures in the location where the five pups were collected were around

164 SOUTHERN CALIFORNIA ACADEMY OF SCIENCES

Fig. 2. The three female and two male scalloped hammerhead, Sphyrna lewini, pups caught in
south San Diego Bay on 6 October 1997.

SPHYRAENA ENSIS AND SPHYRNA LEWINI IN CALIFORNIA 165

24°C during Fall 1997. Furthermore, this area of the bay is also very turbid, with
average transparencies of <2.0 m (Chambers and Chambers 1973; M. Shane
unpub. data).

The physical environmental conditions that exist in south San Diego Bay are
similar to those in Kanahoe Bay, Oahu, Hawaii, which is a known pupping ground
for scalloped hammerheads (Clarke 1971; Holland et al. 1993). Because of the
number of juvenile specimens captured in the southern end of San Diego Bay,
before, during, and after the 1997-98 ENSO, this area may function as both a
pupping ground and warm water refugium for scalloped hammerheads that travel
north during warm water years.

Acknowledgments

The collection of these valuable specimens was made possible through funding
by the California Department of Fish and Game’s Ocean Resources Enhancement
and Hatchery Program administered by S. Crooke. I am especially thankful to G.
Stutzer for assisting with the OREHP assessment efforts and for first observing
the unfamiliar barracuda caught off Oceanside; S. Aalbers for bringing to my
attention his underwater photograph of the school of barracuda; H. J. Walker for
providing access to the specimens in the fish collection at SIO; R. N. Lea for
providing his data on S. /ewini and his review of the manuscript; and for the
critical reviews of R. FE Ford, C. G. Lowe and R. H. Rosenblatt.

Literature Cited

Branstetter, S. 1987. Age, growth and reproductive biology of the silky shark, Carcharhinus falcifor-
mis, and the scalloped hammerhead, Sphyrna lewini, from the northwestern Gulf of Mexico.
Environ. Biol. Fish., 19(3):161—173.

Brooks, A. J. 1987. Two species of Kyphosidae seen in King Harbor, Redondo Beach, California.
Calif. Fish and Game, 17(1):49—50.

Castro, J. I. 1983. The sharks of North American waters. Texas A&M University Press, 180 pp.

Chambers, R. W. and R. L. Chambers. 1973. Thermal distribution and biological studies for the south
bay power plant. Final report. Volume 4A-B thermal measurements May 1973. Environmental
Engineering Laboratory Tech. Report on purchase order #P-25072 for San Diego Gas and
Electric Company, iii + 177 pp.

Chen, C. T., T. C. Leu and S. J. Joung. 1988. Notes on reproduction in the scalloped hammerhead,
Sphyrna lewini, in northeastern Taiwan waters. Fish. Bull., 86(2):389-393.

Chirichigno, N. E 1974. Clave para identificar los peces marinos del Peru. Inf. Inst. Mar Peru, 44:
387 pp.

Clarke, T. A. 1971. The ecology of scalloped hammerhead shark, Sphyrna lewini, in Hawaii. Pac. Sci.,
25:133-144.

Ford, R. E and R. L. Chambers. 1974. Thermal distribution and biological studies for the south bay
power plant. Final report. Volume 5C biological studies September 1972-August 1973. Envi-
ronmental Engineering Laboratory Tech. Report on purchase order #P-25072 for San Diego
Gas and Electric Company, vii + 189 pp.

Fusaro, C. and S. Anderson. 1980. First California record: The scalloped hammerhead shark, Sphyrna
lewini, in coastal Santa Barbara waters. Calif. Fish and Game, 66(2):121—123.

Gilbert, C. H. and E. C. Starks. 1904. The fishes of Panama Bay. California Academy of Sciences,
Memoirs vol. 4; reprinted in Hopkins Seaside Laboratory of Leland Stanford, Jr., Contributions
to Biology, 32:62—63.

Griffith, E. and C. H. Smith. 1834. The class Pisces, arranged by the Baron Cuvier, with supplementary
additions, by Edward Griffith, ER.S., &c. and Lieut.-Col Charles Hamilton Smith, ER., L.S.S.,
&c. &c. London. Class Pisces, Cuvier 1—680.

166 SOUTHERN CALIFORNIA ACADEMY OF SCIENCES

Holland, K. N., B. M. Wetherbee, J. D. Peterson and C. G. Lowe. 1993. Movements and distribution
of hammerhead shark pups on their natal grounds. Copeia, 1993(2):495-—S02.

Hubbs, C. L. 1948. Changes in the fish fauna of western North America correlated with changes in
ocean temperature. J. Mar. Res., 7(3):459—482.

Hubbs, C. L. and L. P. Schultz. 1929. The northward occurrence of southern forms of marine life
along the Pacific coast in 1926. Calif. Fish and Game, 15(3):234-241.

Jordan, D. S. and B. W. Evermann. 1896. The fishes of North and Middle America. Bull. U.S. Nat.
Mus., 47(1):822-826.

Jordan, D. S. and C. H. Gilbert. 1882. List of fishes collected at Mazatlan, Mexico, by Charles H.
Gilbert. Bull. U. S. Fish Comm., v. 2 [1882]:105—108.

Lea, R. N. and R. H. Rosenblatt. 1992. The Cortez grunt (Haemulon flaviguttatum) recorded from
two embayments in southern California. Calif. Fish and Game, 78(4):163—165.

Lea, R. N. and H. J. Walker, Jr. 1995. Record of the bigeye trevally, Caranx sexfasciatus, and Mexican
lookdown, Selene brevoorti, with notes on other carangids from California. Calif. Fish and
Game, 81(3):89-95.

Meek, S. E. and S. E Hildebrand. 1923. The marine fishes of Panama. Field Museum of Natural
History, Publ. 215, 15(1):282—288.

Miller, D. J. and R. N. Lea. 1972. Guide to the coastal marine fishes of California. California De-
partment of Fish and Game, Fish Bulletin 157, 235 pp.

Robins, C. R., R. M. Bailey, C. E. Bond, J. R. Brooker, E. A. Lachner, R. N. Lea and W. B. Scott.
1991a. Common and scientific names of fishes from the United States and Canada, fifth edition.
American Fisheries Society Special Publication 20, 183 pp.

. 1991b. World fishes important to North Americans exclusive of species from the continental
waters of the United States and Canada. American Fisheries Special Publication 21, 243 pp.

Seigel, J. A. 1985. The scalloped hammerhead, Sphyrna lewini, in coastal southern California waters:
Three records including the first reported juvenile. Calif. Fish and Game, 71(3):189-—190.

Sommer, C. 1995. Sphyraenidae. in Guia FAO para identification de especies para los fines de la
pesca. Pacifico Centro-Oriental. (W. Fischer, EF Krupp, W. Schneider, C. Sommer, K. E. Car-
penter, and V. Niem, eds.), Vol. I[I:1618—1621.

Walford, L. A. 1931. Northward occurrence of southern fish off San Pedro in 1931. Calif. Fish and
Game, 17(4):401—405.

. 1937. Marine game fishes of the Pacific coast from Alaska to the equator. University of

California Press, 205 pp. + 69 plates.

Accepted for publication 22 December 2000.

Bull. Southern California Acad. Sci.
100(3), 2001, pp. 167-169
© Southern California Academy of Sciences, 2001

Occurrence of the Loosetooth Parrotfish, Wicholsina denticulata
(Scaridae), from Santa Catalina Island, California

Robert N. Lea,' Erik D. Erikson,” Kelly Boyle,* and Robert Given‘

‘California Department of Fish and Game, Marine Region, 20 Lower Ragsdale
Drive, Monterey, CA 93940
*MetaVisual, Inc., PO Box 592, Carmel, CA 93921
3Department of Biological Science, California State University at Fullerton,
Fullerton, CA 92834
4Marymount College, Rancho Palos Verdes, CA 90275

The parrotfishes, family Scaridae, are characterized as specialized perciform
fishes that closely associate with reefs and are primarily tropical in distribution
(Schultz 1958, 1969 and Nelson 1994). Rosenblatt and Hobson (1969) revised
the systematics of eastern Pacific parrotfishes, recognizing three genera compris-
ing six species. Scarus is considered the typical parrotfish genus, with four species
in the eastern Pacific. Nicholsina, the more primitive (or plesiomorphic) genus,
is monotypic in the eastern Pacific. Calotomus, the third genus, is Indo-Pacific in
origin and rare in the eastern Pacific. Nicholsina denticulata (Evermann & Rad-
cliffe, 1917), the loosetooth parrotfish, is a smaller, less colorful species compared
to the members of the genus Scarus occupying the Panamic Region.

The distribution of Nicholsina denticulata is listed by Thomson et al. (2000)
as, “... throughout the Gulf [of California] and from Bahia Magdalena south
to Peru and the Islas Galapagos.’’ We are aware of two collections, representing
19 specimens, from Bahia Santa Maria (Scripps Institution of Oceanography, Ma-
rine Vertebrates Collection, SIO 64-42 and 64-43). Bahia Santa Maria is approx-
imately 20 kilometers north of the entrance to Magdalena Bay, on the outer coast
of Baja California Sur. While surveying fishes of the Islas San Benito, Baja Cal-
ifornia, Mexico (ca. lat 28°18'N), located 110 km off the coast of central Baja
California and 25 km west of the seaward side of Isla Cedros, divers (R. N. Lea,
R. E. Snodgrass, and D. V. Richards) observed Nicholsina denticulata during
several scuba dives in August 1996 and again on four dives in August 1998.
Nicholsina had not been noted at Islas San Benito on six previous trips by RNL
(since 1984), and there are no known collections of the species from the outer
coast of Baja California north of Bahia Santa Maria. During the Islas San Benito
expedition of 2—6 August 1998, we observed loosetooth parrotfish in relatively
shallow water (8 to 12 m) and often in association with the alga Eisenia; sea
surface temperatures at the islands ranged from 19.1° to 20.9° C. In the Sea of
Cortez, Nicholsina ‘‘is often observed among Sargassum, Padina, and other algae
... (Thomson et al. 2000).

On 22 May 1999, E. Erikson while diving at 6 m at Lovers Cove Reserve,
Santa Catalina Island (lat 33°20.6’N, long 118°19.1'W), noticed a fish swimming
in Eisenia with which he was not familiar. One month later on 20 June Erikson
was able to photograph this unidentified species. The photograph was sent to R.
Given and then to R. N. Lea for identification. The fish was recognized as the

167

168 SOUTHERN CALIFORNIA ACADEMY OF SCIENCES

Fig. 1. _Loosetooth parrotfish from Casino Point Underwater Park, Santa Catalina Island, 12 Sep-
tember 1999. Photograph by E. Erikson.

loosetooth parrotfish based on its general body morphology, large scalation, and
rather drab brownish-green coloration (Fig. 1). The coloration of Nicholsina is
characterized by Thomson et al. (2000) as “ .. . variable, usually reddish to drab
brown or greenish with diffuse dark mottling matching its surroundings.’’ Char-
acteristics separating the various parrotfish genera are primarily based on structure
of the teeth and patterns of scalation (requiring close or in-hand examination).
The photograph is typical of the species.

These observations and photographic documentation represent the first record
of the species, as well as the family, from Californian waters. Following the 22
May sighting, loosetooth parrotfish were observed at Santa Catalina Island, at
Lovers Cove Reserve and Casino Point Underwater Park, by EE on four other
occasions in 1999: 27 May at 6 m, 16.1°C (temperature is at depth of sighting);
20 June at 6 m, 16.7°C; 12 September at 7.5 to 9 m, 17.2°C; and 23 September
at 4.5 m, 16.7°C. On the 12 September dive two parrotfish, which appeared to be
a male and female pair, were observed and photographed over a 45-minute period.
The estimated size for these fish was between 20 to 24 cm total length. Kelly
Boyle also observed loosetooth parrotfish in September 1999 at Santa Catalina
Island, Casino Point Underwater Park. On 11 September, a single loosetooth par-
rotfish was noted swimming at 10 m depth. On 17 September, KB with three
other divers observed a single parrotfish on three separate dives that they assumed
to be the same individual. The sightings were between 4.5 and 10.5 m depth and
the fish was estimated as 25 cm total length; it was grazing on the alga Sargassum
palmeri.

The 1996 and 1998 observations at Islas San Benito are, to our knowledge,
the first records of the species north of Bahia Santa Maria. Magdalena Bay is
considered the northern boundary of the Panamic Biogeographic Province; Bahia
Santa Maria is essentially a northern extension of Magdalena Bay. Oceanograph-
ically, 1992 through 1996 was a period of exceptionally warm water in the eastern

LOOSETOOTH PARROTFISH FROM SANTA CATALINA ISLAND 169

North Pacific Ocean. Commencing in mid-1997, ocean temperatures for this re-
gion became more extreme and were manifested as the 1997—98 El Nifio event,
with the highest recorded sea-surface temperatures for outer Baja California and
southern California during the 20" century (Lea and Rosenblatt 2000). The ob-
servations of loosetooth parrotfish during the colder La Nifia period of 1999 are,
in our opinion, the result of fish that most likely arrived during the 1997-98 El
Nifio and remained unnoticed until the observations discussed in this paper were
made.

Acknowledgments

We would like to thank William Mercadante who aided E. Erikson in his ob-
servations at Santa Catalina Island. We also acknowledge Michael Horn, Camm
Swift, and two anonymous reviewers for their constructive comments regarding
this paper.

Literature Cited

Evermann, B. W. and L. Radcliffe. 1917. The fishes of the west coast of Peru and the Titicaca Basin.
Bull. U. S. Nat. Mus., 95:1—166.

Lea, R. N. and R. H. Rosenblatt. 2000. Observations on fishes associated with the 1997—98 El Nifio
off California. CalCOFI Reports, 41:117—129.

Nelson, J. S. 1994. Fishes of the world. 3" edition. John Wiley & Sons, Inc. New York. 600 pp.

Rosenblatt, R. H. and E. S. Hobson. 1969. Parrotfishes (Scaridae) of the eastern Pacific, with a generic
rearrangement of the Scarinae. Copeia 1969(3):434—453.

Schultz, L. P. 1958. Review of the parrotfishes Family Scaridae. Bull. U. S. Nat. Mus., 214:1-143.

Schultz, L. P. 1969. Taxonomic status of the controversial genera and species of parrotfishes, with
descriptive list (family Scaridae). Smithsonian Contrib. Zool. No. 17. 49 pp.

Thomson, D. A., L. T. Findley, and A. N. Kerstitch. 2000. Reef fishes of the Sea of Cortez: the rocky-
shore fishes of the Gulf of California, revised edition. The Univ. of Texas Press, Austin. 353 pp.

Accepted for publication 21 December 2000.

Bull. Southern California Acad. Sci.
100(3), 2001, pp. 170-174
© Southern California Academy of Sciences, 2001

Increase in Occurrence and Abundance of Zebraperch
(Hermosilla azurea) in the Southern California Bight in
Recent Decades

Erick A. Sturm! and Michael H. Horn

Department of Biological Science, California State University, Fullerton
Fullerton, California 92834-6850

The zebraperch, Hermosilla azurea Jenkins and Evermann 1889, a warm-tem-
perate member of the widespread but mainly tropical perciform family Kyphos-
idae, occurs in coastal waters of southern California and Baja California and in
the Gulf of California (Jenkins and Evermann 1889; Miller and Lea 1972; Es-
chmeyer et al. 1983; de la Cruz-Aguero et al. 1994; Rodriguez-Romero et al.
1994; Thomson et al. 2000). The northerly range limit of this species was given
as Monterey Bay (36° 36’ N) by Miller and Lea (1972) and Eschmeyer et al.
(1983), but the species has been regarded as uncommon in California (Miller and
Lea 1972) and rare north of southern California (Eschmeyer et al. 1983). In the
mid-1980s, zebraperch were captured in the Klamath River estuary in northern
California (41° 31’ N) to establish the northernmost range limit for the species
(Fritzsche et al. 1991). In this note, we provide evidence that the northerly range
extensions recorded for the zebraperch in recent decades correspond to short-term
periods of ocean warming associated with El Nifio conditions. We also offer
support for the hypothesis that this fish has increased in abundance and established
breeding populations in the Southern California Bight over the past 15—20 years
coincident with a sustained warming trend in the region over the same time period.

The zebraperch apparently was noted as a member of the California ichthyo-
fauna during the middle years of the last century, at least according to published
records. The fish was first reported in the Southern California Bight in waters off
San Diego County by Hubbs (1948) who noted that the fish began occurring in
this area during a warm-water event. Lockley (1952) captured juveniles in tide-
pools at La Jolla, California, in the mid 1940s and, since that time, the species
has been recorded as present in the San Diego area (Limbaugh 1955; Quast 1968;
Barry and Ehret 1993).

The occurrence of the zebraperch in more northerly areas of the Southern Cal-
ifornia Bight and north of Point Conception (34° 30’ N) appears to be linked to
short-term periods of ocean warming associated with El Nifio conditions and to
the sustained period of warming that occurred over the last two decades up to
1998 (Table 1). Northerly range extensions of the species to Monterey Bay in
1964 (Phillips 1965) and to the Klamath River estuary in 1985 and 1987-1988
(Fritzsche et al. 1991) followed the respective El Nifio events of 1963 and 1982—
1983. Records of zebraperch at King Harbor in Redondo Beach (Pondella 1997)
and at Santa Cruz Island (Feder et al. 1974) in the early 1970s followed the 1972—

' Current address: National Marine Fisheries Service, Hatfield Marine Science Center, Newport,
Oregon 97365.

170

ZEBRAPERCH INCREASE IN SOUTHERN CALIFORNIA 171

Table 1. Year and location where zebraperch, Hermosilla azurea, were sighted or captured in
California waters north of La Jolla* and the year of the El Nifio event preceding the sighting or
capture.

Sighted
(S) or
Year of sighting Captured Year of
or capture (C) Location El Nino event Reference
1964 & Carlsbad 1963 Marine Vertebrates Col-
33-05 N, IL Pls" W lection, Scripps Insti-
tution of Oceanogra-
phy (SIO 64-92)
1964 C Monterey Bay 1963 Phillips (1965)
36°36’ N, 121°53’ W
1965 Cc Oxnard 1963 Fitch (1966)
34°09’ N, 119°12' W
early 1970s S Santa Cruz Island 1972-1973 Feder et al. (1974)**
34°01’ N, 119°41' W
1974-2001 s King Harbor, Redon- 1972-1973, Pondella (1997) D. Pon-
do Beach 1982-1983, della, pers. comm.
33°50’ N, 118°23"W 1991-1992 &
1997-1998
avo, 1978 & 1979 S Santa Catalina Island 1972-1973 DeMartini and Coyer
33°26’ N, 118°30' W (1981)
1985, 1987 & 1988 C Klamath River Estu- 1982—1983 Fritzsche et al. (1991)
ary
41°3 1A.N;. 124°05-5 W.
1990 & 1996 S Santa Barbara Island 1991—1992 D. Richards, pers.
33°29' N, 119°02’ W comm.
1996 S Santa Barbara 1991-1992 S. Anderson, pers.
34°25' N, 119°41’ W comm.
1996 CG San Clemente Island 1991-1992 Sturm and Horn, current
33, O04 N, 115°337 W. paper
1997-1998 S&C Gaviota Pier, Santa 1997-1998 D. Kushner, pers.
Barbara comm.
34°28’ N, 120°13’ W
1998-1999 S Coal Oil Point, Santa 1997-1998 D. Kushner, pers.
Barbara comm.

34°25’ N, 119°41' W

* The Marine Vertebrates Collection at Scripps Institution of Oceanography also has 18 records
containing H. azurea captured or observed in the La Jolla area with dates ranging from 1939 to 1969.
** This paper did not list the year when zebraperch were sighted at Santa Cruz Island.

1973 El Nifio warming interval. Sightings or captures of zebraperch in the Santa
Barbara area and in the Channel Islands in the 1990s also seem to correspond to
El Nifio events (Table 1) that were closely spaced in time and part of a sustained
ocean warming trend during most of this decade (Smith 1995; Bograd et al. 2000).
The aggregations of zebraperch, estimated in some cases at >100 individuals (D.
Kushner, pers. comm.), seen in the Santa Barbara area in 1997, 1998 and 1999
are indications of an abundant and established population.

Further documentation of the responsiveness of the zebraperch to warmer tem-
peratures and of its expanded distribution in southern California comes from ob-
servations spanning key time intervals at specific locations. Zebraperch were com-
monly observed in the warm-water effluent of the Pacific Gas and Electric

172 SOUTHERN CALIFORNIA ACADEMY OF SCIENCES

(PG&E) steam-generating plant at Morro Bay north of Point Conception (Feder
et al. 1974), apparently in the 1950s and 1960s. By the 1980s, however, the fish
had disappeared from this otherwise cool-temperature locality based on interviews
conducted by one of us (MHH in the late 1980s) with PG&E personnel and
biologists at the California Department of Fish and Game office in Morro Bay.
In contrast, the species has inhabited King Harbor in southern California consis-
tently since 1974 (Pondella 1997; D. Pondella, pers. comm.). King Harbor has
become a haven for warm-water fishes because of the elevated temperatures of
the water discharged into the harbor by the Southern California Edison Redondo
Beach Generating Station and because of its protective breakwaters (Stephens and
Zerba 1981; Brooks 1987; Pondella 1997; Pondella et al. 1998). At San Clemente
Island, Santa Catalina Island and upper Newport Bay, zebraperch were captured
in recent years but not in earlier years even though in some cases similar collecting
methods were used. In a gill net survey of the near-shore fish community at
Wilson Cove, San Clemente Island, Horn (1977) collected no zebraperch in 1975
or 1976, whereas we captured nine zebraperch (mean length 184.8 mm SL; range
170—195 mm) at this location in October 1996 using the same gear in a one-hour
set (unpublished data). Hobson et al. (1981) did not list zebraperch as one of the
major near-shore fishes at Santa Catalina Island; however, beginning in the mid-
1980s, zebraperch have been seen repeatedly at several shallow-water localities
around the island (J. Cvitanovich, pers. comm.). Moreover, on numerous occa-
sions from 1993 through 1998, we observed young-of-the-year fish (<75 mm SL)
and collected large juvenile and adult fish (>200 mm SL) with spear gun and
gill net at various inshore (<5 m) sites at the island (Sturm and Horn 1998;
unpublished data). In an extensive multiple-gear sampling program conducted in
upper Newport Bay in the late 1970s, Horn and Allen (1985) collected no zebra-
perch. However, in the mid-1980s (Allen 1988) and throughout most of the 1990s
(California Department of Fish and Game Bay-Estuary Near-Shore Ecosystem
Survey [BENES], unpublished data; L. Allen, pers. comm.), zebraperch were
captured routinely at gill net stations in the upper and lower bay. Finally, studies
involving the distribution of zebraperch larvae reveal little about the response of
the fish to temperature change except that the larvae occur in shallow, near-shore
waters and have been identified only from samples taken south of Point Concep-
tion—at the San Onofre Nuclear Generation Station (33°22'’ N) by Walker et al.
(1987) from 1978-1980 surveys and in Santa Monica Bay (34°00’ N) by Stevens
et al. (1989) from 1978 and 1981 CalCOFI surveys.

Taken together, the available literature and unpublished observations, including
our Own, indicate that the zebraperch responded differently to the short-term El
Nino conditions of recent decades than to the sustained warming trend in the
Southern California Bight that began in 1977 and extended through to 1994
(Smith 1995) and beyond, culminating in a strong El Nifio event in 1997—1998
(Lea and Rosenblatt 2000) and ending with a La Nifia condition in 1998—1999
(Bograd et al. 2000). The zebraperch appeared to extend its range northward
following an El Nifio event and then fail to establish a resident population in the
new northern locality, in particular, Morro Bay, Monterey Bay or the Klamath
River estuary. This record of extension and retreat is a common pattern that has
been documented for other coastal fishes with warm-water affinities (e.g. Hubbs
1948; Radovich 1961; Norris 1963; Fitch 1966; Bond 1985). On the other hand,

ZEBRAPERCH INCREASE IN SOUTHERN CALIFORNIA 173

under the persistent warming regime of the last two decades, the zebraperch ap-
pears to have established itself widely as a resident, breeding species in the South-
ern California Bight. The records and observations of recent years cited above
provide support for this contention. Whether the zebraperch will persist as an
established population in the Southern California Bight remains to be seen, but
sightings of the species in 1999 at Santa Barbara (Table 1), in May 2000 at Santa
Catalina Island (J. Cvitanovich, pers. comm.) and in September 2000 at Laguna
Beach (K. Boyle, pers. comm.), all following a cool La Nifia period, suggest that
it will continue to be a part of the ichthyofauna of the region.

Acknowledgments

We thank L. Allen, S. Anderson, D. Kushner, D. Pondella, D. Richards and C.
Valle for supplying specimens or unpublished records of zebraperch captures and
sightings. The gill net study we conducted at San Clemente Island in October
1996 would not have been possible without the help of T. Gibson, S. Heid, A.
Lowe, E. Lowe, S. Murray and O. Rivas. We are grateful to R. Lea for his
valuable comments on an earlier version of the manuscript.

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Accepted for publication 29 January Z001.

Bull. Southern California Acad. Sci.
100(3), 2001, pp. 175-185
© Southern California Academy of Sciences, 2001

New and Unusual Reef Fish Discovered at the California Channel
Islands During the 1997-1998 El Nifio

Daniel V. Richards! and John M. Engle?

‘Channel Islands National Park, 1901 Spinnaker Drive, Ventura, California,
93001, Phone: 805-658-5760 Fax: 805-658-5798 Email: dan_richards @nps.gov
?Tatman Foundation and Marine Science Institute, University of California,
Santa Barbara, California 93106

Abstract.—Observations of warm-water species rarely seen in California are often
associated with El Nifo Southern Oscillations (ENSO). Here we document new
occurrences of tropical reef fish at the California Channel Islands. In 1998, three
species, new to California were recorded at San Clemente or Santa Catalina is-
lands (Apogon pacificus, Nicholsina denticulata, and Chromis alta). New island
records of six tropical species (Azurina hirundo, Apogon guadalupensis, Scor-
paenodes xyris, Chaenopsis alepidota, Chaetodon falcifer, and Chilomycterus re-
ticulatus) from the northern Channel Islands extend the northern range of these
species. Several of these species seem well established and appeared to be repro-
ductive. Others diminished during the cold water period in 1999.

The California Channel Islands are bathed in the mix of currents of the southern
California Bight, creating a transition zone with cold temperate waters around
San Miguel and Santa Rosa islands in the northwest to warm temperate water
around Santa Catalina and San Clemente islands in the southeast (Fig. 1). The
location of the islands within this transition zone creates a shift from a northern
species assemblage to a southern species assemblage over a relatively short dis-
tance (Cross and Allen 1993; Engle 1993).

The 1997-1998 El Nifio was one of the strongest on record with some of the
highest temperature anomalies ever recorded (McPhaden 1999). Above normal
sea temperatures defined the El Nino from May 1997 to August 1998 (NOAA
CoastWatch Bulletins). The peak sea-surface temperatures of 1998 capped almost
a decade of above average temperatures in Southern California and the Eastern
Pacific. Late 1998 and 1999 saw a reverse of the warm conditions as La Nifia
conditions prevailed.

With the warm waters of E] Nino we saw a number of tropical and subtropical
species at the islands. Engle and Richards (2001) report new and unusual inver-
tebrate sightings in a companion paper. The fish sightings we report here include
tropical species seen for the first time at the islands and southern species that
appear to be establishing themselves farther north at the colder islands. Large El
Nino events can almost be tracked by following new records of tropical fishes
and invertebrates reported in the literature. Increased sightings followed El Nino
events around 1959 (Radovich 1961; Strachen et al. 1968), 1983 (Lea and Vojk-
ovich 1985; Lea and Rosenblatt 1992), 1992, (Lea and McAlary 1994) and now
1998 (this volume; Lea and Rosenblatt 2000).

175

176 SOUTHERN CALIFORNIA ACADEMY OF SCIENCES

121° “Js aag® EP ear sian 118° 5 117°

nd pais Bia Nag eee et wnt ey see Kee Aes f ss & i ae
anta Barbara | se) ots ot ei asa) Cen rg Pe

Point \

Conception f BRP a LP te Beata ae eR Geet opp
(WVentural iisfih ee ois SES Ts

Miguel Santa Cruz

34° er cn hag

Santa Rosa

Santa Barbara

San & Santa Catalina
Nicolas

San Clemente

121° 120° 119° 118°

Fig. 1. The California Channel Islands.

Methods

The eight Channel Islands off the southern California coast have been surveyed
annually since 1980 in cooperative studies by the Channel Islands National Park
(CINP) kelp forest monitoring program or the Channel Islands Research Program
(CIRP) through support from the Tatman Foundation. CINP divers regularly mon-
itor 16 fixed sites as part of the kelp forest monitoring program and population
dynamics of invertebrate, algal, and fish species are measured. Fishes are quan-
tified in visual transects and Roving Diver Fish Counts twice each year on dif-
ferent dates (Davis et al. 1999). CIRP divers use Roving Dive Fish Counts, gen-
eral surveys and species lists at a broader spectrum of sites to provide an overview
of the island ecosystems. Both programs use a general search method to note
species in the field, often with several divers contributing. Unusual fishes were
observed by multiple divers and photographed whenever possible. Collections
were not made. Roving diver fish counts were developed as a standard means of
quantifying relative abundance of fish species.

New Species Records for the California Channel Islands

Family Apogonidae
Apogon pacificus (Herre 1935), pink cardinalfish

Previous reported range.—Islas San Benito to Peru (Thomson et al. 1987). La
Jolla Canyon, California (Lea and Rosenblatt 2000).

Remarks.—A single pink cardinalfish, Apogon pacificus, was observed and pho-
tographed (R. Herrmann, D. Richards) (Fig. 2) on 13 September 1998 in Bat Ray
Cove on the southeast tip of San Clemente Island (32°49.27' N, 118° 21.03’ W).

NEW AND UNUSUAL REEF FISH AT CHANNEL ISLANDS 177

.
é

: i
vo
a ,

Fig. 2. Pink cardinalfish, Apogon pacificus at Bat Ray Cove San Clemente Island, 13 September
1998. Photo by Richard Herrmann.

The pink cardinalfish was accompanied by at least 15 Guadalupe cardinalfish, A.
guadalupensis, in a small crevice at a depth of about 10 m. The smaller size and
vertical bar set this fish off from the Guadalupe cardinalfish. The larger Guadalupe
cardinalfish seemed to dominate the pink cardinalfish forcing it to the outer open-
ing of the crevice. An individual pink cardinalfish was observed at North Coro-
nado Island, Baja California, Mexico, 11 November 1998 (E. Hessel, pers.
comm.). On 25 May 1998, Robert Snodgrass and Hugh Khim observed several
pink cardinalfish in La Jolla Canyon, and in May 1998, several were collected

by McConnaughey and Zerokski from the same location (Lea and Rosenblatt
2000).

Family Scaridae
Nicholsina denticulata (Evermann and Radcliffe 1917), loosetooth parrotfish

Previous reported range: Bahia Magdalena to Peru including the Gulf of Cal-
ifornia and the Galapagos Islands (Thomson et al. 1987).

Remarks.—Erik Erickson photographed both male and female loosetooth par-
rotfish, Nicholsina denticulata, off Pebbly Beach and Casino Point, Santa Catalina
Island in May 1999 (Lea et al. 2001). This species was observed at the San Benito
Islands, Baja California, Mexico in August 1998 (R. N. Lea and D. Richards,
pers obs.) and photographed at Guadalupe Island, Baja California, Mexico in July
2000. Loosetooth parrotfish are well adapted to kelp beds. The coloration and
shape allow it to be very cryptic, especially among Eisenia arborea blades.

178 SOUTHERN CALIFORNIA ACADEMY OF SCIENCES

s
o

>. ’ at _..
rt 4 ye. .
a Ye ise ;
5 a a" > yy -
aid i, y "Se oe of
wt 2 4 «A
? ‘ ,

4 andi
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oe ~ ~— -
q b-W 7
= . « *

wis

Fig. 3. Silverstripe chromis, Chromis alta at Casino Point, Santa Catalina Island, November 1998.
Photo by Lorraine Sadler.

Family Pomacentridae
Chromis alta Greenfield and Woods 1980, silverstripe chromis

Previous reported range.—Thetis Bank, Mexico to Gulf of California and the
Galapagos Islands (Greenfield and Woods 1980).

Remarks.—In November 1998, Erik Erickson and Lorraine Sadler observed
and photographed an immature damselfish, around Casino Point Dive Park, Santa
Catalina Island at a depth of 12-14 m. An additional sighting was made at a
depth of 22 m at the SUEJAC in the northeast corner of the underwater park of
possibly a second individual. Both fish were approximately 8—10 cm long. The
sightings were originally reported as Cortez damselfish, Stegastes rectifraenum,
however subsequent analysis of photos (Fig. 3) show the fish possessing blue
striping consistent with juveniles of Chromis alta and lacking the dorsal spot
generally observed on S. rectifraenum. Silverstripe chromis are also known from
Islas San Benito, (R. N. Lea, collections made 1985—1990) and Isla Guadalupe
(D. Richards, photos August 2000).

Range Expansions-New Island Records

Family Scorpaenidae
Scorpaenodes xyris (Jordan and Gilbert 1882), rainbow scorpionfish

Previous reported range.—Southern California to Peru including the Gulf of
California and the Galapagos Islands. (Strachen et al. 1968).

Remarks.—Rainbow scorpionfish, Scorpaenodes xyris, like Guadalupe cardi-
nalfish, is a shy crevice-dwelling species not commonly found at the islands. New

NEW AND UNUSUAL REEF FISH AT CHANNEL ISLANDS 179

island records for rainbow scorpionfish were noted with one individual found at
Landing Cove, Anacapa Island (34°00.70 N, 119°21.71 W) on 25 September 1998
and one individual found in the vicinity of Cave Canyon, Santa Barbara Island,
(33°28.68 N, 119° 01.56 W) 9 August 2000. Both juvenile and adult rainbow
scorpionfish were commonly found at various sites around San Clemente Island
and at several locations on Santa Catalina Island in both 1997 and 1998. Rainbow
scorpionfish were very common at San Clemente Island in August 2000 with well
over 100 found on a single dive at Bat Ray Cove. Smaller numbers were seen in
Northwest Harbor. First collected in California in 1966 from San Clemente Island
and 1967 from Santa Catalina Island (Strachan et al. 1968), this species now
seems to be well established and spreading farther north.

Family Apogonidae
Apogon guadalupensis (Osburn and Nichols 1916), Guadalupe cardinalfish

Previous reported range.—Guadalupe Island to San Clemente Island (Hobson
1972) Islas San Benito (R. N. Lea and D. Richards pers. obs., August 1995)

Remarks.—Guadalupe cardinalfish, Apogon guadalupensis, was first recorded
in California in 1967 (Hobson 1969) from the southern end of San Clemente
Island. Most of these cardinalfish were small individuals approximately 50 mm
in length. In 1971, an individual Guadalupe cardinalfish, about 100 mm long, was
found during a night dive (Hobson 1972). Until 1997, sightings were remarkable.
Throughout 1997 and especially 1998; A. guadalupensis were commonly found
at various sites around San Clemente Island. We recorded Guadalupe cardinalfish
as rare when we first found them at Seal Cove on the northwest side of San
Clemente Island in June 1997. A year later we found 30 to 40 Guadalupe car-
dinalfish in Seal Cove. In 1998, we were finding more than 100 individuals on
dives in Pyramid Cove, Smugglers Cove, and Bat Ray Cove where the small
groups were spilling out of the rock cracks into open but protected spaces usually
under an overhang. These fish were approximately 100—120 mm long. Hundreds
were observed at Bat Ray Cove, down to a depth of at least 16 m. Male cardi-
nalfish brood the eggs in their mouths during incubation and many brooding
individuals were observed. Divers considered Guadalupe cardinalfish common
and brooding males were observed at Bat Ray Cove in August 2000.

At least 20 Guadalupe cardinalfish were found in crevices along the eastern
coast of Santa Barbara Island near Cave Canyon on 16 October 1997. Individuals
were approximately 60—80 mm. This was the first record for Guadalupe cardi-
nalfish at Santa Barbara Island. In 1998, Guadalupe cardinalfish were again found
near Cave Canyon, Santa Barbara Island. Individuals were noticeably larger than
in 1997, approximately 100 mm, and were apparently brooding eggs. No cardi-
nalfish were found during a brief survey in 1999. Juvenile rockfish were often
occupying the crevices where cardinalfish had been seen the year before. One
individual, approximately 100 mm long, was found in the same vicinity during a
dive on 9 August 2000. Another new island record occurred when two Guadalupe
cardinalfish were found in Anacapa Landing Cove in July and again in August
and September 1998 (D. Kushner et al. 1999).

180 SOUTHERN CALIFORNIA ACADEMY OF SCIENCES

Family Chaetodontidae
Chaetodon falcifer Hubbs and Rechnitzer 1958, scythe butterflyfish

Previous reported range.—Southern California (Santa Catalina Island) to Cabo
San Lucus and the Galapagos Islands (Thomson et al. 1987).

Remarks.—Scythe butterflyfish, Chaetodon falcifer, have been known from
Santa Catalina Island since 1965 (Freihofer 1966) and from La Jolla since 1970
(Kiwala and McConnaughey 1971). One individual was observed and photo-
graphed at San Pedro Point, on the east end of Santa Cruz Island on 13 August
1997 during a CIRP cruise. This fish was occupying a small cave at a depth of
7.5 m. A scythe butterflyfish, possibly the same individual, had been seen nearby
several months earlier in deeper water (G. Gross, California Dept. of Fish and
Game, pers. comm.). We have been unable to relocate the fish on repeated visits
to the area.

Family Pomacentridae
Azurina hirundo Jordan and McGregor [in Jordan and Evermann 1898],
swallow damselfish

Previous reported range.—Islas Revillagigedo to Santa Catalina Island (Lea
and McAlary 1994).

Remarks.—Swallow damselfish, Azurina hirundo, sightings, while previously
reported from the southern Channel Islands (Lea and McAlary 1994), are very
rare. Two to four individual swallow damselfish were observed and photographed
by Kathy deWet-Oleson in the summer of 1998 at Landing Cove, Anacapa Island.
This is the first record of the species at Anacapa Island. A number of sightings
were made in 1998 at the West End and Casino Point (E. Erickson, L. Sadler
pers. comm.) on Santa Catalina Island. We observed a single swallow damselfish
off Dune Point and 10—20 individuals at a depth of 10-13 m in Bat Ray Cove,
San Clemente Island in September 1998. Two swallow damselfish were present
at Bat Ray Cove on 13 August 2000. This species was also present at North
Coronado Island on 5 June 1998 (R. Herrmann pers. comm.) and 11 November
1998. Typically these swallow damselfish were observed swimming with schools
of blacksmith, Chromis punctipinnis.

Family Chaenopsidae
Chaenopsis alepidota (Gilbert 1890), orangethroat pikeblenny

Previous reported range.—Gulf of California (Thomson et al. 1987), Anacapa
Island to Banderas Bay, Mexico (Stephans et al 1989).

Remarks.—Orangethroat pikeblenny, Chaenopsis alepidota, is well known
from San Clemente and Santa Catalina Islands with a single population at King
Harbor, Redondo Beach (Stephans et al. 1989). Orangethroat pikeblennies have
been observed at Anacapa Island in low numbers since the 1983 El Nino (J.
Engle, pers. obs.). In 1997, we observed them for the first time at Scorpion
Anchorage, Santa Cruz Island (34°02.77 N, 119°32.81 W). Orangethroat pike-
blennies were observed at Pelican Bay, Santa Cruz Island (34° 01.67 N, 119°42.24
W) on 12 May 1999 (D. Kushner, pers. comm.) and a juvenile was observed at
Willow Cove, Santa Cruz Island in 1998 (J. Engle, pers. obs.) Courting males
were common at Anacapa Island in August 1998, displaying above the Chaetop-
terous variopedatus worm tubes that they inhabited.

NEW AND UNUSUAL REEF FISH AT CHANNEL ISLANDS 18]

Family Diodontidae
Chilomycterus reticulatus Linnaeus 1758, spotfin burrfish

Previous reported range.—Southern California to the Galapagos Islands, Ha-
waii and Japan (Lea 1998).

Remarks.—Spotfin burrfish, Chilomycterus reticulatus, is another visitor re-
corded during previous El Nino events. First recorded in California in 1891 near
San Pedro, specimens were collected in 1959 and 1982 (Lea and Vojkovich 1985),
and observed in 1997 (SCMI 2000) off the southern California Mainland. One
specimen of spotfin burrfish was found 3 September 1992, by CINP divers during
a previous El Nino. The fish was captured by hand over a sand bottom in a depth
of approximately 12 m off Arch Point, Santa Barbara Island (33°28.65 N,
119°01.73 W). This fish was photographed and measured (230 mm total length)
before being released at the same location.

Other Observations—Increased Sightings

A number of southern fish species have been occasionally recorded at the Chan-
nel Islands or along the southern California mainland. The frequency of occur-
rence for several fish increased following the 1997-1998 El Nino.

Two juvenile California morays, Gymnothorax mordax (Ayres 1859), approx-
imately 30—45 cm, were observed at Santa Catalina Island near Pumpernickel
Cove during a CIRP cruise on 9 October 1999. California morays are rare to
locally common in the Channel Islands and range from Magdalena Bay, Baja
Calif. Mexico, to Pt. Conception (Miller and Lea 1972). Juveniles are rarely seen,
however.

Juvenile California lizardfish, Synodus lucioceps, (Ayres 1855), were observed
as abundant at sites along northeast Santa Cruz Island in August 1998. Ranging
as far north as Puget Sound (Gonyea 1985), these fish are generally uncommon
at the Channel Islands. We rarely see these fish except at deeper depths on silty
bottoms and have never seen juveniles before. In 1998, we observed hundreds of
juveniles (100-150 mm) over shallow (5-15 m) soft bottoms, some apparently
feeding on mysids.

Purple brotula, Oligopus diagrammus (Heller and Snodgrass 1903), was first
recorded in California, at San Clemente Island in 1966 (Strachan et al. 1968).
During June 1997, and June and September 1998 cruises to San Clemente Island,
purple brotula were found on several dives, mostly around Pyramid Head. Cabrillo
Marine Aquarium divers (SCMI 2000) also reported it from Santa Catalina Island.

Mexican scad, Decapterus scombrinus (Valenciennes 1846), were observed at
Bat Ray Cove, San Clemente Island (13 August 2000), Ship Rock, Santa Catalina
Island (8 October and 18 November 1999), and Prince Island, San Miguel Island
(15 November 1998) Islands. While ranging to at least central California occa-
sionally (Miller and Lea 1972), these fish are uncommon in California. A yellow-
ish belly, a finlet, and less pronounced lateral line arch distinguish Mexican scad
from jack mackerel, Trachurus symmetricus.

Young-of-the-year garibaldi, Hypsypops rubicundus (Girard 1854), were ob-
served at Santa Rosa Island in 1998 during a CINP cruise. Adult garibaldi are
uncommon around Santa Rosa and this is our first record of a juvenile there.
Occurrences of juvenile California sheephead, Semiscossyphus pulcher (Ayres

182 SOUTHERN CALIFORNIA ACADEMY OF SCIENCES

Table 1. Previous and new (1997-1998) records of tropical fishes at the California Channel Islands.
P = previous and N = new. (1997-1998 El Nino).

San Santa Santa
Cle- Cata- Bar- Anaca- Santa

mente lina bara pa Cruz
Apogon pacificus pink cardinalfish N
Chromis alta silverstreak chromis N
Nicholsina denticulata loosetooth parrotfish N
Apogon guadalupensis Guadalupe cardinalfish Pp Pp N N
Scorpaenodes xyris rainbow scorpionfish P P N N
Azurina hirundo swallow damselfish P Pr N
Chaetodon falcifer scythe butterflyfish P F N
Chaenopsis alepidota orangethroated pikeblenny P P P N

1854), and rock wrasse, Halichoeres semicinctus (Ayres, 1859) were common at
all islands. Juveniles of both species are rare to uncommon most years. California
sheephead are known to recruit during El Ninos (Cowan 1985).

Finescale triggerfish, Balistes polylepis Steindachner 1876, range from Chile to
Pt. St. George, Del Norte Co. (Miller and Lea 1972), though are generally un-
common in southern California. Finescale triggerfish are reported from time to
time at the islands and adults were observed on numerous occasions at Anacapa
Island (Kathy deWet-Oleson, pers. comm.) during 1997-1998, mostly along the
north side of West Anacapa Island. Finescale triggerfish were observed at North
Coronado Island on 11 November 1998.

Discussion

During El Nino events, there is a lessening of the equatorward-flowing Cali-
fornia Current and thus an increase in the northward transport (Hickey 1993).
This change in current pattern of the Southern California Bight and the warm
waters of El Nifio provide the means for southern species to find their way to the
Channel Islands. Some species may find refugia at the islands where they are able
to persist.

Three tropical reef fishes (Apogon pacificus, Nicholsina denticulata, and
Chromis alta), new to California in 1998, were observed at the Channel Islands.
Five species previously recorded at one or more of the southern Channel Islands
were documented at more northerly islands since 1997 (Table 1). An additional
species, Chilomycterus reticulatus, was documented for the first time at the Chan-
nel Islands in 1992.

Santa Catalina Island typically has the warmest temperature regime for the
Channel Islands (Engle and Richards 2001). As such we might expect the most
tropical species records to occur there and indeed they do. The popularity of Santa
Catalina Island dive sites and the fact that they are readily accessible by the
resident divers on the island also lend the island to a greater number of sightings
compared to other islands.

The south end of San Clemente Island consistently has been a good area for
tropical fish. Large numbers of Guadalupe cardinalfish and rainbow scorpionfish
along with the only sighting of pink cardinalfish and a moderate number of swal-
low damselfish were found in Bat Ray Cove just north of Pyramid Head. A

NEW AND UNUSUAL REEF FISH AT CHANNEL ISLANDS 183

number of tropical invertebrate species were observed in this same cove (Engle
and Richards 2001) as were a number of warm-water algae including Sporochnus
pedunculatus, Spyridia filamentosa, Cutlaria cylindrica, Chondria californica,
and Liagora californica.

The numbers of juvenile rainbow scorpionfish and the brooding males of Gua-
dalupe cardinalfish seem to indicate that some of these species have become well
established. La Nifia conditions may set back populations temporarily, as we saw
with the decline of Guadalupe cardinalfish at Santa Barbara Island in 1999, but
individuals can survive. Individuals of both Guadalupe cardinalfish and rainbow
scorpionfish were observed in August 2000 at Santa Barbara Island. The first
California records of Guadalupe cardinalfish were observed in the late 1960s at
San Clemente Island and there was a subsequent decline by the early 1970s. In
1998, we were noting Guadalupe cardinalfish at San Clemente Island as common
(10-100 individuals per dive) on fish counts, and though slightly less numerous,
were still common during August 2000.

Recruitment for some species appears to be limited at the northern islands. The
numbers of young-of-the-year sheephead, rock wrasse, and garibaldi observed in
1998 would seem to indicate increased recruitment during El Nifio events. The
increased recruitment may affect a species’ ability to sustain itself on the margins
of its range.

Shifts in the ichthyofauna associated with El Nifio and La Nifia have been
documented before (see Cross and Allen 1993). The number of new species doc-
umented in southern California in this decade seems somewhat unprecedented
however (various authors, this volume). The abnormally warm water throughout
the period from 1992 through 1998 may have established conditions for more
than just the occasional individual to expand its range and perhaps allowed the
establishment of new colony populations.

Acknowledgments

Many individuals participated in the surveys that provided new records for
subtropical fishes at the Channel Islands We thank the Channel Islands Research
Program and the Channel Islands National Park research vessel crews and divers
for their assistance, especially David Kushner for directing the CINP Kelp Forest
Monitoring Program surveys. We thank Erik Erickson, Lorraine Sadler, Eric Hes-
sell, George Gross and Kathy deWet-Oleson, Ventura, CA for providing additional
records. Robert Lea, provided valuable taxonomic and biogeographic information.
The Tatman Foundation (CIRP) and the National Park Service (CINP) sponsored
the surveys. Additional observations were made during a research cruise spon-
sored by the U. S. Geological Survey, Biological Resources Division and the
Love Lab (UCSB).

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NEW AND UNUSUAL REEF FISH AT CHANNEL ISLANDS 185

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Accepted for publication 22 December 2000.

New and Unusual Marine Invertebrates Discovered at the
California Channel Islands during the 1997-1998 El Nino

John M. Engle!’ and Daniel V. Richards?

'Tatman Foundation and Marine Science Institute, University of California,
Santa Barbara, California 93106 Phone: 805-893-8547 Fax: 805-893-8062
Email: j_engle @lifesci.ucsb.edu
Channel Islands National Park, 1901 Spinnaker Drive, Ventura,
California 93001

Abstract.—The occurrence of new and unusual subtropical invertebrates at the
Channel Islands was documented for the exceptional 1997-1998 El Nino and
subsequent 1998—2000 La Nina during periodic shallow subtidal surveys. Six
species (Chloeia viridis, Stenorhynchus debilis, Pleurobranchus areolatus, Chro-
modoris galexorum, Polycera alabe, and Holothuria impatiens) were new to Cal-
ifornia. Six others (Bunodeopsis sp., Hemisquilla ensigera californiensis, Drom-
idia larraburei, Pteria sterna, Arbacia incisa, and Centrostephanus coronatus)
represented new records at one or more islands. Most new records occurred at
the southernmost and easternmost islands (Santa Catalina, San Clemente, and
Anacapa). Repeated sightings of progressively larger size classes provided re-
cruitment, growth, and survivorship information for five species. Increased sight-
ings of subtropical species in California likely are due to northward shifts of
biogeographic provinces that occurred during more than two decades of above
average seawater temperatures.

The California Channel Islands support a great diversity of nearshore marine
life, due primarily to their location within the Southern California Bight, astride
the transition between warm subtropical waters of the Californian Province to the
south and cold temperate waters of the Oregonian Province to the north. The
complex mixing of warm and cold water masses results in unique oceanographic
conditions influencing each of the eight islands (Fig. 1), which in turn affect the
distribution of plant, invertebrate, fish, bird, and mammal species. Overall, there
is an obvious southeast (i.e., Santa Catalina Island) to northwest (i.e., San Miguel
Island) trend of decreasing sea surface temperatures among the islands that cor-
relates well with differences in the composition of species assemblages (Engle
1993, 1994). Individual species distributions may shift northwesterly or south-
easterly over time at the islands, depending on the magnitude and duration of
warm-water (e.g., El Nifio) or cold-water (e.g., La Nina) regimes. New sightings
of subtropical species typically are associated with major El Nifo events (e.g.,
Radovich 1961; Strachan et al. 1968).

Southern California waters have experienced a long-term warming trend that
began in 1976, including major El Nino events in 1983-1984, 1986—1987, 1992—
1993, and 1997—1998. Of these, the 1983—1984 and 1997—1998 EI] Ninos were two
of the strongest on record with some of the highest temperature anomalies ever
recorded (McPhaden 1999). During the recent El Nifio, the Southern California

186

NEW MARINE INVERTEBRATES AT THE CHANNEL ISLANDS 187

Sea Surface Temperatures (°C)

JAN FEB MAR APR MAY JUN JUL AUG SEP OCT NOV DEC

—e— Los Coronados —o— Santa Catalina —y— San Clemente — y— Santa Barbara —m— San Nicolas

—o- Anacapa —e@— Santa Cruz —>— SantaRosa —«a— San Miguel —a— Pt Conception

Fig. 1. Mean monthly sea surface temperatures at the eight Channel Islands for the period 1982—
1999. Data were taken from National Weather Service (Monterey) oceanographic analyses.

Bight experienced above normal sea temperatures for 1.5 yr, from May 1997 to
August 1998 (CoastWatch Bulletins 1997-2000). By September 1998, the El Nino
abruptly switched to La Nifia, which caused cooler temperatures also for ~1.5 yr,
from September 1998 to March 2000 (CoastWatch Bulletins 1997—2000).

This paper presents new distributional records for shallow-water subtropical in-
vertebrates at the California Channel Islands during and after the 1997-1998 El
Nifio. New and unusual fish records at the Channel Islands are reported in a com-
panion paper by Richards and Engle (this volume). Post-El Nino records are im-
portant because some species that recruit during the warm-water period are slow-
growing and only become evident after attaining larger sizes. Periodic surveys allow
determination of growth and survivorship of these exotic species. The invertebrate
observations we report here include six subtropical species seen for the first time
in California waters as well as six other species that have newly appeared (or have
notably increased abundances) at one or more of the eight Channel Islands (Table
1). We have noted some southern California mainland sightings, but have not at-
tempted to include all new mainland records for these species.

Methods

The eight Channel Islands off the southern California coast have been surveyed
periodically since 1980 in cooperative studies by the Tatman Foundation’s Chan-
nel Islands Research Program (CIRP) and Channel Islands National Park (CINP)
Kelp Forest Monitoring Program. CINP divers regularly survey 16 fixed sites at
five islands to monitor population dynamics of key algal, invertebrate, and fish

188 SOUTHERN CALIFORNIA ACADEMY OF SCIENCES

Table 1. Previous and new (1997-1998 El Nino) records for 12 species of subtropical marine inver-
tebrates at the eight California Channel Islands. Abbreviations: Islands: SCL = San Clemente, SCA =
Santa Catalina, SBA = Santa Barbara, SNI = San Nicolas, ANA = Anacapa, SCR = Santa Cruz, SRO
= Santa Rosa, and SMI = San Miguel; Records: P = previous and N = new (1997-1998 El Nifio).

California Channel Island

Phylum Species SCA SCL SBA SNI ANA SCR SRO SMI

Cnidaria Bunodeopsis sp. N N

Annelida Chloeia viridis N

Arthropoda Dromidia larraburei N
Hemisqulla ensigera 's P P Fr
Stenorhynchus debilis N N N

Mollusca Chromodoris galexorum N
Pleurobranchus areolatus N N N
Polycera alabe N N N
Pteria sterna P P P N N N

Echinodermata Arbacia incisa N N N N N
Centrostephanus coronatus FP P r P P Pr N
Holothuria impatiens N

species. Invertebrates are quantified using random point contact, quadrat, and
transect techniques (Davis et al. 1999). CIRP divers conduct qualitative recon-
naissance surveys at a broader spectrum of locations at all eight islands to provide
an overview of island marine assemblages. Both programs include general search
methods to note unusual species at each survey site. Voucher collections and
photographs or videographs maintained at CIRP and California museums (pri-
marily the Natural History Museum of Los Angeles County (NHMLAC)) are
utilized to additionally document new sightings whenever possible. Latitude/lon-
gitude coordinates are provided for island sites not named on National Oceanic
and Atmospheric Administration nautical charts.

First Occurrences in California

Phylum Annelida Class Polychaeta Order Amphinomida Family Amphinomidae
Chloeia viridis Schmarda 1861 Ornate fireworm (Fig. 2A)

Previous reported range.—Throughout the Gulf of California to Panama, and
the entire Caribbean; intertidal and subtidal to at least 91 m (Hartman 1940;
Brusca 1980; Kerstich 1989).

First Channel Islands records.—Over 70 fireworms observed on stable sand
habitats at Santa Catalina Island during October 1998 to May 2000. Sites: Willow
Cove (>60 specimens) at 9-21 m depths (10/98, 5/99, 6/99, 10/99); Empire
Landing (>10 specimens) at 12—20 m depths (5/00). Vouchers: photographs (E.
Erikson) and specimens (NHMLAC).

Remarks.—Chloeia viridis is a distinctive polychaete with long venomous se-
tae. Though common throughout the Gulf of California (Brusca 1980), there are
no records from the Pacific Coast of Baja California (L. Harris, pers. comm.).
One of us (Engle) has surveyed mantis shrimp (Hemisquilla ensigera califor-
niensis) at least annually since 1984 at Willow Cove, yet Chloeia was not found

NEW MARINE INVERTEBRATES AT THE CHANNEL ISLANDS 189

Fig. 2. Warm-water invertebrates representing first occurrences in California. A. Chloeia viridis.
B. Stenorhynchus debilis. C. Pleurobranchus areolatus. D. Chromodoris galexorum. E. Polycera al-
abe. F. Holothuria impatiens. Photos A, C-F by E. Erikson. Photo B by R. Herrmann.

prior to 10/98. No specimens have been reported elsewhere in California. C.
viridis was observed crawling on the surface of sheltered-shore, silty-sand sub-
strates and entering tubes of the parchment worm Chaetopterus variopedatus. On
several occasions, fireworms appeared to be feeding on bat ray (Myliobatis cali-
fornica) feces, and in two instances, an individual was seen consuming the sea
slug Navanax inermis.

Phylum Arthropoda Class Malacostraca Order Decapoda Family Majidae
Stenorhynchus debilis (Smith 1871) Panamic arrow crab (Fig. 2B)

Previous reported range.—Guadalupe Island (Baja California) (M. Wicksten
pers. comm.) and Gulf of California to Chile and the Galapagos Islands; intertidal
and subtidal to 61 m (Brusca 1980; Kerstich 1989; Gotshall 1998).

190 SOUTHERN CALIFORNIA ACADEMY OF SCIENCES

First Channel Islands records.—Several hundred arrow crabs observed at 3—
23 m depths on rocky substrata at three islands during March to October 1998.
Santa Catalina Island: Pebbly Beach, Casino Point, and Ripper’s Cove (>100
specimens, E. Erikson, 3/98); Bird Rock, Lion’s Head, and Blue Cavern Point (L.
Roberson, 3-7/98); and West End (9 specimens, 10/98). San Clemente Island:
Mosquito Cove (1 specimen, 5/98); E. Pyramid Cove (2 specimens, 5/98); Pyr-
amid Head (>100 specimens, 5/98, 9/98); Purse Seine Rock (1 specimen, 5/98);
and Seal Cove (1 specimen, 9/98). Anacapa Island: Frenchy’s Cove (1 specimen,
8/98). Vouchers: photographs (E. Erikson, R. Herrmann) and specimens
(NHMLAC).

Remarks.—Stenorhynchus debilis was observed by various scuba divers at San-
ta Catalina and San Clemente Islands and along the southern California mainland
from Mission Bay to Redondo Beach in spring/summer 1998 (C. Gramlich & D.
Cadien pers. comm.). Also, it was collected in trawling surveys around Santa
Catalina Island (7/98) and off Huntington Beach (8/99) (see Montagne & Cadien
this volume). This short-lived crab is seasonal in the Gulf of California, attaining
maximum sizes in May to July (Kerstich 1989). We observed peak abundances
in spring (few small crabs; most moderated-sized) and summer 1998 (most large),
with only a few heavily-fouled individuals seen in fall 1998 (all large), and none
thereafter. Two spring-collected specimens survived in aquaria until fall 1998. S.
debilis mostly occurred in small crevices or under the spine canopy of the coron-
ado sea urchin Centrostephanus coronatus (29 of 667 C. coronatus surveyed had
a sheltering arrow crab at Pyramid Head on 5/18/98). Some crabs were found
under rocks or mooring blocks in sheltered silty coves (E. Erikson pers. comm.).

Phylum Mollusca Class Gastropoda Order Notaspidea Family Pleurobranchidae
Pleurobranchus areolatus Moérch 1863 Warty sea slug (Fig. 2C)

Previous reported range.—San Benitos and Cedros Islands (Baja California)
(D. Behrens pers. comm.), Gulf of California to Ecuador, throughout the Carib-
bean and tropical west Africa; intertidal and subtidal to 31 m (Keen 1971; Kerstich
1989).

First Channel Islands records.—Seven individuals found at 5—22 m depths on
rocky reefs at three islands during June 1998 to June 1999. Santa Catalina Island:
Casino Point (1 specimen, E. Erikson, 6/98) and West End (1 specimen, 10/98).
San Clemente Island: Pyramid Head (2 specimens, 9/98) and Purse Seine Rock
(32° 52.48’ N, 118° 24.94' W) (2 specimens, 6/99). Anacapa Island: Frenchy’s
Cove (1 specimen, 8/98). Vouchers: photographs (E. Erikson, R. Herrmann, D.
Richards) and specimens (D. Behrens). Also, P. Haaker and M. Tegner (pers.
comm.) collected two specimens at San Clemente Island in August 1998.

Remarks.—Pleurobranchus areolatus is a large (~10-15 cm) distinctive opis-
thobranch, whose dorsal surface is covered with warty orange and reddish-brown
tubercles. Variations in color patterns and tubercle morphology among the spec-
imens raise suspicions that some individuals represent an undescribed Pleuro-
branchus (D. Behrens, pers. comm.); however, these variations may be within the
range of characters exhibited by P. areolatus. Several specimens were collected
during the same period on the mainland at La Jolla (D. Behrens, pers. comm.).

NEW MARINE INVERTEBRATES AT THE CHANNEL ISLANDS 191

Phylum Mollusca Class Gastropoda Order Nudibranchia Family
Chromodorididae
Chromodoris galexorum (Bertsch 1978) Galactic sea slug (Fig. 2D)

Previous reported range.—Guadalupe and Cedros Islands (Baja California) to
the Gulf of California; subtidal 3—45 m (Bertsch 1978; Bertsch and Kerstich 1984;
Kerstich 1989).

First Channel Islands records.—Five galactic nudibranchs found on rocky reefs
along north side of Santa Catalina Island at 10-18 m depths during October 1998
to May 2000. Sites: Ship Rock (1 specimen, 10/98); Blue Cavern Point (1 spec-
imen, 5/00); and Long Point (3 specimens, E. Erikson, 5/00). Vouchers: photo-
graphs (E. Erikson, D. Richards) and specimens (D. Behrens).

Remarks.—Chromodoris galexorum is a colorful nudibranch, with red rhin-
ophores and gills and yellow-ringed reddish spots on a creamy white background.
The previous northern limit at Guadalupe Island was considered an anomaly due
to El Nifio conditions (Kerstich 1989). The live specimen from Big Fisherman
Cove was 83 mm long, more than double the reported size range of 19-38 mm
(Kerstich 1989).

Phylum Mollusca Class Gastropoda Order Nudibranchia Family Polyceratidae
Polycera alabe Collier & Farmer 1964 Inkstain nudibranch (Fig. 2E)

Previous reported range.—Cedros Island (Baja California) to the Gulf of Cal-
ifornia; intertidal and subtidal (Keen 1971; Behrens 1991; Kerstich 1989).

First Channel Islands records.—Three inkstain nudibranchs observed at 8—15
m depths on rocky reefs at three islands from June to September 1998. Santa
Catalina Island: Italian Gardens (33° 24.64’ N, 118° 22.75’ W) (1 specimen, E.
Erikson, 6/98). Santa Barbara Island: Arch Point (1 specimen; 9/98). Anacapa
Island: Cathedral Cove (34° 00.71’ N, 119° 22.29’ W) (1 specimen; 8/98). Vouch-
ers include photographs (E. Erikson) and video (D. Kushner).

Remarks.—Polycera alabe is a small, blue-black, orange-spotted nudibranch
that feeds on bryozoans (Kerstich 1989).

Phylum Echinodermata Class Holothuroidea Order Aspidochirotida Family
Holothuriidae
Holothuria impatiens (Forskal 1775) Brown spotted sea cucumber (Fig. 2F)

Previous reported range.—Rosario Bay (Baja California) and throughout the
Gulf of California to Ecuador and the Galapagos Islands, circumtropical; intertidal
and subtidal to 46 m. (Brusca 1980; Kerstich 1989; Hendler et al. 1995; Gotshall
1998).

First Channel Islands records.—Three individuals were found at 5—8 m depths
under rocks at Pebbly Beach, Santa Catalina Island during November 1998 (E.
Erikson, 1 juvenile and 1 adult 25 cm long) and May 2000 (1 adult ~21 cm
long). Vouchers: photographs (E. Erikson) and specimens (NHMLAC).

Remarks.—Holothuria impatiens adults were golden-brown with numerous pa-
pillae. The juvenile was a lighter cream color. All individuals eviscerated when
handled out of water.

2 SOUTHERN CALIFORNIA ACADEMY OF SCIENCES

New Records at One or More Channel Islands

Phylum Cnidaria Class Anthozoa Order Actiniaria Family Boloceroididae
Bunodeopsis sp. Stinging sea anemone

Previous reported range.—Mission Bay (San Diego) and Puerto Escondido
(Baja California); shallow subtidal (J. Lyjubenkov 1995).

New Channel Islands records.—Bunodeopsis were found as locally abundant
epibionts on eelgrass (Zostera marina), surfgrass (Phyllospadix spp.), and various
brown algae at 3-15 m depths on sheltered sand and rock habitats at two islands
from May 1996 to August 2000. Santa Catalina Island: Big Fisherman Cove
(hundreds on Zostera, 9/97); Catalina Harbor (few on Zostera, 4/98); and Isthmus
Cove (L. Roberson, locally common on Macrocystis pyrifera, Eisenia arborea,
Cystoseira neglecta and other brown algae, 9/98). San Clemente Island: Purse
Seine Rock (hundreds on Zostera, 5/96, 9/98, 8/00) and Pyramid Head (abundant
on Phyllospadix, Sargassum palmeri, Zonaria farlowii, and miscellaneous brown
algae, 9/98). Vouchers: photographs (R. Herrmann, L. Roberson).

Remarks.—Bunodeopsis is a tiny translucent white sea anemone that was dis-
covered on eelgrass in Mission Bay (San Diego) in 1995, where its extensive
cover contributed to a decline in Zostera populations (Sewell & Williams 1995).
This little-known representative of a subtropical/tropical genus is thought to be
an undescribed species (Ljubenkov 1995). The anemone is capable of autotomiz-
ing tentacles, drifting with currents, and stinging exposed skin of divers (Ljuben-
kov 1995).

Phylum Arthropoda Class Malacostraca Order Stomatopoda Family
Hemisquillidae
Hemisquilla ensigera californiensis (Stephenson 1967) Mantis shrimp

Previous reported range.—Point Conception (Santa Barbara County) to the
Gulf of California and Panama; subtidal to 91m (Brusca 1980; Morris et al. 1980;
Kerstich 1989; Gotshall 1994; Jensen 1995).

New Channel Islands records.—Hemisquilla have been present or common at
8—21 m depths in stable sand habitats at Santa Catalina and San Clemente Islands,
but rare at Anacapa and Santa Cruz Islands (Basch and Engle 1993; J. Engle
unpub. data.). During the 1997-1998 El Nifio, recruitment was evident and abun-
dances increased at surveyed island sites. Santa Catalina Island: Cherry Cove
(common: 9/97, 4/98); Big Fisherman Cove (common: 9/97, 4/98); Willow Cove
(adults common, juveniles abundant: 9/97, 10/98) (adults present, juveniles rare:
5/99, 6/99, 10/99); Big Geiger Cove (33° 27.58’ N, 118° 31.04’ W) (common: 4/
98, 4/99); Catalina Harbor (common: 4/98); Parson’s Landing (present: 4/98); East
End (common: 9/98), Arrow Point (present: 4/99); and Empire Landing (present:
5/00). San Clemente Island: Purse Seine Rock (common: 5/98, 9/98, 8/00). An-
acapa Island: Frenchy’s Cove (present: 6/98, 8/98, 7/99, 6/00) and Cathedral Cove
(present: 6/98). Santa Cruz Island: Scorpion Cove (present: 8/98, 8/99); Prisoner’s
Cove (present: 8/98); Potato Harbor (present: 8/99); Twin Harbor (present: 8/99);
Smuggler’s Cove (present: 6/00); and Hazard’s Anchorage (present: 8/99). The
sightings at Prisoner’s Harbor, Twin Harbor, and Hazards Anchorage represent
new northwestern island records.

NEW MARINE INVERTEBRATES AT THE CHANNEL ISLANDS 193

Remarks.—Hemisquilla ensigera californiensis is a large but cryptic mantis
shrimp that inhabits burrows in sheltered sand habitats. This species typically
closes its burrow entrance with a plug of sand during bright midday hours (Basch
and Engle 1989); therefore, abundances likely were underestimated except at Wil-
low Cove where population dynamics have been monitored since 1984 (Engle
unpub. data). Also Hemisquilla can occur at depths to 70 m (Basch and Engle
1993), but our surveys were limited to 21 m depths. Stomatopod burrow densities
increased nearly ten-fold at Willow Cove during 1996-1998 (0.01/m? (1995), 0.1/
m? (1996), 0.06/m? (1997), 0.1/m? (1998), 0.01/m? (1999)), with 80% of the in-
crease due to additional small (<20 mm diameter) burrows.

Order Decapoda Family Dromiidae
Dromidia larraburei Rathbun 1910 Sponge crab

Previous reported range.—Monterey Bay and Long Beach to Magdalena Bay
(Baja California), the Gulf of California, Peru and the Galapagos Islands; intertidal
and subtidal to at least 18 m (Schmitt 1921; Brusca 1980; Kerstich 1989).

New Channel Islands records.—Three individuals were found on a stable sand
slope at Frenchy’s Cove, Anacapa Island in June 1998 (paired male and female)
and July 1999 (1 female) in 6—7 m depths. Vouchers: photographs (J. Carroll, E.
Erikson) and specimens (NHMLAC).

Remarks.—Dromidia larraburei is a small, cryptic anomuran crab known for
using its modified fifth leg to hold a sponge on its back (Kerstich 1989); however,
the 6/98 male and 7/99 female at Anacapa Island were holding brown bubble
kelp (Colpomenia sinuosa) over their bodies. The freshly-molted 6/98 female held
by the male was soft and pink. Dromidia settled in large numbers on Mission
Bay Reef (San Diego) in spring 1998, were still abundant in early 1999, then
disappeared by August 1999 (C. Gramlich pers. comm.).

Phylum Mollusca Class Bivalvia Order Pterioida Family Pteriidae
Pteria sterna (Gould 1851) Pacific wing-oyster

Previous reported range.—Venice (Los Angeles County) and Santa Barbara
Island to Morro Santo Domingo (Baja California), throughout the Gulf of Cali-
fornia to Peru and the Galapagos Islands; subtidal 1-25 m (Keen 1971; Brusca
1980; Coan et al. 2000).

New Channel Islands records.—Pteria commonly observed attached to gor-
gonians at 6—23 m depths at numerous sites around all Channel Islands except
San Nicolas and San Miguel during the period September 1998 to August 2000.
Santa Catalina Island: Church Rock (9/98); Salta Verde Point (9/98); Ship Rock
(10/98, 4/99, 10/99, 5/00); West End (10/98); Willow Cove (on buoy lines: 10/
98, 5/99, 10/99); Blue Cavern Point (4/99); Bird Rock (8/98 (L. Roberson), 4/99,
5/00); Arrow Point (4/99); Long Point (10/99, 5/00); Eagle Reef (5/00); and Hen
Rock (5/00). San Clemente Island: Dune Point (33° 01.58’ N, 118° 33.80’ W) (9/
98); Northwest Harbor (9/98); Pyramid Head (9/98, 8/00); and W Pyramid Cove
(9/99, 8/00). Santa Barbara Island: Southeast Sea Lion (33° 27.45’ N, 119° 01.52’
W) (10/98, 7/99, 6/00); South End (9/99); Arch Point (9/99); Sutil Island (8/00);
and Landing Cove (8/00). Anacapa Island: Landing Cove (34° 00.70’ N, 119°
21.71’ W) (10/98); Admiral’s Reef (34° 00.33’ N, 119° 25.86’ W) (7/99); Cathe-
dral Cove (7/99); Cat Rock (8/99); Survey Rock (34° 00.66’ N, 119° 22.28’ W)

194 SOUTHERN CALIFORNIA ACADEMY OF SCIENCES

(6/00); and West End (6/00). Santa Cruz Island: Potato Rock (8/99); Cavern Point
(8/99); Twin Harbor (8/99); Hazards Anchorage (34° 03.61’ N, 119° 49.73’ W)
(8/99); Forney Cove (8/99); Gull Island (8/99); Blue Banks Anchorage (8/99);
and San Pedro Point (8/99). Santa Rosa Island: Johnson’s Lee (7/99). Vouchers:
photographs (E. Erikson, R. Herrmann, D. Richards) and specimens (J. Engle).

Remarks.—Pteria sterna have appeared in southern California during previous
warm-water periods, but have not established permanent populations (Coan et al.
2000, Engle unpub. data). Prior distributional records for these “‘pearl’’ oysters
at the Channel Islands have been sparse, and their association with sea fans (Order
Gorgonacea) not well documented (Keen 1971, Brusca 1980, Coan et al. 2000).
Except for several wing-oysters found attached to subsurface float lines at Willow
Cove, all Pteria encountered were attached to shallow-water gorgonians, including
Muricea californica, M. fruticosa, Lophogorgia chilensis, and Eugorgia rubens.
Smaller individuals (S—9 cm) predominated in 1998 (shell length variability main-
ly was due to size differences in the anterior spike-like wing). Most Pteria were
large in 1999 and 2000 (10—15 cm). Largest individuals exceeded the published
size limits of 10 cm (Keen 1971, Brusca 1980, Coan et al. 2000). At Willow
Cove, three Pteria on float lines grew on average from 6.5 to 12 cm in one year
(10/98 to 10/99). Increased numbers of empty shells were observed at many sites
in 2000.

Phylum Echinodermata Class Echinoidea Order Arbacioida Family Arbaciidae
Arbacia incisa (Agassiz 1863) Arbacia sea urchin

Previous reported range.—Newport Bay (Orange County) and Gulf of Cali-
fornia to Peru, and the Galapagos Islands; intertidal and subtidal to 90m (H. L.
Clark 1948; Brusca 1980; Morris et al. 1980; Gotshall 1998).

New Channel Islands records.—Several dozen Arbacia found in rocky crevices
and artificial recruitment modules (ARM’s) (Kushner et al. 1999) at 5-18 m
depths at five islands during May 1998 to September 2000. Santa Catalina Island:
Pebbly Beach (1 juvenile, E. Erikson, 10/98). San Clemente Island: Purse Seine
Rock (1 juvenile, 5/98). Santa Barbara Island: Southeast Sea Lion (2 found in
twenty-four 0.25 m? quadrats in 9/98; 6 in 6/99, 3 in 6/00). Anacapa Island:
Admiral’s Reef (ARM: 1 each in 8/98 (10 mm), 8/99, and 8/00 (35 mm)); Landing
Cove (ARM: 1 juvenile in 8/98); and Cathedral Cove (ARM: 1 each in 7/98 (12
mm), 7/99, and 9/00 (32 mm)). Santa Cruz Island: Gull Island (ARM: 1 each in
7/98 (7 mm) and 9/99). Vouchers: photographs (E. Erikson) and specimens
(NHMLAC).

Remarks.—Arbacia incisa was not previously known from the Channel Islands.
Most individuals (8-10 mm diameter recruits in 1998 and larger individuals in
1999 and 2000) were found in concrete recruitment modules surveyed by Channel
Islands National Park. Three juveniles raised in aquaria grew from 8-10 mm in
spring 1998 to 27—33 mm in spring 2000 to 29—36 mm in fall 2000. Arbacia also
were found in San Diego (C. Gramlich, Mission Bay in 4/97 and 1/99).

Order Diadematoida Family Diadematidae
Centrostephanus coronatus (Verrill 1867) Coronado sea urchin
Previous reported range.—California Channel Islands to the Gulf of California
to Peru, and the Galapagos Islands; intertidal to 125m (Brusca 1980; Morris et
al. 1980; Gotshall 1994; Kerstich 1989).

NEW MARINE INVERTEBRATES AT THE CHANNEL ISLANDS 195

New Channel Islands records.—In prior years, Centrostephanus coronatus has
been common/abundant at San Clemente and Santa Catalina Islands, uncommon/
rare at Santa Barbara, San Nicolas, Anacapa, and Santa Cruz Islands, and absent
at Santa Rosa and San Miguel Islands (J. Engle, unpub. data). Large-scale re-
cruitment of 5—25 mm (test diameter) Centrostephanus was documented during
surveys and in ARM’s (Kushner et al. 1999) at numerous island sites during spring
to fall 1998 (and in some ARM’s in summer 1999). Santa Catalina Island: Indian
Rock (4/98); Blue Cavern Point (4/98); Bird Rock (4/98); Church Rock (9/98);
Ship Rock (10/98); West End (10/98); and Torqua Springs (10/98). San Clemente
Island: Northwest Harbor (5/98); Dune Point (5/98, 9/98); Pyramid Cove (5/98,
9/98); Pyramid Head (5/98, 9/98); and Seal Cove (9/98). Santa Barbara Island:
Southeast Sea Lion (9/98: most recruits ever); Arch Point (9/98: most recruits
ever); and Cat Canyon (33° 27.24’ N, 119° 02.47’ W) (9/98). Anacapa Island:
Survey Rock (6/98); Frenchy’s Cove (6/98); Landing Cove (8/98: most recruits
ever (4.1/ARM)), 8/99 (2.3/ARM); Cathedral Cove (7/98: most recruits ever (1.8/
ARM)), 7/99 (0.5/ARM); and Admiral’s Reef (8/98: most recruits ever (4.4/
ARM)), 8/99 (2.5/ARM). Santa Cruz Island: Gull Island (8/98: first recruits ever
(0.7/ARM), 9/99 (1.0/ARM); Fry’s Harbor (7/98: most recruits ever (0.6/ARM),
8/99 (0.4/ARM); Pelican Bay (8/98: most recruits ever (2.7/ARM), 8/99 (0.2/
ARM); Scorpion Cove (8/98 (0.17/ARM); Yellowbanks (9/98: first recruits ever
(0.9/ARM), 7/99 (1.9/ARM); and Potato Rock (8/98). No Centrostephanus <20
mm were found in ARMs in 2000. Two coronado urchins (7/99 (25 mm), 8/00)
found on a transect at Rodes Reef became the first record of this species at Santa
Rosa Island.

Remarks.—The huge settlement of Centrostephanus in late 1997/early 1998
also was observed in San Diego (Mission Bay Reef); numbers of tiny urchins
dropped substantially by late 1998 (C. Gramlich pers. comm.).

Discussion

Six species of subtropical nearshore invertebrates were documented for the first
time in California. New northern geographic range limits based on records at the
Channel Islands include the following: 1) Chloeia viridis: extended from Gulf of
California to Santa Catalina Island; 2) Stenorhynchus debilis: extended from Gua-
dalupe Island to Anacapa Island; 3) Pleurobranchus areolatus: extended from
San Benitos Islands to Anacapa Island; 4) Chromodoris galexorum: extended from
Guadalupe Island to Santa Catalina Island; 5) Polycera alabe: extended from
Cedros Island to Anacapa Island; and 6) Holothuria impatiens: extended from
Rosario Bay to Santa Catalina Island.

Six additional species of subtropical invertebrates, though occurring within or
near their known geographic range limits, were documented for the first time at
one or more of the Channel Islands during or after the 1997—1998 El Nifio period.
New island records include: 1) Bunodactis sp.: previously reported at Mission
Bay, now known at San Clemente and Santa Catalina Islands; 2) Hemisquilla
ensigera californiensis: increased abundances at four islands and newly appeared
near the west end of Santa Cruz Island; 3) Dromidia larraburei: first island record
at Anacapa Island; 4) Pteria sterna: newly found at three northern islands; 5)
Arbacia incisa: previously reported from Newport Bay, now known at five is-

196 SOUTHERN CALIFORNIA ACADEMY OF SCIENCES

lands; and 6) Centrostephanus coronatus: increased recruitment at six islands and
newly appeared at Santa Rosa Island.

The conspicuousness of most of the above invertebrates coupled with extensive
CIRP and CINP surveys dating back to 1980 make it unlikely that these warm-
water species would have occurred at the newly-recorded island locations prior
to the 1997-1998 El Nino without being noticed. The observed temporal pattern
of predominantly smaller individuals during El Nino followed by larger sizes
during La Nifia for Stenorhynchus, Hemisquilla, Pteria, Arbacia, and Centroste-
phanus is consistent with the hypothesis that their larvae settled out from El Nifio-
associated currents flowing north from Baja California (see Hickey 1993). Pre-
vious northern limits for some of these species (e.g., Stenorhynchus, Pleurobran-
chus, Chromodoris, and Polycera) were established after El Nifio events of the
1980’s. Such progressive extensions of northern range limits are likely a result of
the extended warm-water regime in place since 1976 (Engle 1994).

Long-term sea surface temperature patterns show consistent differences among
the eight Channel Islands (Fig. 1). Santa Catalina, the warmest island, had the
most records of subtropical invertebrates (Table 1), as well as subtropical fishes
(see Richards and Engle this volume). Another warm-water island, San Clemente,
and a transitional island, Anacapa, also had many southern species records.
Though more northern, Anacapa Island is close to the mainland where it is influ-
enced by northerly-flowing warm-water currents. The few subtropical species re-
cords at Santa Barbara Island may be due to its paucity of sheltered habitats
(where at least 5 of the species were found) and because this island was surveyed
less often than Santa Catalina, San Clemente, and Anacapa. Remote, military-
controlled San Nicolas Island was only surveyed at two locations in September
1999. The northern islands within Channel Islands National Park were visited
regularly. Only two minor occurrences of subtropical species were noted at Santa
Rosa Island and none at San Miguel, the coldest-water island.

Repeated sightings provided growth and survivorship information for five spe-
cies. Short-lived Stenorhynchus was found only during an eight-month period in
1998. Aquarium-held individuals also died by fall 1998. In contrast, Arbacia,
found as 8-10 mm juveniles in spring 1998, continued to be found as adults in
1999 and 2000. All three aquarium-held Arbacia survived for over two years (as
of 9/2000), having grown from an average of 9 mm to 32 mm test diameter.
Pteria was found in progressively larger sizes at many sites over the two-year
period from fall 1998 to fall 2000, with many empty shells evident in 2000. The
lack of small Stenorhynchus, Arbacia, or Pteria in the two years following the
1997/1998 settlement indicates that these populations are not likely self-sustain-
ing. As has often been observed in populations at their northern limits (e.g., Reaka
1986), these species (as well as Chloeia, Pleurobranchus, and Chromodoris) at-
tained or exceeded maximum recorded sizes. Hemisquilla and Centrostephanus
also experienced El Nifio recruitment peaks. Their established populations on
southern islands may make it easier for further recruitment to northern islands.

The 1997-1998 El Nifio influenced the composition of Channel Islands shal-
low-water species assemblages in many other ways besides the enhancement of
subtropical species (see Tegner and Dayton 1987 for 1983-1984 El Nifo effects).
For example, certain herbivores, planktivores, and seastars, incurred high mortal-
ity apparently due to thermal stress, reduced food availability, and disease (J.

NEW MARINE INVERTEBRATES AT THE CHANNEL ISLANDS 197

Engle and D. Richards, unpub. data). Deterioration of kelp forests reduced habitat,
shelter, and food for many species. Low oceanographic productivity resulted in
less food for suspension-feeders. Seastars and other echinoderms experienced ex-
tensive mortality from a warm-water wasting disease (Eckert et al. 2000). The
rapid switch from El Nifio to La Nifia conditions in fall 1998 reversed thermal
stress, low productivity, and echinoderm disease influences. Also, La Nifia ap-
parently halted further recruitment of subtropical forms, but did not appear to
affect the survival of the subtropical species we monitored. It remains to be seen
whether this La Nifa signals the start of an oceanographic regime shift toward
cooler conditions or is a temporary deviation in the long-term warming trend. If
warm-water conditions resume, we can expect further appearances of subtropical
species at the Channel Islands as biogeographic provinces shift northward.

Acknowledgments

Many individuals participated in the surveys that provided new records for
subtropical invertebrates at the Channel Islands. We thank the Channel Islands
Research Program and Channel Islands National Park research vessel crews and
divers for their assistance, especially David Kushner for directing the CINP Kelp
Forest Monitoring Program surveys. We thank Erik Erikson, Constance Gramlich,
Pete Haaker, and Loretta Roberson for providing additional records of unusual
invertebrates. We greatly appreciate the underwater photographic talents of Jay
Carroll, Erik Erikson, Richard Herrmann, and Loretta Roberson. Valuable taxo-
nomic and biogeographic expertise were provided by Dave Behrens, Don Cadien,
Henry Chaney, Dan Gotshall, Leslie Harris, Gordon Hendler, John Ljubenkov,
Paul Valentich Scott, and Mary Wicksten. The surveys were sponsored by the
Tatman Foundation (CIRP) and National Park Service (CINP).

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Accepted for publication 22 December 2000.

Northern Range Extensions into the Southern California Bight of
Ten Decapod Crustacea Related to the 1991/92 and 1997/98
El] Nino Events

David E. Montagne! and Donald B. Cadien?

‘Ocean Monitoring & Research, County Sanitation Districts of Los Angeles
County, 1955 Workman Mill Road, Whittier, California 90601
*Marine Biology Laboratory, County Sanitation Districts of Los Angeles
County, 24501 S. Figueroa Street, Carson, California 90745

Abstract.—The first recorded appearance in the Southern California Bight (SCB)
of ten decapod crustaceans, all of which have distributions that are primarily
tropical or sub-tropical, is documented. Northern range extensions are provided
for the penaeidean shrimp Metapenaeopsis mineri (Penaeidae) and Sicyonia pen-
icillata (Sicyoniidae), the caridean shrimp Processa peruviana (Processidae), Pan-
tomus affinis, Plesionika beebei, P. trispinus, and P. carinirostris (Pandalidae)
and the brachyuran crabs Stenorhynchus debilis (Majidae), Palicus cortezi, and
P. lucasii (Palicidae). These animals were collected during or in the aftermath of
the 1991/92 and 1997/98 El Nifio events. The specimens were collected in trawl
monitoring programs of shelf and upper slope depths that have been in place for
up to three decades. These long term data sets provide evidence of previous
absence from the SCB, accentuating the novelty of these records.

The warm temperate waters of the Southern California Bight (SCB) are known
as a transitional area between the cool temperate fauna to the north and the tropical
faunas to the south (e.g., the Oregonian vs. Mexican and Panamanian regions of
Briggs 1974). They have been treated as a semi-discrete zoogeographic entity, the
Californian Transition Zone (Newman 1979). The northern limit of many species
with primarily tropical or subtropical distributions often falls within the SCB. The
dominance of the northerly flowing California Countercurrent and California Un-
dercurrent within the Bight (Hickey 1993) and the barrier presented to southern
species by the California Current north of Pt. Conception are the primary physical
determinants of this pattern. In addition, large-scale and interdecadal cycles of
warming seawater temperatures (McGowan et al. 1998) are accompanied by shifts
in the Bight fauna as cool temperate species decline and warm temperate species
are favored (Stephens et al. 1988; Love et al. 1998). Superimposed on these cycles
is the El Nifio/Southern Oscillation (ENSO), warm water (El Nino) and cold water
(La Nifia) events that occur on a cycle of four to ten years with varying intensity.
When intense, an El Nifo may be accompanied by striking incursions into the
SCB of species whose center of distribution lies well to the south (Radovich 1961;
Mearns 1988; Lea & McAlary 1994; Martin & Velarde 1997). These factors
contribute to the distinctive and variable nature of the SCB fauna. This paper
documents the first recorded appearance in the SCB of ten decapod crustaceans,
all of which have distributions that are primarily tropical, subtropical, or Corte-
zian. All but two of these animals were collected during the 1997/98 El Nifio

199

200 SOUTHERN CALIFORNIA ACADEMY OF SCIENCES

period and its immediate aftermath. The remaining two species were taken during
or immediately after the 1991/92 El Nino.

All specimens reported here were collected during shelf and upper slope depth
otter trawl surveys of demersal fish and epibenthic invertebrates. The surveys
include those conducted as part of wastewater impact monitoring programs per-
formed by the County Sanitation Districts of Los Angeles County (CSDLAC),
the Orange County Sanitation District (OCSD) and the City of San Diego Met-
ropolitan Wastewater Department (CSDMWWD). Other material was collected
during powerplant monitoring in Long Beach Harbor by MBC Applied Environ-
mental Sciences or during the Southern California Bight 1998 Regional Moni-
toring Program (Bight’98), a large scale, multi-agency regional survey of the SCB
carried out during July and August of 1998. Most of these specimens are retained
as vouchers or reference specimens by the capture agencies. In some cases spec-
imens have been deposited in the Crustacea collection of the Natural History
Museum of Los Angeles County. All are available for inspection, regardless of
their repository.

Order Decapoda
Suborder Dendrobranchiata
Infraorder Penaeidea
Superfamily Penaeoidea
Family Penaeidae

Metapenaeopsis mineri Burkenroad, 1934

Metapenaeopsis mineri Burkenroad, 1934:25, Figs. 9, 10 [in part]
Metapenaeopsis mineri: Hendrickx, 1996:23—26, Figs. 11 a, b, c, & 12

Type locality.—Bahia Concepcion, Baja California Sur, Mexico.

Material examined.—Off the mouth of the Tijuana River, California: 1 speci-
men, CSDMWWD Station SD-18 (32°32.52'N, 118°11.357'W), 32 m depth, 26
January 1998.

Remarks.—This is a range extension along the Pacific Coast of approximately
8° of latitude. Species of Metapenaeopsis are generally similar in body form to,
but much smaller than, species of Farfantepenaeus with which they co-occur. It
is possible that, if not closely examined, they are sometimes mistaken in the field
for juveniles of the larger species. The genera are distinguished by the presence
of ventral rostral teeth in Farfantepenaeus.

Distribution.—Off the mouth of the Tijuana River, California, USA (this pa-
per); Bahia Magdalena, Baja California Sur, Mexico and throughout the Gulf of
California (Hendrickx 1996) at depths of 13 to 115 m.

Family Sicyoniidae

Sicyonia penicillata Lockington, 1879
Figure 1

Sicyonia penicillata Lockington, 1879: 164

Eusicyonia penicillata: Burkenroad, 1934: 88, Figs. 30, 31, 33
Sicyonia penicillata: Hendrickx, 1984: 285, Figs. 6, 20, 26
Sicyonia penicillata: Pérez Farfante, 1985: 38—43, Figs. 31—34
Sicyonia penicillata: Hendrickx, 1996:109—113, Figs. 56 a, b, c, 57

NORTHERN RANGE EXTENSIONS OF DECAPOD CRUSTACEA 201

Fig. 1. Sicyonia penicillata. Specimen photographed at the head of Redondo Submarine Canyon,
approx. 20 m depth, 6 June 1999. Photo by Mr. Ken Kurtis.

Type locality.—Bolinas Bay [suspected to be Bahia de Ballenas by Hendrickx
1996], Baja California Sur, Mexico, 26 m depth.

Material examined.—Off the Palos Verdes Peninsula, California: 2 specimens,
CSDLAC Station T0-61 (33°48.57'N, 118°25.84'W), 61 m depth, 18 February
1998. 1 specimen, CSDLAC Station T0-23 (33°48.19’N, 118°25.04’W), 23 m
depth, 20 May 1998. Back Channel, Long Beach Harbor, California: | specimen,
Long Beach Generating Station Monitoring Program Station T10 (33°45.30'N,
118°13.00’W), 18 m depth, 12 August 1988. Off Huntington Beach, California:
1 specimen, OCSD Station T11 (33°36.06'N, 118°05.20'W), 56 m depth, 10 Jan-
uary 2000. | specimen, OCSD Station T13 (33°35.54’N, 118°03.64'W), 56 m
depth, 10 January 2000. Off Torrey Pines State Beach, California: 1 specimen,
Bight’98 Station 2349 (32°53.604’N, 117°16.118’W), 32 m depth, 6 August 1998.

Remarks.—This is a range extension along the Pacific coast of approximately
4° of latitude. The well-developed carapace marking readily distinguishes this
species from Sicyonia ingentis, the common species in the SCB. Even so, the
collection of the species in Long Beach Harbor in the aftermath of the 1986/87
El Nifio went undocumented in the literature until now. A photograph of Sicyonia
penicillata was taken by Mr. Ken Kurtis while diving at the head of the Redondo
Submarine Canyon and is included with his permission (Fig. 1). The photograph
was taken at night on 6 June 1999 in approximately 20 m depth. It illustrates the
distinctive carapace spot of this species, although in most specimens examined
by the authors the central field of the spot is lighter in color, contrasting with its
margins. The latitude at the head of the canyon is approximately 33°50’N. Mr.
Kurtis also reports seeing other S. penicillata in the area of the canyon around
this time as shallow as 5 m. Word and Charwat (1976) treat this species, but do
not provide records from Southern California Bight waters.

Distribution.—Off Palos Verdes, California, USA (this paper); southeast of
Punta Canoas, Baja California Norte to Bahia San Lucas, Baja California Sur,

202 SOUTHERN CALIFORNIA ACADEMY OF SCIENCES

Mexico and throughout the Gulf of California (Hendrickx 1996); off Puntarenas,
Costa Rica (Pérez Farafante 1985) at depths of 1 to 180 m.

Suborder Pleocyemata
Infraorder Caridea
Superfamily Processoidea
Family Processidae

Processa peruviana Wicksten, 1983

Processa peruviana Wicksten, 1983: 29-30, Figs. 4—6
Processa sp.: Méndez, 1981: 98, Fig. 294

Type locality.—Isla Manuelita, Costa Rica: 1 specimen, Velero IV Station
19044 (5°36'09"N, 87°01'14"W), 146 m depth, 3 June 1973.

Material examined.—Off the Palos Verdes Peninsula, California: 1 specimen,
near CSDLAC Station T0-61 (33°48.57'N, 118°25.84'W), 50 m depth, 8 Novem-
ber 1995. Off Point Loma, California: 1 specimen, CSDMWwWD ‘Station B11
(33°46.57'N, 117°21.35'W), 89 m depth, 13 July 1999.

Remarks.—Wicksten (1983) indicates this species frequents sandy bottoms. Lo-
cally collected individuals have also come from sites where the sea-floor was
sandy rather than rocky or muddy. Both specimens taken in the Southern Cali-
fornia Bight were gravid females, and it is likely that the species is reproductive
at the northern limit of its range. No juveniles have yet been taken in the area,
however, suggesting that recruitments are unsuccessful.

Distribution.—Off Palos Verdes, California, USA (this paper); Isla San Benito,
outer coast of Baja California to Mancora, Peri (Wicksten 1983), throughout the
Gulf of California and the Galapagos (Wicksten & Hendrickx 1992) at depths of
11 to 180 m.

Superfamily Pandaloidea
Family Pandalidae

Pantomus affinis Chace, 1937

Pantomus affinis Chace, 1937:116—118, Fig. 3
Pantomus affinis: Hendrickx & Wicksten, 1989: 73-75, Fig. 1

Type locality.—Santa Inez Bay, Baja California, Mexico: 65 specimens, Station
147 D-2 (26°56'30’N, 111°48’30”"W), 110 m depth, 17 April 1936.

Material examined.—Off Point Dume, California: 1 specimen, Bight’98 Station
2116 (33°58.878'N, 118°42.530'W), 191 m depth, 19 August 1998. Off the Palos
Verdes Peninsula, California: 12 specimens, CSDLAC Station TO-137
(33°48.83'N, 118°26.36'W), 140 m depth, 5 November 1997. 1 specimen,
CSDLAC Station T4-137 (33°42.06’N, 118°21.05'W), 140 m depth, 19 May 1998.
4 specimens, CSDLAC Station T5-137 (33°41.11'N, 118°19.61'W), 140 m depth,
19 May 1998. 1,132 specimens, CSDLAC Station TO-137 (33°48.83'N,
118°26.36'W), 140 m depth, 5 August 1998. 2 specimens, CSDLAC Station TO-
305 (33°49.23'N, 118°27.09’W), 305 m depth, 5 August 1998. 331 specimens,
CSDLAC Station TO-137 (33°48.83'N, 118°26.36’W), 140 m depth, 6 November
1998. 280 specimens, CSDLAC Station TO-137 (33°48.83’'N, 118°26.36’W), 140
m depth, 12 February 1999. 150 specimens, CSDLAC Station TO-137

NORTHERN RANGE EXTENSIONS OF DECAPOD CRUSTACEA 203

(33°48.83'N, 118°26.36’W), 140 m depth, 13 May 1999. Off Newport Beach,
California: 3 specimens, Bight’98 Station 2119 (33°34.736'N, 117°55.184’W),
117 m depth, 7 August 1998. Santa Catalina Island, California, off West End: 2
specimens, Bight’98 Station 2065 (33°29.494’'N, 118°34.708'W), 199 m depth,
21 July 1998. Off Imperial Beach, California: 1 specimen, CSDMWWD Station
SD-7 (32°35.06’N, 117°18.39'W) 98 m depth, 25 January 1993. 6 specimens,
CSDMWWD Station SD-7 (32°35.06'N, 117°18.39'W) 98 m depth, 23 January
1998.

Remarks.—Gravid females were common in the catches. The large collection
on 5 August 1998 (1,132 specimens) included many gravid females with eggs in
varying stages of development up to the eyed stage. Approximately 17% of the
shrimp in this collection were gravid females. This is a range extension of Pan-
tomus affinis along the Pacific Coast of approximately 8° of latitude. The popu-
lation established around the Redondo and Santa Monica Submarine Canyons has
not been seen since May of 1999 and may no longer exist; the last collection of
P. affinis in the San Diego region was in April 1999 (R. Velarde, pers. com.).

A number of specimens of Pantomus affinis bore parasitic isopods of the genus
Zonophryxus (Family Dajidae) on their carapaces. The species appears to be un-
described, but original descriptions in this group are lacking in detail, and type
material must be reexamined to determine the status of several described species.
Larger Zonophryxus specimens were also seen on Plesionika trispinus collected
in the same locale (qg.v.). They seem to belong to the same species as the smaller
individuals found on Pantomus. The range of the parasite is not known; no de-
scribed members of the genus have been reported from within 20° of latitude
either north or south of the present captures. They have not been observed on
southern populations of Pantomus or Plesionika trispinus (M. E. Hendrickx, pers.
com.).

Distribution.—Point Dume, California, USA (this paper); Bahia Santa Inés,
Gulf of California, Baja California Sur, and Bahia de Santa Maria, Sinaloa, Mex-
ico to Isla Lobos de Tierra, Peri (Hendrickx & Wicksten 1989) at depths of 35
to 744 m.

Plesionika beebei Chace, 1937

Plesionika beebei Chace, 1937:114, Fig. 2
Plesionika beebei: Hendrickx & Wicksten, 1989:76—77, Figs. 4, 5
Plesionika beebei: Hendrickx & Estrada Navarrete, 1996:131—132, Figs. 80, 81

Type locality—Gulf of California, Baja California Sur, Mexico (26°48'N,
111°20’W).

Material examined.—Off the Palos Verdes Peninsula, California: 1 specimen,
CSDLAC Station T5-305 (33°40.85'N, 118°19.85'W), 305 m depth, 6 November
1997.

Remarks.—This is a range extension along the Pacific Coast of approximately
8° of latitude.

Distribution.—Palos Verdes Peninsula, California, USA (this paper); off Punta
Tosca, Baja California Sur, and off Guaymas, Sonora, Gulf of California, Mexico
to Mancora Bank, Peri (Hendrickx & Wicksten 1989) at depths of 73 to 738 m.

204 SOUTHERN CALIFORNIA ACADEMY OF SCIENCES

Fig. 2. Plesionika carinirostris, scale bars = 5 mm. a, Lateral perspective, the rostrum, lost sub-
sequent to collection, is illustrated with dashed lines. All but lst pereopod detached from specimen
and not figured. b, 2nd pereopod, illustrating the subdivision of the carpus into 26 articles. c, Dorsal,
movable carapace spines.

Plesionika carinirostris Hendrickx, 1990
Figure 2 a, b, c

Plesionika carinirostris Hendrickx, 1990:38—39, Figs. 2, 3
Plesionika carinirostris: Hendrickx, 1995:481

Type locality.—Off Isla San Lorenzo, Gulf of California, Mexico.

Material examined.—Off the Palos Verdes Peninsula, California, in the north
arm of the San Pedro Sea Valley: 1 specimen, CSDLAC Station V150
(33°39.429’N, 118°17.325'’W), 145 m depth, 29 June 1999.

Remarks.—Plesionika carinirostris was previously known only from the type
material, a single male collected in the central Gulf of California. While Hen-
drickx (1995) lists the holotype as a female (hembra), the type description clearly
indicates it as male. The new record off Palos Verdes suggests a range through
the southern Gulf of California and along the Pacific Coast of Baja California.
Hendrickx (1990, 1995) remarks on the large size of the type specimen (110 mm
total length, 21 mm carapace length). The Palos Verdes specimen is a gravid
female and also of large size. Since the rostrum was broken before measurement,
the total length is estimated at 122 mm (25 mm carapace length). The color in
life, previously undescribed, is dull scarlet blotches on a translucent white ground.
The antennae are solid scarlet, while the remaining appendages are nearly all
white, without contrasting color on the legs. The entire oral field of the animal is
bright scarlet, the remainder of the ventrum unpigmented. The egg mass is lav-
ender.

NORTHERN RANGE EXTENSIONS OF DECAPOD CRUSTACEA 205

Distribution.—Palos Verdes Peninsula, California, USA, at a depth of 150 m
(this paper); Central Gulf of California (near Isla San Lorenzo), Mexico at be-
tween 360—380 m depth (Hendrickx 1990).

Plesionika trispinus Squires & Barragan, 1976

Plesionika trispinus Squires & Barragan, 1976:113—117, Figs. 1, 2
Plesionika trispinus: Hendrickx & Wicksten, 1989:80—81, Figs. 4, 5
Plesionika trispinus: Hendrickx & Estrada Navarette, 1996:134—136, Figs. 83, 84

Type locality.—Off Pizarro, Columbia.

Material examined.—Off the Palos Verdes Peninsula, California: 6 specimens,
CSDLAC Station T4-137 (33°42.06'N, 118°21.05’'W), 140 m depth, 17 February
1998. 4 specimens, CSDLAC Station T5-137 (33°41.11'N, 118°19.61’W), 140 m
depth, 17 February 1998. 2 specimens, CSDLAC Station T4-137 (33°42.06'N,
118°21.05'W), 140 m depth, 19 May 1998. 2 specimens, CSDLAC Station T1-
137 (33°43.84'N, 118°25.34'W), 140 m depth, 4 August 1998. 1 specimen,
CSDLAC Station T0-305 (33°9.23’N, 118°27.09’W), 305 m depth, 5 August
1998. 1 specimen, CSDLAC Station T1-305 (33°43.55'N, 118°25.64’W), 305 m
depth, 6 August 1998. 2 specimens, CSDLAC Station T5-305 (33°40.85'N,
118°19.85'W), 305 m depth, 6 August 1998. 1 specimen, CSDLAC Station TO-
305 (33°49.23'N, 118°27.09'W), 305 m depth, 11 August 1999. Off Newport
Beach, California: 3 specimens, Bight’98 trawl Station 2119 (33°34.74'N,
117°55.18'’W), 194 m depth, 7 August 1998.

Remarks.—A parasitic dajid isopod of the genus Zonophryxus was taken on
several Plesionika trispinus. They seem to be larger individuals of the same spe-
cies found on Pantomus affinis in the area (q.v.). As the host is larger, the parasite
can attain larger sizes, although reproductively mature even on the smaller host.
Use of multiple hosts is unusual, but not unprecedented in the Dajidae (Koehler
1911; Brandt 1993). This is a range extension along the Pacific Coast of approx-
imately 9° latitude for this shrimp. The range of the parasite is unknown.

Distribution.—Palos Verdes Peninsula, California, USA (this paper); Bahia de
Santa Maria, Sinaloa, Mexico to off Salaverry, Peru (Hendrickx & Wicksten 1989)
at depths of 96 to 500 m.

Suborder Reptantia
Infraorder Brachyura
Superfamily Oxyrhyncha
Family Majidae

Stenorhynchus debilis (Smith, 1871)

Leptopodia debilis Smith, 1871: 87
Stenorhynchus debilis: Rathbun, 1898: 568

Type locality.—Povlon, Bay of Realejo (Corinto), Nicaragua: | specimen, male,
No. 3948, Museum of Comparative Zoology, Harvard.

Material examined.—Off Huntington Beach: 1 specimen, OCSD Station T11
(33°36.06'N, 118°05.20'W), 60 m depth, 11 August 1999. Santa Catalina Island,
California, White Cove: 1 specimen, Bight’?98 Station 2077 (33°23.75’N,
118°21.84’W), 50 m depth, 22 July 1998. West of Salta Verde Point: 1 specimen,

206 SOUTHERN CALIFORNIA ACADEMY OF SCIENCES

BEADS Aah Sige og
Lhe? 7 a: «* a
PS) fiat

Fig. 3. Palicus cortezi, dorsal view, scale bar = 10 mm.

Bight’98 Station 2087 (33°18.57'N, 118°26.76'W), 69 m depth, 24 July 1998. Off
the Palisades: 1 specimen, Bight’98 Station 2116 (33°18.34'N, 118°21.91’W), 39
m depth, 24 July 1998.

Remarks.—In addition to the trawl-caught material examined by the authors,
reports of Stenorhynchus debilis were common and widespread at diving depths
in the central SCB during 1998 (e.g. Engle & Richards, this volume).

Distribution.—Huntington Beach, California, USA (this paper); Bahia Mag-
dalena, Baja California Sur, Mexico, throughout the Gulf of California to Val-
pariso, Chile; Guadalupe Island, Rocas Alijos, Revillagigedo, Cocos, and Gala-
pagos islands (Hendrickx 1999) at depths of 3 to 156 m.

Superfamily Ocypodoidea
Family Palicidae

Palicus cortezi (Crane, 1937)
Figure 3

Cymopolia cortezi Crane, 1937: 75—76; Plate VIII, Fig. 25
Cymopolia cortezi: Garth, 1946: 499-500; Plate 85, Fig. 2

Type locality.—Santa Inez Bay, Gulf of California: 1 specimen, Department of
Tropical Research of the New York Zoological Society Station 147, Dredge 2,
(26°57.5'N, 111°48.5’W), 120 m depth, 17 April 1936.

NORTHERN RANGE EXTENSIONS OF DECAPOD CRUSTACEA 207

Material examined.—Off the Palos Verdes Peninsula, California: 1 specimen,
CSDLAC Station TO-61 (33°48.57'N, 118°25.84'W), 61 m depth, 23 February
1994.

Remarks.—This is a range extension of approximately 7° of latitude, although
the shoreline distance between the two sites is much greater than 420 miles. This
specimen, like the holotype a male, was initially identified as P. lucasii. Exami-
nation by Mr. Todd Zimmerman (NHMLAC) corrected this based on the form of
the pleopod. Aside from the formation of the anterior carapace and the male
pleopods, the two species are quite similar. While several palicids are known from
the Panamic region, this and the following species are the first members of the
family reported from the Pacific Coast of the United States.

Distribution.—Palos Verdes, California, USA (this paper); Santa Inez Bay, Gulf
of California, Mexico; Wenman Island, Galapagos at depths of 61—300 m (Garth,
1946).

Palicus lucasii Rathbun, 1898

Palicus lucasii Rathbun, 1898: 600, Pl. 43, Fig. 2

Cymopolia lucasii: Rathbun, 1918: 193-194, Pl. 44, Fig. 1, 2
Cymopolia lucasii: Crane, 1937: 76

Cymopolia lucasii: Garth, 1946: 500-501, Plate 87, Fig. 1

Type locality.—Off Cabo San Lucas, Baja California Sur, Mexico; 7 specimens,
Albatross Station 2829, (22°52'00'N, 109°55'00”W), 57 m depth, 1 May 1888.

Material examined.—Off Imperial Beach, California: 1 specimen, CSDMWWD
Regional Station 2101 (33°48.57'N, 118°25.84’W), 38 m depth, 30 July 1996.

Remarks.—This is a range extension of approximately 10° of latitude. This
specimen, a male, was examined by Mr. Todd Zimmerman (NHMLAC) along
with the specimen of P. cortezi mentioned above. The form of the male pleopod
in this specimen was essentially the same as that seen in specimens in Zimmer-
man’s collection from several other sites.

Distribution.—Imperial Beach, California, USA (this paper); Cabo San Miguel,
Baja California (Hendrickx & Salgado Barragan 1997); mid to lower Gulf of
California (Hendrickx 1994), Clarion Island (Hendrickx 1992), and Albemarle,
Hood, and James Islands, Galapagos (Garth 1946) at depths of 20-120 m.

Discussion

The use of otter trawls as a means surveying shelf and slope depth communities
has been a common element of marine monitoring programs in the SCB since
the 1970s. Most of this effort has been directed at monitoring the effects of treated
wastewater discharged from large sanitary outfalls located along the metropolitan
coastline between Los Angeles and San Diego. While these programs are local,
being focused on the receiving water area within the effect of a discharge, they
are of long duration and regular frequency. For example, CSDLAC has been
conducting semiannual or quarterly trawls at 16 to 22 sites on the Palos Verdes
shelf and upper slope in depths of 25 to 300 m since 1972. Over 1500 trawls
have been conducted as part of that ongoing effort. The City of Los Angeles, the
OCSD, and the City of San Diego have been conducting similar long term surveys
as well. In addition, the Southern California Coastal Water Research Project

208 SOUTHERN CALIFORNIA ACADEMY OF SCIENCES

(SCCWRP) conducted several hundred trawls within the SCB in the 1970’s to
80’s. Notable within this effort was the SCCWRP control survey of 1977 that
sampled the 60 m isobath from Pt. Conception to the US/Mexico border. More
recently, there have been two very large-scale otter trawl surveys conducted as
steps towards the development of regional monitoring within the SCB. The first
of these was the 1994 Southern California Bight Pilot Project (SCBPP), during
which 114 mainland shelf sites were sampled (Allen et al. 1998). The sites were
randomly allocated across a depth range of 10 to 200 m from Pont Conception
to the US/Mexico border. The second regional survey, Bight’98, was conducted
July and August of 1998, during the 97/98 El Nifio period. Trawls were conducted
at 311 sites in depths of 5 to 100 m along the mainland shelf from Pt. Conception
to the border, the channel islands and within bays and harbors. A cumulative
result of all these surveys is a fairly complete record of the composition of the
epibenthic megainvertebrate fauna living on soft bottoms in shelf and upper slope
depths within the SCB over the last 30 years. During this period there have been
five warm water events classified as El Ninos (72/73, 82/83, 86/87, 91/92, 97/98)
(Wolter & Timlin 1998). Wicksten (1984) provides a picture of the decapod fauna
in the SCB from an earlier period (1900—1930) based upon the collections of the
Anton Dohrn and other surveys. As in the past 30 years, this was also a period
of frequent warm water events (Kiladas and Dias 1989).

The novelty of several heretofore unrecorded decapods in trawl catches in this
region during the recent El Nifio is accentuated when viewed in the light of the
intensity of sampling over the past 3 decades and several El Nios. The possibility
that they previously occurred but were not recognized or were merely noted as
unidentified shrimp or crabs must be considered. However, this possibility is less-
ened by the active effort to assure complete and standardized identifications of
invertebrate taken in monitoring programs that began in the Bight in the early
1970’s. The biologists conducting regular trawl monitoring in the SCB have been
active participants in the SCCWRP Taxonomic Standardization Program (1970's)
and, since 1982, its successor the Southern California Association of Marine In-
vertebrate Taxonomists (SCAMIT). The appearance in trawls of unusual or odd
organisms is quickly communicated throughout this community and is unlikely
to go unnoticed or unrecorded.

The species reported on here have dispersing larval stages: none release larvae
brooded to benthic competence. It is possible, therefore, that at least the shrimp
species either entered the SCB as larvae, or emigrated as young or adult individ-
uals along with a northward flowing water mass. With the three crab species
emigration is not an option, and they arrived either as pelagic larvae, or possibly
as passive rafters on debris or other organisms (Martin and Kuck 1991).

Even long term warming trends eventually end in Southern California waters.
While local adults may be able to survive in the cooler waters that follow, suc-
cessful local reproduction probably ceases. Despite the presence of gravid indi-
viduals among some of the caridean shrimp (i.e., Processa peruviana, Pantomus
affinis, Plesionika carinirostris), it is unlikely that any of these populations are
able to replace themselves. With the breakdown of El Nifio, these isolated pockets
are cut off from their source population and disappear with time (as the locally
dense population of Pantomus affinis in southern Santa Monica Bay apparently
has). However, the high frequency of warm water years since 1980 may have

NORTHERN RANGE EXTENSIONS OF DECAPOD CRUSTACEA 209

allowed these species to gradually extend their range along the Mexican coast
northward of their previous known northern limits, placing them within reach of
the SCB. If so, we may find these species re-appearing in our catches when
oceanographic conditions favor incursion to the north.

Acknowledgments

The authors thank Dr. Michel Hendrickx (Estacién Mazatlan, ICML) who ex-
amined and confirmed the identity of the pandalid specimens reported upon here,
Dr. Mary Wicksten (TAMU) for identifying the processid, Mr. Todd Zimmerman
(NHMLAC) for identifications of the palicids, and Mr. Ken Kurtis for permission
to use his photograph of Sicyonia penicillata. The authors also thank Mr. Atsuhiro
Kubo, who produced the drawings of Plesionika carinirostris and Palicus cortezi.
Ronald Velarde, Dean Pasko (CSDMWWD) and Christina Thomas (OCSD) gen-
erously provided material and collection information for the records attributed to
their agencies. The manuscript benefited from comments received from two anon-
ymous reviewers. This is contribution 14 of SCAMIT.

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Wicksten, M. K., and M. E. Hendrickx. 1992. Checklist of penaeoid and caridean shrimps (Decapoda:
Penaeoidea, Caridaea) from the Eastern Tropical Pacific. Proc. San Diego Soc. of Nat. Hist., 9:
1-11.

Wolter, K., and M. S. Timlin. 1998. Measuring the strength of ENSO—how does 1997/98 rank?
Weather 53:315-324.

Word, J. Q., and D. K. Charwat. 1976. Invertebrates of Southern California Coastal Waters. II. Na-
tantia. Southern California Coastal Water Research Project, El Segundo, California. 238 pp.

Accepted for publication 21 December 2000.

Shifts in Fish and Invertebrate Assemblages of Two Southern
California Estuaries during the 1997-98 El Nino

Gregory D. Williams,' Janelle M. West, and Joy B. Zedler?

Pacific Estuarine Research Laboratory,
San Diego State University, San Diego, CA 92182-1870

Abstract.—Estuarine fish and invertebrate assemblages at Tijuana Estuary and Los
Pefiasquitos Lagoon exhibited changes coincident with the 1997-1998 El Nifio
event. Three fishes [A/bula sp. (bonefish), Ctenogobius sagittula (longtail goby)
and Acanthogobius flavimanus (yellowfin goby)] and three invertebrate species
[Callinectes arcuatus (arched swimming crab), Penaeus californiensis (Mexican
brown shrimp), and Petricola hertzana (bivalve)] were new to estuary monitoring
records. In addition, three historically common species exhibited substantial
changes in abundance and/or size frequency: Mugil spp. (mullet spp.), Grandi-
dierella japonica (amphipod), and Tagelus californiensis jackknife clam). Likely
mechanisms for the observed patterns include modified ocean currents, altered
larval supplies, increased rainfall, and flooding disturbance. Long-term biological
monitoring programs (12-yr) provided valuable baseline data for quantifying these
changes and recording faunal patterns over interannual-decadal time scales.

Introduction

El] Nino events are short-term cycles in the ocean-atmosphere system with a
mean recurrence interval of 3—8 years (Haston and Michaelsen 1994). In the
coastal waters of the Californias, El Nifio is characterized by increases in sea-
surface temperature and sea level. Most El Nifio events also produce abnormally
high rainfall and streamflows in southern California (Schonher and Nicholson
1989; Kahya and Dracup 1994). Particularly strong historical El Nino events have
occurred in 1926—27; 1957-58, 1982-83, 1991-92, and 1997-98 (Hubbs and
Shultz 1929; Simpson 1984; Squire 1987; Lynn et al. 1998). The 1997-1998 El
Nino was one of the strongest of this century (Hayward et al. 1999).

In California, the biological effects of El Nifio conditions have been docu-
mented in many marine habitats. Offshore, these effects include the migration of
subtropical or tropical fishes into more northern latitudes (Hubbs and Schultz
1929; Walford 1931; Hubbs 1948; Ketchen 1956; Radovich 1961; Cowen 1985;
Squire 1987; Karpov et al. 1995). Enhanced development of a northerly coastal
countercurrent (the Davidson current) during El Nifio years also results in the
northward movement of more southerly pelagic invertebrates (e.g., Pleuroncodes
planipes; Squire 1987) and fish larvae (e.g., Semicossyphus pulcher; Cowen
1985). In nearshore waters, growth and canopy cover of giant kelp (Macrocystis
pyrifera) declines, with cascading effects on the associated kelp forest community
(Dean and Jacobsen 1986; Tegner and Dayton 1987; Dayton et al. 1998). Abun-

' Current address: Battelle Marine Sciences Lab, 1529 W. Seqium Bay Road, Sequim, WA 98382.
* Current address: University of Wisconsin, Botany Dept., 430 Lincoln Drive, Madison, WI 53706.

SHIFTS IN FISH AND INVERTEBRATES IN CALIFORNIA ESTUARIES 213

dance and nesting success of some seabirds also plummets in El Nifio years,
presumably due to modification of the nearshore food web (Massey et al. 1992;
Veit et al. 1996).

Few long-term studies have documented El Nifio-related effects on estuarine
biota in southern California. Estuarine ecosystems are characterized by substantial
variability due to their landscape position at the land-ocean interface, where they
are influenced both by their terrestrial watersheds and the tidal marine environ-
ment. During El Nifio years, high rainfall and streamflows in coastal watersheds
can result in rapid flooding, strong freshwater pulses, and substantial sediment
deposition in southern California’s estuaries and lagoons (Onuf and Quammen
1983). El Nifio-related sea level increases and sea storms can lead to dune ov-
erwash (Nordby and Zedler 1991) and enhanced inundation of the tidal marsh
surface. Together with ocean temperature anomalies and altered current patterns,
El Nifio-induced natural disturbances may result in a cascade of changes to shal-
low water estuarine systems. Biotic effects may include a reduction in the diver-
sity and abundance of benthic invertebrate and fish communities (Onuf and Quam-
men 1983; Nordby and Zedler 1991), invasion by exotic and disturbance-colo-
nizing species, and altered patterns of larval recruitment (e.g., Cowen 1985).

The objectives of our study were to identify trends and anomalies in fish and
invertebrate populations from two estuaries in San Diego County during the 1997—
98 El Nifio. Specifically, we used a 12-year monitoring database to identify the
appearance and persistence of new species in these systems coincident with the
1997-98 El Nifio, while documenting shifts in historical assemblage composition
and size frequency.

Materials and Methods
Study Sites

The Pacific Estuarine Research Laboratory (PERL) at San Diego State Uni-
versity has maintained biological monitoring programs at both Tijuana Estuary
(TE) and Los Pefiasquitos Lagoon (LPL) since the mid-1980’s, enabling compar-
ative ecological research on these unique ecosystems (Nordby and Zedler 1991;
Desmond et al. in review). Tijuana Estuary (32°34’N, 117°07'W) is located on
the U.S.-Mexico border, at the terminus of the Tijuana River’s 4403 km? watershed
(Fig. 1). At approximately 1024 ha, it comprises one of the largest remaining,
intact estuarine habitats of its kind in southern California. It is one of 22 NOAA-
designated National Estuarine Research Reserves (NERRs) in the nation (Zedler
et al. 1992). TE is strongly influenced by marine conditions and has historically
remained open to tidal flushing, with a few exceptions (Zedler et al. 1992). Rapid
development of the watershed and floodplain has contributed to the severity of
episodic flooding and sedimentation events, often accompanied by chronic sewage
flows (Marcus 1989). The sampling program for the NERR was initiated in 1986
to monitor TE’s water parameters, soil conditions, and plant, invertebrate, and
fish assemblages (Desmond et al. 1999).

Los Pefiasquitos Lagoon (32° 56’ N, 117° 15’ W) is a relatively small coastal
estuary (252 ha) in northern San Diego County, situated at the outlet of the 420
km? Pefiasquitos watershed (Fig. 1). The lagoon-marsh complex is protected under
its designation as a Natural Preserve, and constitutes the northern portion of Tor-

SOUTHERN CALIFORNIA ACADEMY OF SCIENCES

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SHIFTS IN FISH AND INVERTEBRATES IN CALIFORNIA ESTUARIES 215

rey Pines State Reserve under the jurisdiction of California State Parks. Drainages
flowing into LPL include Carroll, Los Pefiasquitos, and Carmel Valley Creeks,
which were historically perennial streams. LPL closes to tidal flushing on an
annual basis, a process more recently augmented by hydrologic modifications
(including a major reduction in the tidal prism) associated with construction of a
railroad through the lagoon (in 1925), a highway across its mouth (in 1933), and
sedimentation from human impacts in the watershed. During closed-mouth con-
ditions, waters become vertically stratified, leading to anoxic conditions and fish
kills; since 1986 the management approach to these problems has been to reopen
the mouth manually, which enhances tidal mixing and flushing (LPL Foundation
and State Coastal Conservancy 1985, Zedler 1996; Williams et al. 1999b). Sam-
pling in Los Pefiasquitos Lagoon began in 1986 to monitor water parameters, soil
conditions, and plant, invertebrate, and fish assemblages (Williams et al. 1999a).

Physicochemical Conditions

Monthly summaries of rainfall data were obtained from the National Weather
Service at Lindbergh Field, San Diego (http://nimbo.wrh.noaa.gov/sandiego-/
nws.html). Total monthly streamflows of the Tijuana River at the Nestor gauge
were obtained from the International Boundary and Water Commission (IBWC)
(http://www.ibwc.state.gov/). Intensive water monitoring was conducted at One-
onta Slough, near Seacoast Drive in the north arm of TE, using an automated
YSI 6000 upg datalogger which has been operated and maintained continuously
since 1996. This unit samples 6 parameters, including salinity and temperature
(°C), at 30-minute intervals, 24 hours a day, with sensors located 10 cm off the
bottom of the channel.

Biotic Responses

Identical methods were used to sample invertebrate and fish assemblages at TE
and LPL (see below), although sample number and frequency differed. The da-
tabase at TE includes quantitative estimates (species composition, density, and
size-frequency) of fishes and invertebrates collected from three stations (TE#1—
3) in the north arm of the estuary (Fig. 1) on a quarterly basis (spring = March,
summer = June/July, fall = September, and winter = December/January) from
1986-1999. An additional station in a restoration site (TE#4) was added during
1997-99. At LPL, fishes and invertebrates were initially collected from three
stations (LP#1—3; Fig. 1) on a quarterly basis. Sampling frequency at LPL de-
creased to summer and winter for fishes in 1990, and for invertebrates in 1995,
while two additional sampling stations (LP#4 and #5) were added in the upper
lagoon in 1995.

Two sets of benthic invertebrate samples were collected at low tide from each
station. A first set of nine shallow cores was collected by removing the top 5 cm
of sediment with a cylindrical “clam gun” (45 cm length; 15 cm diameter; 176
cm? area). The nine cores were combined in groups of three, yielding three rep-
licate samples (0.053 m? ea.) from each station. Samples were seived through a
l-mm screen in the field. Easily identifiable animals were counted and released,
while all others were preserved in 95% EtOH for later identification; samples
were soaked in a rose bengal solution prior to sorting. A second set of “‘deep”
cores was collected by pushing the same “‘clam gun”’ 20 cm into the sediment to

SOUTHERN CALIFORNIA ACADEMY OF SCIENCES

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218 SOUTHERN CALIFORNIA ACADEMY OF SCIENCES

estimate the abundance of large, deep-dwelling invertebrates (e.g., bivalves, bur-
rowing shrimp). Nine cores, pooled using the same methods as in the shallow
series, were taken at each station. Samples were seived through a 3-mm screen
in the field. Easily identifiable animals were counted and released, others were
preserved as above for later identification. Field observations, including those
made of specimens captured during fish seining (see below), provided additional
data on large and/or mobile taxa not usually sampled with the cores. Because
invertebrate monitoring focused on benthic invertebrates, our protocol for surface
macroinvertebrates was to note the presence of the more mobile taxa (e.g. Pach-
ygrapsus crassipes on banks of channels). When unusual species appeared, their
presence was noted and, time permitting, density and/or size data were gathered.

Fishes and mobile surface macroinvertebrates (e.g., decapod crustaceans) were
sampled from each station during the slack period of a low neap tide using two
blocking nets and one 15-m bag seine with 3-mm square delta mesh. At each
study site a linear distance (~9 to 12 m) was measured parallel to the channel
and two blocking nets were deployed to confine all fishes within this area. The
bag seine was then swept between the two blocking nets and across the channel
to the opposite bank (defining 1 pass). Passes were repeated until the number of
fish captured per pass was less than 5% of the total catch. The species composition
and number of fishes collected was recorded separately for each pass. Subsamples
of at least 25 individuals per fish species were measured and then released outside
the blocking nets. Individuals that were unique or difficult to identify were pre-
served as voucher specimens.

Historical data (i.e., Tables 1—3) was used to identify groups of fish and inver-
tebrate species that exhibited atypical abundance trends coinciding with the strong
1997-98 El Nino event. Although another fairly strong El Nino event (1991-92)
has occurred during our long-term monitoring program, our data indicated mini-
mal responses to this event among the biotic communities of TE and LPL (Tables
1—3). However, because the 1997—98 event had a striking effect on these two
systems, we focused on 1997—98 data from both LPL and TE, identifying species
new to the sampling record and reporting long-term trends in abundance (density)
and size-structure.

Results and Discussion
Physicochemical Conditions

Monthly multivariate El Nino indices indicate that strong El Nifio conditions
extended from April 1997 through July 1998 along the southern California coast
(Hayward et al. 1999). During this time, sea-surface temperatures were anoma-
lously warm, averaging from 2—4 °C above long-term means (Lynn et al. 1998).
El Nifio conditions also produced a substantial increase in mean water levels
during this time, with a maximum anomaly of +0.2 m at the Scripps Pier (La
Jolla, CA) in November 1997 (Lynn et al. 1998).

Precipitation during the 1997—98 water year (7/1/97—6/30/98) was over 45 cm,
which exceeded the long-term average of 25.4 cm yr™! recorded at Lindbergh
Field, San Diego (Fig. 2). An exceptional peak in February 1998 rainfall (19.4
cm) was almost equal to the long-term annual mean. Rain events were accom-
panied by elevated river flows. At the U.S.-Mexico border in April 1998, Tijuana

219

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SHIFTS IN FISH AND INVERTEBRATES IN CALIFORNIA ESTUARIES 224

Rainfall (cm)
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Tijuana River. Mean monthly salinity and temperature (ppt, °C; bottom) within Tijuana Estuary, as
measured by YSI datalogger at station TE#2. El Nifio conditions persisted from approximately April

1997-July 1998.

River flows exceeded 40 m3 sec~!; mean daily flow rates at this site (since 1962)
were 2.31 m? sec-!. No river gauges are maintained in the lower watershed of
Los Pefiasquitos Lagoon.

Exceptional precipitation and river flow-rates also impacted estuarine habitats,
where flooding deposited up to 12 cm of sediment over Tijuana Estuary mudflats
(Ward 2000). Dramatic declines in mean monthly water salinities at TE#2 during
February and April 1998 corresponded with periods of high rainfall and water

flows (Fig. 2).

Biotic Responses

Based on differences before and during the 1997-1998 El Nifo event, we
observed six fish and invertebrate species that were either historically uncommon

222 SOUTHERN CALIFORNIA ACADEMY OF SCIENCES

1997 1997 1997 97/98 1998 1998 1998 98/99 1999 1999
Spr Sum Fall Win Spr Sum Fall Win Spr Sum

Albula spp. TE
Acanthogobius flavimanus TE
LPL
Ctenogobius sagittula TE
LPL
Mugil spp. TE
LPL

Callinectes arcuatus

Penaeus californiensis

Fig. 3. Mean density (per m*) of species collected with the seine (spring 1997 through summer
1999) that exhibited atypical abundance trends during the 1997—98 El Nino event. “‘X”’ indicates that
individuals were observed in low numbers, but densities were not quantified.

or completely new to the monitoring record. During 1997—98 we also documented
shifts in abundance (increase or decrease) and/or size structure of three species
that were common in the historical monitoring record. Descriptive analysis of
these species trends includes the date of first collection, density and relative abun-
dance, persistence in the estuary, size frequency, and discussion of life history.

New/uncommon species.—Most of the fish and invertebrate species new to the
12-year monitoring record at TE and LPL in 1997—98 were collected as juveniles.
Their appearance altered the relative abundance of common species and increased
species richness in lagoon assemblages. New invertebrates were first collected in
winter 1997—98, while fishes were collected later in the summer or fall of 1998,
either due to differential catchability or real differences in larval arrival/avail-
ability (Fig. 3). Each species exhibited variable periods of persistence in these
estuaries. Although it appears that the abundance of several other species (Por-
tunus xantusii—Xantus’ swimming crab, Paralabrax nebulifer—barred sand bass,
Menticirrhus undulatas—California corbina, and Pleuronichthys coenosus—C-O
turbot) may also be correlated with the 1997—98 El Nifio event (Tables 1 and 2),
we are not considering these as “‘new/uncommon species”’ because they are all
regularly found in the local sandy nearshore environment.

Albula sp. (bonefish): A total of 11 Albula spp. \eptocephalus larvae were
collected at TE in spring 1998 (Table 1; Fig. 3). While not abundant (mean density
< 0.03 m~?; < 4% relative abundance), Albula spp. leptocephali were collected
at 3 of 4 sampling stations, indicating wide distribution throughout the estuary.
Albula leptocephali in the Gulf of California grow to lengths of up to 70 mm

SHIFTS IN FISH AND INVERTEBRATES IN CALIFORNIA ESTUARIES 223

standard length (SL) prior to settlement (Pfeiler 1984). Individuals in our collec-
tions ranged in size from 38—68 mm total length (TL).

This is the first time this tropical species has been collected at TE since mon-
itoring was initiated in 1986 (Table 1); none have been collected at LPL. No
additional Albula spp. (larvae, juveniles, or adults) were collected in 1999 or
2000, suggesting that this species did not persist in the estuary either due to
outmigration, mortality, or our inability to capture juvenile stages or adults. Un-
usual recruitment of Albula spp. was also observed in 1998 at nearby Mission
Bay (Talley 2000) and San Diego Bay (Allen 1998).

Because of current uncertainties regarding the taxonomic identity of bonefish
in our region (Pfeiler et al. 1988), we refer to specimens in our collections as
Albula spp. Bonefish are oviparous and presumably have planktonic eggs; larvae
are rare in collections from the California Current region, although they are com-
mon and widespread in the Gulf of California (Moser et al. 1993, Charter and
Moser 1996). Pfeiler et al. (1988) postulated that Albula leptocephali from the
Gulf of California have a larval duration of 6—7 months; during winter and spring
months the larvae actively move into shallow, lagoon nurseries in the first hours
of a nocturnal flood tide, where they metamorphose into juveniles (Pfeiler 1984).
Albula leptocephali are euryhaline, with a salinity tolerance of 4—52 ppt; they
have been reported in both hyper- and hypo-saline lagoon habitats (Pfeiler 1981).
Adult bonefish constitute an important recreational fishery in many areas and
typically inhabit shallow (<0.5 m) sand and seagrass flats, where they feed on a
variety of benthic prey (Mojica et al. 1994, Charter and Moser 1996).

Ctenogobius sagittula (longtail goby): The tropical goby, Ctenogobius sagit-
tula, was first sampled at TE and LPL during summer 1998 (Tables 1 and 2). At
TE, 65 C. sagittula were collected from stations TE#2 and TE#3 in channels of
moderate depth (0.25—0.6 m on a low, neap tide), with strong tidal flows and
bottoms composed of muddy sand or shell hash. Mean density across all stations
was <0.09 m~ (Fig. 3), with C. sagittula averaging over 20% of the catch.
Ctenogobius sagittula persisted in TE for approximately six months, becoming
less common in quarterly samples subsequent to summer 1998. Mean densities
decreased to 0.035 fish m~ by fall 1998 and <0.01 m~? by winter 1998—99. Mean
C. sagittula sizes rapidly increased from 55.6 mm during summer 1998 (range:
33-78 mm TL), to 123.6 mm by fall 1998 (range: 98-200 mm TL).

Ctenogobius sagittula was less abundant at LPL. During the June 1998 sam-
pling period, a total of four C. sagittula measuring 88—93 mm TL were collected
from one station (LP#2), which is located in a warm, shallow side-channel near
the lagoon interior (Fig. 1). Ctenogobius sagittula made up <2% of the mean
catch across all stations, with mean densities of 0.03 fish m~? (Fig. 3). This is the
only LPL record of C. sagittula; no individuals were collected in subsequent
samples. Specimens from both locations have been archived in the Scripps Insti-
tution of Oceanography vertebrate collections (TE—SIO 98-124; LPL—SIO 98-
b23).

Ctenogobius sagittula is currently considered rare (Miller and Lea 1972) or
extirpated (Swift et al. 1993) in southern California. However, the species is com-
mon in the Gulf of California and adjacent waters to Panama (Ruiz-Campos and
Castro-Aguirre 1999), with disjunctive records in warmer Pacific coastal lagoons
of Baja California, Mexico (e.g., San Ignacio lagoon by De La Cruz-Aguero and

224 SOUTHERN CALIFORNIA ACADEMY OF SCIENCES

Cota-Gomez 1998, San Quintin Bay by Rosales-Casian 1996). Ctenogobius sag-
ittula was also observed during spring and summer of 1998 in Mission Bay
marshes (Talley 2000).

Acanthogobius flavimanus (yellowfin goby): Another historically rare goby, the
nonindigenous Acanthogobius flavimanus also appeared during summer 1998
sampling at both TE and LPL (Fig. 3). At TE, A. flavimanus was collected at
densities of 0.49 m~? at one station (TE#2) in the main channel of the north arm.
Averaged across all 3 stations, A. flavimanus densities were 0.16 m~? (4.9% of
the total catch). All A. flavimanus collected at this time were juveniles (<100 mm
TL; Baker 1979) with a size range of 28-88 mm TL. This recruitment pulse
appeared to be a one-time event at TE; the only A. flavimanus specimen observed
since then has been a single 38 mm TL individual collected in June 1999. The
absence of adults in subsequent TE collections suggests that A. flavimanus pop-
ulations do not persist for long in TE, with recruitment events likely dependent
on an influx of larvae supplied from other locations (perhaps San Diego Bay;
Williams et al. 1998a).

A recruitment pulse of Acanthogobius flavimanus was also observed in summer
1998 at LPL, where their mean density was 0.02 m~? and they averaged 6.4% of
the catch across all stations (Fig. 3). Most of these specimens were collected in
the mid-lagoon channels of station LP#1 and LP#2, and ranged in size from 58—
128 mm TL, considerably larger than those collected at TE two weeks later.
However, A. flavimanus were prevalent throughout the lagoon, including upper
lagoon stations LP#4 and LP#5 where surface salinities were low (3—5 ppt) and
generally reflected heavy freshwater inputs (Fig. 1). The summer 1998 cohort of
A. flavimanus presumably persisted in LPL through the next year, growing into
mature individuals (150—220 mm TL) that were later collected both in winter
1998-99 and summer 1999. A new recruitment pulse of juveniles (47-133 mm
TL) also came into the lagoon in summer 1999 at densities averaging 0.02 m~?
(3.4% of the total catch).

Acanthogobius flavimanus is becoming increasingly common in San Diego
County estuaries. Previous studies documented the southern expansion of A. flav-
imanus to San Diego Bay (32°34'N, 117°5’W) in 1989 (Williams et al. 1998a).
However, unpublished records show that a single 96-mm individual was previ-
ously collected at TE in 1990 under the NERR fish monitoring program (Table
1). Acanthogobius flavimanus individuals have been collected episodically at LPL
during summer sampling periods in 1989, 1993, and 1994 (Table 2) and during
fish kills coinciding with extended mouth closure events (G. Williams, pers. obs.).
Tolerant to a wide range of salinities and temperatures, this large (to 290 mm
TL), opportunistic carnivore may negatively impact native fish assemblages, es-
pecially in disturbed habitats (Baker 1979, Usui 1981). While the extending range
and increasing abundance of A. flavimanus is apparent, the long-term ramifications
of these changes are unclear. However, resource managers should be aware of this
species’ presence and potential impacts to the ecology of native aquatic com-
munities (Williams et al. 1998a).

Callinectes arcuatus (arched swimming crab): This crab species is typically
found in estuarine mud or sand substrates (Garth and Stephenson 1966, Paul
1982a). It was initially collected with the seine at TE in winter 1997—98 (0.041
individuals m~?) and at LPL in summer 1998 (0.036 individuals m~?) (Fig. 3).

SHIFTS IN FISH AND INVERTEBRATES IN CALIFORNIA ESTUARIES 2D

Additional specimens were observed at this time in several nearby estuaries, in-
cluding the San Diego River channel and Sweetwater Marsh on San Diego Bay
(G. Williams and J. West, pers. obs.), as well as Mission Bay (Talley 2000).
Southern California represents the northern extension of C. arcuatus’ known geo-
graphic range, which continues south to Peru (Williams 1974).

At TE, C. arcuatus was most abundant during the main pulse of the El Nifio
event (winter 1997—98 through summer 1998; Fig. 3). Callinectes arcuatus had
peak densities of 0.101 individuals m~’ during spring 1998, with a mean carapace
width (CW) of 61.1 mm (range: 40-119 mm). As C. arcuatus densities declined
throughout the following year, the population structure shifted to predominantly
larger adults. Callinectes arcuatus is known to exhibit rapid growth rates of about
8 mm/month, reaching maturity at 80 mm carapace width (CW) (Paul 1982b).
By spring 1999, C. arcuatus densities had declined substantially (0.014 individ-
uals m~’), while the mean size of collected individuals increased to 123.7 mm
CW (range: 105-145 mm). None were collected after summer 1999 (Desmond et
al. 2000). At LPL, C. arcuatus was most abundant in summer 1998 (0.036 in-
dividuals m~’); densities dropped dramatically by winter 1998—99 (0.001 individ-
uals m~?; Fig. 3).

Callinectes arcuatus is considered a euryhaline species tolerant of a wide range
of temperatures. In the Gulf of California it occurs in areas with salinities ranging
from 1—65 ppt and temperatures from 17.5—34°C (Paul 1982a). In a western Mex-
ico lagoon system, C. arcuatus fed primarily on bivalves (particularly Tagelus
affinis), crabs, and fish, while shrimp and gastropods were consumed in lesser
amounts (Paul 1981). :

Penaeus californiensis (Mexican brown shrimp): Juvenile Peneaus californien-
sis were collected with the seine at TE and LPL in winter 1997—98 and summer
1998 (Fig. 3). Seine samples were generally made in shallow water ~1 m depth,
and all individuals collected were juveniles between 14—37 mm carapace length
(CL). There is no previous collecting record of this species at either LPL or TE,
although their native range spans the coast from San Francisco Bay to Peru (Dore
and Frimodt 1987).

The mean density of P. californiensis at TE during winter 1997—98 was 0.614
individuals m~’, yet none were collected the following spring (Fig. 3). LPL den-
sities during winter 1997—98 were lower than at TE (0.131 individuals m~’); LPL
was not sampled in spring 1998. By summer 1998, P. californiensis densities had
declined to < 0.005 individuals m~’ at both LPL and TE.

Penaeus californiensis is an important commercial species in Mexico, where it
constitutes up to 75% of the Mexican Pacific shrimp catch (Dore and Frimodt
1987; Magallon-Barajas 1987). Newly hatched larvae travel up coastal estuaries
into lagoons, where they spend several months growing to a “‘subadult’’ stage
before returning to sea to mature and spawn (Snyder-Conn and Brusca 1975;
McGoodwin 1979). Mature adults, which can reach a maximum size of 210 mm
CL, generally occur on muddy bottoms or sandy mud at depths of 25—50 m (Dore
and Frimodt 1987). In the Gulf of California, P. californiensis abundance naturally
peaks during the winter season, and most individuals live only one year (Snyder-
Conn and Brusca 1975). The P. californiensis fishery in the Gulf of California
experiences substantial interannual variation in catch per unit effort, likely due to
strong recruitment events, which have been positively correlated with elevated

226 SOUTHERN CALIFORNIA ACADEMY OF SCIENCES

200

a. Petricola hertzana

150

100

15000

Mean density per m2

b. Grandidierella japonica

10000

5000

a
ON
ON
jon
NY

ON oO

ON oO
—

a L,

Fall 97 ¥

Win 97/98
Win 98/99

Fig. 4. Petricola hertzana (a) and Grandidierella japonica (b) densities (+ SE) at three Tijuana
Estuary sampling stations from spring 97 through fall 1999.

sea temperature anomalies characteristic of El Nino events (Morales-Bojorquez
and Lopez-Martinez 1999).

Petricola hertzana: The bivalve Petricola hertzana (Petricolidae) was first en-
countered during summer 1998 in benthic core samples collected at station TE#3,
where mean densities reached 145 individuals m~? (Fig. 4a). Since this initial
collection date, P. hertzana abundance has generally decreased, although the spe-
cies continues to persist at low densities (~35 individuals m~’) at this site. During

SHIFTS IN FISH AND INVERTEBRATES IN CALIFORNIA ESTUARIES ps |

fall 1998 P. hertzana was also observed at a nearby station, TE#2. The population
at this site gradually increased, reaching a peak in winter 1998—99 (45 individuals
m-*). No P. hertzana individuals have been collected at TE#2 since spring 1999
(Fig. 4a).

Petricola hertzana is known to nestle among algae (Coan 1997), and adults
range in size from 6—11 mm shell length (SL; McLean 1969). Individuals col-
lected in our samples ranged from 1-11 mm, indicating the presence of both
juveniles and adults. The distribution of P. hertzana ranges from Santa Monica
Bay to Magdalena Bay, Baja California Sur (Coan 1997). Another Petricola spe-
cies (identified as P. pholadiformis, which may in fact be P. hertzana) was doc-
umented in samples conducted at TE from September 1986 to June 1987 (Duggan
1989).

Historically common species.—Several historically common fish and inverte-
brate species at TE and LPL exhibited a substantial change (increase or decrease)
in abundance during 1997—98, often accompanied by shifts in size-frequencies.

Mugil spp. (mullet): Mullet (Mugil spp.) are large, schooling fish with a cos-
mopolitan distribution that reach maturity at approximately 300 mm TL (2-3
years) (Anderson 1958). Adult Mugil cephalus are common and conspicuous in
southern California estuaries and they likely dominate fish biomass in these sys-
tems; however, they are generally not sampled effectively due to their size and
mobility (Allen 1982, Horn and Allen 1985, Williams et al. 1999a, Desmond et
al. 1999). Smaller juveniles, which can be more effectively sampled with most
gear (e.g., seines), have historically been rare in these collections (Desmond et
al. 1999). Low numbers of Mugil curema (white mullet) have also been collected
in southern California waters, and may easily be confused with M. cephalus,
especially as juveniles (Lea et al. 1988). We therefore treat mullets as Mugil spp.
throughout the remainder of the paper, although M. cephalus is likely the domi-
nant species. In both winter 1997—98 and spring 1998, Mugil spp. juveniles were
a major component of catches at TE (22—23% total catch).

Young-of-the-year (YOY) Mugil spp. (41-50 mm TL) were first collected in
September 1997 throughout TE (3 of 4 stations) at average densities of 0.09 m~
(Fig. 3). Small juveniles 18—43 mm TL continued recruitment through December
1997, when they were collected at all four sampling stations at average densities
of 0.63 m~? (17.7% of catch) (Fig. 5). Thereafter, TE mean densities fluctuated
considerably but exhibited a general decline, while mean individual size increased.
By September 1998 (one year post-recruitment), average Mugil spp. size was 165
mm TL; by June 1999, the average size had increased to 265 mm TL (Fig. 5),
indicating a growth rate of between 75 and 125 mm per year at TE.

Under the semiannual sampling schedule at LPL, juvenile Mugil spp. were first
collected in winter 1997/98 at mean densities of 0.035 m~? (Fig. 3; 11.7% of the
total catch). Abundance of juvenile Mugil spp. peaked the following summer
(1998) at 0.32 m~’, when they were collected at all 5 stations and composed
40.9% of the total catch. Mean size at this time was 76 mm TL (Fig. 5). Mugil
spp. were still abundant at LPL one year later (summer 1999), but by this time
average size had increased to 175 mm TL. A comparison of Mugil spp. cohort
growth rates from LPL and TE suggests that individuals from LPL may grow at
a slower pace.

During the spring of 1998, Talley (2000) and Allen (1998) also noted increases

Pa2.: SOUTHERN CALIFORNIA ACADEMY OF SCIENCES

500
400
300
200
100

0.6

Mean density per m2
Mean total length (mm)

0.4

0.2

D
oN
=
=
n

Spr 97
Sum 97
Fall 97
Spr 98
Sum 98
Fall 98
Spr 99

Fig. 5. Columns represent mean density (per m?) of Mugil spp. collected seasonally (spring 1997
to summer 1999) at Tijuana Estuary (TE; top) and Los Pefiasquitos Lagoon (LPL; bottom). Black
dots indicate the mean total length (mm) of individuals collected.

in the abundance of juvenile Mugil spp. from surveys made in Mission Bay and
San Diego Bay, respectively. Mugil spp. are found in most warm seas, including
the Eastern Pacific from the Galapagos Islands to San Francisco Bay. They are
Oviparous, with planktonic eggs and larvae (Sandknop and Watson 1996). Adult
Mugil spp. spawn in surface waters offshore and enter bays and estuaries as
juveniles or larvae (Anderson 1958), often moving upstream into freshwater rivers
where they develop as yearlings (Follett 1960). Small numbers of mugilid larvae
have been collected during annual ichthyoplankton surveys (1951—1984) con-
ducted in the California Current region; the highest larval concentrations occur
in nearshore stations off central and southern Baja California during the summer
and fall (Moser et al. 1993, Sandknop and Watson 1996).

Grandidierella japonica: This exotic corophiid amphipod exhibited a popula-
tion explosion throughout TE during summer/fall 1998. The highest mean G.
Japonica densities at TE#3 (15,119 individuals m~?) and TE#2 (3904 m~’) were
observed in summer 1998, while TE#1 (1113 m7’) peaked in fall 1998 (Fig. 4b).
By winter 1998-99, mean G. japonica density across all sites (96.4 m~’) had

SHIFTS IN FISH AND INVERTEBRATES IN CALIFORNIA ESTUARIES 229

declined substantially, approaching long-term historical densities (mean for 1994—
97 = 93.5 m~’). LPL populations of G. japonica also experienced an abundance
peak during the 1997-98 El Nifio event. The mean density across all sites in
winter 1997—98 was 643 individuals m~’, three times greater than the long-term
average of 203 individuals m~* (Williams et al. 1998b). After this substantial peak
in abundance, G. japonica densities dropped to levels near the long-term average
during the following seasons.

The introduction of G. japonica into the United States was first reported in San
Francisco Bay, California in 1966 (Chapman and Dorman 1975). It was identified
in TE samples in 1994, but may have been present and unidentified in TE prior
to this. Grandidierella japonica is native to Japan and is typically associated with
brackish water and soft sediments, where it inhabits U-shaped tubes. In laboratory
studies, G. japonica is capable of producing 10—12 generations per year (Green-
stein and Tiefenthaler 1997), which could explain the dramatic increase in den-
sities that occurred within a relatively short time period.

Rapidly reproducing, opportunistic species increase in abundance following a
disturbance if they can take advantage of expanded resources (McCall 1977;
Rhoads et al. 1978; Zajac and Whitlatch 1982). El Nifio-related winter storms in
1997-1998 caused heavy sedimentation in Tijuana Estuary (Ward 2000), which
may have smothered other invertebrates and decreased competition for resources.
G. japonica densities in Yaquina Bay, Oregon also increased dramatically follow-
ing a flood event (B. Boese, pers. comm.).

Tagelus californiensis (jacknife clam): This long-time dominant of the inver-
tebrate community at both TE and LPL (Emmett et al. 1991; Desmond et al.
1999; Williams et al. 1999a), exhibited substantial declines at TE during the 1997—
98 El Nifio event. In spring 1997, the T. californiensis population at TE#2 was
composed of individuals ranging in size from 28—70 mm shell length (SL) at a
mean density of 145 individuals m~? (Fig. 6). Densities gradually declined during
summer and fall 1997 (57 and 13 m~’, respectively). No live T. californianus
individuals were collected (although many empty shells were found) during winter
1997-98 or spring 1998, which coincided with rain and flooding in the estuary.
Summer 1998 collections were marked by an influx of new recruits ranging in
size from 7-15 mm SL at densities of 138 m~ (Fig. 6). Although 7. californianus
densities decreased in the following months (94 m~ in fall 1998, 57 m~? in winter
1998-99), summer 1999 collections had high densities (270 m~’). However, even
by the summer of 1999, the population at TE#2 was still composed entirely of
juveniles (10-56 mm SL).

Tagelus californiensis has a wide geographic distribution, ranging from Cape
San Lucas, Baja California, Mexico to Cape Blanco, Oregon, but it is most abun-
dant from TE to Morro Bay, California (Emmett et al. 1991). Tagelus califor-
niensis occupies a permanent burrow where it feeds on phytoplankton and other
suspended particles (Morris et al. 1980). Sexual maturity is reached between 60—
120 mm shell length (Merino 1981). Peak spawning of T. californianus occurs
in spring, with some limited spawning continuing year-round (Emmett et al.
199T).

Summary and Conclusions

Observed changes in the fish and invertebrate assemblages at TE and LPL
during 1997-98 were likely related to El Nifo-driven ocean anomalies (altered

230 SOUTHERN CALIFORNIA ACADEMY OF SCIENCES

500
‘ 400 |
Samy
vo
=F
ae 10,0) |
=
omm
DN
=|
vo \
= 200
i |
oo}
= T
100 Ff
‘ , ,
sip" iY
0 eT | uae MO rt. Stes Ty aes et eee ee | ie Se ee liv ie.
RPRRALKRRRARAFFRFRRERFERAFGRARARARS
SREZSESEBZEZSMEA SEATS EFLABASCAEBEARCRBERMPEER
ase Zu ZEMEEMZee Are Awe Are GAHEr AE
= S S = = = =
FPP LLL a

1997-98 El Nino

Fig. 6. Mean density of Tagelus californianus (jacknife clam) collected seasonally (winter 1990—

fall 1999) in 20-cm-deep cores at Tijuana Estuary sampling station TE#2. Error bars represent + one
standard error.

current patterns, water levels, and increased temperatures) and watershed distur-
bances (flooding and sedimentation). Altered larval supply, habitat disturbance,
and species interactions (e.g., predation and competition) offer several likely
mechanisms for the patterns observed. Our analysis of long-term monitoring re-
cords is the first documentation of unique changes in estuarine species assemblage
composition during El Nino conditions. Continuous monitoring and baseline data
are essential to understand the ecology of these estuarine systems and their in-
herent variability over interannual-decadal time scales. This study also provides
the groundwork for future empirical studies to clarify the relationship between El
Nino events and species abundance patterns in estuarine habitats, and for devel-
oping predictive models to understand change and appropriately manage estuarine
resources.

Episodic, El Nifo-associated events may affect the composition of fish and
invertebrate assemblages in southern California estuaries by modifying larval sup-
ply. Of the six new fish and invertebrate taxa appearing in our 1997-1998 col-
lections, most were species with warm-water affinities commonly associated with
coastal embayments in southern Baja California and the Gulf of California. Al-
most all specimens were first collected as juveniles that likely arrived at local
estuarine habitats as planktonic larvae, riding northward with warm surface cur-
rents. During “‘typical’’ years, the southward flowing California current (O—200
m deep) carries most nearshore surface waters equator-ward, while coastal up-
welling contributes to offshore transport (Parrish et al. 1981; Simpson 1984).
However during “‘anomalous” El Nino years, upwelling is reduced and a pole-
ward-flowing countercurrent dominates coastal flows, transporting warm, high
salinity waters northward and displacing the California current offshore (Simpson

SHIFTS IN FISH AND INVERTEBRATES IN CALIFORNIA ESTUARIES 231

1984; Hayward et al. 1999). Long-duration, anomalous flow conditions can result
in episodic pulses of planktonic eggs and/or larvae from southern sources, which
are located “‘downstream”’ of southern California.

Flow anomalies account for the variable recruitment success of some coastal
fisheries stocks (Parrish et al. 1981) and may be important in structuring nearshore
benthic communities (Tegner and Dayton 1987). Because long-lived species nat-
urally form age-structured populations and are persistent members of the com-
munity, size-frequency analysis provides one of the best indicators of recruitment
events. Paralabrax maculatofasciatus (spotted sand bass), a long-lived (=14 yrs)
subtropical species that persists in warm-water bay refugia in southern California,
displayed episodic recruitment pulses that matched peaks in summer sea-surface
temperatures during 1984-85 and 1989-90 (Allen et al. 1995). High recruitment
of Semicossyphus pulcher (sheephead) to temperate reefs at its northern distri-
butional limit (Point Conception, CA) coincided with years of El Nifio-associated
variation in the coastal current regime (Cowen 1985). From our data we suggest
that estuarine populations of Mugil spp., another long-lived species (=15 yrs;
Hendricks 1961), also appear to be positively influenced by episodic larval re-
cruitment events (Fig. 5). Furthermore, some portion of the Mugil spp. complex
collected during our monitoring efforts may have been Mugil curema, a species
also documented in California waters during the 1982-83 El Nifio (Lea et al.
1988).

As ocean conditions transitioned to a cool-water, La Nifia state in 1998 (Hay-
ward et al. 1999), few warm-water species recruited to TE and LPL. Most of
these species have ocean-going larvae which were likely exported offshore and
carried southward by the California current, which was then in place. Recruitment
did not occur despite reproductive output by some individuals that survived to
maturity in local systems. For example, ovigerous female Callinectes arcuatus
were observed on several dates (G. Williams, pers. obs.), but no juveniles were
observed in local lagoons thereafter. However, reproducing individuals from these
populations may have contributed larvae to other populations “‘downstream’’.

In the absence of additional recruitment events, persistence of many warmwater
species appeared to be influenced by the longevity of individuals that recruited
during the 1997—98 El Nino. Short-lived species (e.g., Ctenogobius sagittula and
Penaeus californiensis) generally persisted for <6 months in estuaries, while lon-
ger-lived species (e.g., Callinectes arcuatus and Petricola hertzana) persisted and
grew for more extended periods (up to 2 years). Persistence patterns suggest that
these populations are ephemeral and depend on larval replenishment from else-
where. Short persistence times for some of these tropical species may also be a
result of rapid mortality due to low thermal tolerance. However, in our region
hydrographic constraints on dispersal likely play a more important role than ther-
mal tolerance in determining faunal distribution and persistence (Cowen 1985).

Changes in the abundance of two historically common benthic invertebrate
species may be a response to El Nino-related flooding disturbance and sedimen-
tation events rather than larval availability. Grandidierella japonica, an exotic
disturbance-opportunist, exhibited extraordinary peaks in abundance following the
winter floods, while populations of Tagelus californiensis, a native bivalve, plum-
meted in many areas. Similar impacts were observed at Mugu Lagoon in 1978,
when flooding and sedimentation from winter storms resulted in long-term im-

232 SOUTHERN CALIFORNIA ACADEMY OF SCIENCES

pacts to the distribution and composition of fish and invertebrate assemblages
(Onuf and Quammen 1983, Onuf 1985). Sedimentation is an important factor that
can lead to both gradual and abrupt changes in community dynamics in coastal
estuaries (Onuf and Quammen 1983, Zedler et al. 1992, Desmond et al. in review).
Immobile invertebrates in permanent burrows may be buried by catastrophic sed-
imentation events, leading to suffocation and mortality (Peterson 1985). In con-
trast, many epibenthic organisms (e.g., capitellid and spionid polychaetes, coro-
phiid amphipods) opportunistically colonize newly deposited sediments, rapidly
taking advantage of space and food resources (McCall 1977, Zajac and Whitlatch
1982, Levin et al. 1996).

Sedimentation rates appear to be considerably greater at TE than LPL (G.
Williams, pers. obs.), perhaps due to differential levels of watershed disturbance
and area (4403 km? and 420 km/’, respectively), and differences in impacts were
reflected by benthic community responses. Mean sediment accretion on TE tidal
mudflats during the winter of 1997—98 was over 8 cm, but reached levels of 12
cm in some areas (Ward 2000). This is higher than long-term TE marsh sedi-
mentation rates of 1 cm yr~! (Weis 1999), and dramatically more variable than
East and Gulf coast sedimentation ranges of 0.1—1 cm yr~! (Stevenson et al. 1986).
Episodic sedimentation events illustrate the extreme influence which storms may
have on Tijuana Estuary and point to a need to plan for long-term sediment
management solutions (Zedler et al. 1992; Desmond et al. 1999). Furthermore,
these impacts indicate the necessity of evaluating the possibilty of habitat shifts
related to sedimentation events in future restoration efforts (Zedler 1996).

While the individual impacts of sedimentation and larval recruitment likely
exerted major effects on estuarine assemblage composition, their combined, syn-
ergistic effects should not be ignored. Interspecific interactions with novel pred-
ators or competitors in disturbed habitats can substantially modify feeding patterns
and abundance (Moyle et al. 1986, Moyle 1997). While storm-induced sedimen-
tation events may have led to the rapid decline of Tagelus californiensis popu-
lations, predation by Callinectes arcuatus may have also played a role. Callinectes
arcuatus are active, voracious predators of bivalves (Paul 1981), and the peak in
crab abundance coincided with declines of 7. californiensis. Similar declines in
Penaeus californiensis numbers may be due to increased competition from C.
arcuatus juveniles, which utilize similar resources and indirectly compete for food
and space (Paul 1981). Related studies show that feeding patterns of some juvenile
fish species (e.g., Paralichthys californicus and Clevelandia ios) shifted during
El] Nino years due to accompanying changes in prey abundance patterns at TE
(G. Williams et al. in prep.).

This study provides an important record of faunal patterns and variability over
interannual-decadal time scales. Furthermore, it suggests that some of southern
California’s coastal lagoon’s may act as a north-south metapopulation for a num-
ber of fish and invertebrate taxa. Long-term datasets provided by biological mon-
itoring programs are an irreplaceable resource that allows evaluation of subtle
ecosystem responses to climatic cycles (e.g., El Nifio events), anthropogenic im-
pacts, exotic species invasions, and other events. Because southern California has
an inherently variable environment, complete characterization of a ‘normal’ year
is doubtful (Allen 1982, Desmond et al. in review). Thus, knowledge of temporal
variability is needed to understand ecological patterns. Those who wish to test

SHIFTS IN FISH AND INVERTEBRATES IN CALIFORNIA ESTUARIES 733

hypotheses about community membership, population structure, and species per-
sistence in regions influenced by El Nifio or other ‘‘events”’ will benefit from the
continuation of long-term monitoring programs. In fact, researchers and resource
managers cannot expect to understand today’s assemblages or conserve their hab-
itats without referring to records of historical composition and change.

Acknowledgments

This work was accomplished in cooperation with a large number of individuals
over many years. We wish to thank the LPL Foundation and NOAA Sanctuaries
and Programs division for funding ongoing monitoring efforts at LPL and TE,
respectively, and the staff at Torrey Pines State Reserve and the Tijuana Estuary
Visitor Center for their continued support. Julie Desmond, Sharook Madon, John
Callaway, Robert Lea, Drew Talley, Camm Swift, and others encouraged this
work, and their suggestions, ideas, and comments improved the manuscript.

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Accepted for publication 21 December 2000.

New Range Records of 12 Marine Invertebrates: The Role of El
Nino and Other Mechanisms in Southern and Central California

Steve I. Lonhart'” and Jeff W. Tupen?

'Department of Ecology and Evolutionary Biology, University of California,
Santa Cruz, CA 95064, USA
?Morro Group, Inc., 1422 Monterey St., Suite C200,
San Luis Obispo, CA 93401

Abstract.—The occurrence of marine organisms northward of their known range
limit along the eastern Pacific during El Nino Southern Oscillation (ENSO) events
is an increasingly well-studied phenomenon. However, in addition to ENSO re-
lated range extensions, there are several mechanisms potentially contributing to
the occurrence and persistence of extralimital populations. We report 12 new
records of intertidal or shallow subtidal marine invertebrates (11 mollusks and 1
brittle star) along the southern and central coast of California. The 1997-98 ENSO
event accounted for only one of these records, although previous ENSO events
presumably contributed to the nine remaining northward records. Other mecha-
nisms, such as thermal refugia and sampling artifacts, provide more likely expla-
nations for nine of the northern and both of the southern new records.

The ephemeral occurrence of marine organisms extending beyond their typical
geographic range is a well-documented effect of El Nino Southern Oscillation
(ENSO) conditions along the eastern Pacific coast of North America (e.g., Wooster
and Fluharty 1985; Glynn 1990). During 1982—83 and 1997-98, the two strongest
ENSO events of the 20" century (McPhaden 1999) caused large scale northward
shifts of tropical and warm-temperate marine species along the eastern Pacific
(Pearcy and Schoener 1987; McGowan et al. 1998). Among the various ocean-
ographic effects of an ENSO event along the coast of California, the strengthening
of the poleward flowing Davidson Current (Glynn 1961; Thurman 1985) is ar-
guably the greatest contributor to changes in distribution of coastal marine or-
ganisms. As this countercurrent builds, fishes actively track the warm water (Ra-
dovich 1960), and plankton, including the larvae of benthic organisms, passively
drift northward along the coast (Pearcy and Schoener 1987).

For most marine organisms these northward excursions are ephemeral, with
southern species disappearing soon after oceanic conditions return to normal
(Pearcy and Schoener 1987; Dayton and Tegner 1990; Richmond 1990). In ad-
dition to these ephemeral occurrences, ENSO events also may either establish
relict populations or sustain marginal populations. Relict populations, as used
here, are disjunct from southern source populations and persist for one generation
in areas influenced by the ENSO event. Marginal populations are also disjunct
from southern populations but persist as long as ENSO events or other mecha-
nisms allow recruitment (i.e., they act as “‘sinks’’). However, besides these ENSO-

* Corresponding author.

238

EL NINO AND NEW RANGE RECORDS OF MARINE INVERTEBRATES 239

mediated changes in geographic range, there are several other mechanisms poten-
tially contributing to the detection, occurrence, and persistence of extralimital
populations.

We discuss 12 new range records of marine invertebrates along the southern
and central coast of California. For each species, we present evidence to address
whether or not these new records are the result of ENSO events, and discuss other
mechanisms such as localized thermal anomalies associated with the thermal
plumes of coastal power plants and sampling artifacts.

Methods

Specimens were collected by the authors from Monterey Bay (SIL), Morro Bay
(JWT), Diablo Canyon (JWT), and Santa Catalina Island (SIL), California (Fig.
1), spanning a latitudinal distance of 550 km. We collected specimens from eight
sites characterized as either intertidal rocky benches or subtidal (=20 m) kelp
forests on rocky reefs. Many of the specimens from Diablo Canyon were collected
at permanent intertidal and subtidal stations during a 24 yr study on the effects
of the Diablo Canyon Nuclear Power Plant (DCPP) on the marine environment.
Details of the spatial and temporal sampling design are provided elsewhere (Te-
nera 1997). Collections in Monterey Bay and at Santa Catalina Island were made
at study sites selected for other projects. Species were identified initially by the
authors, verified by taxonomic specialists at natural history museums, and voucher
specimens were deposited at one of the following California museums: Natural
History Museum of Los Angeles County (LACM), Santa Barbara Museum
of Natural History (SBMNH), and California Academy of Sciences (CAS)
(Table 1).

The known geographic range for each species was compiled from commonly
used field guides (Abbott 1974; McLean 1978; Morris et al. 1980; Behrens 1991;
Coan et al. 2000), by personal inspection of museum collections at SBMNH and
CAS, and from searches of museum collections by curators at the LACM, San
Diego Natural History Museum (SDNHM), Academy of Natural Sciences, Phil-
adelphia (ANSP), and the Delaware Museum of Natural History (DMNH). Un-
published range records discovered during inspection of museum collections that
exceeded our field data are also included.

Nomenclature follows McLean (1978) and Morris et al. (1980). Intertidal ele-
vations in meters (m) are relative to mean lower low water (MLLW).

Results

We collected 12 species of eastern Pacific coastal marine invertebrates (11
mollusks and 1 brittle star) at sites beyond their published geographic ranges
(Table 1), with ten records northward and two southward. At our study sites,
extralimital populations of four species (Ophiactis simplex, Musculus pygmaeus,
Norrisia norrisi, and Nucella canaliculata) were well established, with evidence
of multiple size-classes or local reproduction. For the remaining eight species,
relatively few specimens were observed and there was no evidence of local re-
production, which suggests these represent either ephemeral occurrences or relict
populations. We present results separately for each species. Table 1 summarizes
the broadest extent of occurrence for each species based on either our collections
or unpublished museum material, whichever was more extensive.

240 SOUTHERN CALIFORNIA ACADEMY OF SCIENCES

“-

Moss Beach
Otter Point y,
N
Marine ' »}
Station McAbée & Monterey
Carmel
Field's
Cove
: Morro Bay
a mene © Diablo Canyon
Diablo
Seo Shell Beach

Seal h

Haul Out N

A Bird Rock S
N

Intake
pipes =

Wrigley

= Institute for
Environmental
Studies

Santa Catalina
|| :
Two Harbors Island

Fig. 1. Location of study sites and new range records along the coast of California, USA.

\ 241

EL NINO AND NEW RANGE RECORDS OF MARINE INVERTEBRATES

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242 SOUTHERN CALIFORNIA ACADEMY OF SCIENCES

Norrisia norrisi.—Norris’ topsnail is relatively common in Diablo Cove
(35°12'40"N, 120°51'25”W; Tenera 1997). Juveniles were collected within the in-
tertidal red alga Gastroclonium subarticulatum in summer/fall 1993 and summer
1994. Large snails (to 45 mm) were first observed subtidally in Diablo Cove in
1991 (Tenera 1997). By 1998, Norrisia was commonly observed (>20 snails per
dive) on the subtidal stipitate kelps Pterygophora californica and Macrocystis
pyrifera in Diablo Cove. Despite this local abundance, Norrisia has not been
observed subtidally or intertidally at adjacent locations outside of Diablo Cove
(Tenera 1997). Four lots (LACM 152433 through 152436, all 1993 except
152434, 1991) of one juvenile each from the intertidal zone (+0.3 m) of Diablo
Cove were deposited as voucher material. Museum specimens establish that N.
norrisi has occurred, at least sporadically, north of Point Conception since the
late 1800’s (ANSP 319023, likely pre-1900, Monterey, California; ANSP 388241,
undated, Monterey, California; LACM 46-35.8, 1946, north of Cayucos, Califor-
nia). Data and a discussion of conflicting published range limits for Norrisia are
presented elsewhere (Lonhart and Tupen in prep.).

Trivia solandri.—Five live and several freshly dead shells of Solander’s trivia
have been collected since 1986 at Diablo Canyon. In April 1999, a single 18 mm
specimen (LACM 152582, 1999) was collected by J. Carroll at a depth of 3 m
in Diablo Cove. Between 1959-1964, J. McLean collected a single shell (LACM
59-12.50) intertidally at Pacific Grove, Monterey County, California, which rep-
resents the northern-most record of occurrence.

Opalia funiculata.—The scalloped wentletrap is a gastropod that parasitizes
large anthozoans (Morris et al. 1980). In July 1993, a single intertidal specimen
(12.8 mm) associated with the tubiculous polychaete Pista elongata was collected
in Diablo Cove. In July 1999, two additional individuals (19.7 and 15.5 mm)
were collected in Diablo Cove on an intertidal (0 m) Anthopleura elegantissima.
All three were deposited as voucher specimens (LACM 152437, 1993; LACM
152583, 1999). Unpublished museum material was collected at Cayucos, San Luis
Obispo County, California (LACM 128091, undated; SBMNH 145295, 1966) and
at Moss Beach, San Mateo County, California (CAS 116964, 1947). The single
specimen from Moss Beach is the northern-most record of occurrence.

Maxwellia gemma.—In 1998, a single specimen (33.2 mm) of the gem murex
was collected subtidally (17 m depth) at McAbee Beach (Fig. 1; 36°37'00"N,
121°53'45”W) and deposited as voucher material (LACM 152452, 1998). In May
2000, a second snail (33 mm) at this site was observed but not collected.

Maxwellia santarosana.—Since 1996, the Santa Rosa murex has been observed
or collected nine times in Monterey Bay at depths from 10 to 17 m. In 1996, a
large (>30 mm) snail was observed in a kelp forest at Otter Point (36°37'45’N,
121°55'15”"W). Five months later, a single adult was observed in the Hopkins
Marine Life Refuge (HMLR; 36°37'18"N, 121°54’10"W), 2 km southeast of Otter
Point. In 1997, a third snail was observed on an offshore pinnacle within 1 km
of Otter Point. In 1998 at McAbee Beach, one specimen (32.1 mm) was collected
amidst filamentous red algae covering a patch of rocky reef and a second specimen
(32.4 mm) was collected on a large boulder; two additional snails were observed
at McAbee Beach later that year. In 1999, a 32.5 mm snail was observed at HMLR
on a rocky reef and a second snail (31.6 mm) collected at McAbee Beach was
eating the vermetid snail Petaloconchus montereyensis. Four snails from McAbee

EL NINO AND NEW RANGE RECORDS OF MARINE INVERTEBRATES 243

Beach were deposited as voucher material (2 in CAS 112494, 1998; 2 in LACM
152451, 1998).

Nucella canaliculata.—The channeled dogwhelk is fairly abundant but patchy
(about 1—3/m7?) at Seal Haul Out, a rocky intertidal bench (+0.9 m) near the DCPP
intake facility characterized by cooler than normal surface temperatures due to a
steep slope (Tenera 1997). Snails at this site are commonly nestled among Cali-
fornia mussels (Mytilus californianus), a common prey item. The presence of egg
capsules, from which crawl-away juveniles emerge, and the persistence of mul-
tiple size-classes suggest this population is self-sustaining. Twenty snails were
deposited as voucher material (LACM 152447, 1998). Unpublished museum ma-
terial (a single, live-collected specimen CAS 116961, 1969) collected from Shell
Beach, San Luis Obispo County, California represents the southern-most record
of occurrence.

Pteropurpura festiva.—In May 1998, the first observation of the festive murex
in Diablo Cove was a large, subtidal (3 m depth) individual next to vase-shaped
egg capsules. This species was absent from samples taken between 1976—95 (Te-
nera 1997). Since 1998, eight large specimens (=30 mm) have been observed in
Diablo Cove, with a single 43.3 mm specimen deposited as voucher material
(LACM 152446, 1998). Subtidal searches in the Morro Bay Power Plant discharge
canal (12 km northward of Diablo Cove; 35°22’16”N, 120°51'57”W) from 1991
to 1998 produced no specimens. However, in November 1999, a single 45.5 mm
P. festiva was collected from the discharge canal by M. Behrens and deposited
as voucher material (LACM 152588). Several museum specimens were collected
from Morro Bay (DMNH 18216.3, undated; SBMNH 110345, 1939; CAS 116957
through 116959, unrelated lots, all undated). Data and a discussion of conflicting
published range limits for Pteropurpura are presented elsewhere (Lonhart and
Tupen in prep.).

Odostomia eucosmia.—During 1980-1995, 19 specimens of this small (to 3
mm) shelled heterobranch were collected within the intertidal (+0.3 m) red alga
Gastroclonium subarticulatum at Diablo Canyon: 11 of these were from Diablo
Cove and 8 were from Field’s Cove (35°12’56"N, 120°51'30”W), which is ap-
proximately 1 km upcoast of Diablo Cove. Four specimens, ranging in shell height
from 1.7 to 2.4 mm, were deposited as vouchers (LACM 152438 through 152441,
all 1993 except 152439, 1987). In 1981, J. McLean collected a single specimen
(LACM 81-47) of O. eucosmia at Carmel, Monterey County, California, which
represents the northern-most record of occurrence.

Turbonilla kelseyi.m—During 1980-1995, only two specimens were collected
from Field’s Cove, but 82 were found in Diablo Cove. Most of the specimens
(n=57) from both intertidal sites (+0.3 m) were associated with the intertidal red
alga Gastroclonium subarticulatum, and the rest with either the fleshy red alga
Chondracanthus canaliculatus or the coralline alga Corallina vancouveriensis.
Four voucher specimens (LACM 152442 through 152445, all 1981 except
152445, 1993) ranged in size from 2.6 to 3.6 mm.

Polycera alabe.—In May 1998, two specimens of P. alabe were collected in
kelp forest habitat (33°26'53"N, 118°28'45”W) near the Wrigley Institute for En-
vironmental Studies on Santa Catalina Island (Fig. 1). These strikingly colored
nudibranchs—readily distinguished from congeners by their elongate papillae and
dark pigmentation—were collected off the bryozoan Bugula neretina at 6 m depth

244 SOUTHERN CALIFORNIA ACADEMY OF SCIENCES

near the intake pipes (Fig. 1). Species verifications were made by Gary McDonald
(UCSC Long Marine Laboratory) viewing live specimens and by Terry Gosliner
(CAS) viewing slide material. None of the specimens were preserved as voucher
material but slides were deposited at CAS. Specimens observed at Anacapa Island
in 1998 (D. Richards personal communication) represent the northern-most record
of occurrence.

Musculus pygmaeus.—The Monterey dwarf-mussel is a very small (to 4.5 mm)
bivalve, almost exclusively found attached to the red alga Endocladia muricata
within the mid- to high-intertidal zone (+0.9 m). During 1980—95, measured
densities of this brooding mussel reached 86600/m? within E. muricata in Diablo
Cove and consisted of many sizes (range 0.5—4 mm). Two lots of 20 individuals
from Field’s Cove and Diablo Cove were deposited as voucher specimens
(SBMNH 144900 and 144901, respectively, 1993).

Ophiactis simplex.—In 1991 in Diablo Cove (Fig. 1), several specimens of this
small (2—6 mm disk diameter), six-armed brittle star were collected from the
rhizomatous holdfasts of the intertidal (+0.3 m) red alga Gastroclonium subar-
ticulatum. Fewer specimens were also collected within vacant sand tubes of the
polychaete Phragmatopoma californica and vacant micromollusk shells (typically
Alia spp. and Lacuna spp.). By 1993, O. simplex density in Diablo Cove increased
to 7200/m? (Tenera 1997). Subtidal specimens were also abundant and generally
larger than intertidal specimens, and typically occupied rock fissures or holdfasts
of foliose red algae such as Gymnogongrus linearis. Subtidal brittle stars were
restricted to areas and depths of the cove with elevated temperatures (generally
<3 m depth). In August 1999, O. simplex was found 12 km northward of Diablo
Cove within the thermal discharge canal of the Morro Bay Power Plant at Estero
Bay, where abundance estimates reached 5000/m?’. Seven intertidal (+0.3 m) and
nine subtidal (3 m depth) specimens from Diablo Cove were deposited as voucher
material (LACM 93-174.1, 1993 and 98-37.1, 1998, respectively), as were 40
specimens from Estero Bay (LACM 99-024.001, 1999).

Discussion

Four of the 12 species presented in this study have established marginal pop-
ulations beyond their known geographic range, while the remaining eight species
may represent either relict populations or ephemeral occurrences. Four species
(Norrisia norrisi, Nucella canaliculata, Musculus pygmaeus, and Ophiactis sim-
plex) have established marginal populations that are consistently abundant at our
study sites, and the density and size structure of these four species are similar to
those found within their known geographic range. Further study is needed to
determine if N. norrisi and O. simplex populations in Diablo Cove are sustained
by local reproduction or by larvae from southern California. Of the eight remain-
ing species, four (Maxwellia gemma, M. santarosana, Odostomia eucosmia, and
Turbonilla kelseyi) were uncommon at their new range limits but consistently
found over multiple years. Since only large adults were observed and there was
no evidence of recruitment, these four species may represent ENSO-related relict
populations. The remaining four species (Opalia funiculata, Polycera alabe, Pter-
opurpura festiva, and Trivia solandri) were rarely found, with only two to several
individuals observed over multiple years.

Environmental conditions and ecological processes constantly modify the tem-

EL NINO AND NEW RANGE RECORDS OF MARINE INVERTEBRATES 245

poral and spatial extent of a species (Brown et al. 1996). In marine ecosystems,
the rate of geographic expansion has accelerated (Elton 1958; Vermeij 1991; Co-
hen and Carlton 1998) due primarily to anthropogenic introductions via ship bal-
last water (Carlton and Geller 1993). Natural transport mechanisms, such as larval
dispersal by oceanic currents, are unlikely contributors to range expansions during
normal oceanic conditions. However, anomalous currents generated during an
ENSO event have the potential to transport pulses of recruits to areas beyond a
species’ known geographic range. In addition to anthropogenic introductions and
recent ENSO events as dispersal mechanisms, other factors, such as habitat mod-
ification due to climate change or thermal effluent, and search artifacts, may also
explain these new range records.

ENSO Events

During an ENSO event, countercurrents (e.g., Davidson Current) strengthen
along the northeastern Pacific (Norton et al. 1985), moving warm, nutrient-poor
water poleward. In general, there are three range-related consequences of this
anomalous circulation pattern along coastal California. First, ephemeral occur-
rences of sub-tropical and warm-temperate species are noted as organisms move
well beyond their typical northern range limits. This is the most well known
consequence and there are numerous published reports of organisms, such as
fishes, that track the warm water as it flows northward (e.g., Hubbs and Schultz
1929; Hubbs 1948; Radovich 1960; Pearcy and Schoener 1987). Passive transport
has been documented for holoplanktonic organisms and species with dispersive
larval stages (e.g., Glynn 1961; Pearcy and Schoener 1987; Bertsch et al. 2000),
and it is possible for some brooding invertebrates to raft on algal mats (Highsmith
1985). These species are rarely observed and only during the ENSO event. In
this study, four species were rarely found, but only the range record of Polycera
alabe is concordant with a particular ENSO event. This nudibranch was not seen
at Santa Catalina Island until the 1997—98 ENSO event, when two adults were
collected in summer 1998 near the intake pipes at the Wrigley Institute for En-
vironmental Studies (Fig. 1). In fall 1998, the observation of a single P. alabe at
Santa Barbara Island and Anacapa Island, both north of Santa Catalina Island,
and its absence at those sites from 1982 to 1997 and after 1998 (D. Richards
personal communication) further support this as an ephemeral occurrence due to
the 1997-98 ENSO event. In addition, three new northern records of other opis-
thobranchs were reported along the coast of Baja California during the 1997—98
ENSO event (Bertsch et al. 2000), suggesting P. alabe was one of several opis-
thobranch species responding to the ENSO event.

Second, southern larval recruits may establish northern relict populations
(Hutchins 1947) that persist after the ENSO event but slowly decline in abundance
and eventually disappear. These small, isolated populations should consist pri-
marily of species capable of long-ranging dispersal and should have only one or
a few size classes indicative of infrequent recruitment. At our study sites Max-
wellia gemma, M. santarosana, Odostomia eucosmia, and Turbonilla kelseyi were
uncommon and consisted almost exclusively of adults, which suggests these spe-
cies represent ENSO-related relict populations. Because we know of no size-age
relationships for these species, we cannot estimate time of settlement to determine
if it corresponds to a previous ENSO event.

246 SOUTHERN CALIFORNIA ACADEMY OF SCIENCES

Third, the recruitment of larvae produced by southern “‘source’’ populations
may sustain persistent extralimital “‘sink’’ populations that have little or no local
reproductive success during normal oceanic conditions (Mileikovsky 1971; Lewis
et al. 1982). For example, recruitment of barnacle larvae to the intertidal within
their geographic range was higher than normal during the onset of the 1997-98
ENSO event along central California (Connolly and Roughgarden 1999). As a
corollary of their study, recruitment was also higher beyond the northern range
limit of these barnacles. Marginal populations are expected to have more age- and
size-classes than relict populations, some missing cohorts, and a bias towards
larger and older individuals (Lewis et al. 1982). For example, Kelletia kelletii
(Kellet’s whelk) in Monterey Bay generally fits this pattern, with no recruits (<15
mm), few juveniles (20—40 mm), and many large (70—100 mm.) adults (Lonhart
unpublished data). The lack of local reproductive success in Monterey Bay sug-
gests this whelk population is dependent upon recruits from southern California
during years of anomalous oceanic conditions. In the present study, populations
of both Norrisia norrisi and Ophiactis simplex were almost certainly transported
northward to Diablo Cove during past ENSO events. However, the establishment
and maintenance of populations in Diablo Cove has been facilitated by thermal
effluent from DCPP (see below). It remains unclear whether the thermal discharge
allows larvae from southern California to recruit and settle, or supports local
reproduction, or does both.

Alternative Mechanisms

Despite the strong impact of ENSO events on species distribution, additional
factors that impact the known distribution of organisms must be considered. The
significance and effects of these additional factors, which include anthropogenic
introductions and climatic warming, are discussed in detail elsewhere (Lonhart
and Tupen in prep.). Here we present a summary of the effects of thermal refugia
and sampling artifacts. Thermal refugia are localized areas of consistently anom-
alous sea surface temperature that allow populations to survive in relatively small,
isolated areas separated from their native range by stretches of thermally unac-
ceptable waters (Dawson 1945; Hubbs 1948; Lindberg 1991). The Diablo Canyon
Power Plant began full operation in 1986, creating a year-round thermal plume
in Diablo Cove (4—5°C above ambient) that closely resembles the warm-temperate
waters of southern California. We propose that of the 12 species presented here,
only Norrisia norrisi and Ophiactis simplex are truly responding to the thermal
plume: both are found only in the thermally elevated parts of Diablo Cove and
invaded (O. simplex) or increased in abundance (both species) after DCPP oper-
ation began (Lonhart and Tupen in prep.).

Existing range data are likely incomplete for all but a few well-studied species
because of sampling artifacts. There are three general explanations: (1) the spatial
and temporal scale of most studies is extremely limited; (2) the taxonomy and
ecology of most species is poorly known; and (3) new range records deposited
in museum collections are infrequently published. Not surprisingly, collection
trips to poorly studied or remote areas often discover new range records (e.g.,
Vermeij et al. 1990; Bertsch et al. 2000). In this study, eight new range records
were from Diablo Cove, which has limited public access. Although pre- and post-
operational studies at Diablo Cove cover a limited spatial scale, they have been

EL NINO AND NEW RANGE RECORDS OF MARINE INVERTEBRATES 247

ongoing since 1976 (Tenera 1997). Unpublished museum records for four species
(Trivia solandri, Opalia funiculata, Nucella canaliculata, and Odostomia eucos-
mia) were beyond those reported in the literature and our study sites.

We have shown that only one of 12 new range records is the result of the
1997-98 ENSO event, and that other mechanisms, such as thermal refugia and
sampling artifacts, have contributed to the presence of the remaining 11 species
beyond their known geographic range. Understanding how various factors alter
our knowledge of the spatial and temporal extent of a species’ geographic range
is an important first step towards designing research programs that accurately
monitor the effects of habitat loss and species invasions, assess native biodiversity,
and study biological responses to climate change.

Acknowledgements

We thank Jim McLean, Lindsey and Cathy Groves, Gordon Hendler, Don Ca-
dien, and George Davis (LACM); Henry Chaney, Paul Scott, and Patricia Sad-
eghian (SBMNH); Eugene Coan, Liz Kools, Chris Mah, and Bob Van Syoc
(CAS); Carole Hertz and Tom Demere (SDNHM); Al Chadwick and Tim Pearce
(DMNH); and Gary Rosenberg (ANSP) for taxonomic and range verifications and
voucher material deposition. We acknowledge the assistance of Mike Behrens and
Jay Carroll (TENERA) in the field, and Dan Richards (Channel Islands National
Park Service) for unpublished data. We also thank Jim McLean, Alan Miller, John
Pearse, Don Potts, Pete Raimondi, Kerstin Wasson, and an anonymous reviewer
for constructive comments on earlier versions of the manuscript.

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Richmond, R. H. 1990. The effects of the El Nino/Southern Oscillation on the dispersal of corals and
other marine organisms. Pp. 127—140 in Global ecological consequences of the 1982-83 El
Nino-Southern Oscillation. (P. W. Glynn, ed.), Elsevier, xx + 563 pp.

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discharge. Diablo Canyon Power Plant: Thermal effects monitoring program analysis report,
Chapter 1, Technical Report E7-204.7. Tenera Environmental Services.

Thurman, H. V. 1985. Introductory oceanography. Merrill Pub. Co., vii + 503 pp.

Vermeij, G. J. 1991. When biotas meet: understanding biotic interchange. Science, 253: 1099-1104.

Vermeij, G. J., A. R. Palmer and D. R. Lindberg. 1990. Range limits and dispersal of mollusks in the
Aleutian Islands, Alaska. Veliger, 33: 346—354.

Wooster, W. S. and D. L. Fluharty. 1985. El Nifo north: Nifio effects in the eastern subarctic Pacific
Ocean. Wash. Sea Grant Prog. Univ. Wash., v + 312 pp.

Accepted for publication 21 December 2000.

INDEX TO VOLUME 100

Allen, M. James. First Occurrence of Blackspot Wrasse, Decodon melasma Go-
mon 1974 (Pisces: Labridae) in California. 131

Allen, M. James. First Occurrence of Speckletail Founder, Engyophrys sanctilau-
rentii Jordan & Bollman 1890 (Pisces: Bothidae), in California. 137

Allen, M. James, see Ami K. Groce

Allen, M. James, see Daniel J. Pondella II

Applegate, Shelton P., see Harry L. Fierstine

Armitage, Mark, Cercarial Emergence from Rediae in California Snail Tissues. 51

Arrubarrena, Luis Espinosa, see Harry L. Fierstine

Bell, Christopher J., see Jim I. Mead
Boyle, Kelly, see Robert N. Lea
Bursey, Charles R., see Stephen R. Goldberg

Cadien, Donald B., see David E. Montagne

Chase, Shawn D., Contributions to the Life History of Adult Pacific Lamrey
(Lampetra tridentata) in the Santa Clara River of Southern California. 74

Craig, Matthew T., see Daniel J. Pondella II.

Curtis, Michael D., First Record of the Pacific Cornetfish, Fistularia corneta Gil-
bert and Starks 1904, a New Species to the Southern California Fauna During
the 1997-1998 El Nino. 156

Davis, Jana L. D., Spot Pattern of Girella nigricans, the California Opaleye:
Variation among Cohorts and Climate Periods. 24

Engle, John M., New and Unusual Marine Invertebrates Discovered at the Cali-
fornia Channel Islands during the 1997—1998 El Nino. 186

Engle, John M., see Daniel V. Richards

Erikson, Erik D., see Robert N. Lea

Fierstine, Harry L., A Fossil Blue Marlin (Makaira nigricans Lacépéde) from the
Middle Facies of the Trinidad Formation (Upper Miocene to Upper Pliocene),
San José del Cabo Basin, Baja California Sur, México. 59

Given, Robert, see Robert N. Lea

Goldberg, Stephen R., Persistence of the Nematode, Oswaldocruzia pipiens (Mol-
ineidae), in the Pacific Treefrog, Hyla regilla (Hylidae), from California. 44

Goldberg, Stephen R., Helminths of Six Species of Colubrid Snakes from South-
ern California. 109

Goldberg, Stephen R., Helminths of the California Treefrog, Hyla cadaverina
(Hylidae), from Southern California. 117

Gonzdlez-Barba, Gerardo, see Harry L. Fierstine

Grismer, L. Lee, An Evolutionary Classification and Checklist of Amphibians and
Reptiles on the Pacific Islands of Baja California, México. 12

249

250 SOUTHERN CALIFORNIA ACADEMY OF SCIENCES

Groce, Ami K. Addition of Blacklip Dragonet, Synchiropus atrilabiatus (Garman,
1899) (Pisces: Callionymidae) to the California Ichthyofauna. 149

Groce, Ami K. Addition of the Calico Lizardfish, Synodus lacertinus Gilbert, 1890
(Pisces: Synodontidae) to the Ichthyofauna of the Southern California Bight.
133

Groce, Ami K., see M. James Allen

Herbinson, Kevin T., see Michael D. Curtis
Horn, Michael H., see Erick A. Sturm

Lagos, Steven L., see Ami K. Groce

Lea, Robert N., Occurrence of the Loosetooth Parrotfish, Nicholsina denticulata
(Scaridae), from Santa Catalina Island, California. 167

Lei, Simon A., Diversity of Parasitic Cuscuta and their Host Plant Species in a
Larrea-Atriplex Ecotone. 36

Lei, Simon A., Combined Effects of Drought and Phoradendrom juniperinum
Infestation Severity on Fruit Characteristics of P. juniperinum and its Juni-
perus osteosperma Hosts. 86

Lei, Simon A., Spatial Distribution of Blackbrush (Coleogyne ramosissima Tort.)
Populations in the Mojave Desert. 96

Lei, Simon A., Postfire Seed Bank and Soil Conditions in a Blackbrush (Coleo-
gyne ramosissima Torr.) Shrubland. 100

Lonhart, Steve I., New Range Records of 12 Marine Invertebrates: The Role of
El Nino and Other Mechanisms in Southern and Central California. 238

Mead, Jim I., Pliocene Amphibians and Reptiles from Clark County, Neveda. 1

Montagne, David E., Northern Range Extensions into the Southern California
Bight of Ten Decapod Crustacea Related to the 1991/92 and 1997/98 El
Nino Events. 199

Nestler, Eric C., see Ami K. Groce

Pondella, Daniel J. Il. Proceedings of Special Symposium: New and Rare Fish
and Invertebrate Species to California during the 1997—1998 El Nifio. 129

Pondella, Daniel J. II. First record of the sabertooth blenny, Plagiotremus azaleus,
in California, with notes on its distribution along the Pacific coast of Baja
California. 144

Reiswig, Henry M., A New North Pacific Heterochone Transferred from Aphro-
callistes (Porifera: Hexactinellida). 123

Richards, Daniel V., New and Unusual Reef Fish Discovered at the California
Channel Islands During the 1997—1998 El Nino. 175

Richards, Daniel V., see John M. Engle

Rosenblatt, Richard H., see Ami K. Groce

Schwennicke, Tobias, see Shelton P. Applegate
Shane, Michael A., Records of Mexican Barracuda, Sphyraena ensis, and Scal-

INDEX TO VOLUME 100 251

loped Hammerhead, Sphyrna lewini, from Southern California Associated
with Elevated Water Temperatures. 160

Sturm, Erick A. Increase in Occurrence and Abundance of Zebraperch (Hermo-
silla azurea) in the Southern California Bight in Recent Decades. 170

Tupen, Jeff W., see Steve I. Lonhart
West, Janelle M., see Gregory D. Williams
Williams, Gregory D., Shifts in Fish and Invertebrate Assemblages of Two South-

ern California Estuaries during the 1997—98 El Nino. 212

Zedler, Joy B., see Gregory D. Williams

New and Unusual Reef Fish Discovered at the California Channel Islands
During the 1997-1998 El Nino. Daniel V. Richards and John M.
Engle

New and Unusual Marine Invertebrates Discovered at the California Channel
Islands during the 1997-1998 El Nifo. John M. Engle and Daniel V.
Richards

Northern Range Extensions into the Southern California Bight of Ten
Decapod Crustacea Related to the 1991/92 and 1997/98 El Nino Events.
David E. Montagne and Donald B. Cadien

Shifts in Fish and Invertebrate Assemblages of Two Southern California
Estuaries during the 1997-98 El Nifo. Gregory D. Williams, Janelle
M. West, and Joy B. Zedler

New Range Records of 12 Marine Invertebrates: The Role of El Nifio and
Other Mechanisms in Southern and Central California. Steve I.
Lonhart and Jeff W. Tupen

Index to Volume 100

£75

186

199

CONTENTS

Proceedings of Special Symposium: New and Rare Fish and Invertebrate
Species to California during the 1997-1998 El Nifio. Daniel Jo
Pondella, Il and M. James Allen, Editors __________-___ iia

First Occurrence of Blackspot Wrasse, Decodon melasma Gomon 1974, Be ie’
(Pisces: Labridae) in California. M. James Allen and Ami K. |
Cree ie iy NORE eT CSN oe ae AR ie

First Occurrence of Speckletail Flounder, Engyophrys sanctilaurentii J ordan | % nN
& Bollman 1890 (Pisces: Bothidae), in California. M. James Allen
anduAmi K: Groce ee SE ee : ;

First record of the sabertooth blenny, Plagiotremus azaleus, in California
with notes on its distribution along the Pacific coast of Baja California.
Daniel J, Pondella, 11 and Matthew T. Craig: 2 ee

Addition of Blacklip Dragonet, Synchiropus atrilabiatus (Garman, 1899)
(Pisces: Callionymidae) to the California Ichthyofauna. Ami K. Groce,
Richard H. Rosenblatt, and M. James Allen’ 2... Sa ee

Addition of the Calico Lizardfish, Synodus lacertinus Gilbert, 1890 (Pisces:
Synodontidae) to the Ichthyofauna of the Southern California Bight.
Ami K.. Groce, Steven L. Lagos, and.Ernie’C. Nestler i.) 2 ae

First Record of the Pacific Cornetfish, Fistularia corneta Gilbert and Starks ©
1904, a New Species to the Southern California Fauna During the |
1997-1998 El Nino. Michael D. Curtis and Kevin T. Herbinson __._ | 156

Records of Mexican Barracuda, Sphyraena ensis, and Scalloped
Hammerhead, Sphyrna lewini, from Southern California Associated
with Elevated Water Temperatures: Michael A. Shane 20

Occurrence of the Loosetooth Parrotfish, Nicholsina denticulata (Scaridae),
from Santa Catalina Island, California. Robert N. Lea, Erik D.
Erikson, Kelly Boyle, and Robert Given... ee

Increase in Occurrence and Abundance of Zebraperch (Hermosilla azurea) in
the Southern California Bight in Recent Decades. Erick A. Sturm and —
Michael Fi: Fiorano ses a |

COVER: Loosetooth parrotfish from Santa Catalina Island. Photo by E. Erikson

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