GULF

RESEARCH

REPORTS

Vol. 8, No. 4
December 1992

ISSN: 0072-9027

Published by the

GULF COAST RESEARCH LABORATORY

Ocean Springs, Mississippi

Gulf Research Reports

Volume 8 | Issue 4

January 1992

Eleven New Species of Free-Living Marine Nematodes

Edwin J. Keppner

DOI: 10.18785/grr.0804.01

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Part of the Marine Biology Commons

Recommended Citation

Keppner; E. J. 1992. Eleven New Species of Free-Living Marine Nematodes. Gulf Research Reports 8 (4): 333-362.
Retrieved from http;//aquila.usm.edu/gcr/vol8/iss4/l

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Guif Research Reports. Vol. 8, No. 4, 333-362. J992

Manuscript received September 7, 1991; accepted November 6, 1991

ELEVEN NEW SPECIES OF FREE-LIVING MARINE NEMATODES OF THE
GENUS HALALAIMUS DE MAN, 1888 (NEMATODA: ENOPLIDA) FROM
FLORIDA WITH KEYS TO THE SPECIES

EDWIN J. KEPPNER

306 Hibiscus Avenue, Panama City Beach, Florida 32413

ABSTRACT. The genus Halalaimus is reviewed and divided into four groups based on characters of the male. Characters
used to separate the groups of males include presence or absence of caudal alac and the presence or absence of a precloacal
sensillum and/or pKire. Ten new species are described from St. Andrew Bay, Bay County, Florida, and H. gerltKhi n. sp. is
proposed for H. gracilis sensu Gerlach, 1967. New species from St. Andrew Bay are H. thalassinus, H. tarjani, H. bayensis.
H. bulbocaudatus. H. variabilis, H.paracomatus, H. americanus, H.floridanus. H. brimi, and H. parafletcheri. Keys to the
species of each group are provided based on characters of the male. A key to the females of the genus is also provided.

Introduction

De Man (1888) erected the genus Halalaimus to ac-
commodate a species of free-living marine nematode from
the North Sea. The genus Halalaimus was differentiated
from other genera on the basis of the extremely elongated
and longitudinally orientated amphid. The head region of
the type species, Halalaimus gracilis De Man, 1888, pos-
sessed three circles of scnsilla. The first circle of sensilla
contained six setae (inner labial sensilla), die second circle
contained six setae (outer labial sensilla), and the third
circle contained four setae (cephalic sensilla). The cuticle
was thick and not transversely striated except for the caudal
region of the male where there was a scries of coarse
transverse striaiions restricted to the lateral fields. A
buccal cavity was absent. The esophagus was long and
narrow anteriorly and broad posteriorly, and it followed the
form of the anterior part of the body which tapers signifi-
cantly from the csophago-intestinal junction to the attenu-
ated anterior extremity.

Southern (1914) erected the genus Nuada for the
spQCiQS Nuada leptosoma Southern. 1914 from the coast of
Ireland, The genus Nuada was characterized by a slender
body, thick cuticle, thin-walled head region, four subme-
dian cephalic setae (questioned by Southern. 1914), and the
absence of amphids. N. leptosoma was represented by two
specimens, a male and a female. The four submedian
cephalic setae appeared to be present in one specimen and
were absent from the other specimen.

Cobb (1920) erected die genus Tycnodora for a species
of free-living marine nematode. Tycnodora pachydermata
Cobb, 1920, from Key West, Florida. This species has a
circle of outer labial sensilla and a circle of cephalic
sensilla (6 + 4) in close proximity to one another, whereas
the inner labial sensilla were absent or not observable.

Filipjev (1927) recognized the three genera, Hala-
laimus De Man, 1888; Nuada Southern, 1914; and Tycno-

dora Cobb, 1920; and described new species in each genus.
He described Nuada as liaving two circles of sensilla close
together in the head region and an amphid similar to that of
Halalaimus. He stated reasons for considering 7/ and
Tycnodora as subgenera of Halalaimus and suggested that
Halalaimus pondcus Filipjev, 1922 represented a new
subgenus of Halalaimus or a new genus.

Stekhoven ( 1935) placed Nuada in synonymy with the
gems Halalaimus, and AUgen (1953) then placed Nuada as
a subgenus of Halalaimus. Wieser (1953) summarized the
information regarding the genus Halalaimus, He recog-
nized two subgenera, Halalaimus s. str. and Tycnodora
Cobb, 1920, and erected the third subgenus Pachydora
Wieser, 1953 in which he placed H. ponticus and a new
species, Halalaimus climactericus Wieser, 1953. He ob-
served that the distinction between the subgenera Hala-
laimus and Tycnodora (distance between the anterior and
posterior circles of anterior sensilla) is not absolute because
transitional species were known. The distinguishing crite-
rion was that the posterior circle of cephalic sensilla in
Tycnodora was no farther posterior from the circle of outer
labial sensilla than the outer labial sensilla were from the
anterior end. In the subgenus Halalaimus s. sir., the circle
of cephalic sensilla was farther posterior from the circle of
outer labial sensilla than the outer labial sensilla were from
the anterior end. Wieser (1953) provided a key to the
subgenera and the species within each subgenus. The key
emphasized the location and length of the anterior circles of
sensilla and the location and length of the amphid.

Mawson (1958) discussed the genus Halalaimus, de-
scribed new species, and constructed a key to the species of
the subgenera Halalaimus and Tycnodora. The keys em-
phasized the length and position of the anterior sensilla imd
the shape of the tiiil. Based on the specimens available to
her, Mawson (1958) concluded that the length and position
of the amphids was sufficiently variable to render imprac-
ticable the use of these characters in a key to the species.

333

334

Keppner

Mawson (1958) also stated that the anterior circles of
sensilla were not clear in a number of the specimens
available to her, and she itssumed that lliese sensilla were
present in Uie usual numbers.

Tijum (1961) described a number of new species of
Halalaimus, Twoof these new sp^ciQS, Halalaimusseiosus
and Halalaimus fiUcollis were described as having six
cervical (cephalic) sensilla. Rao (1989) redescribed 11.
setosus and H. fiUcollis and confirmed the presence of six
cervical (cephalic) sensilla in these species.

Viiiello (1970) described a number of new species of
Halalaimus and discussed the characters used ui differen-
tiat’mg the species in the genus. His collections yielded a
liirge number of species of Halalaimus. but few specimens
of each species. Viticllo (1970) expressed tlie opinion that
the difficulty in identifying Uie species of was
due to the rather subtle differences between species imd the
incompleteness of some of the previous descriptions. He
observed dial the txansverse striations in the cuticle arc best
observed in die caudal region and the area of the posterior
end of the amphid. He also observed, as did Mawson
(1958), the variability in the position of the amphid in
relation to the anterior end of the body and die variability
in the length of the amphid. He also stated that die tail is
easily broken, and that often it is difficult to determine
whether the tail is complete or not. This variability and the
subtle differences between species renders specific deter-
mination difficult. He also questioned the validity of the
subgenus Pachydora.

Gcrlach and Riemann (1974) placed the subgenus
Tycnodora in synonymy with die subgenus Huada and
listed the species then known for the Uiree subgcnera.
Riemann et til. (1970) discussed the morphology of the
amphid in the genus Halalaimus, Juario (1974) erected a
new subgenus, Nualaimus, for those species of the genus
Halalaimus with a distinct circle of iimer labial sensilla in
addition to the circles of outer labial and cephalic sensilla.

Lorenzen (1981) did not accept the subgenera Nuada
imd Pachydora. He also did not recognize the subgenus
Nualaimus. He placed Nualaimus in synonymy with Hala-
laimus because the type species of the genus Halalaimus
and subgenus Halalaimus s. str., Halalaimus gracilis De
Man, 1888, possessed a circlcof inner labial sensilla as well
as the outer labial and cephalic sensilla* Juario ( 1974) had
not included//, gracilis \n submenus Nualaimus. Tlicre-
fore, die genus Halalaimus is not currently divided into
subgeiiera. Halalaimus contains a rather large number of
species, and there is a practical reason for subdividing the
species into subgenera or groups to mtike identification
easier during ecological studies. However, the traditioniil
subgenera wifi not be used in this paper in accordance witli
Loren/cn (1981), nor will new subgenera be erected.

Platt and Warwick (1983) discussed the species of
Halalaimus from Uie British Isles and provided figures of

four species. They stated that “Uie cuticle of some species
can be seen to be faintly striated (perhaps all species have
striated cuticles but some are beyond Uie resolving power
of Uie light microscope.)”

The purpose of this paper is to describe die spec imens
of the genus Halalaimus collected from Bay County, Flor-
ida and provide a key to the species of the genus Hala-
laimus. In addition, specimens of the genus were obtained
from Uie Smithsonian Institution through the courtesy of
Dr. W. Duane Hope and from Dr. Armen C. Tarjan of Uie
University of Florida. Additional specimens were obtained
from the LI. S. Fish and Wildlife Service Field Office,
PanamaCily , Rorida. These specimens were collected as
part of a sediment contaminant study of St. Andrew Bay,
Florida.

Collections of free-living marine nematodes from
estuarine and marine sediments from Bay County, Florida
yielded a large number of species of Halalaimus, but each
species is represented by very few specimens. This is
similar to the reports by Mawson (1958) and Vitiello
(1970). Many of the specimens examined during Uiis study
are not described herein because Uicy were represented by
a single specimen or juveniles Uiat could not be associated
wiUi a described species.

Materials and Methods

Sediment samples were obtained from shallow water
in St. Andrew Bay with corers of various diameters to a
depth of 5-10 cm in the sediment. Sediment samples taken
by Uie U. S. Fish and Wildlife Service from deep water in
St. Andrew Bay, Bay County, Rorida were obtained wiUi
a Ponar grab, and a core was taken from Uie surface of Uie
grab sample. Sediment samples from the Gulf of Mexico
were obtained with SCUBA equipment. Nematodes were
removed from the sediments by repeated decantation prior
to fixation in hot alcoliol-formalin-acetic acid, or the entire
sedunenl sample was fixed with 10% formalin in .sea water
prior to removal of Uie nematodes. Nematodes were
mounted in anhydrous glycerol on Cobb slides. Measure-
ments were made with a calibrated ocular micrometer or
were obtained from drawings made wiUi Uie aid of a
drawing tube. Measurements are given in pm unless oUi-
erwise stated, and measurements are given as the mean of
the population followed by the range of the population in
parentheses. Observations were made wiUi a Nikon Op-
tiphot microscope wiUi Nomarsky Differential Interfer-
ence Contrast and a Wild M-20 microscope wiUi an oil
immersion objective with an N. A. of 1.30.

Only those specimens collected by the author or pro-
vided by Dr. Hope, Dr. Tarjan, or the U.S. Fish and Wiliife
Service were examined directly. OUierwise, the work is
based on descriptions of species provided in the literature.

New Species of Halalaimus

335

Results

The Nomarsky DIC optics made sensilla, lateral cu-
ticular modifications, transverse cuiicular striations, and
cuticular vermiculations more easily observed. However,
the same structures were adequately visible with bright
field microscopy, and they probably would not be over-
looked.

The body of the members of the genus Halalaimus is
broadest near the midpoint, and the anterior end tapers
greatly from the esophago-intestinal junction to the head.
The tail of most species also tapers greatly from the anus to
the tail tip. Specimens mounted with supports equal to the
width at midbody often yielded specimens in which the
head and tail ends were curved upward or downward. This
often resulted in the long outer labial and cephalic sensilla
following a tortuous course. Accurate me<tsurements of
their length was difficult to determine under these circum-
stances. If the anterior end was turned up or down, the
distance of the amphid from the anterior end, tlie length of
the amphid, and the distance between circles of outer labial
and cephalic sensilla were difficult to determine accu-
rately.

The anterior end has two or three circles of sensilla tliat
arc discernible with a light microscope (Fig. 1 ). Tlte circle
of inner labial sensilla may be present in all species, but
may not be discernible with the light microscope when
minute. When discernible, tlie inner labial sensilla vary
from papilliform to sedform. When small and papilliform,
they may be difficult to observe if the other sensilla obscure
them. The circles of outer labial and cephalic sensilla may
be close together or far apart, and the length of the sensilla
in one circle may be different from that in the other circle.
In some instances, it was obvious that the outer labial or
cephalic sensilla were broken at the junction with the
cuticle.

In general, the cuticle is thin from the anterior end to
the level of the cephalic sensilla. The cuticle posterior to
the cephalic sensilla is greatly thickened and remains so to
the junction of the conical and cylindrical parts of the tail.
Setiform cervical, somatic, and caudal sensilla are present
in two species, and some species have small, widely spaced
pits in the cuticle (Fig. 1). These pits are located sublater-
ally and begin just posterior to, or at the level of, the
posterior end of the amphid and may extend the lengtli of
the body, A narrow duct penetrates the cuticle from the
base of each pit.

The cuticle of the body may be smooth or have very
fine transverse striations. As staled by others, these stria-
tions are often best observed at the posterior end of the
amphid or in the anal region of the body. In a few species
observed during this study, the striations appeared to be-
come minute punciaiions in die midbody or precloacal
region of the male or preanal region in the female.

The cuticle of the conical pan of the tail may be
smooth or have fine transverse striations in both sexes.
Males may have a prominent pattern of broad, elongate
elaborations called vermiculations (Fig, 2) which have not
been observed in females. These venniculations appear to
be internal and may be resiricicd to the ventral surface or
may occur both ventrally and dorsally to the lateral line.
The cylindrical pan of the tail may have transverse stria-
lions that extend almost to the tail tip (Fig. 2). These
striations are more prominent Uian the transverse striations
of the body or conical part of the tail and are referred to as
“coarse” striations.

The appearance of the lateral field on each side of the
body m some species may be modified to present the
appeanmceof alae (Fig. 2), Gerlach (1967) referred to diis
modification as “wings." The examination of this modifi-
cation in whole mounts and coarse transverse sections cut
with a razor blade did not reveal a distinct expansion of the
cuticle that is characteristic of alae. This cuticular modifi-
cation appears to be internal, and may not be an ala in the
true sense of the term. However, until scanning and
transmission electron microscope studies can be performed
on this modification, the term ala will be used.

When present on the body, the somatic alae begin
between the posterior end of the amphid and the nerve ring
over each lateral line and extend the length of the body.
Wlien present on the conical part of the tail of females, the
alae are extensions of the somatic alae and have no elabo-
rations. The alae on the conical pan of the male tail may be
present in the absence of somatic alae. If they are present
in the male, these lateral alae may have an elaborate scale-
like pattern termed “ornamented” (Fig. 2). If the orna-
mentations are absent, the alae are referred to as “unor-
namenied,” When somatic and ornamented caudal alae are
present in males, the somatic alae terminate just anterior to
the beginning of the caudal alae (Fig. 2).

The tail in tlie species of Halalaimus examined during
this study consists of a proximal conical part followed by a
cylindrical pan that can be filiform or relatively thick. The
tail tip is pointed, blunt (expanded or not), or very narrow
and divided into two (bifurcate) small terminal appendages
(Fig, 3). Caudal glands were observed in the specimens
examined- Tlie spinneret was observable in those species
with a blunt tail tip but was not observable in those with a
bifurcate tail lip.

Males examined during this study may have a single,
ventro-median, setiform, precloacal sensillum (Fig, 2); a
single, ventro-median, precloacal pore; botli tlie sensillum
and the pore; or the sensillum and pore may be absent.
When present, the pore has a duct that penetrates the cuticle
and tum.s anteriorly in the body. These structures have been
described in other species of the genus, and the presence or
absence of these structures is valuable in differentiating
species.

336

Keppner

New Species of Halalaimus

337

Based on the observations made during this study, it
appears that the males possess the best characters for
differentiating species. The characters of the male empha-
sized herein are the shape of the tail op (bifurcate or not),
the pattern of cuiicular siriations on the tail, the presence or
absence of somatic transverse cuticular striations, the pres-
ence or absence of caudal alae and their ornamentation, the
presence or absence of a midvcniral prccloacal sensillum
and/or pore, the presence or absence of a pattern of ver-
miculaiions in the cuticle in the cloacal region , the shape of
the spicules, and the shape and presence or absence of the
gubemaculum. The riistance of the amphids from the
anterior end, the length of the amphid, the length of the
outer labial and cephalic sensilla, and the ability to discern
the circle of inner labial sensilla with a light microscope are
also useful in identifying the species. The method of fixing
the specimens did not appear to affect the ability to discern
the somatic alae, ornamented or unomamented caudal alae,
striations, or vermiculations. These characters were equally
visible after formalin or alcohol-formalin-acetic acid fixa-
tion.

Tlie characters of the female that appear most reliable
are the presence or absence of coarse transverse striations
on the cylindrical part of the tail, shape of the tail lip, the
presence or absence of somatic transverse cuticular stria-
lions, the distance of the amphids from the anterior end,
length of the amphids, the ability to discern the circle of
inner labial sensilla with a light microscope, and length of
the outer labial and cephalic sensilla.

The specimens of the species of Halalaimus examined
were restricted to those mentioned previously. Compari-
sons with other species of the genus Halalaimus were based
on the descriptions in the literature rather than actual
examinations of type specimens. This requires that some
assumptions be made. It was assumed that iimer labial
sensilla were not discernible, that transverse cuticular
striations were absent, that the somatic and caudal alae
were absent, and that a piecloacal setiform sensillum and/
or pore were absent unless they were mentioned in the
description or shown on the figures of the species.

Generic Diagnosis - Halalaimus De Man, 1888

Enoplida, Oxystominidac, Type species: Halalaimus
gracilis DcMim, 1888. Amphid greatly elongated longitu-
dinally. Anterior and posterior ends of body attenuated.
Six irmer labial sensilla present or absent (possibly present
in all species but not discernible with a light microscope in
some). Six outer labial Sensilla and four or six (two species)
cephalic sensilla present. Cuticle quite Uiick, abruptly
reduced in Uiickness at level of cephalic sensilla, anus, and
again at junction of conical and cylmdrical parts of tail;
transverse cuticular siriations present or absent. Tail coni-
cal then cylindrical; lip blunt, or bifurcate. Cylindrical part

of tail with or without transverse cuticular striations. Caudal
glands present; sp'mneret present or undetermined. Species
mostly marine and estuarine. Coomans and Jacobs (1983)
discuss those species not found in estuarine and marine
environments.

The specimens described and discussed herein are
divided into groups based on male characters in order to
provide some degree of organization and points of refer-
ence. A key to the males of the species in each group is
given at the end of the account of the species in that group.
A separate key to the females of all species is given at the
end of the taxonomic section, because they arc not as easily
separated into groups as tlie males. Those species of the
genus os inquirenda inCerlachand Riemann, (1974)
are not included m the following keys. A list of the species
included in the following discussions and keys to the
species of Halalaimus follows.

Known Species

Halalaimus alaius Timm, 1952
Halalaimus algeriensis Coomans and Jacobs, 1983
Halalaimus amphidellus Viiicllo, 1970
Halalaimus amphistrius Viliello. 1970
Halalaimus ow/ie Sergeeva, 1972
Halalaimus brachyaulux Mawson, 1958
Halalaimus brevispiculum Sergeeva, 1973
Halalaimus capiiulatus Boucher, 1977
Halalaimus caroliniensis Chitwood, 1936
Halalaimus ciliocaudatus Allgen, 1932
Halalaimis cirrhatus Gerlach, 1953
Halalaimus climactericus Wicser, 1953
Halalaimus Wieser, 1953

Halalaimus cubanus Andrassy, 1973
Halalaimus curvicaudaius Juario, 1974
Halalaimus delamarei Viticllo. 1970
Halalaimus diacros Mawson, 1958
Halalaimus diplocephalus Filipjev. 1927
Halalaimus fiUcollisTurm, 1961
Halalaimus filicorpus Viliello, 1970
Halalaimus filum GQTlnch, 1962
Halalaimus fletcheri Mawson, 1958
Halalaimus flare scens Gerlach, 1%7
Halalaimus gracilis De Man, 1888
Halalaimus horridus Gerlach, 1956
Halalaimus isaiishikovi Filipjev, 1927
Halalaimus jaltensis Sergeeva, 1973
Halalaimus lepioderma Platonova, 1971
Halalaimus leplosoma Southern, 1914
Halalaimus lineatoides Timm. 1961
Halalainuis lineatusTimm, 1961
Halalaimus longicaudaius Filipjev, 1927
Halalaimus longicollis Allgen, 1932
Halalaimus longisetosus Hopper, 1963

338

Keppner

Halalaimus longisiriatus Timm, 1961
Halalainms luiarus Viiiello, 1970
Halalaimus luiicolus Tunm, 1961
Halalaimus nmcquariensis Mawson, 1958
Halalaimus marri Mawson. 1958
Halalaimus meyersi Wieserand Hopper, 1967
Halalaimus minisculus Tchesunov, 1978
Halalaimus monstrocaudalus Viiiello. 1970
Halalaimus nigrilapidarius Boucher, 1977
Halalaimus pachyderma Filipjev, 1927
Halalaimus pachydermatus Cobb, 1920
Halalaimus pachydoroides Viiiello, 1970
Halalaimus papilUfer Gerlach, 1956
Halalaimus parvus Chi i wood, 1936
Halalaimus ponticus Filipjev, 1922
Halalaimus rectispiculatus Platonova, 1971
Halalaimus relaius Gerlach, 1967
Halalaimus sarsi Gerlach, 1967
Halalaimus sderaiusT\mm, 1952
Halalaimus setosus Timm, 1961
Halalaimus similis Allgen, 1930
Halalaimus sobakini Sergeeva, 1973

Halalaimus stammer i Schneider, 1940
Halalaimus striaius Gerlach. 1956
Halalaimus supercirrhatus Gerlach, 1955
Halalaimus tenuicapitatus Filipjev, 1946
Halalaimus terrestris Gerlach, 1959
Halalaimus turbidus Viiiello, 1970
Halalaimus wodjanizkii Sergeeva, 1972
Halalaimus zenkeviishi Filipjev, 1927

New Species Described Herein.

Halalaimus thalassinus n. sp
Halalaimus tarjani n. sp.

Halalaimus bayensis n. sp.

Halalaimus bulbocaudaius n. sp,
Halalaimus variabilis n. sp.

Halalaimus paracomatus n. sp.
Halalaimus americanus n. sp
Halalaimus floridanus n. sp.

Halalaimus gerlachi n. sp.

Halalaimus brimi n. sp.

Halalaimus parafletcheri n. sp.

Artificial Key to the Groups of Males of
the Genus Halalaimus De Man, 1888.

The male characters used to define the groups are the presence or absence of caudal alae and the presence or absence
of a precloacal sensillum and/or precloacal pore. These characters are used in combination to distinguish four artificial
groups in the following key:

1 . Caudal alae present 2

Caudal alae absent 3

2(1). Precloacal sensillum and/or pore present Group 1

Precloacal sensillum and/or pore absent Group 2

3(1). Precloacal sensillum and/or pore present Group 3

Precloacal sensillum and/or pore absent Group 4

Group 1

Males of the species in this group have caudal alae, and
a setiform precloacal sensillum and/or pore is present. The
known species and those described as new herein have
ornamented caudal alae. However, two male specimens of
apparently different species were examined that had unor-
namenied caudal alae, but they are not described here
because each is represented by a single spcc'unen. Dis-
tinctly visible circle of inner labial sensilla present or not
discernible. Outer labial sensilla may be longer or shorter
than cephalic sensilla, and the two circles are of varying
distances apart. Species in this group all have a tail with
blunt lip and visible spinneret.

Wieser (1953) described Halalaimus comatus on Uie
basis of female specimens collected from the coast of
Chile. Mawson (1958) described the male of H. comatus
from the Antarctic. Tlie male has ornamented caudal alae
and a single, ventro-median. precloacal sensillum. H.
comatus was unique in the presence of these characters.
However, the collections from Florida waters yielded a
number of additional species witli these characters.

Halalaimus thalassinus n. sp.

Figs. 4-9

Cuticle with fine transverse striations. Lateral somatic
alae present, begin just posterior to amphid, indistinct at

New Species of Halalajmus

339

Figs. 4-9. Halalaimus thalassinus n. sp. Fig. 4. Male, cloacal region, left lateral view. Fig. 5. Male, anterior end, left lateral
view. Fig. 6, Male, posterior end, left lateral view. Fig. 7. Female, anterior end, left lateral view. Fig. 8. Female, anal region,
left lateral view. Fig. 9. Female, posterior end, left lateral view. Scale bars in pm.

340

Keppner

first then more evident, vermiculated anteriorly, smooth
over most of body, then vermiculated precloacally in male.
Somatic alae terminate just anterior to the cloaca in male,
ornamented caudal alae present. Somatic alae terminate
postanally in female at junction of conical and cylindrical
parts of tail, not vermiculated pieanally, and caudal alae
not ornamented. Setiform cervical sensilla present from
just posterior to amphid to level of strongly defined lateral
alae in males, become papilliform on remainder of body,
then setiform precloacally and caudally. Setiform cervical
sensilla present, somatic and caudal sensilla absent in
females. Excretory pore not observed. Inner labial sensilla
papilliform. Outer labial and cephalic sensilla equal in
length, in two well-separated circles. Males witli precloa-
cal setiform sensillum present; pore absent. Cylindrical
part of tail with fine transverse striations. Tail lip ex-
panded, blunt; spiimeret present.

Male(n = l): Length 2.24 mm. Width at midbody 22.
Head diameter4.2at level of cephalic sensilla. Outer labial
and cephalic sensilla 1 1 long. Labial surface to amphid 22
and nerve ring 229. Amphid 23 long. Cervical and caudal
sensilla 5 long. Esophagus 466 long. Tail 216 long. Width
at cloaca 20. Spicules 30 long, alate. Gubemaculum 9.6
long; consists of a plate with keel-like extension between
spicules and a cup-shaped part lateral to tip of each spicule.
a= 101.8. b = 4.81. c = 10.4.

Female (n = 1): Length 2.21 mm. Width at midbody
27. Head diameter 4.8 at level of cephalic sensilla. Outer
labial and cephalic sensilla 10 long. Labial surface to
amphid 24 and nerve ring 240. Amphid 27 long. Cervical
sensillaS long. Esophagus 47 3 long. Tail 213 long. Width
at anus 16. Reproductive system amphidelphic; reflexed.
Vulva 1.18 mm from anterior end. a = 81.9. b = 4.67. c =
10.4. V = 53%.

Specimens: Male holotype, USNM 77260; female
allotype, USNM 77261.

Locality: St. Andrew Bay, Bay County, Florida (85°
42M3"W, 30° 08’33'’N) at the National Marine Fisheries
Service Laboratory, from a seagrass bed {Thalassia tes-
tudinum) about I meter deep.

Etymology: from the Greek Thai ass, the sea.

Remarks: Halalaimus thalassinus n. sp. is unique
among the species in Group 1 in the possession of cervical,
somatic and caudal sensilla in the male and cervical sen-
silla in the female. The only other species in the genus
Halalaimus with distinct cervical and caudal sensilla is
Halalaimus delamarei Viiiello, 1970, which has been placed
in Group 3. H. delamarei does not have caudal alae in the
male, the cervical and caudal sensilla are very short, and
iimer labial sensilla are not discernible.

Halalaimus tarjani n. sp.
Figs. 10-19

Cuticle with fine transverse striations. Lateral somatic
alae not observed. Ornamented caudal alae present in
male, absent in female. Inner labial sensilla setiform.
Outer labial and cephalic sensilla setiform and unequal in
length; cephalic sensilla longer; circles well-separated.
Excretory pore not observed. Lateral alae not observed.
Males with precloacal sensillum, pore absent; ornamented
caudal alae present. Tail conical then cylindrical. Cylin-
drical part of tail with coarse transverse striations. Tail tip
clavatc; spinneret present.

Males (n = 4); Length 1 .09 mm ( 1 .05- 1.13). Width at
midbody 22,7(22-24). Head diameter 5. 1 (4 .4-5.3) at level
of cephalic sensilla. Outer labial and/or cephalic sensilla
were broken or missing on three males. One male with all
sensilla present with outer labials 2.4 long, cephalic sen-
silla 4,0 long. Cephalic sensilla in holotype 4.8 long.
Labia] surface to amphid 8.6(7 .8-9.6) and nerve ring 186(182-
190). Amphid 38,8(38-40) long. Esopliagus 37 1.8(353-
378) long. Tail 159(154-165) long. Width at cloaca 19(1 9-
19). Spicules 39(38-40) long, alate. Gubemaculum 10.(X9.6-
11.0) long, consists of a plate with keel-like extension
between spicules and cup-shaped extension lateral to each
spicule tip. Vemiiculations not observed on conical part of
tail, a = 46.5(46.7-48.2). b = 2.93(2.88-3.00). c =
6.90(6.75-7.06).

Females (n = 2): Ungth 1.06 mm (1.02-1.09). Width
at midbody 33(29-37). Head diameter 6.4(6.4-6.4) at level
of cephalic sensilla. Outer labial sensilla2. 1(2. 1-2.1) long.
Cephalic sensilla 4.3(4.3-4.3) long. Labial surface to
amphid 10(10-10) and nerve ring 179(178-180). Amphid
32(32-32) long. Esophagus 346,5(321-372) long. Tail
176.5(17 1-182) long. Widthatanus 15(14-16). Reproduc-
tive system amphidelphic; reflexed. Vulva 589(567-61 1)
from anterior end. a = 32.4(29.5-35,2). b = 3.06(2,93-
3.V8). c = 5.98(5.96-6.00). V = 56%(56-56).

Specimens: Holotype male, USNM 77262; three
paraiype males, USNM 77263-77265; allotype female,
USNM 77497; paratype female USNM 77499.

Locality: St. Andrew Bay, Bay County, Florida (85°
39’46"W, 30° 08’34"N) waier 13 meters deep, (85° 38’52’W,
30° 07’38"N) water 7.5 meters deep, and (85° 39’46"W,
30° 08’40"N) water 12,2 meters deep.

Etymology: Named for Dr. Armen C. Tarjan, Univer-
sity of Florida.

Remarks: Halalaimus tarjani n. sp. belongs with
those species in Group 1 that have discernible inner labial
sensilla, ornamented caudal alae, and the cylindrical part of
tail has coarse striations. H. tarjani n. sp. differs from the
only other species with these characters, Halalaimus bay-
ensis n. sp. (to be described next), in that the outer labial and
cephalic sensilla are much shorter and unequal in length
(0,29-0.33 & 0.78-0.92 versus 2,8-3,0head diameters), the
amphid begins much closer to the anterior end (1.7 versus
5.3-6.0 head diameters), the spicules are longer (2.0-2. 1

New Species of Haimmmus

341

V\gs. 10-19, Halalaimustarjani a. up. Fig. 10. Male, cloacal region, right lateral view. Fig. 11. Male, anterior end, right lateral
view. Fig. 12. Male, cloacal region, right lateral view. Fig. 13. Male, anterior end, right lateral view. Fig. 14. Male, posterior
end, right lateral view. Fig. 15. Male, anterior end, left lateral view. Fig. 16. Female, anterior end, left lateral view. Fig. 17.
Female, posterior end, left lateral view. Fig. 18. Female, anterior end, left lateral view. Fig. 19. Female, posterior end, left lateral
view. Scale bars in pm.

342

Keppner

versus 1.7 cloacal diameters), and the gubemaculum is of
a different shape.

H. tarjani n. sp. is also similar to those species of the
genus Halalaimus with a broad amphid, Wieser (1953)
placed those species with a broad amphid (40% of corre-
sponding body diameter at midlength of the amphid) in the
subgenus Pachydora. This subgenus contained two spe-
cies, Halalaimus {Pachydora) ponticus Filipjev, 1922 and
Halalaimus (Pachydora) cUmactericus Wieser, 1953. Vidcllo
(1970) described Halalaimus pachydoroides and discussed
the relationship between amphid width and corresponding
body diameter and demonstrated that the relationship de-
creases from the anterior to posterior end of die amphid in
H. pachydoroides and H. ponticus.

H. tarjani n. sp. also demonstrates this relationship.
The amphid is 29.8%(27-32) of die corresponding body
diameter anteriorly and 24%(20-27) posteriorly. H. tarjani
n. sp. females differ from H, cUmactericus females (male
unknown) in the presence of coarse transverse striations on
the cylindrical part of the tail, presence of discernible inner
labial .scnsilla, and in the longer outer labial and cephalic
sensilla (2.1 & 4.3 versus l.O and 2.0). //. tarjani n. sp.
differs from H. pachydoroides {Gtx>up^) in the presence of
discernible inner labial scnsilla, shape of die tail (cylindri-
cal part short, blunt versus cylindrical part long, flagellate),
in the greater distance between circles of outer labial and
cephalic scnsilla ( L 1 - L2 versus 0.4 head diameters), and in
the shorter length of the tail (males = 6.75-7.06,
females “c” = 5.96-6.00 versus males "*c” = 4.7-5.0,
females *‘c” = 4.9-6. 1). H. tarjani n. sp. differs from //.
ponticus in the presence of a discernible circle of inner
labial sensilla, and in die presence of ornamented caudal
alae in the male.

Halalaimus bayensis n. sp.

Figs. 20-27

Cuticle with fine transverse striations, appear puncUitc
at midbody. Cuticular pits present, Lateral alae not
observed. Ornamented caudal alae restricted to conical
part of male tail; absent in female. Cuticle in male cloacal
region faintly vermiculated on ventral surface in holotype,
more distinct in paratype. Inner labial sensilla papillifonn.
Outer labial and cephalic scnsilla equal in length within and
between circles; in two well-separated circles. Excretory
pore not observed. Males with sciifonn prccloacal sensil-
lum; pore absent. Cylindrical part of tail with coarse
transverse striations. Tail lip blunt; spinneret present.

Males (n = 2): Length 1.24 mm (1.19-1.28). Widdial
midbody 20(1 9-21). Head diameter 3.6(3.6-3.6) at level of
cephalic seasilla. Outer labial and ccpliahc sensilla 1 1. 5(11-
12) long. Labial surface to amphid 23.5(23-24) and nerve
ring 184(182-186). Amphid 48(46-50) long. Esophagus
302(296-308) long. Tail 190.5(189-192) long. Width at

cloaca 14(14-14). Spicules 24(24-24) long, alate. Guber-
naculum 8(8-8) long, consists of plate with keel-like exten-
sion between spicules and cup-shaped extension lateral to
each spicule tip. a =62. 1(56.7-67.4). b = 4.09(4.02-4. 16).
c = 6.49(6.30-6.67),

Juvenile female (n = 1): Length 1.10 mm. Width at
midbody 16. Head diameter 3.6 at level of cephalic
sensilla. Outer labial and cephalic sensilla 11 long. Labial
surface to amphid 37 and nerve ring 158. Amphid 37 long.
Esophagus 265 long. Tail 160 long. Widlh at anus 11.
Reproductive system amphidelphic; reflexed. Anterior
end to vulva 536. a = 68.8. b = 4.15. c = 6.88. V=49%.

Specimens: Holotype male, USNM 77498; allotype
female, USNM 77500.

Locality: St. Andrew Bay, Bay County, Florida (85®
39’46‘W. 30® 08’40'‘N and 85® 36’43"W, 30® 06’52"N).
Water 9.5 and 12.2 meters deep.

Etymology: Named for the geographic locality. Bay
County, Florida.

Remarks: Halalaimus bayensis n. sp, belongs with
Uiosc species in Group 1 that have a discernible circle of
iimer labial sensilla, ornamented caudal alae, and the
cylindrical part of the tail has coarse transverse suialions.
//. bayensis ti. sp. differs from H. tarjani n. sp. as described
under the remarks section for tarjani n. sp. H, bayensis
n. sp. males are also similar to males off/, variabilis n. sp.
and H. jloridanus n. sp. (both described below), H.
bayensis n. sp. differs from //. variabilis n. sp. in the
presence of a prccloacal seiiform sensillum, tlie absence of
a prccloacal pore, and the pre,scncc of discernible inner
labial scnsilla. //. bayensis n. sp. differs from H. Jloridanus
n. sp. in tile shorter outer labial and cephalic sensilla (2,8-
3.0 versus 4.4-4.5 head diameters long), distance from the
labial surface to the amphid (5.3-6-0 versus 2.9-3. 1 head
diameters), length of the tail (13.5-13.7 versus 7.5-9.4
cloacal diameters long), ‘ ‘a’ ’ value (56.0-67.4 versus 78.0-
89.5), and the presence of discernible iimer labial sensilla.

Halalaimus bulbocaudatus n. sp.

Figs. 28-34

Cuticle with faint urnsverse striations, best observed
in prccloacal region in male. Lateral somatic alae not
observed. Omajnenicd caudal alae present in male, absent
in female. Inner labial seasilla papillifonn. Outer labial
and cephalic sensiUa equal in length, circles well-sepa-
rated. Ajnphid relatively short, situated well posterior to
cephalic sensilla. Excretory pore not observed. Male with
prccloacal sensillum; pore absent. Cylindrical pan of tail
witiioul coarse transverse striations. Tail tip in both sexes
with nearly spherietd swelling at lip; spinneret present.

Male (n = 1): LcngUi 1 .16 mm. Widlh at midbody 20.
Head diameter 3.8 at level of cephalic sensilla. Outer labial
and cephalic scnsilla 4.2 long. Labial surface to amphid 2 1

344

Keppner

Figs.26>27. HaUtUthnusbayensisn.sp. Fig. 26. Juvenile female^ anterior endjeft lateral view. Fig. 27. Juvenile female^pasterior
end Jeft lateral view. Fig!>. 28-34. H alalaimus bulbocaudatus n.sp. Fig. 28. Male, cloacal region, right lateral view. Fig. 29.
Male, anterior end, left lateral view. Fig. 30. Female, anterior end, left lateral view. Fig. 31. Female, posterior end, left lateral
view. Fig. 32. Male, posterior end, right lateral view. Fig. 33. Female, tail tip. Fig. 34. Male, tail tip. Scale bars in pm.

New Species of Halalmmus

345

and nerve ring 200. Amphid 19 long. Esophagus 334 long.
Tail 155 long. Width at cloaca 14. Spicules 23 long.
Gubemaculum 8 long, consists of a plate with keel-like
extension between spicules and extension lateral to each
spicule tip. Postcloacalcuticularvenniculaiions absent, a
= 58.0. b = 3.47. c = 7,84.

Female (n = 1): Length 1,05 mm. Width at midbody
20. Head diameter 3.8 at level of cephalic sensilla. Outer
labial and cephalic sensilla 4.2 long. Labial surface to
amphid 20 and nerve ring 184. Amphid 19 long. Esopha-
gus 315 long. Tail 152 long. Width aianus 13. Reproduc-
tive system amphidelphic; reflexed. Anterior end to vulva
580. a = 50.0. b = 3.33. c = 6.91. V = 55%.

Specimens: Holotype male, USNM 77266; allotype
female. USNM 77267.

Locality: St, Andrew Bay, Bay County, Florida (85°
38’ 19’'W, 30° 07’44"N). Water 12.2 meters deep.

Etymology: from Latin bulbo meaning ‘ ‘a bulb’ ’ and
Latin caudatus meaning “having a tail."

Remarks: Halalaimus bulbocaudaius n. sp. belongs
with those species in Group 1 that have ornamented caudal
alae, coarse transverse sirialions are absent from the cylin-
drical part of the tail, and the inner labial sensilla are
discernible, /f. bulbocaudaius n. sp. differs from H. tha-
lassimis n. sp. in the absence of setiform cervical and
caudal sensilla. the presence of a spherical swelling at the
tail lip, iuid the outer labial and cephalic sensilla are shorter
(LI versus 2.2 head diameters).

A spherical swelling at the tail tip is also present in
Halalaimus similis Allgen, 1930 (only the female is known),
and the same was also described for this species by Bresslau
and Stekhoven (1940). Wieser (1953) described Hala-
laimus comatus with a knob-like swelling at the tail tip.
Mawson (1958) described the tail lip in specimens of H.
comatus as swollen in the female and as a distinct spherical
swelling in the male similar to that described for//, similis.

H. bulbocaudaius n. sp. is similar to//, comatus in the
presence of onuunented caudal alae and a precloacal seti-
form sensillum in ilte male and in the absence of coarse
transverse siriations on the cylindrical part of the tail in
botli sexes. H. bulbocaudaius n. sp. differs from //. coma-
tus in the presence of a discernible circle of inner labiiU
sensilla and the greater distance between the circles of
outer labial and cephalic sensilla ( 1 .0 head diameter versus
0.23 head diameter). //. bulbocaudaius n. sp. females
differ from //. similis females (males unknown) in the
presence of a discernible circle of inner labial sensilla.

Halalaimus variabilis n. sp.

Figs. 35-43

Cuticle witli fine transverse siriations, appear punctate
in midbody region, gradually become vermieu Unions ante-
rior to cloaca in male; not present in female. Lateral alae

not observed. Ornamented caudal alae present in male,
absent in female. Cmicular pits present for length of body.
Inner labial sensilla not discernible. Outer labial and
cephalic sensilla equal in length, in two well-separated
circles. Excretory pore not observed. Conical part of tail
with vermiculations on ventral surface in male, absent in
female. Precloacal sensillum absent, precloacal pore pres-
ent. Cylindrical part of tail with coarse transverse sirialions
in both sexes. Tail Up narrow, blunt: spinneret presenL

Males (a = 2): Length 1.85 mm (1.72-1.97). Width at
midbody 22.5(21-24). Head diameter 5.1(4.8-5.4) at level
of cephalic sensilla. Outer labial and cephalic sensilla
17(15-19) long. Labial surface to amphid 18,5(16-21) and
nerve ring 208(200-2 16). Amphid 53(38-68) long. Esopha-
gus 381.5(353-410) long. Tail 203(198-208) long. Width
at cloaca 16,5(16-17). Spicules 20.5(19-22) long. Guber-
naculum 9.8(9.6- 10.0) long, consists of a plate with a keel-
like extension between .spicules, and an extension lateral to
each spicule lip; distal end cup-shaped, a = 82.0(81.9-
82.1). b = 4.84(4.80-4,87). c = 9.11(8.27-9.95).

Females (n =2): Length 1.81 mm (1.58-2.03). Widili
at midbody 26.5(26-27). Head diatneter 5.1(4.8-5.4) at
level of cephalic sensilla. Ouicrlabial and cephalic sensilla
17.5(17-18) long. Labial surface to amphid 18.5(16-21)
and nerve ring 201(194-208). Amphid 53(46-60)long.
Esophagus 365.5(321-410) long. Tail 217.5(213-222) long.
Width at anus 1 5( 15- 15). Reproductive system amphidel-
phic, reflexed, Vulva919.5(^4-995)fTomanteriorend. a
=68.3(58.5-78.1). b= 4.94(4.92-4.95). c= 10.5(9.5-11.4).
V = 51%(49-53).

Specimens: Male holotype, USNM 77503; male para-
type, USNM 77504; female allotype, USNM 77544.

Locality: Mouth of Freshwater Bayou off St. Andrew
Bay. Bay County, Florida (85° 39’00”W, 30° 07’30"N).
Water 2.1 meters deep.

Etymology: From Latin variabilis meaning ‘ ‘to vary."

Remarks: Halalaimus variabilis n. sp. is the only
species in Group 1 in which the males have ornamented
caudal alae, a precloacal pore is present, a precloacal
sensillum is absenu and inner labial sensilla arc not discern-
ible.

Halalaimus paracomatus n. sp.

Figs. 44-50

Cuticle with transverse sirialions, most evident poste-
rior to nerve ring. Lateral alae present. Ornamented caudal
alae present in male, unomamented caudal alae present in
female. Inner labial sensilla papilliform. Outer labial and
cephalic sensilla equal, in two circles close together. Mjile
with setiform precloacal sensillum; precloacal pore absent.
Excretory pore not observed. Conical part of tail without
vermiculaUons in botli sexes. Cylindrical part of tail with
coarse transverse siriations. Tail tip blunt, slightly bul-

346

Keppner

Figs, 35-41. Halalaimusvariahilisn,sp. Fig. 35. Male» anterior end, left lateral view. Fig. 36. Male number 1, cloacal region,
left lateral view. Fig. 37. Male number 1, cloacal region, right lateral view. Fig, 38. Male number 3, posterior end, right lateral
view. Fig. 39, Male, anterior end, right lateral view. Fig. 40. Male, cloacal region, right lateral view. Fig. 41. Male, posterior
end, right lateral view. Scale bars in pm.

Figs. 42-43. Hahlaimus variabilis n.^sp. Fig. 42. Female, anterior end, right lateral vi«w. Fig. 43. Female, posterior end, right
lateral view. F'igs. 44-50. Halalaimusparacomatusn.sp. F'ig.44. Male, anterior end, right lateral view. Fig. 45. Male, posterior
end, right lateral view. Fig. 46. Male, anterior end, left lateral view. Fig. 47. Male, cloacal region, left lateral view. Fig. 48,
Male, cloacal region, right lateral view. Fig. 49. Female, anterior end, right lateral view. Fig. 50. Female, posterior end, right
lateral view. Scale bars in pm.

348

Keppner

bous; spinneret present.

Males (n = 2): Length 1.41 nun (L40- 1.42). Widthat
midbcxly 24.5(24-25). Head diameter 4.2(4 .2-4 .2) at level
of cephalic sensilla. Outer labial and cephalic sensilla
6.1(5.5-6,6) long. Labial surface to amphid 16.5(16-17)
and nerve ring 252.5(251-254). Amphid 38(37-39) long.
Esophagus 450.5(447-454) long. Tail 192(1^-198) long.
Width at cloaca 15.5(15-16). Spicules 24.5(24-25) long.
Gubcmaculum 9,5(9-10) long» consists of a plate with an
extension lateral to each spicule tip; distal end cup-sliaped;
keel-like extension weakly developed, a = 57.6(56.8-
58.3). b = 3, 13(3.13-3.13). c = 7.35(7.07-7.63).

Female (n = 1): Length 1 .36 nun. Width at midbody
24. Head diameter4.8 at level of cephalic sensilla. Outer
labial and cephalic sen.silla 6.4 long. Labial .surface to
ampliid 1 3 and nerve ring 264. Amphid 44 long. Esopha-
gus 473 long. Tail 181 long. Width at anus 11. Reproduc-
tive system amphidelphic; reflexed. Vulva 762 from
anterior end, a = 56.7. b = 2.88. c = 7.5 1 . V = 56%.

Specimens: Male holoiype, USNM 77268; male para-
type. USNM 77269.

Locality: St. Andrew Bay, Bay County, Florida (85°
40’59‘'W, 30° 08’23"N) and (85° 38’52" W. 30° 07’38"N).
Water 7 meters and 11.1 meters deep.

Etymology: from Latin para meaning “near or be-
side’ ‘ and convjtus specific epithet ioillalalaimus cotmtus
Wieser, 1953.

Remarks: Halalaimus paracomatus n. sp. is very
similar to Halalaimus cotmtus Wieser, 1953. //. paraco-
rnatus n. sp. differs from H. comat us in diat the cylindrical
part of the tail has coarse transverse smations, the tail tip
does not have a spherical swelling, outer labial and ce-
phalic sensilla are about equal in length, and tlie amphid is
longer (5.3-8.8 versus 3.5 head diameters). H. paraconia-
tus n. sp. is also similar to Halalaimus americanus n. sp.
(described next) in the length of the outer labial and
cephalic sensilla and absence of a a spherical swelling at
the tail tip. //. paracomatus n. sp. differs from H. america-
nus n. sp. in that the circles of outer labial and ccphiilic
sensilla are closer together (0.67 versus 1. 7-2.0 head di-
ameters apan), the amphid is shorter (5. 3-8.8 versus 19.3-
20.3 head diameters), and the gubcmaculum is rectangular
without the distinct keel-like extension between the spic-
ules that is present in H. americanus n. sp.

Halalaimus americanus n. sp.

Figs. 51-59

Cuticle smooth, faint su-iaiions present at posterior end
of lateral alac in one specimen. Broad lateral alae present,
commencing at posterior end of amphid, fade into orna-
mented caudal alae in male. Inner labial sensilla not
discernible. Outer labial and cephalic sensilla in two well-
separated circles, unequal in length; outer labials shorter.

Excretory pore not observed. Precloacal sensilluin present;
precloacal pore absent. Conical part of tail with vermicu-
lations. Cylindrical part of taU with coarse transverse
striations. Tail tip blunt; spinneret present. Female un-
known.

Males (n = 3): Length 1 .45 mm ( 1 .39- 1 .5 1). Width at
midbody 23.3(22-24). Head diameter 3. l(3.0-3.2) at level
of cephalic sensilla. Outer labial sensilla 3.5(3.0-4.4) long;
cephalic sensilla 5.5(5.0-6.4) long. Labial surface to jmiphid
31(26-37) and nerve ring 246.5(235-258). Amphid 56.7(51-
61) long. Esophagus 525.3(504-536) long. Tail 174(160-
192) long. Width atcloaca 17(16-18), Spicules 26(24-27)
long. Gubcmaculum 8.5(8.0-9.6) long wiili narrow keel-
like extension between spicules and extension lateral to
each spicule; distal end of lateral extcn.sion cup-shaped.
Cuticle on conical part of tail vemiiculated. a = 62.3(60.8-
63.2). b = 2.76(2.72-2.80). c = 8.40(7.86-8.69).

Specimen.s: Holotype male, USNM 77270; paratype
males, USNM 77506 & 77507.

Locality: St. Andrew Bay, Bay County, Florida, (85°
39’07'’W, 30° 08’29”N) and (85° 39’46"W, 30° 08’40"N).
Water 2.0 to 12.2 meters deep.

Etymology: Named after geographical location,
America.

Remarks: H, americanus is similar to II. paracoma-
tus n. sp. and differs from that species as discussed in the
remarks section for H. paracomatus n. sp.

Halalaimus floridanus n. sp.

Figs. 60-67

Cuticle faintly striated, appears punctate from midbody
to precloacal region in male and anal region in female;
cuticle of lateral fields also faintly vermiculated from
midbody to cloacal region in male and amil region in
female. Lateral alae not observed; ornamented caudal alae
present in male; absent in female. Inner labial sensilla not
discernible. Outer labial and cephalic sensilla equal in
length. Lateral outer labial sensilla greater *m diameter than
other sensilla. Excretory pore not observed. Precloacal
sensillum present and precloacal pore absent in male.
Cuticle of conical pan of tail vermiculated in male, not so
in female. Cylindrical part of tail with coarse transverse
striations. Tail tip blunt; spinneret present.

Males (n = 4): Length 1.53 mm (1.34-1.70). Widthat
midbody 18.5(16-21). Head diameter4.4(4.0-4.8) at level
of cephalic sensilla. Outer labial and cephalic sensilla
19.8(18-21) long. LabuU surface to amphid 15.5(14-19)
and nerve ring 202(192-208). Amphid 65.5(55-76) long.
Esophagus 314.6(277-359) long. Tail 185.5(176-206) long.
Width at cloaca 15(13-17). Spicules 20.8(18-24) long.
Gubcmaculum 8(8-8) long with small kcel-like extension
between spicules, and an extension lateral to each spicule
tip; distal end of lateral extension cup-shaped, a = 82.7

New Species of Halaiaimus

349

Figs.51-59, Halalaimusamericanusn.sp. Fig.Sl. Male, cloacal region, left lateral view. Fig.52. Male,anteriorend, right lateral
view. Fig. 53. Male, posterior end, right lateral view. Fig. 54. Male, cloacal region, right lateral view. Fig. 55. Male, posterior
end, right lateral view. Fig. 56. Male, cloacal region, right lateral view. Fig. 57. Male, anterior end, right lateral view. Fig.
58. Male, cloacal region, right lateral view. Fig. 59. Male, posterior end, right lateral view. Scale bars in pm.

350

Keppner

Figs. 60-67. Halalaimusfloridanus. n.sp. Fig. 60. Male, anterior end, left lateral view. Fig. 61. Male, anterior end, left lateral
view. Fig, 62. Male, cloacal region, left lateral view. Fig. 63. Male, doacal region, left lateral view. Fig. 64. Male posterior
end, left lateral view. Fig. 65. Male, posterior end, left lateral view. Fig. 66. Female, anterior end, left lateral view. Fig. 67.
Female, posterior end, left lateral view. Scale bars in pm.

New Species of Halaiaimus

351

(74.4-89.5). b = 4.86(4.67-5.13). c = 8.22(7.61-9.16).

Female (n = 1): Length 1.58 mm. Width at midbody
27. Head diameter 4.8 at level of cephalic sensilla. Outer
labial and cephalic sensilla 16 long. Labial surface to
amphid 15 and nerve ring 194. Amphid54 long. Esopha-
gus 321 long. Width at anus 15. Tail 227 long. Anterior
to vulva 884, Reproductive system amphidelphic; re-
flexed. a = 58.5. b = 4.92. c=11.4. V = 53%.

Specimens: Male holotype» USNM 7727 1 ; male para-
types, USNM 77272-77275; female allotype, USNM 77276.

Locality: Mouth of Freshwater Bayou off St. Andrew

Bay. Bay County, Florida (85*^ 39’00’'W. 30^ 07’30"N).
Water 1 .0 meter deep. Two male paratypes from Biscayne
Bay, Dade County, Florida provided by Dr. Tarjan.

Etymology; Named for the geographic lociity, slate
of Florida.

Remarks: Halaiaimus floridanus n. sp. is the only
species in group 1 with the followmg combination of
characters: cylindrical part of tail with coarse transverse
striations, precloacal scnsillum present, precloacal pore
absent, and the outer labial and cephalic sensilla are 4.4
head diameters long or longer.

Artificial Key to the Males of Group 1
(HD = head diameter; CD = cloacal diameter)

1 .

Cervical, somatic, and caudal sensilla present Halaiaimus thalassinus n. sp.

Cervical, somatic, and caudal sensilla absent 2

2(1). Precloacal pore present; precloacal sensillum absent 3

Precloacal pore absent; precloacal sensillum present 4

3(2). Precloacal pore with large glandular structure: outer labial and cephalic sensilla 1 .0 HD long .

Halaiaimus sabakini Sergeeva, 1973

Precloacal pore without large glandular structure; outer labial tmd cephalic sensilla 3.3 HD long

Halaiaimus variabilis n. sp.

4(2). Cylindrical part of tiiil with coarse transverse striations 5

Cylindrical part of tail without coarse transverse striations 9

5(4). Outer labial and cephalic sensilla equal to or greater than 3.0 HD long 6

Outer labial and cephalic sensilla less than or equal to 2.0 HD long 7

6(5). Outer labial and cephalic sensilla 3.0 HD long; inner labial sensilla discernible; amphid begins 7.0 HD from

anterior end Halaiaimus hayensis n. sp.

Outer labial and cephalic sensilla 4.5 HD long; inner labial sensilla not discernible; amphid begins 3.5 HD
from anterior end Halaiaimus floridanus n. sp.

7(5). Outer labial and cephalic sensilla in two well-separated circles, 1.0- 1.8 HD apart; outer labial sensilla

shorter than ccpltalic sensilla 8

Outer labial and cephalic sensilla in two circles close together, 0.43-0.50 HD apart; outer labial and cephalic
sensilla equal in length Halaiaimus paracomatus n. sp.

8(7). Broad lateral somatic alae present; spicules 1.5 CD long; amphid narrow, 17-19 HD long; inner labial

sensilla not discernible * Halaiaimus americanus n. sp.

Broad lateral somatic alae absent; spicules 2.0-2. 1 CD long; amphid broad, 7.5-8.6 HD long; inner labial
sensilla discernible Halaiaimus tarjani n. sp.

9(4). Outer labial and cephalic sensilla in two well-separated circles, 1.2 HD apart; inner labial sensilla

discernible Halaiaimus bulbocaudaius n. sp.

Outer labial and cephalic sensilla in two circles close together, 0.2 HD apart; inner labial sensilla not
discernible Halaiaimus comaius Wieser, 1953

352

Keppner

Group 2

Males of the species in this group have caudal alae that
are ornamented or unomamenied. Precloacal sensillum
and precloacal pore absent. Inner labial scnsilla discernible
in some species. Outer Uibial and cephalic sensilla of
varying length between circles. Circles of sensilla varying
distances aparL

Cylindrical part of tail with or without coarse trans-
verse striaiions. Tail tip blunt, bifurcate, or flagellate.

Halalaimus gracil's De Man, 1888

Halalaimus gracilis has been reported from a number
of localities world- wide and various descriptions have been
published. I>e Man (1888) described H. gracilis on the
basis of a male and a female from tlte North Sea. A circle
of setiform inner labial sensilla is present in addition to the
circles of outer labial and cephalic scnsilla. The male has
ornamented caudal alae, and a setiform precloacal sensil-
luin and pore arc absent. Tlie gubemaculum is figured as
a narrow plate witltout an apophysis or lateral extensions.
De Man (1922) described additional specimens of H.
gracilis.

Stekhoven (1935) described specimens of a species of
Halalaimus as //. gracilis, but did not mention or figure the
presence of the ornamented caudal alae. In the absence of
this information, H. gracilis sensu Sleklioven (1935) is
considered a species inquirenda. Steklioven (1935) also
placed Halalaimus droebachiensis Allgen, 193 1 as a syno-
nym of /f. gracilis sensu Stekhoven (1935). The descrip-
tion given by Allgen ( 1931) was based on a female speci-
men and does not mention or figure the inner labial sensilla
present in H. gracilis. Therefore, tliis species is also
considered to be a species inquirenda.

Bresslau and Stekhoven (1940) described specimens
of a species of Halalaimus as H. gracilis but did not
describe or figure the ornamented caudal alae or inner
labial sensilla cliaracteristic of H. gracilis. These speci-
mens appear similar to those described by Stekhoven
(1935) and are, therefore, considered to be a species in-
quirenda. Stekhoven (1950) described what he considered
to be a female of H. gracilis. Inner labial sensilla are not
described, but the figure indicates tlial they may be present.
In view of the doubt as to the presence or absence of iimer
labial sensilla, the specimen is considered a species in-
quirenda.

Tinun (1952) described a male specimen of a species
of Halalaimus that he referred to as H. gracilis. However,
he did not describe or figure the presence of inner labial
scnsilla and did not mention or figure the presence or
absence of ornamented caudal alae. Timm (1952) did suite
that the specimen had a smooth cuticle and lateral alae were
absent. In view of the absence of information and figures,

H. gracilis sensu Timm, 1952 is also considered to be a
species inquirenda.

Halalaimus gerlachi n, sp.

Synonym: Halalaimus gracilis sensu Gerlach, 1967;
nec H. gracilis De Man, 1888.

Gerlach (1967) described specimens of Halalaimus
from the Red Sea as H. gracilis. Inner labial scnsilla are not
discernible and lateral alae are present in the specimens.
Males have ornamented caudal alae, and die gubemaculum
has a caudally d irecied apophysis. The absence of the inner
labial sensillaand the presence of a gubemacular apophysis
is sufficient to differentiaie the specimens from H. gracilis
and designate them as a new species, Halalaimus gerlachi
n. sp. (Gerlach 1967). The holotype of the species is the
specimen on which Gerlach (1967) based his description.
The only other species ol Halalaimus with a gubemaculum
with an apophysis is Halalaimus sarsi Gerlach, 1967. H.
gerlachi n. sp. differs from H. sarsi in the presence of
ornamented aiudal alae and shorter outer labial and ce-
phalic sensilla (1.5 versus 2.0 head diameters long).

Platt and Warwick (1983) described specimens of
Halalaimus as H. gracilis. The inner labial sensilla are not
mentioned or figured, caudal alae are absent in the male,
and a precloacal sensillum is present. Based on the descrip-
tion, these specimens cannot be H. gracilis. They belong
in group 3 below along with those species in which a
precloacal sensillum is present and caudal alae arc absent.

Halalaimus brimi n. sp.

Figs. 68-72

Cuticle wiUi transverse siriations. Lateral alae not
observed. Ornamented caudal alae present in male; caudal
alae absent in female. Inner labial sensilla noi discernible.
Outer labial scnsilla longer than cephalic sensilla; circles
far apart. Excretory pore not observed. Eh^ecloacal sensil-
lum and pore absent. Conical part of tail without vermicu-
lation.s; cylimlrical part of tail with coarse transverse stria-
tions. Tail tip bifurcate.

Male (n = 1): Length 1.27 mm. Width at midbody 22.
Head diameier4.7 at level of cephalic sensilla. Outer labial
sensilla 7,0 long. Cephalic sensilla 3.3 long. Labial
surface to iimphid 16 and nerve ring 203. Amphid 4 1 long.
Esophagus 328 long. Width at cloaca 16. Tail 192 long.
Spicules 23 long. Gubemaculum 6.8 long, expanded
distally, narrowed proximally. a=57.7. b = 3.87. c = 6.61.

Female(n = 2): Length 1.31 nun (1.30-1.32). Width
at midbody 26(25-27). Head diameter 4.6(4.5-4.7) at level
of cephalic sensilla. Outer labial sensilla 6.3(6.3-6.3) long.
Cephalic sensilla 3.3(3.3-3.3) long. Uibial surface to
amphid 14.5(14-1 5) and nerve ring 198(191-205). Amphid
36(35-37) long. Esophagus 360(359-361) long. Width at

New Species of Halalajmus

353

Figs. 68-72. Halalaimus brimi n. sp. Fig. 68. Male, anterior
end, left lateral view. Fig. 69. Female, anterior end, left
lateral view. Fig. 70. Male, posterior end, left lateral view.
Fig. 71. Female, posterior end, left lateral view. Fig. 72. Male,
cloacal region, left lateral view. Scale bars in pm.

anus 14(14-14). Tail 198(196-200) long. Vulva 681(674-
688) from anterior end. Reproductive system amphidel-
phic; reflexed, a = 50.3(48.1-52.4). b = 3.63(3.62-3.64).
c = 6.58(6.50-6.65). V = 52.5%(52-53).

Specimens: Male, holotype, USNM 77277; female
allotype, USNM 77278; female paratype, USNM 77509.

Locality: St. Andrew Bay, Bay County, Florida (85°
38’52"W, 30° 07’38’'N), Water 8.0 meters deep.

Etymology: Named for Mr. Michael Brim of the
United States Fish and Wildlife Service, Panama City,
Florida without whose support many of the specimens
included in this study would not luive been obtained.

Remarks: Halalaimus brimi n. sp. is the only species
in this group willi a bifurcate tail tip and with outer labial

sensilla longer than cephalic sensilla. H. brimi n. sp. is
similar to Halalaimus diacros Mawson, 1958 *m the pres-
ence of a bifurcate tail. H. brimi n. sp. differs from //.
diacros in the presence of ornamented caudal alac and the
presence of outer labial sensilla that are longer than the
cephalic sensilla. H, brimi n. sp- is also similar to Hala-
laimus horridus Gerlach, 1956 in that the outer labial
sensillaare longer than the cephalic sensilla. //. brimi n. sp.
differs from H. horridus in the shorter length of the labial
and cephalic sensilla (1. 3-1.5 and 0.7 versus 3.0 and 1.0
head diameters long), in the presence of a bifurcate laD lip,
and in the presence of coarse transverse siriations on the cy-
lindrical part of the tail.

354

Keppner

Artificial Key to the Males of Group 2
(HD = head diameter; CD = cloacal diameter)

1. Caudal alae unomamented 2

Caudal alae ornamented 7

2 ( 1 ).

Inner labial sensilla discernible Halalaimus alatus Timm, 1952

Inner labial sensilla not discernible 3

3(2). Tail nageUaie 30-42 CD long 4

Tail not flagellate 8-16 CD long 5

4(3). Tail 30 CD long; outer labial and cephalic sensilla 1.7 HD long, in two circles 0.2 HD apart

Halalaimus relatus Gerlach, 1967

Tail 42 CD long; outer labial and cephalic sensilla 1 .2 HD long, in two circles 1 .0 HD apart

Halalaimus filum Gerlach, 1962

5(3). Gubcmaculum with dorso-caudally directed apophysis Halalaimus sarsi Gerlach, 1967

Gubemaculum without dorso-caudally directed apophysis 6

6(5). Outer labial sensilla papilliform; cephalic sensilla 0.33 HD long; "a" = 58.5

Halalaimus lineatoides Timm, 1961

Outer labial and cephalic sensilla setiform, 1.0 HD long; "a" = 100.0

Halalaimus lineatus Timm, 1961

7(1). Tail lip bifurcate Halalaimus brimi n. sp.

Tail lip not bifurcate 8

8(7). Gubcmaculum willi dorso-caudally directed apophysis; inner labial sensilla not discernible .

Halalaimus gerlachi n. sp.

Gubemaculum without dorso-caudally directed apophysis; inner labial sensilla discernible

Halalaimus gracilis De Man, 1888

Group 3

Males without caudal alae. Precloacal sensillum and/
or precloacal pore present. Inner labial sensilla discernible
in some species, not so in others. Outer labial and cephalic
sensilla can vary in length between circles. Circles of
varying distances apart. Cylindrical part of tail with or
without coarse transverse striations. Tail tip blunt, bifur-
cate, or flagellate.

Halalaimus parafletcheri n. sp.

Figs. 73-81

Cuticle smooUi. Lateral and caudal alae not observed,
limer labial sensilla setiform. Outer labial sensilla shorter
than cephalic sensilla. Excretory pore notobserved. Small
precloacal sensillum present, precloacal pore absent in

males. Conical part of tail without vermiculations; cylin-
drical part of tail without coarse transverse striations. Tail
tip bifurcate.

Males (0 = 3): Length 2.29 mm (2. 17-2.44). Width at
midbody 34(32-35). Head diameter 6.4(6.4-6.4) at level of
cephalic sensilla. Inner labial sensilla 2.6(2.4-3.0) long.
Outer labia! sensilla 6. 1(5 .6-6.4) long. Cephalic sensilla
7.7(7 .2-8.0) long. Labial surface to amphid 35.3(34-37)
and nerve ring 449(432-459). Amphid 42.3(40-45) long.
Esophagus 628(605-649) long. Width at cloaca 21.7(21-
22). Tail 320(304-336) long. Spicules 32(32-32) long;
right spicule broader than left. Gubemaculum 16(16-16)
long with keel-like extension between spicules and exten-
sions lateral to spicule, distal end of each lateral extension
cup-shaped, a =67.5(62.0-70.9). b = 3.65(3.59-3.76). c =
7.18(6.76-7.63).

Females (n = 2): Length 2.53 mm (2.27-2.78). Width
at midbody 45.5(43-48). Head diameter 6.4(6.4-6.4) at

New Species of Halalajmus

355

Figs. 73-81. Halalaimus parafletcheri n. s^. Fig. 73. Male, anterior end, right lateral view. Fig. 74. Male, anterior end, left
lateral view. Fig. 75. Male, posterior end, right lateral view. Fig. 76. Female, posterior end, left lateral view. Fig. 77. Female,
anterior end, left lateral view. Fig, 78. Male, cloacal region, right lateral view. Fig. 79, Male, cloacal region, left lateral view.
Fig. 80. Male, cloacal region, right lateral view. Fig. 81. Male, cloacal region, left lateral view. Scale bars in pm.

356

Keppner

level of cephalic sensilla. Inner labial sensilla 2.0(2.0-2.0)
long. Outer labial sensilla 6.4(6.4-6.4) long. Cephalic
sensilla 8.0(8.0-8.0) long. Labial surface to amphid 3 1 (30-
32) and nerve ring 472(432-512). Amphid 33.5(32-35)
long. Esophagus 680(617-743) long. Width at anus 18( IS-
IS). Tail 321.5(307-336) long. Anterior to vulva 1.40 mm
( 1 .20- 1 .59). Reproductive system amphidelphic; reflexed,
a =55.4(52.8-57.9). b= 3,71(3.68-3.74). c = 7.83(7 .39-
8.27). V = 55%(53-57).

Specimen.s: Holotype male, USNM 77204; paratype
males, USNM 77206 & 77207; allotype female, USNM
77205; paratype female, USNM 77208.

Locality; Holotype male, allotype female from Fresh-
water Bayou off St. Andrew Bay, Bay County, Florida (85°
39’00"W, 30° 07’33''N), water 1.0 and 2.0 meters deep.
Paraiypes from Sl Andrew Bay, Bay County, Florida at the

National Marine FLsherievS Service Laboratory (85° 42’43"W,
30° 08’33"N), water 0.3 meter deep.

Remarks: Halalaimus parafletcheri n. sp. is the only
species in Group 3 with a bifurcate tail tip. H. parafletcheri
n. sp. is similar to Halalaimus fletcheri Mawson, 1958
(Group 4) in the presence of die bifurcate tail lip, absence
of cuticular slriaiions, absence of lateral and caudal alae,
and the presence of seiiform inner labial sensilla. H.
parafletcheri n. sp. differs from //. fletcheri in that the
males have a prccloacal sensilluin , the spicules are unequal
in width, and the circle of outer labial and cephalic sensilla
are closer together (2 pm versus 4 pm apart). H. parafletch-
erin. sp. is also $'um\ 2 cr to Halalaimus filicollisT’imm, 1961
(Group 4) in the presence of a bifurcate tail lip. H.
parafletcheri n. sp. differs from that species in that the
males have a precloacal sensillum, cuticular striaiions arc
absent, and the spicules are unequal in widili.

Artificial Key to the Males of Group 3
(HD = head diameter; CD = cloacal diameter)

1 .

Tail tip bifurcate Halalaimus parafletcheri n. sp.

Tail tip not bifurcate 2

2(1). Cylindrical part of tail with coarse transverse striations 3

Cylindrical part of tail without coarse transverse striations 4

3(2). Tail 106 CD long; "a" = 187.0 Halalaimus monstrocaudatus Vitiello, 1970

Tail 9.0-9.2 CD long; "a" = 58.9-60.6 Halalaimus curvicaudatus Juario, 1974

4(2). Cuticle with transverse striations 5

Cuticle without transverse striations 7

5(4). Outer labial sensilla shorter (0.5-0.6 HD long) than cephalic sensilla (11-12 HD long); short cervical

and caudal sensilla present Halalaimus delamarei Vitiello, 1970

Outer labial sensilla longer than cephalic sensilla; cervical and caudal sensilla absent 6

6(5). Outer labial sensilla three limes length of ceplialic sensilla; tail 9.0 CD long

Halalaimus horridus Gerlach, 1956

Outer labial sensilla 1.25 times length of cephalic sensilla; tail 14 CD long

. , Halalaimus striatus Gerlach, 1956

7(4). Precloacal sensillum present, pore absent 8

Precloacal sensillum absent, pore present Halalaimus cubanus Andrassy, 1973

8(7). Gubernaculum with apophysis Halalaimus minusculus Tchesunov, 1978

Gubemaculum without apophysis 9

9(8). Outer labial ttnd cephtdic sensilla less than 1.0 HD long .... Halalaimus terrestris Gerlach, 1959

Outer labial and cephalic sensilla 1.5 HD or greater in length 10

10(9). Outer labial and cephalic sensilla equal in length 11

Outer labial sensilla shorter than cephalic sensilla Halalaimus marri Mawson, 1958

11(10). "a" = 223; outer labial and cephalic sensilla 2.4-3.4 HD long; amphid 18.3 HD long

Halalaimus cirrhatus Gerlach, 1953

"a" = 84.4-118.7; outer labial and cephalic sensilla 1.4 HD long; amphid 9-10 HD long

Halalaimus nigrilapidarius Boucher, 1977

New Species of Halalaimus

357

Group 4

Males without caudal alae. Precloacal sensillum and
precloacal pore absent. Inner labial sensilla discernible in
some species, in other species not so. Outer labial and
cephalic sensilla can vary ’m length between circles. Circles

varying distances apart. Cylindrical part of tail with or
without coarse transverse striations. Tail tip blunt, bifur-
cate or flagellate. Single specimens of Halalaimus species
belonging to this group were examined but are not included
in the following key or described.

Artificial Key to the Males of Group 4
(HD = head diameter; CD = cloacal diameter)

1.

Outer labial and cephalic sensilla in two circles of 6 and 6
Outer labial and cephalic sensilla in two circles of 6 and 4

2

3

2(1).

Tail tip bifurcate

Tail tip not bifurcate

3(1).

Cuticle with coarse longitudinal striations

Cuticle without coarse longitudinal striations

4

4(3).

Tail lip bifurcate

Tail lip not bifurcate

5

6

5(4).

Cylindrical part of tail with coarse transverse striations . .
Cylindrical part of tail without coarse transverse striations

Halalaimus diacros Mawson, 1958

Halalaimus fletcheri Mawson, 1958

6(4).

Cylindrical part of tail with coarse transverse striations . .
Cylindrical part of tail without coarse transverse striations

7

9

7(6).

Amphid width 23-36% of corresponding body diameter . .
Amphid width 10-16% of corresponding body diameter . .

. . . Halalaimus pachydoroides Viiiello, 1970
8

8(7).

Gubemaculum present

Gubemaculum absent

9(6).

Cephalic sensilla equal to or greater than 4.0 HD long . . .
Cephalic sensilla less than or equal to 2,2 HD long

10

13

10(9).

Tail 44.6 CD long

Tail equal to or less than 20.4 CD long

Halalaimus meyersi Wicser & Hopper, 1967
11

1 1(10). Outer labial sensilla shorter (2.1 HD long) than cephalic sensilla (4.0 HD long)

Halalaimus florescens Gerlach, 1967

Outer labial and cephalic sensilla equal, 4.0'6.0 HD long 12

1 2( 1 1). Circles of outer labial and cephalic sensilla well-separated (2.2-2.6 HD apart); gubemaculum without ventral

curve Halalaimus supercirrhatus Gerlach, 1955

Circles of outer labial and cephalic sensilla closer togetlier (1.0 HD apart); gubemaculum with ventral curve
Halalaimus capUulatus Boucher, 1977

13(9). Inner labial sensilla discernible . .
Inner labial sensilla not discernible

Halalaimus papillifer Gerlach, 1956
14

358

Keppner

14(13). Cuticle with transverse striaiions 15

Cuticle without transverse striations 18

15(14), Tail filiform, 17.7-24.5 CD long, lip pointed 16

Tail not filiform, 8.3-15.0 CD long, tip pointed or blunt 17

16(15). Amphid 23 HD long; circles of outer labial and cephalic sensilla close together (0.33 HD apart)

Halalaimus luiarus Vitiello, 1970

Amphid 8.6 HD long; circles of outer labial and cephalic sensilla far apart (1.0 HD apart)
Halalaimus longicollis Allg6n, 1932

17(15). Tail 8.3 CD long, tip pointed Halalaimus macquariensis Mawson, 1958

Tail 10.5-15.0 CD long, tip blunt Halalaimus longicaudatus Filipjev, 1927

18(14). Gubcmaculum absent or rudimentiuy 19

Gubernaculuin present, well developed 20

19(18). Gubernaculum absent Halalaimus reciispiculaiusV\^\.oao\^. 1971

Gubemaculum rudimentary, a small plate at distal end of spicules

Halalaimus leptodenna VldXonoMdi, 1971

20(18). "a" =217.7 Halalaimus leptosoma Southern, 1914

"a" = 130.0 or less 21

21(20). Tail lip pointed 22

Tail tip blunt 23

22(21). Outer labial iind cephiilic sensilla 1.7 HD long, in two circles close together

Halalaimus anne Sergeeva, 1972

Outer labial and cephalic sensilla 0.2 HD long, in two well-separated circles

Halalaimus ciliocaudatus Allg6n, 1932

23(21), Cylindrical part of tail 12% of total tail length Halalaimus pachyderma Filipjev, 1927

Cylindrical part of tail 25% or more of total tail length 24

24(23). Outer labial and cephalic sensilla less than I.O HD long 25

Outer labitil and ceplutlic sensilla greater than 1.0 HD long 26

25(24). Circles of outer labial and cephalic sensilla 1.7 HD apart; amphid 8.6 HD from anterior end; distal end of

gubemaculum expanded laterally Halalaimus zenkeviishi Filipjev, 1927

Circles of outer labial and cephalic sensilla 0.78 HD aptm; amphid 2.2-4 .6 HD from anterior end; dlsuil end
of gubernaculum not expanded laterally Halalaimus isaitshikovi Filipjev, 1927

26(24). Circle.s of outer labial and cephalic sensilla 1.0 HD apart Halalaimus parvus Chitwood, 1936

Circles of outer labial tind cephalic sensilla 0.5 HD or less apart 27

27(26). "c" = 15.9 Halalaimus brevispiculum Sergeeva, 1973

"c" = 9.0 or less 28

28(27). Amphid 5.6 HD from anterior end. 9.2 HD long Halalaimus wodjanizkii Sergeeva, 1972

Amphid 3.0-3.2 HD from anterior end, 6.0-12.0 HD long 29

29(28). Amphid 6.0 HD long; gubemaculum without lateral extensions

Halalaimus caroliniensis Chitwood, 1936

Amphid 12.0 HD long; gubemaculum with lateral extensions

Halalaimus jaUensis Sergeeva, 1973

New Species of Halalaimus

359

The consiniction of a key to the females of the species
of Halalaimus is more difficult than for males. Characters
are not as distinct and many descriptions are not suffi-
ciently complete to separate individual species. The fol-
lowing key ends with groups of similar species that could

not be easily separated. Females are not known for a
number of species. The following species were not in-
cluded due to tlie absence of necessary information; Hala~
laimus leptoderma Platonova, 1971 and Halalaimus lep-
losoma Southern, 1914.

Artificial Key to the Females of the Genus Halalaimus
(HD = head diameter, AD = anal diameter)

1 .

2(1).

3(1).

4(3).

5(4).

6(5).

7(5).

8(4).

9(8).

10 ( 8 ).

Outer labial and cephalic sensilla in two circles of 6 + 6 2

Outer labial and cephalic sensilla in two circles of 6 + 4 3

Tail tip bifurcate Halalaimus filicoUis Timm, 1961

Tail tip not bifurcate Halalaimus seiosus Timm, 1961

Cuticle with coarse longitudinal stiiations Halalaimus longisiriaius Timm, 1961

Cuticle without coarse longitudinal stiiations 4

Tail lip bifurcate 5

Tail lip not bifurcate 8

Cylindrical part of tail with coarse stiiations 6

Cylindrical part of tail without coarse striations 7

Outer labial sensilla twice length of cephalic sensilla Halalaimus brimi n. sp.

Outer labial and cephalic sensilla equal Halalaimus diacros Mawson, 1958

Circles of outer labial and cephalic sensilla well-separated (0.73-0.83 HD apart)

Halalaimus fletcheri Mawson, 1958

Circles of outer labml and cephalic sensilla close together (0.30-0.38 HD apart)

Halalaimus pai'afletcheri n. sp.

Cervical and caudal sensilla present 9

Cervical and caudal sensilla absent 10

Lateral alae present; outer labial and cephalic sensilla equal; inner labial sensilla papillifonn

Halalaimus thalassinus n. sp.

Lateral alae absent: outer labial sensilla shorter than cephalic sensilla; inner labial sensilla not discernible
Halalaimus delamarei Vitiello, 1970

Tail lip a spherical bulb 11

Tiiil lip not a bulb 13

11(10). Circles of outer labial and cephalic sensilla well-separated (1.0 HD apart); inner labial sensilla papillifonn

Halalaimus bulbocaudatus n. sp.

Circles of outer labial and cephalic sensilla well-separated or not; inner labial .sensilla not discernible . .

12

12(11). Circles of outer labial and cephalic sensilla well-separated (greater ilian 1.0 HD apart)

Halalaimus similis Allg6n, 1930

Circles of outer labial and cephalic sensilla close together (0.14 HD apart)

Halalaimus comatus Wieser, 1953

360

Keppner

13(10). Cylindrical part of tail with coarse transverse striations 14

Cylindrical part of tail without coarse transverse striations 21

14(13). Outer labial and cephalic sensilla equal to or greater than 3.0 HD long 15

Outer labial and cephalic sensilla less than or equal to 2.0 HD long 18

15(14). Outer labial sensilla 5.0 HD long; cephalic sensilla 3.0 HD long

Ilalalaimus longisetosus Hopper, 1963

Outer labial and cephalic sensilla equal in length and less than 3.5 HD long 16

16(15). Inner labial sensilla discernible tialalaimus bayensis n. sp.

Inner labial sensilla not discernible 17

17(16). Lateral outer labial sensilla greater in diameter than other sensilla Halalaimus floridanus n. sp.

Lateral outer labial sensiUa equal in diajneter to other sensilhi Halalaimus variabilis n. sp.

18(14). Inner labial sensilla discernible 19

Inner labial sensilla not discernible 20

19(18). Outer labial sensilla shorter than cephalic sensilla, in two well -separated circles (1.0 HD apart)

Halalaimus tarjani n. sp.

Outer labial and cephalic sensilla equal in length and in two circles close together (0.29 HD apart) . . .
Halalaimus paracomalus n. sp.

20(18). Ainphid broad, 23-33% of corresponding body diameter; tail tip flagellate

Halalaimus pachydoroides Vitiello, 1970

Amphid nturower, 20% or less of corresponding body diameter, tail tip not flagellate

Halalaimus turbidus Vitiello, 1970

21(13). Freshwater or inland species 22

MiU'ine or estuarine species 23

22(21). Body length 0.73-0.91 mni; c = 12.5-17.1 Halalaimus algeriensis Cooinans and Jacobs, 1983

Body length 1.41-1.47 mm; c = 6A-13 Halalaimus stammeri Schneider, 1940

23(21). Amphid broad, about 40% of body diameter at midlength of amphid 24

Amphid narrow, 25% or less of body diaineter at midlength of mnphid 25

24(23). Anterior end of ainphid at level of cephalic sensilla Halalaimus dimactericus Wicser, 1953

Anterior end of amphid far posterior to cephalic sensilla Halalaimus ponticus Filipjev, 1922

25(23). Inner labial sensilla discernible 26

Inner labial sensilla not discernible 28

26(25). Outer labial sensilla shorter (0.25-0.33 HD long) than cephalic sensilla (1.0 HD long)

Halalaimus alatus Timm, 1952

Outer labial iind cephalic sensilla equal in length 27

27(26). Outer labial and cephalic sensilla in two well-separated circles (1.0 HD apart)

Halalaimus gracilis De Man, 1888

Outer labial and cephalic sensilla in two circles close togetlier (0.25 HD apart)

Halalaimus papillifer Gerlach, 1956

New Species op Halalaimus

361

28(25), Outer labial sensilla 4.7 times as long as cephalic sensilla Halalaimus horridus Gerlach, 1956

Outer labial and cephalic sensilla equal or subequal in length 29

29(28). Outer labial and cephalic sensilla equal to or more than 2.0 HD long 30

Outer labial and cephalic sensilla equal to or less than 1.5 HD long 31

30(29). Outer labial and cephalic sensilla in two well-separated circles (1.0 HD or more apart)

Halalaimus capitulatus Boucher, 1977

Halalaimus cirrhatus Gerlach, 1953

Halalaimus nigrilapidarius Boucher, 1977

Halalaimus sarsi Gerlach, 1967

Halalaimus scleratus Timm, 1952

Halalaimus supercirratus Gerlach, 1955

Outer labial and cephalic sensilla in two circles close together (less dian 1.0 HD apart)

Halalaimus marri Mawson, 1958

Halalaimus monstrocaudatus Vitiello, 1970

31(29). Outer labial and cephalic sensilla in two well-separated circles (1.0 HD or more apart) 32

Outer labial and cephalic sensilla in two circles close together (less than 1.0 HD apart) 33

32(31). Outer labial sensilla less than 1.0 HD long Halalaimus brachyaulax Mawson, 1958

Halalaimus diplocephalus Filipjev, 1927

Halalaimus isaitshikovi Filipjev, 1927

Halalaimus minusculus Tchesunov, 1978

Halalaimus tenuicapilatus Filipjev, 1946

Outer labial sensilla equal to or greater than 1.0 HD long Halalaimus amphidellus Vitiello, 1970

Halalaimus gerlachi n, sp.

Halalaimus parvus Chitwood, 1936

Halalaimus zenkevitshi Filipjev, 1927

33(31). Outer labial sensilla less than 1.0 HD long Halalaimus terrestris Gerlach, 1959

Halalaimus wodjaneskii Sergeeva, 1972

Outer labial and cephalic sensilla equal to or greater than 1.0 HD long

Halalaimus amphistrius Vitiello, 1970

Halalaimus caroliniensis Chitwood, 1936

Halalaimus longicaudatus Filipjev, 1927

Halalaimus longicollis Allg6n, 1932

Halalaimus luticolus Timm, 1961

Halalaimus pachydermatus Cobb, 1920

Halalaimus rectispiculatus Platonova, 1971

Acknowledgments

Sincerest appreciation is expressed to Dr. W. Duane
Hope of the Smithsonian Institution for the time spent in

reviewing the manuscript, examining the specimens, and
the many helpful suggestions and comments that he pro-
vided.

362

Keppner

Literature Cited

Allg6n, C. 1931. Freilebende marine Nematoden aus dem
Drobakabschnittcs des Oslofjords. ZooL Jb, { 61 : 211-
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Allg6n,C. 1953. Zur Synonymic derGattungNuada Southern,
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Vidensk. Selsk. Fork 26: 43-47,

Bresslau, E. and Stckhoven, J. H. Schuurmans. 1940, Marine
freilebende Nematoden aus dcr Nordsee. Mus, R. Hist. Nat.
Belg. Bruxelles 1940: 1-74.

Cobb, N. A. 1920. One hundred new nemas (type species of 100
new genera). Contrib. to a Science of Nematology (Balti-
more) 9: 21-343.

Coomans, A. and Jacobs, L. J. 1983. Halalaimus algeriensis n.
sp. (Nematoda) from the Sahara, Hydrobiologia 102: 39-44.

DeMan.J.G. 1888. Surquelqucs Nematodes libresdc la merdu
Nord nouvcaux ou peu connus. Mem. Soc. Zool. Fr. 1: 1-51.

De Man, J. G. 1922. Vrijlcvende Nematoden. In: H. C. Redeke
(ed.), Flora en Fauna der Zuiderzee, Te Helder(C. de Boer)
1922: 214-261.

Filipjev.I.N. 1927. Les Nematodes librcs des mers septentrion-
alcs appartenant a la famille des EnopUdac. Arch. Naturgesch.
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Gerlach, S. A. 1962. Freilebende Mecresnematoden von den
Maldiven. Kieler Meeresforsch 18: 81-108.

Gerlach, S. A. 1967. Freilebende Meeres-Nematoden von den
Sarso-Inseln (Rotes Meer). Meteor-Forschungsergebnisse
2: 19-43.

Gerlach, S. A. and Riemann, F. 1974. The Bremerhaven
checklist of aquatic nematodes. Verqff. Inst. Meeresforsch.
Bremerh Suppl, 4, p. 1-735.

Juario, J. V. 1974. Neue freilebende Nematoden aus dem
Sublitoral der deutschen Bucht. Veroff. Inst. Meeresforsch.
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Lorenzen, S. 198 1 . Entwurf eines phylogenetischen systems der
freilebenden Nematoden, Veroff. Inst. Meeresforsch. Bre-
merh. Suppl. 7, p. 1-472.

MaWson.P.M. 1958. Free-living nematodes section 3: Enoploi-
dea from subantarctic stations. Rep. B. A. N. Z. Antarctic
Res. Exped. (B) 6: 307-358.

Platt. H. M. and Warwick, R. M. 1983. Free-living marine
nematodes. Part 1. British Enoplids. Cambridge Univ.
Press. Cambridge,, 307 p,

Rao, G, C. 1989. On some free-living marine nematodes of the
Bay Islands. J. Andaman Sci. Assoc. 5: 1-23.

Riemann, F., Rachor, E., and Freudenhammer, I. 1970. Das
Seitenorgan von Halalaimus zur Morphologic eines vermut-
lich sensorischen Organs von freilebende Nematoden. Veroff.
Inst. Meeresforsch. Bremerh. 12: 429-441.

Stekhoven, J. H. Schuurmans 1935. Nematoda: Systematischer
Teil, Nematoda errantia. In: Grimpe, G. and Wagler, E. Die
Tierwelt derNord-und Osisee. (Leipzig, 1935) 5b: 1-173.

Stekhoven, J. H. Schuurmans 1950. The free-living marine
nemas of the Mediterranean. I. The Bay of Villefranche.
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Southern, R. 1914. Nemathclmia, Kinorhyncha and Chae-
tognatha (Clare Island survey, part 54). Proc. R. Irish Acad.
31: 1-80.

Timm, R. W. 1952. A survey of the marine nematodes of
Chcsap>eake Bay, Maryland. Contrib. Chesapeake Biol.
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Vitiello, P. 1970. Nematodes libres marins des vases profondes
du Golfc du Lion. I. Enoplida. Tierfrys 2; 139-210,

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155.

Gulf Research Reports

Volume 8 | Issue 4

January 1992

Isopods of the Genus Excorallana Stebbing^ 1904 (Crustacea^ Isopoda^ Corallanidae)
from the East Coast of Mexico with a Supplemental Description ofE. subtilis

Antonio Cantu-Diaz Barriga

Instituto de Biologia UN AM, Mexico

Elva Escobar Briones

Instituto de Ciencias del Mar y Limnologia UNAM, Mexico

DOI: 10.18785/grr.0804.02

Follow this and additional works at: http:/ / aquila.usm.edu/ gcr

Part of the Marine Biology Commons

Recommended Citation

Barriga, A. C. and E. E. Briones. 1992. Isopods of the Genus Excorallana Stebbing, 1904 (Crustacea, Isopoda, Corallanidae) from the
East Coast of Mexico with a Supplemental Description of£. subtilis. Gulf Research Reports 8 (4); 363-374.

Retrieved from http://aquila.usm.edu/gcr /vol8/iss4/2

This Article is brought to you for free and open access by The Aquila Digital Community. It has been accepted for inclusion in Gulf and Caribbean
Research by an authorized editor ofThe Aquila Digital Community. For more information, please contact Joshua.Cromwell^usm.edu.

Gulf Research Reports. Vol. 8, No. 4, 363-374. 1992

Manuscript received September 20, 1990; accepted January 15, 1992

ISOPODS OF THE GENUS EXCORALLANA STEBBING, 1904
(CRUSTACEA, ISOPODA, CORALLANIDAE) FROM THE EAST COAST
OF MEXICO WITH A SUPPLEMENTAL DESCRIPTION OF E. SUBTILIS

ANTONIO CANTC-DIaZ BARR10A> AND FXVA ESCOBAR BRIONI-:S^

‘Coleccidn Carcinoldgica; Instituio de Biohgfa UNAM: A.P. 70-153: 04510 Mexico Ci:y
^Laboraiorio de Ecologla del Demos; Instiiuto de Ciencias del Mar y Limnologia UNAM;
A.P. 70-305 ; 04510 Mexico City

ABSTRACT Eight species of Excorallanar E. acuticauda. E. delaneyi. E. oculaia. E. sexticornis. E. subtilis, B. iricornis
tricornis. E. warmingii, and Excorallana sp. arc recorded for the eastern coast of Mexiett. The range of E. delaneyi is extended
south in the Gulf of Mexico. Excorallana oculaia and E. subtilis are reported for the first lime in the Gulf. Based on spe^:!-
rnens from the east coast of Mexico, a supplemental description of E. subiilis is presented and its taxonomy to other closely
related specie.s discussed. A key is provided to the adult males of the species oi Excorallana now known to occur in the south-
western Gulf of Mexico and the Caribbean coast of Mexico.

Introduction

A viiriety of marine isopod crustaceans have been
collected in conjunction wiili ongoing ecological and fau-
nal surveys off the eastern coast of Mexico. This study
deals with the new distribution records fur the cxcorallanid
isopod genus Excorallana Stebbing, 1904 from the Gulf
and Uic Caribbean coasts of Mexico. Except forE. oculaia,
which occurs in both die eastern (west coast of Africa) and
the western Atlantic, the 21 other species oi Excorallana
are restricted to the tropical and temperate waters of the
Atlantic and Pacific coasts of die Americas. Of these, 16
species are endemic to the western Atlantic between 30“N
and the Equator (Lemos de Castro and Lima 1971; Delaney
1989). The range of E. delaneyi is extended soutli in die
Gulf. Excorallana oculaia and£. subiilis are reported for
die first time in the Gulf. Six female specimens of the latter
species were collected in Sabancuy, Campeche and Puerto
Morelos, Quintana Roo, allowing its redcscripiion and the
delermiiiation of differences among the specimens re-
ported from Brazil by Lemos de Castro and Lima in 1 97 1.

Materials and Methods

Specimens used for this study were obtained from
several localities and sites along the eastern coast of Mex-
ico (Fig. 1), These were Isla de Sacrificios off Veracruz,
Sabancuy and El Cayo in Terminus Lagoon; Seibaplaya,
Campeche; Yucalpci6n and Rio Lagartos, Yucat^, Isla
Mujercs, and along the shore tmd the barrier reef off Puerto

Morelos in the Y ucatan Peninsula. Specimens from Termi-
nus Lagoon were collected during 1983 in seagrass beds
(Thalassia tesiudinum) using a 0,65m wide (0.451mm
mesh) Cohnan-Segrovc sled (Eleftheriou and Holme 1985).
Other specimens wcreobiainal from liand-collccicd sponges
living on the seagrass beds at El Cayo. Material from the
Yucat^ Peninsula and Sacrificios Island was hand-col-
lected while skin diving and SCUBA diving during several
field trips from 1985 to 1987.

The specimens examined during this study are depos-
ited in Uie (Zarcinological Collection at the Instituio de
Biologla, National University of Mexico (IB-UNAM).
Water temperature was recorded in the field with a hand
thermometer. Tlic four to five digit catalogue numbers for
tliese specimens are precederd by the letters EM. Speci-
mens were fixed in 10% seawater fonnalin, soned in the
laboratory, identified, catalogued, and stored in 70% etha-
nol. The sex, total length <L) imd width (W) of each
specimen is indicated under material examined for each
species. The lengtii and width were determined using a
calibrated ocular micrometer in a dissecting microscope.
Illustrations were made with the aid of a camera lucida.

Results

Eight species of Excorallana taken along the coast of
eastern Mexico have been identified in die collections of
IB-UNAM. Specific information on the occurrence, habi-
tat, and hosts, when known, is presented for each species
treated.

363

364

Canto and Escobar

figure 1. Sampling sites of Excorallana specimens recorded in this study in the southwestern Gulf of Mexico and the Mexican
Caribbean.

Excorallana acuticauda (Miers 1881)

Fig. 2 a-c

Material examined. Puerto Morelos; EM-9588 f
L:6.6, W:2.0mm,

Diagnosis. Eyes large, not contiguous, separated by a
distance of half the length of an eye. Males and females
without cephalic horns. Tcison with lateral noiclics and
mid-dorsal excavation. Frontal hunina elongate, distal end
round.

Distribution. Key West, Florida; St. Thomas
(Richardson 1905); South Bank. Texas (Clark and Robertson
1982); Caribbean and Brazil (Delaney 1989), New record:
Puerto Morelos, Quintana Roo. Mexico,

Ecological notes: Occurs in reefs, low tide (Richardson
1905). Intertidal (Schultz 1969). At Puerto Morelos, asso-
ciated with the coral reef, in shallow water; collected at
temperature 29.5®C.

Excorallana delaneyi Stone and Heard, 1989
Fig. 3 a-c

Material examined. Terminas Lagoon, Gulf of Mexico;
EM-9248-f m 1:8.3, W:3.2; ov L:9.8. W:2.9; EM-9519 f
L:3.6, W:1.2; EM-9224 m L:8.4, W:3.5; ov L:9.1, W:3.5;
ov L:9.6, W;3.6; EM- 1056 1 m L:7,0, W:2.6; m L:7.7,
W:7.7; m L:8.1, W:2.7; f L:7, W:2.1; f L:5.4, W:1.7; f
L:4.6, W:1.5; f L:5.2, W:1.5; ov 1:6.7, W:2.0; ov L:7.0,
W:2.3; ov L:7.2, W:2.2; ov L:6.2, W:2. 1 ; ov L:7.9, W:2.3;
ov L:7.1, W:2.2; ov 9.1, W:3.3; ov L:6.0, W;2.1. Yucal-
pei6n; EM-7530 m 1:6.6, W:2.5; EM-74 1 1 m L:8.2, W:2.9;
ov L:8.1.W:3.0; ov L:8.4, W:3.2. Ri'o Lagartos; EM-4960
mL:8.8,W:3.0.

Diagnosis. Eyes separated. Three cephalic horns in
male and two rudimentary horns or tubercles in female;

Excorallana from the East Coast of Mexico

365

Figure 3. ExctitaUaaa delatteyi Stoue and Heard, 1989: a, male cephalun; b, fronlal lamiaa; c, lelson.

366

Canto and Escobas

raslral horn in male cyJmdrical similar to tlie lateral horns
Telson wnhout lateral notches, with four terminal .spines'
^ w^lycrennlaie. Frontal latninaelimgale. distal end

Distribution. Gulf of Mexico: St. Joseph's Bay
Honda (Stone and Heard 1991). New records; Terminos

” ’^“caian

Ecological Notes. Associalcdwitlisponge.sinJiabitinK

r/w flisto ,e„udmiim seagrass beds in sluOlow water from

( 1 , ? bolloms of marsh

lUiLs (Uiis Study and Stone and Heard 1989).

Excoraffana oculata (Hansen 1890)

Fig. 4 a-c

r' Sacriljcios Island off Veracruz

Gulf of Mexico: EM-8768 in L;6.6. W:2 J .

Diagnosis. Eyes large, contiguous. Males find fc-
males without cephalic liorn.s. Telson with lateral notche.s
hronltd lamina elongate, narrow, distal tip rounded.

Dtstribution. Caribbean. Brazil, and Annabon Island.

Gulf of Guinea. West Africa (Delaney 1989). New record:
Sacrincios Island off Veraenjz. SouUiwesiern Gull of Mex-

ICO.

Ecological Notes. ShiUlow water, associaicd wiUi

coral reefs.

Excoraliarta sexticorm (Richardsm 1901)

Fig. 5 a-d

PU Puerto Morelos, QuiniiuiaRoo;

LM-«55ft ov L:6,2. W:2.2; EM-9161-a ov L-7 0 W2 4-
EM-9177-a f L;7.(), W:2.5; m L:6..5. W: 2.n m^: 't'
W;2,4; m I.:6.0. W:2.2; m L:7.5. W;2.3; m L:7.0 W2 i '
EM-9M8 m L- 6.4. W;2.l: EM.96H7-a in L;7,(). W:2.3-'n.'
L.6.(), W;2.l; I L;r)..3, W:2.2; f L:7.X, W2 6' f L-6()
W:2. 1 : f L;6.9. W:2..3; f L:7.5, W;2..<i. ‘

Diagnosis. Eyes nonnid. separated. Male wtlli lour
cephidic horns and two on ba.sal segraems ol' ftrsl taitenttae,

_ em^es wiili four small tubercles on posterior hull' of the
bead Telson with lateral notches. Frontal lamina short

roundeti

Distribution. Key West, Florida (Ricliardson 1 905)

Caribbean (Delaney
989). Behze (Kcn.sley tind Scbulle 1989). New record-
Fuerto Morelos. Quimaiui Roo. Mexico.

Ecological Notes. In shtilJow water to i , 5 m depth in

I Pr'Jsciice of Iwo cephalic tubercles in

lemaies ol Uiis species was cited by Richardson (1905).

bevenolonrcightreinales have foursliglillydeveloped ce-
llulite tubercles between die eyes, two located on the same

ExcoraUaaa subtUii (Hansen 1890 )

Figs. A a-g, 7 a-c

Material cammed; Seihaplaya. Campeche. SouUt-

weslOT of Mexico: EM-56KI f L:9.0. W:2.6: Puerto
Morales. Qutntoa Roo: EM.5705 f L:7.5, W:2.1: EM-

yioJ f L;6.0. W:2.0; EM-9177 f L:6 9 W*2 3- f T -7 s
W:2.3; EM.9687 ov L:6.0, W:L8, ‘

Oiagnoars. Eyeij medium in size, separated. Females
wiLhoui ceplialic horns or fuberdcs. Tdson witli lateral
noiLhcs. Fromd lamina subtiuadrale. excavated venirally.

Description. Female; witlioui cephalic horns or lu-
fercles. aniei^r cephalic mfirgin produced between bases

in siy.e. sepju-aled

anteriorly by a distance sHghUy greater than the length of
im eye amennae witJi Uirec pcduijcuhir articles, basis
s ongly dilated; wtlli six to eight flagellar firtides (Fig 6b)

irs '■ if'"™"*'

il'if . , ‘’“Cellar articles (Fig. 6c). articles two to

eiSlu densely setose. Frontal lamina .sulx|nadrate. a li„|e
longer Uian wide, somewhat narrower lowttrds the widely
rounded apex tind excavated vcmrally nem die base (Fig

™. i 'i Partially concealed; labrum con-

ce. e . Maxdhpcd with epipndile reduced, palp with five
segments, widt sinooUt margms, anle-penullimatc segment
s on. pciiulumate segment curved proximally. Up of distal
segment wtd. tuft of setae (Fig. 6e), Right mandible wid,
lour subaptcal cusps, one just below die incisor process the
other diree forming the apical pari t,f a medium broad'nat
tubercle (Fig. 60: left mandible with dtreesubapical cusps
irsi and second located below incisor process, third lu-

rSr ',r "'“"dibles with lacinia

mobi Its, wtthoiii molar process. Peraonilcs 1-VIT widiout
donsaJ tuberclesorselae. Pereopods I- ID prehensile; differ-
ing atiiong Ihem. m common merus with four short spines
on postenor medial margin, ischium with one short spine
on posierodistal median margin (Fig.7a). Pleoniles one to
live wiUioiil dorsal tubercles, naked. Pleopods 1-5 widt
plumose margimU seme. Pleoleison sublriangular. without
durstd settle; two pronmicm .submedian mhei cles on dorsal
surface near ba.se; iriargin fringed widt seuie. lateral mar-
gms with deep nolchcs (Ftg. 7b); apex rather acute, with

iwosma Ispincs cachtippedwiihahairlFIg, 7c). Uropods

ghdy longer thtm pleoielson; fringed widi setae: iiropo-
dul endopod brotid. posteriorly sublrancale. distal lateral
angles pomicd. lateral umer mtirgiu armed with six short
spines, latenU outer mnrgm widt one spine; ijro,Kxlal cxoptxl
css than ludl the width of the endopod, narrowing to a bilid
Up, laieiul inner margiti widiout spines, lateral outer mar-
fiin wjUi tme spine.

Malt*; unkjit) wn.

Excorallana from the East Coast of Mexico

369

Distribution. St. Thomas, West In(Iies(Hansen 1890).
New records: Seibaplaya, Campeche, southwestern Gulf of
Mexico, and Puerto Morelos, Quintana Roo.

Ecological Notes. Inhabiting shallow waters from 1 to
2m depth; associated with dead coral heads, algae on coral
rock and submerged wood.

Remarks. Since Hansen’s description (1890) of a
single molting female specimen from St. Thomas, the
identity of this species has been regarded as uncertain by
several authors. Two females of E. subiilis were reported
by Lemos de Castro and Lima (1971) in Brazil and re-
garded as a synonym of E. antillensis due to their close
morphological resemblance and sympatric distribution.
The affinity with E, richardsonae was also observed in the
similarity of the first antennae and frontal lamina. Delaney
(1989) mentioned the similarity of E. subtilis with E.
acuiicauda and E. richardsonae, and considered at the
same time E. antillensis to be a junior synonym of E.

acUticauda. Kensley and Schoiie (1989) expressed their
uncertainty to the identity of tlie only known specimen.
Nevertheless, the redescription of £. subtilis from speci-
mens found in the southwestern Gulf of Mexico and the
Mexican Caribbean validates the existence of Hansen’s
species. A comparison with the description of the Brazil-
ian specimens of Lemos de Cairo and Lima (1971) shows
that the latter specimens belong to a different species due to
the presence of tubercles on piconite 5; the presence of
submedial rows of setaealong the lelson; the lack of the two
apical spines; the anterior part of the frontal lamina with a
more pronounced angle; the maxilliped with a surface
covered with tubercles; and the absence of subapical cusps
and lacinia mobilis m both mandible,s. Therefore, we
consider a species complex formed by E. acuticauda. E.
richardsonae, and E. subtilis in which each of the species
can be recognized.

a

b

c

Figure 7. Excorallana subtilis (Hansen 1890): a, pereopod I; b, telson; c, tip of telson.

Excorallana tricornis tricornis (Hansen 1890)

Fig. 8 a-c

Material examined. Tenninos Lagoon, Southwest-
ern Guh of Mexico: EM-93 1.5 f L:4.0, W: 1 .5; ov L:6.7, W:

1.9; Puerto Morelos, Quintana Roo; EM-.5643 in L:6.6,
W:2.4; Isla Mujeres, Quintana Roo; EM-7320 m L:6.6,
W:2.4; m L:6.0, W:2.3; EM-7327 m L:10.2. W:3.5, m
L: 10.8, W3. 8, ov L: 10.8, W:3.6; EM-7379 m L:7.9, W:3 . 1 ;
in L:7.8, W:2.9; f L;6.i, W:2.3; ov L:11.0, W:3.7; EM-

370

Canto and Escobar

Figure 8. Excorallana tricornis tricornis (Hansen 1890): a, male cephalon; b, frontal lamina; c, telson.

7459 ov L:8.5, W:3.0; ov L:7.6, W:2.4.

Diagnosis. Eyes separated; male wiUi three cephalic
horns, rostral horn concave, broad, lateral horns cylindri-
c;il; horns in female rudimcniary; telson with lateral notches,
apex with four short spines, rows of setae on eiOier side of
medial longitudinal area. Frontal lamina elongate, distal
end triangular.

Distribution. Gulf of Mexico and Caribbean (De-
laney 1989). New records; Tenninos Lagoon, southwest-
ern Gulf of Mexico; Isla Mujeres, and Puerto Morelos,
Quintana Roo, Mexico.

Ecological Notes. Reported depths varying from the
intenidal to I83m (Delaney 1984) from 44 io503m (Schultz
1969), and from 18 to 73m in the noriheasiem Gulf (Men-
zies and Kruezynski 1983). Found in shallow waters of 1

to 2 m depth in Uiesc samples. Material from the Caribbean
was found on dead conU heads and submerged rocks. The
species was associated witli Thalassia testudinum seagrass
beds in Terminos Lagoon.

Excorallana warmingii (Hansen 1890)

Fig, 9 a-c

Material examined. No material available in collec-
tions in Mexico.

Diagnosis. Eyes large, scinispherical, contiguous,
most of surface of head; males and females without ce-
phalic horns; telson without notches on lateral margins,
dorsal surface smooth. Frontal lamina elongate, distal end
narrowing and ending in a sphere.

Excorallana from the East Coast of Mexico

371

Figure 9. Excorallana warmingii (Hansen 1890); a, cephalon; b, frontal lamina; c, telson (after Richardson 1905).

DistributioD. Off Cape Catoche, Yucauin (Richardson
1905), Caribbean (Delaney 1989),

Excorallana sp.

Fig* 10 a-c

Material examined. EM-7601 ov L:9.4, W:2.8.
Diagnosis. Eyes large, not contiguous, separated by less
than 0.25 the length of an eye; female without cephalic
honis or tubercles; lelson with lateral notches, dorsal sur-
face smooth. Frontal lamina elongate, narrowing distally,
ending in a triangular lip.

Occurrence. Puerto Morelos, Quintana Roo.

Ecological Notes. Occurs in shallow water at 1.5ni
depth, associated with coral.

Remarks. The ovigerous female of Excorallana sp.,
occurring in Puerto Morelos is an isolated record requiring
more material to be described as a new species. Affinities

to the existing species of Excorallana are its resemblance
to E. aciuicauda in the lack of cephalic tubercles, the
presence of large eyes separated by less tlum half an eye-
length, and the presence of lateral notches on the iclson.
The female differs from E. acuikauda in the smooth dorsal
surface of the pleoiiiles, the absence of the median longitu-
dinal depression and the two proximal tubercles on the
lelson, the shape of Uie frontal lamina, imd the larger eyes.
The texture of the dorsal surface of the pleonites has been
considered important and has previously been recognized
in subspecies differentiation even to its high degree of
variability (Bowman l977;MenziesajidKruczynski 1983).
Comparing the female Excorallana $p. with females of E.
acaticaiida, the authors discard the possibility that die
characters of the fonncrcoiild belong to a juvenile form due
to the size and ovigerous state of the specimen, suggesting
that it could be a new species.

372

Cantu and Escobar

The following iclenlificaiion key is provided for the seven Excorallana species recorded from eastern Mexican waters.

1. Eyes contiguous 2

Eyes separated, large or medium in size 3

2. Telson with lateral notches E. oculala

Telson without laiend notches E. warmingii

3. Eyes large; disumce bet\veen them lialf or less the length of an eye 4

Eyes medium sized; distance between them greater than the length of an eye 5

4. Pleotelson with two submedian tubercles proximally; distance between eyes almost half the length of an eye

E. acmicauda

5 Telson without laienil notches; adult male with 3 cephalic horns, rostral horn cylindrical; adult female with

cephalic tubercles in same position as male horns E. delaneyi

Telson with lateral notches 6

6. Witli cephalic honts (males) or tubercles (females) 7

Without cephalic honts or tubercles; only females known £. suhiilis

7. Male with 3 cephalic horns, rostral horn wide at base and concave; female witli slightly developed cephalic

tubercles in same position as horns in male E. tricornis irkoniis

Male witli four cephalic horns, larger ones between eyes, two smaller ones in anterior position, small horns
on base of antcnnular peduncle; female with four small tubercles slightly developed between eyes

E. sexticornis

Figure 10. Excorallana sp.: a, cephalon; b, frontal lamina; c, telson

Excorallana from the East Coast of Mexico

373

Discussion

Twenty-lwo species of the genus Excorallana have
been described for the tropical western Atlantic and eastern
Pacific, of which only 20 were included in the revision of
the family Corallanidae by Delaney (1989). Excorallana
bicornis (Lemos de Castro and Lima 1971) was omitted in
that list and is herein included as an additional species
occurring in the western Atlantic. Occurrence of the genus
in the Gulf of Mexico, following Antoine’s (1972) subdivi-
sion of the Gulf, has been recorded forjE;. acuiicauda (Clark
and Robertson 1982; Menzies and Kruezynski 1983), E.
delaneyi (Stone and Heard 1989), mexicana, E, tricornis
iricornis (Menzies and Kruezynski 1983), E. warmingii
(Richardson 1905) and E. sexticornis (Rouse 1969). The
new records herein extend the range of E. delaneyi south in
the Gulf of Mexico and increase the number of species
occurring in this region to eight with the new reports of E.
oculata and E. subiilis in the Gulf.

Distribution of these species is probably habitat-
selective, since most occur in reef patches in the Gulf as
well as in seagrass beds. The inclusion of some of the spe-
cies in the souUiwesiern Gulf of Mexico can be explained
by the parasitic behavior reported for £. tricornis tricornis
(Delaney 1984) andE. berbicensis (Slone and Heard 1989)
and may follow the distribution patterns of host fish.

Western Atlantic species fall into two groups: a southern
group of seven species restricted to the Brazilian coast and
part of the Caribbean, and a northern group of 10 species
distributed in the Gulf of Mexico, the West Indies and the
Caribbean. The geographical distribution of these groups
shows a diffused pattern probably related to direct develop-
ment, besides the geographical barriers.

Acknowledgments

The authors wish to express their appreciation to Dr.
Thomas E. Bowman of the Smilhsoni«m Insiiluiion, Dr,
Ricliard C. Brusca of San Diego Natural History Museum,
Dr. Richard Heard of Gulf Coast Research Laboratory , and
Dr. Luis A. Solo and Bidl. Jos6 Luis Villalobos of UNAM
for tliem critical reviews on an earlier version of this
manuscript. Gratitude is expressed to Patricia Flores,
Enrique Lira, Juan Carlos Nates, Patricia Scluniisdorf, Ma.
Dolores Valle, Bruno Gdinez and the Benthic Ecology Lab
for llteir support in the field. This research was sponsored
by CONACyT project PCCNCNA-031542 and DGAPA-
208089. This is Contribution No. 678 from tlie Instiluto de
Ciencias del Mar y Limnologia.

Literature Cited

Antoine, JW. 1972. Slruclare of the Gulf of Mexico, pp. 1-34.
In: Rezak, R. and V.J. Henry (Eds.) Contributions on the
geological oceanography of the Gulf of Mexico, Texas
A&M University Oceanographic Studies, Gulf Publishing
Company.

Bowman, T.E. 1977. Isojwd Crustaceans (except Anthuridae)
collected on the presidential cruise of 1 938, Proc. Biol. Soc.
Washington 89;653-666.

Carvacho, A.and C. Yahez. 1971. Excorallana meridionalis n.
sp. primer Excorallaninac para la costa del Pacifico sudori-
cntal (Isopoda, Cirolanidac). Rev. Dial. Mar. 14:129-134.

Clark, S.T. and PP. Robertson. 1982. Shallow water marine
isopods of Texas. Contr, Mar. Sci. 25:45-59.

Delaney, P.M, 1982. The .synonymy of Excorallana kathyae
Menzies, 1962 with Excorallana truncata (Richardson,
1899), with a rcdcscription of the species (Crustacea, Iso-
poda. Excorallanidae). J. Crust. Biol. 2:273-280.

Delaney, P.M. 1984. Isopods of the genus ExcortaZ/a/ifl Siebbing,
1904 from the Gulf of California, Mexico (Crustacea, Iso-
poda. Corallanidae). Bull. Mar. Sci. 34:1-20.

Delaney, P.M. 1989. Phylogeny and biogcography of the marine
isopod family Corallanidae (Crustacea, Isopoda, Flabellif-
era). Contr. Sci. Natl. Hist. Mus. Los Angeles County.
409:1-75.

Eleftheriou, A. andN.A. Hohne. 1985, Macrofauna techniques.
In: Holme, N.A. and A.D. McIntyre (Eds.) Methods for the
study of marine benthos. Blackwell ScicniiFic Publications.
394pp.

GuzmSn, H.M.. V.L. Obando. R.C, Brusca, and P.M. Delaney.
1988. Aspects of the population biology of the marine
isopod Excorallana tricornis occidentalis Richardson , 1905
(Crustacea: Isopoda; Corallanidae) at Cano Island, Pacific
Costa Rica. Bull. Mar. Sci. 43:77-87.

Hansen, H.J. 1890. Cirolanidacctfamiliaenonullaepropinquac
Musci Hauniensis. Videnskabemes Selkab Skriftcr, 6 Raekkc,
Naturvidenskabclig og Mathematisk Afdeling 5:239-426.
Kensicy , B. and M. Schotte. 1989. Guide to the marine Isopod
Crustaceans of the Caribbean. Smithsonian Institution Press.
308 pp.

Lemos de Castro, A. 1 960. Quatro cspecies novas brasileiros de
Excorallana Stebbing, 1904. Arq. Mus. Nai. Rio Janeiro
50:61-77.

Lemos de Ca.stro. A. and I.M.B. Lima, 1971 . Ocorrcncias de
Excorallana subtiiis (Hansen), Excorallana oculata (Hansen),
Excorallana warmingii (Hansen) c dcscricao de um a cspecic
nova Excorallana bicornis do litoral norle do Brasil. Arq.
Mus. Hist. Nail.hl35A53.

374

Cantu and Escobak

Lemos dc Castro, A. andl.M.B. Lima. 1976. Dcscri^ao dc uma
espccic nova brasileira de Excorallana (Isopoda: Excoral-
lanidac). At. Soc. Biol. Rio Janeiro 18:75-76.

Menzies, RJ. and W.L, Kruczynski. 1983. Isopod Crustacea
(exclusive Epicaridca). Mem. Hourglass Cruises 6: 126pp.

Miers, E.J. 1881. Crustacea from the survey of H.M.S. Alert.
Proc. Zool. Soc. London 1:61-79.

Richardson, H.R. 1901 . Key to the isopod.s of the Atlantic coast
of North America, with description of new and little known
species. Proc. U.S.Natl. Mils. 23:493-579.

Richardson, H.R. 1905. A monograph on the isopods of North
America. U.S. Nall. Mas. Dull. 54: 1-727.

Rouse, W.L. 1969. Littoral Crustacea from southwest Florida.
Quart. J. Fla. Acad. Sci. 32:127-152.

SchuUz.G.A. 1969. How to know the marine Lwpodcrustaceans.
W.C. Brown Pub. 359pp.

Stebbings, T.R. 1904. Marine Crustaceans XE. Isopoda, with
description of a new genus. In: Fauna and geography of the
Maidive and Laccadive Archipelagoes. J-S. Gardiner (Ed.)
2:699-721. Cambridge University Press.

Stone, I. and R.W. Heard. 1989. Excorallana delaneyi n.sp.
(Crustacea: Isopoda: Excorallanidae) from the northwestern
Gulf of Mexico, with observations on adult characters and
sexual dimorphism in related species of Excorallana Steb-
bing, 1904. Gulf Res. Repts. 8:199-21 1.

Gulf Research Reports

Volume 8 | Issue 4

January 1992

Ecological History^ Catastrophism^ and Human Impact on the Mississippi/Alabama
Continental Shelf and Associated Waters: A Review

Rezneat M. Darnell

Texas A&M University

DOI: 10.18785/grr.0804.03

Follow this and additional works at: http:/ / aquila.usm.edu/ gcr

Part of the Marine Biology Commons

Recommended Citation

Darnell, R. M. 1992. Ecological History, Catastrophism, and Human Impact on the Mississippi/ Alabama Continental Shelf and
Associated Waters: A Review. Gulf Research Reports 8 (4): 375-386.

Retrieved from http:// aquila.usm.edu/gcr/vol8/iss4/ 3

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Gulf Research Reports, Vol. 8. No. 4. 375-386. 1992

Manuscript received June 26, 1991; accepted August 3, 1992

ECOLOGICAL HISTORY, CATASTROPHISM, AND HUMAN IMPACT
ON THE MISSISSIPPI/ALABAMA CONTINENTAL SHELF
AND ASSOCIATED WATERS: A REVIEW

REZNEAT M. DARNELL

Departmeni of Oceanography, Texas A&M University. College Station, Texas 77843

ABSTRACT The Mississippi/A labama continental shelf and associated coastal waters together form a complex ecological
system of interrelated parts. The biological system of the area has become established during the period of sea level rise
following the last continental glacial maximum about 18.000 years ago. Contemporary biological populations of the inshore
waters arc subject to episodic catastrophic events caused by exceptional cold fronts, flooding, major storms, hypoxia, red tide
outbreaks, and major droughts. Most of these events are not known to affect the shelf populations directly, but indirect effects
through food chain disruptions are likely. Loop Current intrusions and entrainment of deep Gulf waters could directly impact
the shelf species. Imposed upon these events are various human intrusions which have severely reduced the quality and
quantity of inshore habitats. Increase in commercial and recreational fishing pressure in the inside waters and on the
continental shelf during the past two decades has been accompanied by dramatic decline in populations of demersal and
pelagic fish species. In order to be able to manage resources of the area successfully, there is an urgent need to understand
the namial functioning of the entire complex ecological system.

Introduction

The Mississippi/AIabama continental shelf and the
surrounding marshes, bays, estuaries, and lagoons form a
large complex ecological system of interconnected compo-
nents. The subsystems are related through the flow of
nutrients, suspended particulates, and migratory species.
Major efforts to bring portions of this system into focus
include those of Christmas (1973), Darnell and Kleypas
(1987), and Vittor (1985). However, virtually iill of our
knowledge of the larger system derives from study of
individual components, and dynamic relations between the
subsystems are poorly understood. Yet a comprehensive
understanding of the larger system is essential if manage-
ment efforts are to be successful in maintaining basic
ecological relationships in the face of mounting human
intrusion. The present article provides a focus on the larger
system by reviewing pertinent literature concerning eco-
logical history, natural catastrophic events, and human
impacts. This is viewed as a necessary first step in
examining the larger picture.

Ecological History

During Pleistocene time, the coastal and coniinenial
shelf environments off Mississippi and Alabama under-
went dramatic changes. Associated with repealed advance
and retreat of the continental ice sheets, the sea level
receded nearly to the outer edge of the continental shelf and
then rose again to approximately its present stand or higher.
With each retreat of the sea, the shelf became exposed to
subaerial erosion and oxidation, and streams passing through

Uie area carved deep valleys. Subsequent rise in sea level
saw filfmg of the valleys and smoothing of the surface.
Associated changes involved shifting of the position of the
Mississippi River delta, barrier island formation and de-
struction, and formation and filling of bays and estuaries.

Following the last glacial maximum about 18,000
years ago, the sea level has risen to its present stand, and
repopulation of the northern Gulf shelf, bays, and estuaries
has taken place. Mew tropical immigrants brought in by the
Gulf Loop Current and possible other means (Humm and
Dafnell 1959; DameUand Kleypas 1987) Iiavc been added
to the normal biota of the northern Gulf. Considering the
variability of the environments, the recency of their availa-
bility, and the periodic addition of new faunal elements
from the south, it Ls reasonable to conclude that the proc-
esse.s of genetic adjustment are still underway.

This conclusion is borne out by the fact that at least the
key species of the ecological system appear to exhibit
R-type life history strategies — that is, they are opportunis-
tic pioneering species with short life histories and high re-
productive rates. They are adapted for rapid exploitation of
new ecological opportunities and for persistence in the area
despite local habitat loss, great variability in environmental
factors, and the occasional occurrence of natural catastro-
phes. These key species include the brown and while
shrimp, blue crab, gulf menhaden, sand seatrout, spot,
Atlantic croaker, and striped mullet (all estuary depend-
ent), as well as the longspine porgy and several flatfish
(non-estuary dependent). Despite wide annual variations
in abundance, these species have persisted and flourished
in the area and have contributed to the stability of the shelf
ecological system.

375

376

Darnell

Natural Catastrophism

The coastal environments of the northern Gulf of
Mexico undergo regular cycles of seasonal changes in
atmospheric, hydrographic, and oceanographic factors.
Likewise, the life histories of the various species involve
annual responses to the regular environmental changes
(Benson 1982). However, on the continental shelf and in

related coastal environments of the Mississippi-Alabama
area, certain major changes occur irregularly, and these
episodic events may interrupt the normal biological pat-
terns. Some are known to result in mass mortalities, and
probably place major stress on populations of the area.
Biological effects of these events (Table 1) have not been
studied adequately.

TABLE 1

Major catastrophic events which affect the environments and biota of the Mississippi-Alabama marine
systems.

Catastrophic

Events

Effects

Estuaries

Continental Shelf

Cold fronts

Recorded from Mississippi and Alabama

Can cause mass mortality of invertebrates
and fishes.

Not known to affect species on the shelf
but may induce some stress.

Probably limits establishment of tropical
species in shallow water habitats.

Floods

Recorded around Mississippi River Delta,
Lake Pontchartrain, Lake Borgne,
Mississippi Sound, and Mobile Bay.

Short term effect is to place much fresh
water, sediment, and debris into estuaries,
destroy bottom habitat and oyster reefs,
and kill or chase out mobile species.

Long term effect is to bury pollutants and
increase fertility.

Recorded from the southwestern half of
the shelf.

Short term effect is to increase young
fishes on the inner shelf and move older
fishes to deeper water.

Long term effect may be to increase
fertility.

Major storms and
hurricanes

Affect entire coastline

Cause major flooding and extensive
habitat damage (sedimentation of bottoms,
destruction of marshlands and submerged
vegetation, burial of oyster reefs, and
erosion of shorelands).

Affect the entire coastline.

Induce strong currents; stir up bottom
sediments to a depth of 8 m or more;
may restructure barrier islands.

Biological effects unknown.

Hypoxic events

Known from Lake Pontchartrain and
Mobile Bay.

May cause mass mortality of invertebrates
and fishes.

Not known from the Mississippi/
Alabama continental shelf.

Red tide outbreaks

Recorded from Chandeleur Sound, Lake
Borgne, Mississippi Sound, and Mobile
Bay.

Reported between and near barrier
islands off Louisiana and Mississippi.

Small fish kill reported.

Catastrophism and Human Impact on Coastal Waters

377

Cold fronts

During exceptional winters, major cold waves strike
the northern Gulf Coast and rapidly chill the estuarine and
lagoonal waters. Immobilized by the sudden chill, inverte-
brates and fishes are unable to escape and die in great
numbers. Such events have been reported along most of the
northern Gulf Coast from south Texas through the Florida
peninsula. Low temperature fish kills liave been reported
from coastal waters of Mississippi (Christmas 1973; Over-
street 1974) and from Mobile Bay (Reagan 1985; Johnson
and Seaman 1986). No effects of low temperature have
been reported for populations of the shelf but it is likely
that some tropical species which have become established
on the shelves of south Texas and peninsular Florida are
excluded from the Mississippi-Alabama shelf by excep-
tional extremely cold conditions.

Floods

Flooding of low coastal areas in the Mississippi River
delta was a normal occurrence prior to the construction of
artificial levees (Gunter 1952). Today it occurs east of the
della when the Boruiet Carr^ spillway is opened to permit
floodwaters to pass through Lakes Pontchartrain imd Bor-
gne and Mississippi Sound to the Mississippi-Alabama
shelf. Flooding may also occur when heavy rains fall in the
drainage basins of the coastal streams, particularly the
Pascagoula and Mobile Rivers, or when the coastal areas
themselves are inundated from winter rainstorms or sum-
mer tropical depressions. The immediate physical effects
are to replace or greatly dilute the saline waters of bays,
estuaries, and sounds; markedly increase the level of sus-
pended sediments; reduce oxygen values in the hypo-
limnion; and deposit a carpet of new sediments on the
bottom (Schroeder 1977; Schroeder ei aL 1990). Runoff
erodes the banks and may bring much terrestrial debris into
the bays and estuaries. Depending upon the season, the
freshwater inflow may cause a dramatic temperature shift.
These physical changes may also occur on the continental
shelf if the flooding is persistent.

Biological effects of flooding in the Mississippi-Ala-
bama area have been reported by Butler (1952), Butler and
Engle (1950), Christmas (1973), Dardeau el aL (1990),
Dawson (1965), Gunter (1952, 1953. 1979), Hawes and
Perry (1978), Poirrier and Mulino (1975, 1977), Russell
(1977), and Stout (1990). Marine plankton is replaced by
freshwater species within bays and sounds (Hawes and
Perry 1978; Simmons and Thomas 1962; Thomas and
Siirunons i960). Some benthic species die, and bottom
areas suffer a reduction in species abundance and diversity.
Immobile forms such as the American oyster are buried,
and large populations simply perish (Butler 1952; Butler
andEngle 1950; Stout 1990). The young of estuary-related

species, such as shrimp and the Atlantic croaker, are unable
to penetrate to the estuaries and remain on the timer
continental shelf. Adults are forced to move to deeper
waters of the middle or outer shelf (Russell 1977) . Mortal-
ity among these mobile species is not known, but certainly
there must be major losses among the eggs, larvae, and
juveniles which are barred from entering the nursery areas.
The blanket of sediments deposited is generally rich in
nutrients so that when recovery begins the following year,
biological production may be higher than normal for a few
years thereafter.

Major storms

Major storms and hurricanes frequently strike the
northern Gulf Coast, accompanied by high winds, torren-
tial rains, elevated sea levels, heavy wave action, and
extensive coastal flooding. Strong water currents are
generated out on the continental shelves, and bottoms may
be stirred to a depth of at least 80 m/260 ft (Dinnel 1988).
Impacts on coastal waters and on barrier islands and other
land forms may be dramatic. Effects of major storms on the
biota of bays and estuaries of the area have received little
attention, but they have been addressed by Dardeau et aL
(1990) and Stout (1990). Since the storms are generally
accompanied by heavy precipiuiiion, all the effects of
flooding discussed above occur. In addition, the waves and
strong water currents may cause direct physical damage to
hard bottom species such as oysters, uproot submerged
vegetation, tear up marshlands, and bury soft bottom spe-
cies (Stout 1990). There have been no reports on the effects
of major storms on the biota of the Mississippi-Alabama
continental shelf.

Hypoxic events

Waters of the bays, lagoons, and continental shelf
normally contain high levels of dissolved oxygen. How-
ever. the oxygen in the near bottom waters may be reduced
to very low levels (hypoxia) or used up completely (anoxia)
under conditions of high organic loading, rapid bacterial
decomposition, and poor circulation (often due to summer
stradfication of the water column). Seawater is rich in
sulfates, and under anoxic conditions, the sulfate becomes
chemically reduced to the highly-toxic hydrogen sulfide
gas and metal sulfides, some of which are soluble in
seawater. Depending upon the severity of the event,
hypoxia may induce avoidance, stress, or death in a few
sensitive species, or it may result in mass mortality in many
species due to asphyxiation and hydrogen sulfide intoxica-
tion.

In the Mississippi-Alabama area, hypoxia has been
reported from Lake Pontchartrain (Junot et aL 1983; Poir-
rier 1979; and Sikora and Sikora 1982), St. Louis Bay,

378

Darnell

Biloxi Bay» Pascagoula River marshes (Christmas 1973),
and Mobile Bay (Dardcau et al. 1990; Loesch 1960; May
1973; Schroeder and Wiseman 1988; and Schroeder et al
1990). In Lake Pontchartrain, low diversity in benthic
communities accompanied hypoxic conditions. Small fish
kills have been associated with hypoxia in Mississippi. In
Mobile Bay, severe summer hypoxia results in mass avoid-
ance and mass mortality of many invenebrate and fish
species- Hypoxic conditions have not been reported from
the Mississippi- Alabama continental shelf area.

Red tide outbreaks

Phytoplankton blooms are a regular occurrence in the
inshore and nearshore waters of the northern Gulf. Two
phytoplankton species produce chemical substances into
the water which aie extremely toxic to other marine life.
These arc the dinoflagellaics Gonyaulax monilata and
Ftychodisciis breve. When appropriate conditions prevail,
extremely dense populations of one of these species may
develop, giving the surface waters a reddish tint. Hence,
the occurrence is called a “red tide.” Such events liave
been recorded off most of the northern Gulf Coast. In tlie
Mississippi- Alabama area, a single red tide event was
reponed by Perry et al. (1979) due to a bloom of Gonyaulax
monilata. This bloom persisted for about two weeks until
dissipated by a hurricane. It was most intense in the
western sector of Mississippi Sound south of St. Louis Bay,
in the pass between Cat and Ship Islands, and in the upper
portions of Chandeleur Sound. Lower concentrations
extended eastward through Mississippi Sound into Ala-
bama and on ilie nearshore shelf off Horn and Petit Bois
Islands. Some of ilie Alabama blooms were apparently
heavy (Perry et al. 1979). Only a small fish kill was
reported.

Other events

The present section has documented five types of
natural catastrophic events which may affect coastal popu-
lations of the Mississippi-Alabama area Two additional
types of events may be added to this list. Prolonged
droughts reduce the amount of freshwater entering coastal
bays tmd estuaries, leading to greatly elevated salinity
levels in iJie inside waters. Populations of mobile and
immobile estuarine species with low salinity tolerances are
greatly reduced and replaced by high salinity forms. Nor-
mally excluded marine parasites and predators range freely
and exact a significant toll on oysters and other estuarine
species (Stout 1990). Anoilier event of possible signifi-
cance is the periodic intrusion of Loop Current water or of
deep Gulf water up DeSoto Canyon. However, nothing is
known about the biological consequences of such intru-
sions.

Implications of natural catastrophic events

The episodic events reported here often cause mass
mortalities which can lead to major fluctuations in popula-
tion abundances of the coastal species. Although the
primary effects are generally felt by species inhabiting the
inside waters, some of the events directly affect popula-
tions of the continental shelf. In either case, the ecological
systems of the shelf are affected through reduction in food
supplies and subsequent modification of the shelf food
chains. Except for extreme cold weather which may limit
the distribution of fropical species, none of the events is
likely to eliminate species populations from the area.
Although recovery from an event eventually takes place,
population levels may be reduced during and after an event,
and the surviving individuals probably are under some
measure of physiological stress. Thus, they would be more
susceptible to additional stress imposed by human activi-
ties. Considering the wide fluctuations imposed upon the
populations by natural events, discernment of the impacts
of specific human activities may be extremely difficult.

Homan Influences

Estuary-related species of the Mississippi-Alabama
area utilize four basic nursery areas imd appear to migrate
seaward through the passes (Figure 1). Such migratory
pathways would be consistent with adult distribution pat-
terns observed on the continental shelf (Darnell 1985). In
any event, this division of the nursery areas provides a
convenient basis for the discussion of the local human
activities and their major cnviromnental effects (Table 2).

Area 1 - Mississippi River delta through Biloxi marshes

Human activities and their effects in this area have
been addressed by Craig and Day (1977), Craig et al
(1979), Gagliano and vanBcck (1970), and Rounsefell
(1964). Leveeing of the lower Mississippi River during the
past century has deprived much of the lower delta of its
normal annual nourishment of sill. As a result, subsidence
and erosion are causing a land loss of over 14 feet per year.
The Mississippi River Gulf Outlet Canal constructed in the
early 1960s and related waterways have modified drainage
patterns and permitted saltwater intrusion well into the
productive Biloxi marshes.

Area 2 - Lake Pontchartrain through western Mississippi
Sound

Human activities and environmental effects in this
area have been discussed by Craig et al (1979), Christmas

379

380

Darnell

TABLE 2

Summary of human activities and major effects on estuarine and continental shelf environments of the
Mississippi'Alabama area.

Human Activities

Major Environmental Effects

•

Estuarine areas

Area 1. Mississiooi River Delta through Biloxi Marshes

- Leveeing of Mississippi River

- Loss of estuarine habitat

- Channelization of marshes

- Saltwater encroachment

Area 2. Lake Pontchartrain through western Mississippi Sound

- Leveeing and revetment of shorelines

- Loss of estuarine habitat

- Land development

- Reduction of submerged vegetation

- Shell dredging

- Loss of organic detritus food resource

- Dumping of municipal and industrial wastes

- Deterioration of soft bottoms

- Agricultural runoff

- Saltwater intrusion

- Eutrophication

- Creation or intensification of hypoxia

- Accumulation of chemical pollutants

Area 3. Central and eastern Mississiooi Sound

- Land development

- Loss of estuarine habitat

- Dredging and spoil placement

- Interference with natural circulation

- Dumping of municipal and industrial wastes

- Creation or intensification of hypoxia

- Chemical pollution

Area 4. Mobile Bay through Pensacola Bav

- Land development

- Loss of estuarine habitat

- Dredging and spoil placement

- Reduction of submerged vegetation

- Channelization

- Modification of circulation

- Addition of municipal and industrial wastes

- Saltwater intrusion

- Agricultural runoff

- Creation or intensification of hypoxia

- Logging

- Chemical pollution

Continental Shelf

- Overfishing

- Drastic reduction in fish populations

Catastrophism and Human Impact on Coastal Waters

381

(1973)»Englande etal. (1979), Junot etal, (l983),Poirrier
(1979), Sikora and Sikora (1982), Sikora ei. al (1981),
Stone (1980), Stone et al. (1982), and Turner et cfi (1980).
During the past four decades, the environment of Lake
Pontchartrain has been modified subsianiially by human
activities (Stone el al. 1982). Levees and stone revetments
placed along the south shore have cut off shallow wetlands
and reduced wave erosion of the marshes. As a result,
prime nursery areas have been sealed off, and the major
source of organic detritus, formerly important in the local
food chains, has been eliminated. Persistent and extensive
shell dredging ha.s reduced most of the lake bottom to a thin
clay gel incapable of supporting the weight of adult rangia
clams (Sikora ei al. 1981). Virtual elimination of rangia
and other benthic species has furtho- reduced the food
supply for estuary-related species (Sikora et al. 1981),
Disposal into the lake of large volumes of domestic sewage
by municipalities of Jefferson Parish and street runoff by
the city of New Orleans have added organic matter and
many chemical pollutants. Additional pollutants now enter
the lake from agricultural and industrial sources along the
northshore streams and from (he industrial canal. The latter
permits intrusion of a bottom saltwater wedge bringing
various heavy metals and a high oxygen demand. Hypoxic
areas or “dead zones“ now occur periodically off the
mouth of the industrial canal and extend well into the lake
(Sikora and Sikora 1982), Frequent openings of the Bonnet
CarT6 spillway during the past two decades have caused
long periods of low salinity and high turbidity and have
added fme sediments and additional chemical pollutants to
the lake. Recent surveys have shown the submerged
vegetation beds to be greatly reduced (Turner ei al. 1980).
As a result of these various human intrusions, the useful-
ness of the lake as a nursery area for estuary-related species
has been greatly diminished.

The Pearl River marshes still appear to be largely
intact, but sulfites and other chemicals from upstream
paper mills and other industry may be reducing water
quality. St. Louis Bay is affected by excess BOD loading,
and hypoxic conditioas with associated fish kills have been
reported from this area (Christmas 1973).

Area 3 - Central and Eastern IVf ississippi Sound

Human activities and their effects in this sector have
been reported by Christmas (1973) and McBec and Brehm
(1 979), The increasing human population has given rise to
considerable land development, dredging and spoil place-
ment, and dumping of municipal and industrial wastes.
Such activilies have been particularly prominent around St.
Louis Bay, Biloxi Bay, and low reaches of the Pascagoula
River, This has resulted in considerable loss of estuarine
habitat, chemical pollution, and the creation or intensifica-

tion of local hypoxic events accompanied by fish kills.
Channel dredging and spoil placement have modified cir-
culation patterns within the bays and facilitated saltwater
intrusion (Christmas 1973). Spoil banks extending across
the eastern sector of Mississippi Sound have created a
virtual dam, resulting in separate circulation patterns east
and west of the banks. Undoubtedly, these spoil banks
constitute a barrier to the movement of many marine
species as well.

Area 4 - Mobile Bay through Pensacola Bay

Human activilies and environmental effects in the
eastern sector have been discussed by Dardeau ei al.
(1990), Friend ei al. (1981), Horn (1990), Isphording and
Flowers (1990), Schroeder^/ al, (1990). and Stout (1990).
Mobile Bay has been modified extensively by land devel-
opment, dredging and spoil placement, channelization,
logging, influx of municipal and industrial wastes, and
upstream channelization and agricultural runoff into the
Mobile River (Stout 1990). Documented changes in the
bay include considerable loss of estuarine habitat and over
35 percent reduction of submerged vegetation beds.
Remaining beds are being replaced by introduced and less
desirable species (Stout 1990). Circulation patterns have
been altered by dredging and creation of spoil mounds,
ridges, and islands. Channelization has facilitated saltwa-
ter intrusion (Schroeder era/. 1990). Chemical pollution of
the waters, sediments, and oyster tissue is severe (Isphor-
ding and Flowers 1 990). Hypoxia in the bay appears to be
a natural event, but certainly it has been exacerbated by
human activities, especially through restriction of circula-
tion and the addition of oxygen-demanding chemicals
(Schroeder ei al. 1990). Perdido and Pensacola Bays are
less severely affected by human activities, but land devel-
opment has reduced estuarine habitat, and some municipal
and industrial pollution has occurred.

As noted by Darnell et al. (1976), certain river basin
modifications may have profound effects on coastal sys-
tems, Upstream damming, channelization, and leveeing of
floodplains are particularly important. In general, these
entail retention of sediments and reduction in coastal beach
nourishment. They often result in abnonnal seasonal
freshwater flow pailems in the receiving bays and estuar-
ies. They may also diminish the contribution of leaf litter
and other organic detritus from floodplains, thereby reduc-
ing the base of organic material supporting the coastal
ecosystems. Stout (1990) discussed a number of anthropo-
genic changes in river basins feeding Mobile Bay, but
specific biological effects were not documented. The
recent opening of the Tennessee-Tombigbec Waterway
could greatly influence the ecology of Mobile Bay, but no
information has been found on effects of this development.

382

Darnell

Continental sbelf

The Mississippi-Alabama continental shelf has been
modified by dredg'mg and spoil disposal, channelization,
creation of artificial reefs, and limited development of oil
and gas resources (Vittor 1985). Whatever the local
influences may have been, these activities are not consid-
ered to have caused major or widespread effects on the
environment or biota. Commercial fishing on the shelf has
been growing since the Second World War, and it has been
particularly intense during the past decades (Browder et
al. 1990). Activities include purse seining for menhaden,
trawling for demersal shrimp and fish species, and use of
hook-and-liiie (trolling, bottom fishing, and longlining) for
reef-related as well as coastal and offshore pelagic species.
The port of Pascagoula, Mississippi rqxiits the second
highest level of commercial fish landings in the nation
(U.S. Dept, of Commerce 1991). Since 1980, there has
been a dramatic increase in the harvest of reef-related and
pelagic species (Browder flf. 1990). Recreation fishing
also has increased greatly during this period, with more
fishennen using party/charter boats and private or rented
craft capable of harvesting deeper reefs and larger pelagic
species. Incidental fish species taken in the menhaden

fishery have been reported by Christmas ei al. (1960), and
those caught by bottom trawls are listed in Darnell (1985),
Darnell and Kleypas (1987), Franks el al (1972), and
McEachran ei al. (1992). Invertebrates taken by Iwuom
trawls have been reported by Defenbaugh (1976), Franks et
a/. (1972), and Soto (1972),

Intensified fishing^efforts have been accompanied by
alanning declines in the estimated sizes of remaining fish
stocks (Browder et al. 1990; Brown et al 1990). Data for
these estimates (Figures 2-5) encompass the shelf area from
west of Barataria Bay, Louisiana to DeSoto Canyon, and
are pertinent to the (^sissippi-Alabama shelf (Browder,
personal communication). Between 1960 and 1988, the
menhaden harvest more than doubled and the shrimping
effort almost quadrupled (Figure 2). Between 1972 and
1987, the biomass of bottom fishes declined from 116 kg/
ha to around 26 kg/ha, approximately 22 percent of the
original level (Figure 3). I^spUe greatly intensified fish-
ing effort, the annual red snapper harvest declined between
1979 and 1986 from 16 million to about 4.5 million pounds
(Figure 4). During the same period, the spawning stock of
king mackerel declined to about one-third of its former
level (Figure 5). Similar decreases have been observed for
Spanish mackerel as well as in offshore pelagic species

YEAR

Figure!. Trends in the harvest of menhaden and shrimping effort on the north centralGulfshelf between 1960 and 1988. (After
Browder et aL, 1990 and Brown et al.^ 1990.)

Catastrophism and Hljman Impact on OoAffTAL Waters

383

YEAR

Figure 2, Estimated biomass of bottom fishKon the north central Gulf shelf between 1972 and 1987. (After Browder etaL 1990
and Brown et aL 1990.)

YEAR

Figure 4. Commercial and recreational harvest of red snapper in the north central Gulf between 1979 and 1986. (After Browder
et oJL 1990 and Brown etaL 1990.)

INDEX

384

Darnell

Figure 5. Estimated spawniag slock of the king mackerel in the north central Gulf f^om 1979 through 1988. (After Browder
et al 1990 and Brown et al 1990.)

(including bluefin tuna, swordfish, and others). Overfish-
ing appears to be the primary reason for the declines.
However, as noted earlier, there has been a simultaneous
reduction in both the extent and quality of the nursery areas
for estuary-related species. Significani diminution in the
annual crop of estuary -related species would reduce the
level of prey species and modify food chains of the conti-
nental shelf. In turn, this would likely be reflected in food
chains supporting the larger predators just beyond the shelf
edge. Undoubtedly, both overfishing and inshore habitat
deterioration are responsible for this decline of fish stocks.

Conclusions

The Mississippi-Alabama continental shelf and re-
lated coastal waters have undergone certain long-term
changes related to Pleistocene sea level stands. On shorter
time scales, the system is subject to modificalion by natural
catastrophic events, some of which may alter population
levels over periods of one or two years. Imposed upon these

natural trends and events is the recent massive intrusion by
human aclivities which has had major effects upon the
nearshore and possibly offshore environments and popula-
tions. The contributing factors are many and complex, and
the biological data are too recent and unrefined to permit
association of each cause with its specific effects or to
understand synergistic effects of several factors acting in
combination. It is against this background thatefforLs must
be made to interpret the current ecological systems of the
Mississippi-Alabama shelf and related coastal waters.
Considering the rale of coastal habitat deterioration and
population decline, the need to develop a comprehensive
technical understanding of this complex system is most
urgent.

Acknowledgments

This study was carried out under U,S. DepL of the
Interior Minerals Management Service Contract 14-12-
0001-30346.

Catastrophism and Human Impact on Coastal Waters

385

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Vittor, Barry A. and Associates, Inc. 1985. Tuscaloosa Trend
Regional Data Search and Synthesis Study. Report to U.S.
DepL of the Interior Minerals Management Service, New
Orleans, Louisiana, Contract 14-12-0001-30048. Vol. I.
477 pp.

Gulf Research Reports

Volume 8 | Issue 4

January 1992

Long-Term Adult Population Fluctuations and Distribution of the Spop Leiostomus
xanthurus, in Mississippi

Brian D. LeBlanc

Gulf Coast Research Laboratory

Deborah L. Murphy

Gulf Coast Research Laboratory

Robin M. Overstreet

Gulf Coast Research Laboratory , robin.overstreet^usm.edu

Michael J. Maceina

Auburn University

DOI: 10.18785/grr.0804.04

Follow this and additional works at: http:/ / aquila.usm.edu/ gcr

Part of the Marine Biology Commons

Recommended Citation

LeBlanc, B. D., D. L. Murphy, R. M. Overstreet and M. J. Maceina. 1992. Long-Term Adult Population Fluctuations and Distribution
of the Spot, Leiostomus xanthurus, in Mississippi. Gulf Research Reports 8 (4): 387-394.

Retrieved from http://aquila.usm.edu/gcr /vol8/iss4/4

This Article is brought to you for free and open access by The Aquila Digital Community. It has been accepted for inclusion in Gulf and Caribbean
Research by an authorized editor of The Aquila Digital Community. For more information, please contact Joshua.Cromwell(®usm.edu.

Gu^ Research Reports, VoL 8. No. 4. 387-394, 1991

Muuiscript leceived March 12, 1991; accepted April 8, 1991.

LONG-TERM ADULT POPULATION FLUCTUATIONS

AND DISTRIBUTION OF THE SPOT, LEIOSTOMUS XANTHURVS,

IN MISSISSIPPI

BRUN D. LEBLANC*^, DEBORAH L. MURPHY’,

ROBIN M. OVERSTREET’, AND MICHAEL J. MACEINA’

^Present address: Louisiana State UrtiversUy Agricultural Center! Louisiana Cooperative
Extension Service, 8201 W. Judge Perez Drive, Chalmette, Louisiana 70043

Coast Research Laboratory, P,0. Box 7000, Ocean Springs, Mississippi 39564
^Department of Fisheries and Allied Aquaculture, Auburn University, Alabama 36849

ABSTRACT Adult specimens of thespoULeiostomusxanthurus, were collected from bayou. Mississippi Sound, and barrier
island locationa elon^ the Gulf Coast of Mississippi from November 1982 to July 1989. The mean total length of all spot
sampled in comparable gill net sets was 219 mm (± 14 standard deviation, n=4,338). Ninety-live percent of the spot were
collected in the island and sound areas, where the salinity was higher than in the bayous. Catch per unit effort was high at
island and sound atatioos in spring and autumn, with relatively few Rsh caught during the winter spawning season and summer.
The relatively high frequency of spot observed at the island stations in the autumn was probably influenced by spawning
migrations, and the high spring values may represent a combination of two abundant year classes. The two greatest yearly
collections, in 1983 and 1986, may have been influenced by sampling conditions or by environmental conditions favorable
to survival either during those years or earlier when those fxsh were postlarvac. The smallest yearly catch occurred in 1985
and may have reflected the hanh weather conditions that year.

iNTRODUenON

The spot, Leiosiomus xanthurus, is a common fish in
estuaries along the Gulf Coast of Mississippi. Several
studies on the life history of this species have been con-
ducted (e.g., Pearson 1929;HildebTand and Schroder 1928;
Hildebrand and Cable 1930; Dawson 1958; Parker 1971).
Limited information is available on long-term population
fluctuations. Kobylinski and Sheridan (1979) examined
the long-term seasonal distribution and abundance of spot
in Apalachicola Bay, Florida, and Joseph (1972) studied
populalion trends along the mid-Atlantic Coast Long-
term monitoring of adult spot may indicate fluctuations in
populations influenced by natural changes in the environ-
ment. The objectives of this study were to examine the
seasonal and annual variation in catch rales of larger spot at
island, sound, and bayou habitats in Mississippi in relation
to temperature, salinity, and reproductive influences.

Materials anp Methods

Spot samples and hydrological data were collected
monthly from November 1982 through July 1989 ai six
stations along the Mississippi Gulf Coast (Fi gure 1 ). Speci-
mens were collected with 183-m long by 2.4-m deep
monofilament gill nets* The nets were comprised of four
45J-mpanels with 7.0, 9.5 , 15 2,and20.3-cm stretch mesh
that were anached together. The net was set on the
substratum perpendicular to the shore with the smallest
mesh panel abutted to or near the shoreline. It was set in a

water depth of 0.5 to 3,0-m one hour before sunset and
retrieved four hours later.

Spot were returned to the laboratory where total length
(TL) and standard length (SL) were measured to the nearest
millimeter. Representative samples were examined to
determine the state of sexual maturity using methods
similar to those established by Overstreet ( 1983) . The date,
water temperature, salinity, turbidity, cloud cover, and sea
conditions were recorded prior to each net set. Water tem-
perature was measured to the nearest PC with a hand-held
ihennomeler. Salinity was measured to the nearest 1 ppt
with a lemperamre-compensated refractometer or conduc-
tivity meter, and turbidity was measured with a secchi disk
to the nearest cm. Most water temperatures and salinities
were taken within 1 0 cm of the surface.

Three habitat types, represented by a total of six loca-
tions, were sampled from the study area (Figure 1). Bayou
stations were located adjacent to Biloxi Bay near Fort
Bayou and Popps Ferry bridges. Sound stations were
located off the north central portion of Deer Island and the
northwest portion of Round Island. Island stations were
located on the northcentral areas of Horn and Ship Islands.

A one-way analysis-of-variance test (ANOVA) was
used to detect significant differences between mean values.
In cases where differences were detected, means were
compared using Tukey’smultiplerange test(Tukey 1953).
Mean catch values in Figures 2 and 3 are presented as
arithmetic means. The variance was proportional to mean
values, hence Iog,Q irajisformations of data were performed
prior to using the ANOVA and multiple range tests.

387

388

LeB1j\NC et al.

Linear regression was perfonned to compare the rela-
tionship between TL and SL in nonhem Gulf of Mexico
spot to that calculated by Dawson in 1958 using South
Carolina spot. Spot measured by the same bioiechnician
were compiled from a larger database consisting of spot we
collected in the same geograj^cal area as the data used for
other statistical analyses perfoamed in this study. The
regression equation was calculated using the mean TI. for
a given SL to compare to Dawson's (1958) equation
calculated from means of 5 mm class intervals.

Results

Gill nets selected larger spot; 96% of the specimens
caught were greater than 200 mmTL (Table 1). Mesh sizes
of 7.0, 9.5, 15.2, and 20.3 cm captured 95.3, 4.4, 0.2, and
0.1% of the spot, respectively, from the combination of
bayou, sound, and island stations. Mean size of spot
captured did not vary significantly among the bayou,
sound, and island stations: 2 19 mm ± 16 (n=224), 221 mm
± 16 (n=l,382), and 219 mm ± 12 (n=2,732), respectively.
The linear regression between TL and SL calculated for
specimens from the northern Gulf of Mexico spot was
TL=1.135[SL]+ 14,2,r2=0.994.

Monthly mean catch rates of adult spot varied among
bayou, sound, and island stations (Figure 2). A high
percentage (63%) of the total catch occurred in the high-to-
moderate salinities of the island stations, whereas 32%
occurred in the moderate-salinities of the sound and 5%
ocemred in the lower-salinities of the bayou. Temperature
and salinity varied among locations and seasons (Table 2),
and correlation analysis indicated a weak but significant
relationship between salinity and the number of spot caught
(p= 0.20, Table 3). A bimodal frequency of catch was
evident because relatively large numbers of adult spot were
collected ai the island and sound statiems in March-April
and in October (Figure 2). Numbers of spot captured from
the bayou siadons were relatively low during each month
throughout the study period. Although mean catch values
among years were not significantly (p > 0.05) different
within each station, the total catch values from island and
sound stations exhibited considerable annual variation,
with especially large catches occurring in 1983 and 1986
(Figure 3).

Examination of spot gonads taken hrora bayou, sound,
and island stations demonstrated that gravid females and
ripe males occurred in all three habitats (Figure 4). Most of
these individuals were observed from the island and sound
stations in October and November. A low number of ripe
males and gravid females, however, were collected from
the bayou from October to December.

Dbcxission

Townsend (1956) examined the age-length relationship
of spot in Florida using scales and length-frequencies, and
he ^termined that spot between 150-185 mm SL (TL=
187-230 mm using the equation TL=1.233[SL] + 2 from
Dawson [1958]) were priiWily age-2 fish, Parker (1971)
determined that spot t^en from the Gulf of Mexico grew
approximately 1 1 mm per month during their first year and
5,5 mm per month during their second year. Consequently,
these dka would suggest that 220 mm TL fish were
approximately 2.5 years old. Our data indicated 79% of the
spot captured were between 190 and 229 mm TL and were
probably 2 years old. Although our data represent length-
frequency distribution skewed toward larger spot ( 1 90-33 1
mm TL), pre.sumably in the 2- and 3-year age classes, we
rarely observed individual spot larger than 250 mm TL.
Only 66 out of 4,330 (1.5%) spot caught by gill net were
larger than 255 mm. Gunter (1950) similarly noted only
2% of 1 ,246 spot longer than 255 mm TL c^turcd by trawl
along the Gulf Coast. Southeast Area Monitoring and
Assessment Program (SEAMAP) data from 1982-1989 on
spot captured from stations in Gulf of Mexico offshore
waters bounded by 29°10' to 30'*10’N latitude and 87°30' to
89°00*W longitude indicated only 1% of the 1395 spot
measured were larger than 255 mm (personal communica-
tion, Kenneth Savastano, National Marine Fisheries Serv-
ice, NSTL. MS 39529 SEAMAP 1991). In addition,
Dawson (1958) summarized catch data of spot collected by
trawlers off the Atlantic Coast (Hildebrand and Schroder
1928; Hildebrand and Cable 1930) and reported 10 of
27,227 (0.04%) ^ 255 mm TL. Our data from Uie Missis-
sippi gill net study and those by others mentioned above
demonstrate the infrequency of large spot in both estuarine
and offshore areas, suggesting low survival of spot beyond
3 years of age.

Our HVSL regression equation was not used because
we did not have age data corresponding to that of Dawson
( 1958), Our regression equations and those of Dawson are
more similar for smaller spot than larger ones and are
probably not significantly different from each other in the
150-185 mm SL range. However, the lengths differ by
more than 10 mm for fish greater than 220 mm SL.

Monthly variation in catch could have been influenced
by migration, by short-term and long-term environmental
variations, by spawning periods, and by sampling. Dawson
(1958) noted the number of spot ^ 150 mm TL in his
samples from South Carolina was greater in March than in
late spring. Those relatively small catches in late spring
persisted until the start of autumn when the number in-
creased (Dawson 1 958). A similar trend was also observed
in our study for adults sampled from the island and sound

Population Fluctuations and Dettubution of Adult Spot

389

Figure 1. Locations of the six sampling areas in Mississippi: Popps Ferr Fort Bayou, l>eer Island, Round Island, Ship Island,
and Horn Island.

stations in Mississippi Hildebrand and Cable (1930) noted
a comparable trend for juvenile spot from near Beaufort,
North Carolina. The large number of adults we collected in
October (Figure 2) may have resulted in part firom a migra-
tion of the fish from inshore and coastal habitats tooffshore
spawning areas. Several studies have reported spawning
migrations Of spot during autumn based on large catches of
adults from offshore spawning grounds relative to simulta-
neous small catches from inshore areas (Hildebrand and
Schroder 1928; Pearson 1929; Gunter 1938, 1945; Dawson
1 958). We corroborate that conclusion with similar obser-
vations (Figure 2).

Large numbers of migrating spot collected from the
sound and island stations during late autumn had fully
developed gonads. As expected from earUer reports (Gunter
1938, 1945; Dawson 1958), few spot were collected during
Dccember-February . Larger mean catches of spot from the
island stations in March (mean=75) and April (mean=75)
may have been influenced by the spent (spawned) or
developing adults moving into and out of the area. These
movements may have been triggered by gradual increases
in water temperature in conjunction with consistent moder-
ate- to-high salinities that occurred during those months.
The relatively high number of spot observed for the seven-
year period at the island stations during March and April
were influenced by especially high catch rates in those

months in 1983, 1984, and 1986. C!olIections made in
March of 1983 and 1986 accounted for 67% of the total
seven-year catch for March, and 57% of the total number
for April was caught in 1983 and 1984, A review of salinity
and temperature data we collected each week during and a
few months preceding the peak collection periods revealed
no variations in conditions that would readily explain why
the above periods were more productive than intermediate
periods. Samples of a non-dispersed population during
different conditions of water and air probably contributed
to some of the variation. Pertiaps favorable environmental
conditions existed when these fish were larvae andposUar-
vae, contributing to the development of strong year classes.
If data for the months of March 1983 and 1986 and April
1983 and 1984 wwe removed firom the total data, the total
number of occurrences for the months of March and April
would not be significantly different (p > 0.05) from those of
May-September, The data indicate long-term stability of
the spot population from March to September during the
years 1983 to 1988.

Annual variation in the spot population is typical of a
fish with a relatively short life cycle (Joseph 1972). Joseph
also stated that population fluctuations could be influenced
by survival of early stages, possibly resulting from environ-
mental conditions that prevailed on the spawning grounds.
However, detrimental conditions in the nursery grounds.

390

LeBlanc et al.

TABLE 1

Total length-frequency distribution in 10 mm increments of all specimens of Leiostomus xanihurus measured
fh)m Mississippi waters on a monthly basis from November 1982 to July 1989

TL (mm)

Jan

Feb

Mar

Apr

May

Jun

Jul

Aug

Sep .

Oct

Nov

Dec

Totals

120-129

2

2

130-139

1

1

2

140-149

1

1

2

150-159

1

1

2

160-169

1

1

1

3

170-179

1

2

1

1

5

180-189

1

3

2

3

2

2

2

15

190-199

1

2

5

29

9

19

25

16

15

22

9

5

157

200-209

9

15

42

160

65

51

61

60

53

129

35

9

689

210-219

25

12

160

270

104

100

97

105

87

281

85

37

1,363

220-229

23

35

264

230

64

71

55

65

37

251

97

23

1,215

230-239

20

23

147

120

25

24

12

10

18

100

70

7

576

240-249

8

6

58

28

6

7

1

1

3

48

30

3

199

250-259

1

1

14

3

2

1

1

7

29

1

60

260-269

3

1

1

3

18

26

270-279

1

1

5

7

280-289

3

1

4

290-299

1

1

300-309

310-319

320-329

1

1

330-339

1

1

Mean saJinity (ppt) and temperature ^C) of bayou, sound, and island stations by months — November 19S2 to July 1989

Population Fluctuattons and DisTWBunoN of Adult Spot

391

s

2

cn

C

s

'w'

c

+1

+1

+1

Tl

+t

+1

Vi

+1

<s

s

cs

a

?}

CCS
+1 +1 +l

g

s

s

s

5

S

5

S

@

s

+1

+1

+1

+1

+1

+1

+1

+1

Tl

+1

+1

+1

?5

a

a

R

cn

CS

cn

cs

Si

r-*

cs

c

s

s

c

S

s

s

s

s

c

+1

+1

+ 1

Ti

+1

+1

+!

+1

+1

+1

+1

+1

+1

t

(l\

CJ

^2

s

s

cs

o

cn

On

CS

?S

lo

cs

s

VO

Q

CO

'w'

So

6

§

s

oo

$

s

6

s

$

+1

+1

+1

+1

+1

Vi

+1

+1

+1

+1

Vi

+1

+1

'cS

CO

ON

VO

VO

»n

^2

VO

r-

CO

cs

a

<s <r>

s

s

s

s

s

V— >

s

s

+1

Vi

+1

+1

+1

+l

+1

+1

+1

i2

s

?3

a

?5

a

z} +1 +1 +1 +1 +1 +1 +1 +1 +1 +• +1

cn VO m NO tri

^Standard deviation

Mean number of spot collected ^ f Mean number of spot collected

392

LeBlanc et al.

JaB Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec

Month

2. Mean number of adult spot by month from three sampling locations from November 1982 through
>89. The letter Indicates a significant difference (p > 0.05).

1983 1984 1985 1986 1987 1988

Year

Figure 3. Mean number of adult spot by year fbom three sampling locations from 1983 through 1988.

394

LeBlanc et al.

TABLE 3

Correlation matrix for salinity, temperature, localily, and number of spot collected

Salinity

Temperature

Location

No. fish
collected

Salinity

-0.07

0.74*

OiO*

Temperature

Locality

Number of Cases

492

0,003

0.03

0.32*

*1 -tailed sigmficance .001

such as extended periods of low temperature* could also
affect survival and migration of young spot into the bays
during spring, subsequently effecting the strength of those
yearclasses. For example, ourcollection of wedcly weather
data indicated that in January 1985, water temperature
plunged from a mean of 10.3X to a low of 2.5®C for at least
48 hours* with ice forming in many bayous. Also during
that year, three hurricanes moved through the area. Those
extreme weather conditions possibly dispersed or moved
many adults into offshore waters in 1985 and negatively
influenced survival of young fish in the bayous and sound.
The lower total catch of adult spot seen in 1985 may be
related to the harsh weather conditions occurring in that
year. Moreover, the relatively low numbers of larger, adult

spot in 1987 and 1988 may also have been influenced by
those same harsh conditions adversely effecting the sur-
vival of larvae or young-of-the-year fish during the winter
of 1985.

Acknowledgments

We thank Ronnie Palmer, Helen Gill, Randy Pierce,
Nate Jordan, Pat Murphy. George CantreU, Stuart Harri-
son, and Walt Brehm firom GCl^ who aided in different
aspects of this study. Others also assisted at different
periods. The study was conducted in cooperation with the
U.S. Department of Commerce, NOAA, National Marine
Fisheries Service, Grant No. NA90AA-D-IJ217.

LiT^tATURE Cited

Dawson, C. E. 1958. A survey of the biology and life hisloiy of
the spot, Leiostomus xanthurus^ with special reference to
South Carolina, Conlribidions from Bears Laboratory

28:M8.

Gunter, G. 1938. Seasonal variations in the abundance of certain
estuarine and marine fishes in Louisiana, with parU'cular
reference to life histories. Ecological Monographs 8:31 3-
346.

Guntcr.G. 1945. Studies on marine fishes of Texas. PuW/cor/o/u
of the Institute of Marine Science, University of Texas 1 :9-
190,

Gunter, G. 1950. Correlation between temperature of water and
size of marine fishes on the Atlantic and Golf Coast of the
United States. Copeia 1950(4):298-304,

Hildebrand, S. F. and L. Cable. 1930. Development and life
history of fourteen telcostoan fishes at Beaufort, North
Carolina. Bulletin of the United States Bureau of Fisheries
46:383-488,

Hildebrand, S.F. and W.C. Schroder. 1928. Fishes of Chesap-
eake Bay. Bulletin of the United States Bureau of Fisheries
43:1-366.

Joseph, RB. 1972. Thestatusofthcsciaenidslocksofthcmiddlc
Atlantic Coast. Chesapeake Science 13:87-100.

Kobylinski, G. J. and P. F. Sheridan. 1979. Distribution,
abundance, feeding and long-tcnn fluctuations of spot,
Leiostomusxanihurus, and cioakjci^Micropogonias undula-
tus, in Apalachicola Bay, Rorida, 1972-1977. Contribu-
tions in Marine Science 22: 149-161 .

Overstreet, R. M. 1983. Aspects of the biology of the spotted
seatrout, Cynoscion nebulosus, in Mississippi. Gu^ Re-
search Reports, Supplement 1:1-43.

Parker, J, C. 1971, The biology of the spot, Leiostomus
xanthurus, and the croaker, Micropogonias undulatus, in
two Gulf nursery areas. Texas A&M Sea Grant Publication
Number TAMU-SG-71-210, 182 pp.

Pearson, J. C. 1929. Natural history and conservation of the red
fish and other commercial sciacnids on the Texas coast.
Bulletin of the UnitedStates Bureau of Fisheries 44:29-2 14 .

Townsend, B.C. 1956. A study of the spot, L«/o,r/£>/7tusxnn//iw-u;r
Lacqjcdc, in AIligaiorHarhor, Florida. M,S.Thcsis,Ocean-
ography Institute, Rorida State University. 43 pp.

Tukey, J.W, 1953. Thcproblemofmultiplccomparisons. Ditto,
Princeton University, Princeton, New Jersey.

Gulf Research Reports

Volume 8 | Issue 4

January 1992

Feeding Biology, Distribution^ and Ecology of Two Species of Benthic Polychaetes:
Paraonisfulgens 2Lnd Paraonis pygoenigmatica (Polychaeta: Paraonidae)

Gary R. Gaston

University of Mississippi

Jerry A. McLelland

Gulf Coast Research Laboratory

Richard W Heard

Gulf Coast Research Laboratory, richard.heard^usm.edu

DOI: 10.18785/grr.0804.05

Follow this and additional works at: http:/ / aquila.usm.edu/ gcr

Part of the Marine Biology Commons

Recommended Citation

Gaston, G. R., J. A. McLelland and R. W. Heard. 1992. Feeding Biology, Distribution, and Ecology of Two Species of Benthic
VolychsLetes: Paraonisfulgens and Paraonis pygoenigmatica (Polychaeta; Paraonidae). Gulf Research Reports 8 (4): 395-399.
Retrieved from http:// aquila.usm.edu/gcr/vol8/iss4/ 5

This Article is brought to you for free and open access by The Aquila Digital Community. It has been accepted for inclusion in Gulf and Caribbean
Research by an authorized editor ofThe Aquila Digital Community. For more information, please contact Joshua.Cromwell^usm.edu.

Gu^Research RepoHs, VoL 8, No. 4, 395-399, 1992

Manuscript Received July 16, 1992; accepted August 10, 1992

FEEDING BIOLOGY, DISTRIBUTION, AND ECOLOGY

OF TWO SPECIES OF BENTHIC POLYCHAETES: PARAONIS FULGENS

AND PARAONIS PYGOENIGMATICA (POLYCHAETA: PARAONIDAE)

GARY R. GASTONS JERRY A. MCLELLAND*, AND
RICHARD W. HEARD'

J Department of Biology, University of Mississippi, University, Mississippi 38677
^Gulf Coast Research Laboratory, P.O. Box 7000, Ocean Springs. Mississippi 39S64

AB^RACT Paraonis fulgent and Paraonis pygoenigmatica inhabit sandy Ultoral and subliltoral sediments of the northern
Gulf of Mexico and U.S. East Coast, but seldom overlap in distribution. The purpose of this study was to compare the feeding
ecology and distribution of these species. We analyzed distributions and gut contents of Gulf of Mexico specimens and found
that P. fulgent inhabited substrates with slightly more silt and clay than those inhabited by P. pygoenigmatica. Although
Paraonisfulgens ingested more diatoms than P. pygoenigmatica, this distinction likely resulted from habitat differences, not
selective feeding. Previous studies suggested that P.fulgens fed selectively on diatoms only.

Introduction

The genus Paraonis Cenuti, 1909, contains just two
species, Paraonis fulgens and Paraonis pygoenigmatica.
Paraonis fulgens is distributed worldwide in shallow estu-
arine and marine habitats (Strclzov 1973). However, P.
pygoenigmatica occurs only in coastal waters of the U,S.
Atlantic (Jones 1968) and northern Gulf of Mexico (Gaston
1984). Both species inhabit sandy substrates; P.fulgens
generally inhabits littoral and sublittoral sediments and P.
pygoenigmatica lives in slightly deeper water. Apparently,
only P.fulgens occurs in dense populations (Gaston 1984).
Ro^ (1971) and Risk and Tunniclif fe ( 1978) reported that
P.fulgens fed solely on diatoms, but little else is known
about the feeding ecology of these species.

The purpose of this study was to compare the feeding
ecology and distribution of these two species in northern
Gulf of Mexico habitats. We investigated ingested foods to
determine if differences m food accounted for their distinct
distributions.

Materials and Methods

Most of the specimens examined for this study were
collected by Gulf Coast Research Laboratory (GCRL)
personnel off Biloxi, Mississippi, Ship and Horn Island,
Mississippi and Perdido Key, Florida (Rakocinski et al.
1991, McLelland and Heard 1991). Additional specimens
were collected as pan of a Bureau of Land Management
(now M inerals Management Service) Gulf of Mexico Outer
Continental Shelf baseline study conducted during 1975-
1981 (Uebelacker and Johnson 1984); along the Florida
Gulf Coast by Mote Marine Laboratory personnel; off
Padre Island, Texas (Rabalais and Flint 1983); in Pelican
Bay, Alabama during the EPA Environmental Monitoring

and Assessment Program (EMAPO; and off Alabama, Texas,
and the Middle Atlantic Bight by the author (Gaston 1985,
1987).

Percentage of ingested food was estimated under
compound microscopy as percentage represented by dia-
toms (estimated volume) versus percentage represented by
detritus. None of the guts examined were entirely empty.
Statistical analyses involved aT-test for significant differ-
ences (a = 0.05) between species (when the Bartlett Test
indicated homogeneity of variables) using arcsine-trans-
formed percentage data (percentage of food represented by
diatoms).

Results and Discussion

Both P.fulgens andP, pygo enigma! tea inhabited sandy
substrates with similar seduneni characteristics (Table 1).
Paraonisfulgens was most abundant in sandy intertidal and
shallow subtidal habitats with 96-99% sand (i.c., less than
4% silt and clay) as indicated in Table 2. Paraonis pygoe-
nigmatica inhabited slightly deeper-water habitats with
2-3% sill and clay (Tables 1 and 2).

Paraonis fulgens was one of the most abundant mac-
robemhic organisms collected in the shallow waters off
Perdido Key, Florida and Horn and Ship Islands, Missis-
sippi. Their numbers peaked at both Ship Island and Horn
Island during August 1990 at over lO.OOO/m^ (Table I).
Colonization of the sediments by settling juveniles appar-
ently occurred during summer. Paraonis pygoenigmatica
was seldom as abundant as (Table 1). It occurred

from subtidal to outer continental shelf waters, and seldom
was collected at the same sites as P.fulgens (Table 1). In
Perdido Key, P. fulgens inhabited sandy sediments be-
tween the beach and sand bar just offshore (0 - 5.5m) and
P. pygoenigmatica occurred beyond the sand bar (5.5 -
5.8m) as shown in Table 2.

395

396

Gaston

TABLE 1

Selected distribution records and population densities of Paraonisfulgens and Paraonis pygoenigmatica in the
Gulf of Mexico and southern Florida Atlantic Coast Depths in meters.

Site

Depth(s)

Sediments

Denaty/m^

Source

Paraonisfulgens

Horn Island, MS

<1.0-30.0

>97% sand

1500-10,000

GCRL*

Ship Island, MS

15.0-30.0

>96% sand

2000-12,000

GCRL*

Biloxi Bay, MS

0.1-0.2

sand

<500

Matulewski **

Pelican Bay, AL

2.4

sand

<10

Gaston **

Mobile Bay, AL

2.4-3.6

sand

20-800

Gaston **

Mobile Bay, AL

4.0-6.5

sand

<500

Johnson 1980

Perdido Key, FL

1.0-5.5

sand **

500-8000

GCRL*

FL Continenlal Shelf

19.0-20.0

fine sand

<10

Gaston 1984

Marco Island, FL

0.5-1.0

sand

<50

Milligan **

Padre Island, TX

0.1-2.0

fine sand

mean = 200

Rabalais et al. 1983

Paraonis pygoenigmatica

Ft. Lauderdale, FL

10.0

sand

Milligan **

Perdido Key, FL

1.0-5.5

sand ***

<50

GCRL*

off Tampa, FL

20.0-24.0

fine sand

10-60

Gaston 1984

* Data from two Gulf Coast Research Laboratory studies (McLellaitd and Heard, 1991; Rakocinski et al. 1991).

** UnpubDshed data: K. Maiulewski (University of Southern Mississippi), G. Gaston (University of Mississippi),
M. Milligan and A. McAllister (Mote Marine Laboratory), EMAP-NC 1991 Gulf of Mexico estuary survey.

*** See Table 2 for more sediment data

Paraonis fulgens is a subsurface detriti vore. It feeds in
tight spirals beneath the sediment surface, and moves
upward or downward as it completes a feeding spiral (Risk
and Tunnicliffe 1978). Previous research indicated thatP.
fulgens selectively ingested benthic diatoms (Roder 1971,
Risk and Tunnicliffe 1978), whereas other paraonids feed
on drift debris or detritus and are probably non-selective
(Fauchald and Jumais 1979, Gaston 1983). Roder (1971)
noted dial specimens he examined contained no detritus,

only dialoms. Although diatoms were ingested by many
specimens that we examined (Table 3), diatoms were
apparently ingested passively with other detritus. Most of
our specimens were filled with detritus, which included a
few dmoflagellate and diatom tests. It did not appear that
diatoms and/or dinoflagellates were selectively ingested;
most ingested diatoms were small, unlike those observed
by Roder (1971), and there were several diatom species
represented. Furthermore , diatoms seldom composed even

Feeding Ecology of Paraonis sit.

397

TABLE!

Habitat and sediment characteristics of sites where Paraonis fulgens (F/) and Paraonis pygoenigmaSka iP.p,)
were coDected at Perdido Key» Florida. Abundances; C = Common (>1000 m'^); R = Rare (<20 m‘^). From
Rakocinski et aL (unpublished data).

Station

Abundance

P/./P.P.

Depth (m)

% Sand
(md. dia)

% Sili/clay

1. Littoral *

C -

1.0

98.8 (0.29)

1.2

2. Littoral

C -

2.0

99.6 (0.25)

0.4

3. Longshore bar

c -

1.0

98.9 (0.21)

1.1

4. Sublittoral **

c -

2.1

99.6 (0.20)

0.4

5. Sublittoral

c -

3.7

98.6 (0.20)

1.4

6. Sublittoral

c -

4.3

98.7 (0.28)

1.3

7. Sublittoral

C R

5.5

99.5 (0.30)

0.5

8. Sublittoral

- R

5.5

99.7 (032)

0.3

9. Sublittoral

- R

5.5

97.4 (0.28)

2.6

10. Sublittoral

- R

5.5

96.7 (0.25)

3.3

11. Sublittoral

- R

5.8

97.7 (0.24)

2.3

Littoral = between beach and longshore bar.

** Sublitioral = outside the longshore bar.

half of the matter ingested (Table 3), and many lacked
chlOTOphyU. indicating that they were probably empty
frustules when ingested.

Like many paraonids. P. pygoenigmaiica is a subsur-
face detridvore (Fauchald and Jumars 1979, Gaston 1983).
It is less commonly collected than P.fulgens, as evidenced
by the few numbers of specimens on Table 3. Whether or
not it feeds in spirals is unknown. Gut contents of speci-
mens collected in Perdido Key and in the Middle Atlantic
Bight were filled with detritus, but included fewer diatoms
than were ingested by P. fulgens (P < 0.01 . Table 3),

These two species of Paraonis are members of the
sandy littoral and sublittoral communities of the Atlantic
and Gulf of Mexico. Their communities were numericaUy
dominated by crustaceans in the northern Gulf; off West
Ship Island, Mississippi the dominant taxa were an am-
phipod (Lepidactylus sp.), an isopod {Exosphaeroma dimi-
nu/um), acumacean {Spilocuma watlingi\ two polychaetes

{P, fulgens and Dispio undnaia\ and a tanaid {Kalliapseudes
sp.) (Rakocinski et al. 1991). A similar trophic group
dominated their communities off Mobile Bay, Alabama
and Perdido Key, Florida, including haustoriid amphipods,
the isopod {B. diminutum), and (he same polychaetes (Gaston
1986, R 2 kkocinsld et al„ manuscript). These dominants
were collected in habitats of both species of Paraonis al
Perdido Key, even though P. fulgens and P. pygoenig-
matica seldom were collected together (Table 2),

The sediments where P, fulgens was most abundant
were more dynamic than those inhabited by P. pygoenig-
matica. Perhaps more diatoms were buried in the dynamic
sediments and became detritus for grazing P. fulgens, as
suggested by Risk and Tunnicliffe (1978). Unfortunately,
the environmental and gut-contents data provided Little
additional information on the distinction of the habitats of
these two species. Apparently, P. fulgens feeds on detritus
that includes diatoms, but P, pygoenigmatica does noL

398

Gaston

TABLE 3

Gut-contents data of two species of Paraonis from three locations in the Gulf of Mexico. Percentage values
are percent volume, estimated to the nearest 5%. Specimens collected in different samples are presented as
separate data.

Site

Number examined

% Diatoms

% Detritus

P. futgens

Horn Island, MS

6

10

90

Horn Island, MS

2

25

75

Horn Island, MS

1

50

50

Perdido Key, FL

2

<5

95

Perdido Key, FL

4

10

90

Perdido Key, FL

7

25

75

Perdido Key, FL

4

50

50

Pelican Bay, AL

1

<5

95

Totals/Means

27

21.1

78.9

P. pygoenigmatica

Perdido Key, FL

10

<5

>95

off Tampa. FL

2

0

100

Totals^eans

12

1.6

98.4

Thus, even though these two species are closely related,
their feeding biology is distinct We propose that dissimilar
habitats, and the abundance of diatoms in those habitats,
account for their distinctive feeding biology. P. futgens
forages for detritus (which may be diatom-laden detritus)
in dynamic sediments of littoral and subliiioral zones,
while P. pygoenigmatica is associated with less diatoma-
ceous detritus in lower energy habitats beyond the swash
zone.

Acknowledgments

We thank K. Matulewsld (GCRL) for help with speci-
men collections and C. Rakocinski (GCRL) for help with
data pioccssing. A. McAllister and E. Fenstermacher
reviewed the manuscript and helped with specimen dissec-
tions. We thank M. Milligan (Mote Marine Laboratory) for
providing specimens.

Feeding Ecology of Paraonis spp.

399

Literature Cited

Fauchald, K. and R A. Jumais, 1979. The diel of worms: a study
of polychaelc feeding guilds. Oceanogr, Mar. Biol. Rev. 17:
I93-2S4.

Gaston, G.R. 1983. Benthic Polychactaof the Middle Atlantic
Bight: feeding and distribution Ph.D. Dissertation. College
of William and Mary. Williamsburg, Virginia. 186 pp.

Gaston, G.R, 1984. Family Paraonidae Cerruti. 1909. Volume
I, Chapter 2 ini Polychaeta of the Northern Gu^ of Mexico,
B.A. Vittor and P.G. Johnson (eds.). Vittor and Associates,
Publications, Mobile, AL.

Gaston, G.R. 1985. Effects of hypoxia on macrobcnlhos of the
irmcr shelf off Cameron, Louisiana. Estuar. Coastal Shelf
Sd. 20:603-613.

Gaston .G.R. 1986. Mocrobenthic oomniunity study of potential
m arine pipeline routes inMobile Bay and offshore Alabama.
Report to Exxon Company, New Oilcans, Louisiana.

Gaston, G.R. 1987. Benthic Poly chaela of the Middle Atlantic
Bight: feeding and distribution. Mar. Ecol. Prog. Ser. 36:
251-262.

Johnson, P.G. 1980. Seasonal variation in benthic community
structure in Mobile Bay, Alabama. M.S. Thesis. University
of Alabama in Birmingham. 1 18 pp.

Jones, M.L. 1968. Paraonis pygoenigmatka new species, a now
annelid from Massachusetts (Polychaeta; Paraonidae). Pwc.
Biol. Soc. Wash. 81:323-334.

McLcUand, J.A.andR.W, Heard. 1991- AsUidyofinterlidaland
shallow water macroinvextebrate populations exposed to an
oil spill on Horn Island. Mississippi. Report to National Park
Service, U.S. Dept of the Interior. CA-5320-8'8001, CA-
5320-0-9004.

Rabalais, S.C. and R.W, Flint. 1983. DCTOC-l effects on
intertidal andsubtidal infauna of south Texas Gulf beaches.
Contrib. Mar. Sci, 26:23-35.

Rakocinski, C,, R.W. Heard, T, Simons, and D. GlcdhilL 1991.
Macroinvcrtcbratc associations from beaches of selected
barrier islands in the northern Gulf of Mexico: important
environmental relationships. Bulb Mar. Sci. 48: 1-13.

Risk, M.J. and VX TunnicUffc. 1978. Intertidal spiral burrows:
Paraonis /ulgens and Spiophanes wigleyi in the Minas
Basin, Bay of Fundy. /. Sed. Petrol. 48: 1287-1292.

Roder, H. 1971. Gangsysteme von Levinsen

1883 (Polychaeta) in okologischcr, ethologischer und akuo-
palaoniologischcr Sicht. SenckenbergUma Maritima 3:3-
51.

Stielzov,V.E. 1973. Polychaete worms of the family Paraonidae
Cerruti, 1909 - Pblychaeta Sedentaria. Akad. Nauk. SSSR,
Leningrad. 170 pp.

Ucbclackcr, J.M. and P.G. Johnson. 1984. Taxonomic guide to
the polychaetes of the northern Gulf of Mexico. Barry A.
Vittor & Assoc., Mobile, Alabama. 7 Vols.

Gulf Research Reports

Volume 8 | Issue 4

January 1992

Closed System Culture ofPenaeus vannamei

John T. Ogle

Gulf Coast Research Laboratory

Jeffrey M. Lotz

Gulf Coast Research Laboratory, jefF.lotz(^usm.edu

DOI: 10.18785/grr.0804.06

Follow this and additional works at: http:/ / aquila.usm.edu/ gcr

Part of the Marine Biology Commons

Recommended Citation

Ogle, J. T. andj. M. Lotz. 1992. Closed System Cxilture ofPenaeus vannamei. Gxilf Research Reports 8 (4): 401-413.
Retrieved from http;//aquila.usm.edu/gcr/vol8/iss4/6

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GuJf Research Reports. Vol. 8, No. 4. 401-413, 1992

Maouflcript rcceived June 12, 1991; accepted August 1, 1991

CLOSED SYSTEM CULTURE OF PENAEUS VANNAMEI

JOHNT.OGLEANDJEFFREYM.LOTZ

Gulf Coast Research Laboraiory, P.O. Box 7000. Ocean Springs, Mississippi 39564

ABSTRACT Penaeus wannamei were cultured utilizing three different closed recirculating seawater systems. The
Hist system used biological filtration for water treatment. The second system utilized both physical and chemical
filtration, but no biological filtration. The third system used a combination of biological, physical, and chemical
filtration . Shrimp gro wlh w as monitored for a 1 2-wcek.pcriod for each system . Shrimp ftoin the biological filtration
system had a growth rate of 0.82 g/wk and an overall survival rate of 45.6%. Shrimp from the closed system which
used physical and chemical filtration had a growth rate of 0.99 g/wkand a survival ratcof 29.2%. In the third system
which combined both types of filtration, the shrimp growth rate averaged 0.65 g/wkand the survivalrate was 56.9%.

Introduction

The intensive culture of marine shiimp has been of
interest since shrimp fanning first began in the late 1960s.
Initial grow -out trials at the Bureau of Commercial Fisher-
ies in Galveston, Texas began inraceway tanks in I972and
continued into 1980. One commercial venture. Intensive
Culture Systems (Summerland Keys, Florida), attempted
to grow shrimp in intensive closed systems as early as 1974.
One of the largest attempts at closed system marine shrimp
culture was by Aquabiotics (King James, Inc., Park Forrest,
Illinois) in 1979. Currently, there arc at least three com-
mercial ventures working with closed systems for the
culture of marine shiimp: the Stillman Ranch and Red
Ewald in Texas, and Aquamar in Florida. Two research
facilities, the University of Texas Marine Science Institute
(Port Aransas. Texas) and the Gulf Coasi Research Labo-
ratory (Ocean Springs, Mississippi) are researching closed
system culture on a small scale.

Materials and Methods

Three grow-out trials were conducted during 1989.
The first two trials were run simultaneously and shrimp
growth in the two unreplicaicd systems was compared.
Shrimp system 1 (SS- 1 ) utilized biological filtration, while
shrimp system 2 (SS-2a) utilized both physical and chemi-
cal filtration with no biological filtration. The third trial,
shrimp system 3 (SS-3a), utilized a combination of biologi-
cal, physical and chemical water treatment. All systems
were housed in a passively-heated greenhouse.

Shrimp System 1. SS-l (Fig. I) consisted of a 1.8 m
X 7.3 m X 0.28 m reciangular raceway with an area of 1 3.28

and a volume of 5.74 m^. Wastewater was collected in

{Use of trade names does not imply endorsement.)

a 5,08 cm diameter PVC slotted pipe nmning the length of
the tank and passed by gravity flow through the end wall
into a settling tank. The settling tank, 0.93 m x 1.85 m x
0.61 m, was packed with a plastic media, Norpac (Jaeger
Products, Inc., Spring, Texas). A chamber at one end pro-
vided room for a submersible sump pump (Little Giant 6CI ,
MR #5069 13 , Oklahoma City, Oklahoma) which supplied
water through a 3.81 cm PVC pipe .split into three distribu-
tion pipes. Two of the pipes were plumbed into the lop of
a pair of protein skimmers, 0. 15 m in diameter and L8 m
high, sparged with compressed air. Water exiled the
bottom of the skimmers and was elevated by gravity to two
rotating spray bars. Water from the spray bars irrigated two
aerobic trickling filters.

The fillers were constructed of a synthetic spawning
matmaierial (Anderson Bait Company, Lonoke, Arkansas)
wound in a spiral around corrugated fiberglass panels
whichrcstedon top of a biological filter. Effluent from the
spiral filters trickled into the top of the submerged trickling
biological filter. The biological filter was constructed in a
0.96 m X 1.9 m X 0.2 m fiberglass lank. Plastic egg crate
louvering suspended off the tank bottom with 2.54 cm di-
ameter PVC pipe served as a support for clam shell and a
media of ground PVC. Water flowed down through the
media and out a bottom drain into the raceway. A 5. 1 cm
diameter PVC standpipe maintained water in the sub-
merged trickling biofilier at a depth of 17.8 cm. The third
pipe from the pump was directed to a spray bar running the
length of the raceway and suspended above the water.

Additional circulation was provided by a Vi hp Jacuzzi
pump (Model 5L, Little Rock, Arkansas). The intake pipe
was placed inside acircular basket perforated with 1.27 cm
square holes and covered with screen. The basket was used
to prevent shrimp from being aspiratedby thepump. Water
passed through the basket into a submerged 2.54 cm diame-
ter spray pipe Tunning the length of the raceway. A venturi
injector (Sophisticated Systems, Palm Harbor, Florida)

401

Figure I . Cross-section diagram of SS-1 utilizing biological filtration: P - pump, V - venturi injector, R - raceway,
ST - settling tank, TK • trickling filter, SF - spiral filter, SB - spray bar, SK - skimmer, A - site of air injection, S -
site of sample collection.

was instaDed in the supply pipe lo oxygenate the water.
Total area of the system including fillers was 16.9 and
total volume was 6.6 m^. Ten net substrates, 30.5 cm x 152
cm with 0,6 cm mesh openings, were secured across the
culture lank lo provide shelter. Water flow for SS- 1 was 28
gpm with a turnover rate of 23 limes per day (Table 1).

In week 11, water lost throughout the study was re-
placed (80% water change) and the system was cleaned.

Shrimp System 2a. A rectangular raceway, 1.8 m x
7.3 m X 0.6 m, a lamellar separator and reservoir box
containing six protein skimmers were the main compo-
nents of SS-2a(Rg. 2). A 7.6 cm slotted PVC pipe running
the length of the raceway collected wastewater. Tlie water
was pumped (Little Giant, 6CI MR #506913, Oklahoma
City, Oklahoma) into the bottom of a lamellar separator
inside a 0.76 m x 2. 1 m x 0,9 1 in lank elevated 0,2 m above
the floor. Water flowed up though the angled lamellar
media and cascaded into the reservoir box, 1 .0 m x 0.91 m
X 1.3 m, wliich contained the six protein skimmers.

The protein skimmers were constructed of PVC pipe
10.1 cm in diameter and 1.6 m in length. A 2.54 cm hole
located 1.1 m from the bottom of the skimmer allowed

water to flow into the skimmer pipe. Water flowed out the
bottom of the skimmer through a 5.08 cm diameter PVC
pipe connected lo a manifold constructed of 30.48 cm PVC
pipe. A 5.08 cm diameter PVC pipe in one end of the
manifold connected through the sidewall of the reservoir
box to the intake of a Jacuzzi lAhp pump (Model 5L. Little
Rock, Arkansas), Water was directed Uuough a venturi as-
pirator (Sophisticated Systems, Palm Harbor, Florida) into
a submerged spray bar nmning the length of the raceway.
Activated air (ozone) generated from a UV unit (Water
Management, Inc., Pascagoula, Mississippi) was sparged
into the six protein skimmers and injected inlo the venturi.
Ten 1.5 m X 0.30 m nets were hung vertically across the
culture tank to provide additional substrate for shrimp.
Water flow for SS-2a was 32 gpm with a turnover rate of 20
times per day. Tire system had a total area of 13.5 and
a total volume of 8.7

Shrimp System 3a. SS-3a was constructed later in
1989 by utilizing some components from the other two
systems as noted. The system consisted of four circular
tanks, 1 .8 m in diameter, 66,0 cm in depth with a capacity
of 2,273 L each (Fig. 3). A screened standpipe allowed

Closed System Culture of P. vannamei

403

TABLE 1

Physical and biological parameters for three closed systems.

System

SS-1

SS-2a'

SS-3a

Area

total

16.9

13.5

12.2

filter %

213

11.9

14.9

ratio f/i*

0.27

0.13

0.17

Volume

total m^

6.6

8.7

10.1

gallons

1752

2303

2767

filter %

13.5

30.5

33.1

ratio C/f'

0.15

0.44

0.49

Water

flow (gpm)

28

32

24

tumover/day

23

20

13

exchange %/wk

7.1

1.8

3.3

Stocking

number

3300

3300

4480

tank

#/m^

248

277

430

#/m^

575

500

663

system

195

244

367

#/m^

497

378

444

Harvest 12 wk

mean size (g)

11.60

13.02

8.09

growth g/wk

0.82

1.00

0.65

survival %

45.6

29.2

56.9

production kg

12.5

17.4

20.7

kg/m^

1.9

2.0

2.0

gal/lb

118

73

88

ratio of filler to tank

Figures. A cross-section diagram ofSS-Sa utilizing chemical, physical and biological water treatments: L -lamellar
separator, P - pump, SK - skimmer, BF - biological filter, R - reservoir tank, T - culture tank, O - site of ozone
injection, S - site of sample coUection.

Closed System Culture of F. va^namei

405

water to flow out of the tanks through 5.08 cm center drains
where it was directed to Uie bottom of the lamellar separa-
tor used in SS-2a. Water flowed up tlie mclmed media of
the separator and overflowed mio a pump chamber. The
pump chamber, a 81 .3 cm x 7 1 .1 cm x 81 .3 cm fiberglass
tank, had a 3.81 cm PVC bulkhead fitting in the sidewall
which connected directly to a lip Jacuzzi pump.

The pump supplied water to the top of a 30.5 cm
diameter,2.4 m tall tank with a conical insert having a 5.08
cm center hole, all of which served as a protein skimmer.
Water exited the bottom of the skimmer and entered the
bottom of a biofillcr. The biofdler was constructed of a
conical-botlomed 0.029 m cylindrical tank 1 .5 m tall. A
diffusor plate with holes on 2.54 cm centers was placed at
the lop of the conical part of the filter tank. Gravel placed
on top of the diffusor retained the carbon used as a filter
media. Water flowed up through the filter, which caused
some fluidization, where it was collected in an overflow
trough and directed to a reservoir chamber used in SS-2a.
Water entering the reservoir flowed through a cylindrical
plastic perforated basket used in SS- 1 containing a bonded
filter malting (Fritz Aquaculture, Dallas, Texas). Four
separate bulkhead fittings exited the sidewall of the reser-
voir and directed the water back to the culture tanks.

Flow rates were controlled by valves. Excess water
from the reservoir was directed by an overflow pipe back to
the pump chamber. Ozone was sparged into the skimmer,
the reservoir and directly into each of die four culture tanks.
Total area for SS-3a was 12,2 and total volume was
10. 1 m^. The flow rate was 24 gpm with a turnover rate of
13 times per day .

Hatchery-reared Penaeus vannamei postlarvae, cul-
tured to a minimum size of 1 g, were hand counted into the
three systems. SS-1 and SS-2a were stocked in February
1989 with 3,300 shrimp each. SS-3a was stocked in August
1989 willi 1 , 1 40 shrimp per tank for a total of 4,480 shrimp.
Salinily varied from 16 to 20 ppt and temperature ranged
from 23to28'’C.

Shrimp were fed continuously utilizing automatic Zeigler
baby belt feeders (Gardners, Pennsylvania). Rangen (Buhl,
Idaho) and Ziegler (Gardners, Pennsylvania) aniTicial shrimp
grower feeds were fed to shrimp at a rate of 5% body
weight. A sample of no less than 25 animals were individu-
ally weighed each week to the nearest 0.01 g on an
electronic balance. Feeding rates were adjusted weekly for
all systems. Shrimp growth was monitored for a period of
12 weeks, at which tune tanks were harvested and survival
rales deiennined. Water quality values for pH and ammo-
nia were determined weekly by using an Orion pH/ion
analyzer. Nitrite and luirate were determined by standard
methods (EPA 1983) each week. Sodium carbonate was
added as needed in an attempt to regulate pH. Water was
added only to replace loss and after occasional flushing of
the lamellar separator. In addition, total hetrotrophic

bacteria were determined by plating on marine agar and
counting colony-fonning units. Presumptive Vibrio col-
ony- fonning units cultured on TCBS agar were counted
weekly for SS-I and SS-2a. Additional weekly water
quality samples were taken from the inflow and outflow for
each filter component of SS-2a and SS-3a for three weeks
prior to the 12-week inventory. After the systems were
modified, additional samples wore taken for three weeks
prior to the 20lh-week harvest. The difference between
values for inflow and outflow for each component was
calculated and expressed as percent instantaneous change
for ammonia and for nitrate.

After the 1 2- week period when shrimp were harvested ,
SS-2a and SS-3a were modified and labelled as SS-2b and
SS-3b, respectively. Additional water quality samples
were analyzed from the individual filter components.

For SS-2b, six 0.16 1.5 m high skimmers were

plumbed directly into the lamellar outflow (Fig. 4). Water
fiowed down though the skimmers, out llie bottom and was
directed back up over the side of the reservoir chamber.
SS 3b (Fig. 5) was modified by addition of a hydrocyclone
(Flo Trend Systems, Inc, Demon, Texas) for particulate re-
moval. The hydrocyclone was plumbed inline between the
pump and the skimmer. The 30.48 cm diameter skimmer
was replaced with a 45.72 cm diameter cylinder. The
biofilter was replaced with a flat bouomed cylinder with a
conical top 61 cm in diameter. Water exited the top of the
filler through a 5.08 cm diairieier P VC pipe which directed
the water though the sidewall of the reservoir.

Results

Results for the three systems were significantly differ-
ent. Shrimp growth averaged 0.82, 0.99 and 0.65 g/wk and
survival rales for the 12- week period were 45.6%, 29.2%
and 56.9% for SS- 1 , SS-2a and SS-3a, respectively. Total
production was 12.5, 17.4 and 20.7 kg or 1.9, 2.0, and 2.0
kg/m^ for SS-1, SS-2a and SS-3a, respectively (Table 1).
Water varied in pH from 7. 1 2 to 7.87 for SS- 1 , 7.22 to 7.93
for SS-2a, and 7,33 to 7.80 for SS-3a (Fig. 6). Total
ammonia flucutated from 0.01 to 0.254 ppm for SS-1,
0.094 to 0.455 ppm for SS-2a, and 0.083 to 1.06 ppm for
SS-3a (Fig. 7). Nitrite flociutated from 0,098 to 2.12 ppm
for SS-1, 0.074 to 2.35 ppm for SS-2a, and 0.063 to 1.38
ppm for SS-3a (Fig. 8). Nitrate increased from 0.1 18 to
55.3 ppm for SS- 1 , varied between 1 .35 to 23 .6 ppm for SS-
2a, and ranged from 4.79 to 12.5 ppm for SS-3a (Fig. 9).
Nitrate was actually reduced in SS-2a and SS-3a, A com-
parasion was made of tlic water quality data for systems 2a,
2b, 3a and 3b for the 'mdividual filter components. The
pump removed anunonia from all systems ranging from
3.2% to 13.5%. The lamellar separator was also removing
ammonia except in SS-3a where ammonia was added. The
skimmer for SS-2a and 2b also increased the ammonia

Figure 4. A cross*sectioQ diagram of SS-2b after modification: R - raceway, P > pump, L • lamellar separator,
SK - skimmer, RV - reservoir tank, V - venturi injector, O - site of ozone injection, S - site of sample collection.

Figure 5. A cross-section diagram of SS-3b after modification: L - lamellar separator, P - pump, C - hydrocyclone
particle separa tor, SK - skimmer, BF - biological filter, R - reservoir tank, T - culture tank, O - site of ozone injection,
S - site of sample collection.

Parts per Million

Closed S ystem C ulture of P. vannamei

407

O 1 234567B9 10 1112

WEEK

LEGEND

SS 1 BIOLOGICAL

SS 2 OZONE

SS 3 COMBINATION

Figure 6. Graph of pH monitored over a 12 -week period for three shrimp systems*

LEGEND

SS

1

BIOLOGICAL

„ SS

2

OZONE

SS

3

COMBINATION

Figure 7* Graph of total ammonia monitored over a 12-week period for three shrimp systems.

Parts per Mon Parts per Million

408

Ogle andLooz

LEGEND

SS 1 BIOLOGICAL

SS 2. OZONE

SS 3 COMBINATION

Figure 8. Graph of nitrite monitored over a 12-vFeek period for three shrimp systems.

LEGEND

SS 1 BIOLOGICAL

SS 2 OZONE

SS 3 COMBINATION

Figure 9. Graph of nitrate monitored over a 12-week period for three shrimp systems.

Closed System Culture of P. yannamei

409

concentration, while the skimmer for SS-3a and 3b reduced
the ammonia level. Ammonia was removed by the venturi
in SS-2a and by ihe filter in SS-3a (Table 2). Nitrate was
removed at a rate of 0^6 to 0.81 ppm from all systems
except SS-2a, Mostremoval of nitrate from the systems oc-
curred in the lamellar separator (Table 3).

The hetrotrophic bacterial levels remained about the
same throughout the study for both SS-I and SS-2a (Fig.
10). Levels were basically the same for Ihe two systems
until week 11, when SS -1 was cleaned and a 80% water
change was made. Although the bacterial level increased
in SS-2a for this week, SS-l levels decreased below the
initial level. Numbers of presumptive Vibrio spp, de-
creased slightly for both systems through week 4 and in-
creased through week 11. In all but one sample, (week 4),
counts for the ozonated system were higher than for the
biological system (Fig. 11). During two of the weeks,
counts were considerably higher than initial levels.

Discussion

Growth of P, vannaniei in the closed systems was
consistent with rates recorded for the species in various
systems. Under experimental conditions, growth as high as

3 g/wk have been reported (Ogle 1992). At higher stocking
densities, Reid (1989) reported growth of 0.57 and 0.61
g/wk (Table 4). Under commercial pond production with
high flushing rates, F. vannamei growth rates of 0.27 to
1.85 g/wk have been recorded (Table 5). Flowever, the
target production period of 12 weeks resulted in 9 to 13 g
animals. In order to achieve three crops per year, 1 .8 g/wk
growth will be neccdssary for reliable production of a 20 g
animal in a i 2 -week giowout period.

Survival rales were dis^poiniing. Commercial ponds
expect an 80-95% survival rate to make production fea-
sible. In SS-1, SS-2a and SS“3a, numerous shrimp were
lost when they jumped out of the culture tanks and escaped
into other parts of the system.

Bacterial levels were expected to be minimal in SS-2a
with ozone treatment. Actually, hetenotrophic bacteria
counts were higher in SS-2a than in SS-1 formostofthe 12-
week period. Apparently, ozone was being consumed in
the system by the high solid organic content. Before
repeating this study, modifications should be made to
remove solids from the system.

Some biological filtration and denitrification was
occurring in the lamellar. The nitrification occurring in the
pump was unexpected and suggests that oxidation may
have taken place due to air entrapment

TABLE 2

Percent change in total ammonia between inflow and outflow of different filter components for four
closed systems.

System

2 a

2 b

3a

3b

Pump

-13.5

-8.9

-15.5

-3.2

Lamellar

-8.5

- 2.2

+3.2

-6.3

Cyclone

-1.5

Skimmer (O 3 )

+19.7

+4.1

^.0

-7,0

Filter

-17.7

- 12.2

Venturi (O 3 )

-25.2

- 12.8

Reservoir

-26.8

Total ppm

-0.043

-0.050

-0.30

-0.047

All numbers based on an average of three samples.

410

Ogle and Lotz

TABLE 3

Percent change in nitrate levels between the inflow and outflow of different filter components for
four closed systems.

System

2a

2b

3a

3b

Pump

-15.7

+0.2

+2.7

-0.6

Lamellar

+9.5

-2.8

-23.7

-19.8

Hydrocyclone

-1.0

Skimmer (O3)

+3.4

+ 1.7

+1.9

-3.9

Filler

-2.0

+ 1.0

Venturi (O3)

+ 19.4

0.0

Reservoir

+ 15.4

Total ppm

+ 1.28

-0.26

-0.37

0.81

All numbers based on average of three samples.

1.000E+08

10000000

1000000

100000

CFU/ML

J Biological
UV - Ozone

0 1 3 4 8 9 11

Weeks

Figure 10. Total lieterolrophic bacteria determined weekly for SS-1 and SS-2a.

10000000

1000000

100000

10000

1000

Closed System Culture of P. vannamki

CFU/ML

411

100

Biological
UV - Ozone

0 1 3 4 8 9 11

Weeks

Figure 11. Presumptive Vibrio spp. sampled weekly for SS-1 and SS-2a.

TABLE 4

Closed system growth (g/wk) of penaeid shrimp

Species

Minimum

Maximum

References

P. aztecus

034

0.55

Forster and Beard 1974

0.20

0.53

Mock, Ross and Salser 1977

P. indicus

0.60

0,83

Forster and Beard 1974

P. japonicus

0.55

0.80

Forster and Beard 1974

P. merguiefisis

0.33

0.55

Beard, el al. 1977

P. inonodon

0.80

1.58

Forster and Beard 1974

P. occidentalis

0.57

0.78

Forster and Beard 1974

P. orienialis

0.91

1.42

Forster and Beard 1974

P. seitfeius

0.32

0.42

Forster and Beard 1974

0.25

0.52

Mock, Neal and Salser 1973

P. stylirostris

0.12

0.39

Kennedy 1980

P. vannamei

0.57

0.61

Reid Ym

0.59

0.99

Ogle 1992

412

Ogle and Lxyiz

TABLES

Growth of Penaeus vannamei at various densities.

System

Size

System

Type

Density

Growth

g/wk

Wyban and Sweeney 1990

330

pond

45

1.4

75

1.75

100

1.4

150

1.07

Aquacop 1989

1000

pond

139

0.60, 0.72

Reid 1989

—

closed

970

0.57

1539

0.61

Ogle (unpublished data)

100

pond

100

0.38

16

0.80

1

1.85

Ogle 1992

1.8 in^

lank

6.5

3.29

13.7

2.31

27.3

1.40

This report

closed

200

0.87, 0.99

367

0.59

Sandifer, et al. 1987

28

lank

10

1.41^

20

1.35^

40

l.ll^

Siindifer, ei al. 1988

0.25 ha

pond

12

0.94^

42.5

0.84^

20

0.56^*

40

0.52^^

60

0.51“

100

0.57**

Trimble, W. 1980

0.08 ha

pond

2.5

1.8

♦calculated, ♦♦estimated for 166-dlay growout

Closed System Culture of P. vannamei

413

AcKNOWLEDGME?NnrS

We thank Kathy Beaugez for reviewing the manu-
scnipt and collecting data. Appreciation is also extended to
Casey Nicholson^ Vicki CiW and Leslie Christinas for
data collection and their iremendons support; Waste WaiM-

Tteatraenu Inc. for supplying and setting up the ozone
treatmcni; Patsy Browing for water analysis; and Cheryl
Kerr and Dr. David Cook for bacteriological work. This
project was funded by Grant 85-(SRS‘2-2537) and
85-(SR5 -2-2538) from the U.S. Department of Agricul-
ture.

Literature Cited

Aquecop. 1989. Production results and operating costs of the first
super'intensive shrimp farm in Tahiti. Absi. World Aquac-
ult. Soc. 20(1):12A.

Beard, T.W.,J.F.Wickcns andDJt. Arnstcin. 1977. The breeding
and growth of Penaeus merguiensis Dc Man in laboratory
recirculation systems. AquacuUitre 10:275-289.

EPA. 1983. Chemical analysis for water and waste. EPA-625-16/
14i003. Revised March 1983.

Forster, I.R.M. andT.W. Beard. 1974. Experiments to assess the
suitability of nine species of prawns for intensive cultiva-
tion. Ai/Moctf/fKrc 3:335-368.

Kennedy, R.M. 1980, Recycling and reuse of water for the
intensive culture of shrimp. M.S. Thesis, Univ, ofHouston,
Texas. 45 pp.

Mock, C.R„ R. A. Neal and B .R. Salscr 1973. A closed raceway
for the culture of shrimp. Proc. World Markult, Soc.
4:247-259.

Mock, C.R.. L.R. Ross and B.R. Salser. 1977. Design and
preliminary evaluation of a closed system for shrimp
culture. Proc, World MaricuU, Soc. 8:333-369.

Ogle, J.T. 1992. Variability in growth of postlarval P, vannamei.
Gulf Res. Rept.: 8(4):423^26,

Reid, B. 1989. Evaluation of a recirculating raceway system for
the intensive culture of the penaeid shrimp Penaeus van-
namei Boone. M.S. thesis. Corpus Chrisli State Univ,,
Corpus Christl. Texas. 70 pp.

Sandifer, P.A., J.S. Hopkins and A.D. Stokes. 1987. Intensive
culture potential of Penaeus vannamei. J. World Aqacult.
Soc. 18(2):94-100.

Sandifer, P.A., J.S. Hopkins and A.D. Stokes. 1988. Intensifica-
tion of shrimp culture in earthen ponds in South Carolina:
Progress and prospects./. World Aquacult, Soc, 19(4):218'
226,

Trimble, W.C. 1980. Production trials for monoculture and
polyculture of white shrimp (Penaeus vannamei) or blue
shrimp (P, stylirostris) with Florida porapano (Trackinotus
carolinusym Alabama, 1978-1979./. World Maricult. Soc.
11:44-59.

Wyban, J.A. and J.N. Sweeney. 1990. A systems approach to
developing intensive shrimp growout technology. Pp. 91-
94. In: R. HLrano and I. Hanyu (cds.). Second Asian
Fisheries Forum. Asian Fisheries Society, Manila, Philip-
pines. 991 pp.

Gulf Research Reports

Volume 8 | Issue 4

January 1992

Effects of Salinity on Survival and Growth of Postlarval Penaeus vannamei

John T. Ogle

Gulf Coast Research Laboratory

Kathy Beaugez

Gulf Coast Research Laboratory

Jeffrey M. Lotz

Gulf Coast Research Laboratory, jefF.lotz(^usm.edu

DOI: 10.18785/grr.0804.07

Follow this and additional works at: http:/ / aquila.usm.edu/ gcr

Part of the Marine Biology Commons

Recommended Citation

Oglc; J. T.; K. Beaugez and J. M. Lotz. 1992. Effects of Salinity on Survival and Growth of Postlarval Penaeus vannamei. Gulf Research
Reports 8 (4): 415-421.

Retrieved from http:// aquila.usm.edu/gcr/vol8 /iss4/7

This Article is brought to you for free and open access by The Aquila Digital Community. It has been accepted for inclusion in Gulf and Caribbean
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Gulf Research Reports, Vol. 8, No. 4, 415-421, 1992

Manuscript received June 13, 1990; accepted March 19, 1992

EFFECTS OF SALINITY ON SURVIVAL AND GROWTH OF
POSTLARVAL PENAEt/S VANNAMEI

JOHN T. OGLE, KATHY BEAUGEZ, AND JEFFREY M. LOTZ

Gulf Coast Research Laboratory, P. O. Box 7000, Ocean Springs, Mississippi 39564

ABSTRACT Eight and 22-day-old Penaeus vannamei postlaivac were exposed to several salinities for 24 hours and 1 20 hours
by direct transfer from 32 ppt salinity to lower salinity waters. The challenge study included six experiments conducted on
8 -day-old postlarvae (PL-8) and five experiments conducted on 22-day-old posllarvae (PL-22). Each experiment consisted
of ten replicates of ten animals each- Shrimp were held in I L plastic containers with 5(X)-ml of seawater. Lowered salinity
resulted in lower survival for shrimp of both ages. Longer exposure time resulted in lower survival for shrimp of both ages.
Younger shrimp exhibited lower survival than older shrimp. Survival of 8-day-old posllarvae after 24-hour exposure to
salinities of 32. 16. 8,4. and 2 ppt was 97.3%. 92.8%, 19.8%, 8.2% and 1.7%, respectively. Survival of 22-day-old posllarvae
after 24-hour exposure was 99.2%, 97.8%, 83.8%, 63.4% and 40.2%, respectively. A second scries of experiments investi-
gated the effect of salinity upon growth of 22-day-old postlarvae which had been acclimated to four different salinities (16.
8,4, and 2 ppt),Thirly shrimp were stocked in triplicate into 11 3 L (30 gal) aquaria and fed a prepared commercial feed. Growth
was determined after 30 days at 16*^ and 28-30*C. Growth was greatest at higher temperatures, but statistically significant
differences due to salinity were not detectable. Nonetheless, best observed growth occurred at the intermediate salinities of
8 and 4 ppL

Introduction

Shrimp of the genus Penaeus encounter a wide variety
of salinities throughout their life cycle. Most penaeid
species mature and reproduce in high salinity open ocean
waters . Subsequently, the larvae migrate into lower salinity
esruarine nursery areas where they metamorphose into
postlarvae and grow rapidly (Gunier etal. 1964). Juveniles
of Penaeus aztecus have been captured in Gulf of Mexico
waters of 0.80 ppt salinity, and juveniles oiP.fluviatilis (=
P. setiferus) have been found ui salinities as low as 0.42 ppt
(Gunter and Shell 1958). At the other extreme, juvenile P.
setiferus have been captured in water witli salinities as high
as 43.3 ppi (Gunter 1961) andP, brasHi€nsis\mye. been
captured in waters ranging from 40-60 ppt (Chung 1980).

Although young shrimp tolerate a wide variety of
salinities, they may show preferences for salinities within
narrower ranges. For example, Chung (1980) found that
80% of the posilarval P. brasiliensis which he tested pre-
ferred salinities from 5-28ppt,even though ihe animals had
been captured in a high saUnity (40-60 ppt) lagoon. On the
other hand, Zein-Eldin (1963) demonstrated lhat wild-
caught P, aztecus, P. duorarum, and P. setiferus postlarvae
all liad high survival rates tmd exhibited no differences in
growth rate in salinities ranging from 2 to 40 ppt. This led
Zein-Eldin to surmise Uiat salinity may be of less impor-
tance than other factors in ijosdarval development.

Penaeus vannamei, tlie most popular aquacultured
shrimp in the Western Hemisphere, has been reponed to

have the greatest tolerance for low salinity water (1-8 ppt)
of four penaeids from west Mexico (Mair 1980). In Ecua-
dor, wild-caught P. vannamei postlarvae have been re-
poned to grow in ponds with salim'ties below 2 ppt by
Chauvin (1983) and in 0 ppt salinity by Garston (1986).
Wulff (1987) reported culturing lliis species in Arizona
utilizing total freshwater. In laboratory experimenis, Oiin
and Fast (1987) determined that transfer of 5 to 12-day-old
postlarval P. vannamei from 32 ppt salinity water directly
into water of 20 or 36 ppt salinity resulted in survivals of
89% and 99%, respectively.

The only experimental data forP. vannamei growth in
low salinities is that of Huang (1983). He measured the
growth of postlarvae P. vannamei after 30 days in waters of
5, 15, 25, 35, and 45 ppt and found lhat fastest growth
occurred at 25 ppt, while poorest growth occurred at 45 ppt.

Studies on the survival and growth of postlarval P.
vannamei in low salinity water are valuable to shrimp
fanners along Uie NorUiem Gulf of Mexico. Coastal
salinities may be as low as 2 ppt in the spring (Ogle 1 989),
when postlarvae are generally slocked into ponds. Further,
shrimp in ponds are often subjected to rapid salinity drops
after rainfall.

In this paper, we report tlie results of investigations
concerning the effect of rapid salinity decreases on the
survival of postlarval P. vannamei. We also attempt to
determine the effect of low salinity on growth of P. van-
namei after a period of acclimation to low salinity.

415

4J6

Ogle et al.

Materials and Methods

All studies were conducted using anificial sea sails
(Instant Ocean) dissolved in lap waler. For each experi-
ment, waters of various salinities were prepared from a
common Slock of seawater wiihasalinity of32ppt. At least
three days prior to each expeiimeni, the slock seawater was
diluted with fresh lap water to achieve salinities of 1 6, 8, 4,
and 2 ppt. Higher salinities (32 and 16 ppl) were measured
with a refraclomeler, while lower salinities (8. 4 and 2 ppt)
were measured with a hydrometer. During each experi-
ment, continuous illumination was provided by six 40-watt
fluorescent bulbs.

Five-day-old posilarval slirimp were obtained from
two Florida-based commercial hatcheries. Shrimp arrived
at Ib-lS^C in 32-34 ppt seawater. Posllarvae from each
shipment were held for three days in 32 ppt seawater and
fed brine shrimp nauplii {Artemia sp.) three limes daily, ad
libitum, before begiiming experiments. Each sliipmenl of
shrimp was divided into three groups, one for each of three
studies.

Salinity Shock

Study 1: 8-day-old postlarvae

The first group of shrimp from each shipment was
challenged when they were 8 days old by direct transfer
into waters of one of five salinities (32, 16, 8, 4, or 2 ppl).
White 1 L plastic bowls containing 500 juI of seawater were
used as experimental chambers, 'fen chambers for each
salinity (32, 16, 8, 4, and 2 ppO were utilized. Each
chamber was slocked with ten postlarvae. Two hours were
required to transfer the posllarvae to the experimental
chambers. Chambers were loosely fitted wiili lids to reduce
evaporation. Temperatures were maintained by placing
cliambers in a constant-temperature water baili.

Experiments were conducted on six separate ship-
ments of 8-day-old postlarvae. Animals were fed live
Anemia sp, nauplii and freeze-dried calanoid copepods
(Kordon microplankion) immediately after being slocked
and three times daily thereafter. Dead shrimp were re-
moved daily. Survival of animals in each chamber was
recorded at 24 hours and 120 hours.

Study 2: 22‘-day-otd posllarvae

The second group of animals from each shipment was
held in water of 32 ppl salinity until they were 22-days-old.
The slniinp were then challenged by direct iriinsfer to
waters with salinities of 32, 16, 8, 4, and 2 ppt. All
procedures employed in Study 1 were followed for the five
experiments conducted on 22-day-old posllarvae.

Salinity acclimation

Study 3: Survival and growth of 22-day-old post-larvae
accliinated to lower salinilies

The third group of posilarval shrimp was gradually
acclimated to the various salinilies prior to the start of the
experiments. Slirimp were divided among four 1 13 L aq-
uaria and acclimated separately to the lower salinities of
16, 8, 4, and 2 ppt. Salinity in each aquarium was lowered
at a rate of 2 ppt per day by adding aged lap water. The
acclimation regime achieved the desired salinities by the
lime that the experiment was initialed (Day 0). Acclima-
tion of shrimp to 2 ppt began 14 days prior to slocking, to
1 6 ppt began seven days before stocking and so on. During
tile acclimation period, shrimp were gradually weaned
from a diet of Anemia sp. nauplii and copepods to a
Rangen-Zeigler posilarval feed.

These experiments were performed in triplicate in all-
glass aquaria containing 1 13 Lof seaw'aler. Each aquarium
was stocked with 30 posllarvae. Shrimp were individually
weighed to the nearest 0.0 1 g on an electronic balance. A
subsample of 25 posllarvae from each of the salinilies was
weighed on Day 0 after the acclimation period and prior to
the Stan of each experiment When the experiments began,
posllarvae were less than 0,01 g (wet weight). All surviv-
ing shrimp were weighed on Day 30. Total weight gain was
used as an indicator of growtli because Zem-Eldin (1963)
and Raj and Raj (1982), working with posilarval penaeid
shrimp, found that weight increased faster than length and
was Uierefore a more sensitive indicator of growth.

Three separate experiments were conducted in this
study. The first two experiments were nm simultaneously
using shrimp from the same shipment. In experiment 1,
water temperatures were maintained at 30'’C ± (high
temp). In experiment 2. water temperatures were main-
tained al 16^C ± 2‘^C (low temp). The third experiment was
run at a different lime and utilized a different shipment of
shrimp than the first two experiments. During experiment
3, water temperatures were maintained at 28°C ± 1°C.
Temperatures were controlled by regulating the room
temperature or by aquarium healers. All three experiments
were conducted at each of four salimlies (16, 8, 4, and 2

ppl).

No substrate was used in the aquaria. Filtration was
provided by an external power filter (Dynaflow 600).
Pievious experiments on 22-day-old posllarvae demon-
strated that the postlarvae were too small to handle the cur-
rents and would be held against the filler screens during the
first week. Death resulted whtm the shrimp were held
against the screens for periods longer than an hour. To
prevent loss of postlarvae, the intake pipe of the power
filter was screened. Additionally, during the first week of
growth the fillers were run only an hour a day.

(Use of trade names does not imply endorsement,)

Effects of Salinity on Postlarval Penaeus vannamei

417

Saliniiies were checked twice weekly and mainiained
at Ihe appropriate salinity levels by the addition of freshwa-
tec Salinity fluctuaiions were less than I ppt. Addition of
plexiglass lids reduced evaporation and prevented the
shrimp from jumping out of the tanks.

Data Analysis

Survival data were analyzed as percent survival using
the Kruskal-Wallis nonparametric analysis of variance.
Pairwise comparisons were performed with the Maim-
Whitney U-lest us'mg Bonferroni's criterion of signifi-
cance. Differences were considered to be significant if P <
0.05.

Growth was determined as final wet weight of shrimp.
The analysis of growth as a function of temperature and
salinity was analyzed using a two-way nested analysis of
variance where the replicated aquaria provided the error
term for hypothesis testing. Differences were considered to
be significant if P < 0.05.

Results
Salinity Shock

Effect of age at exposure on ability to survive a
salinity drop

Figure 1 displays the survival of 8 -day-old postlarvae
(PL-8) and 22-day -old posilarvae (PL-22) of P, vannamei
at 24 hours and 120 hours after challenge to various
lowered salinities. The Kruskal-Wallis lest delected sig-
nificant differences in overall survival (combined 24 hours
and 120 hours) between PL-8 and PL-22. Mann-Whitney
U-tests at each salinity revealed that overall survival (com-
bined 24 hours and 120 hours) was significantly lower for
eight-day-old postlarvae Uian for 22-day-old postlarvae at
16, 8, 4, and 2 ppt salinity. No differences in survival due
to age were delected at the initial salinity of 32 ppt

Effect of salinity challenge on survival of 8-day-old
postlarvae

Survival of 8-day-old posUarvae after 24 hours expo-
sure to salinities of 32, 16, 8, 4, and 2 ppt was 97.3%,
92.8%, 19.8%, 8.2%, and 1.7%, respectively. The Kruskal-
Wallis test detected significant differences in overall sur-
vival due to salinity. There was no significant difference
(Mann-Whilney U-lcst) in survival percentage between
PL-8s transferred to 32 ppt (control) and those transferred
to 16 ppt (Figure 2). There was no significant difference in
survival between PL-8s exposed to 4 and 2 ppt. Survival
was significantly higher for PL-8s transferred to 8 ppt than
those transferred to lower salinities. There was a signifi-
cant reduction in survival between animals exposed to 16

ppt imd those exposed to 8 ppt. This trend was obvious in
both Uie 24-houi and 120-hour experiments.

Figure 2 reveals that although the observed survival
rales were lower at 120 hours than at 24 hours, the differ-
ences were statistically significant by the Mann-Whitney
U-tesi only at the higher salinities (32 ppt and 16 ppt).

Effect of salinity challenge on survival of 22-day-old
postlarvae

Survival of 22-day-oId po.stlarvae after 24 hours expo-
sure to 32, 16, 8, 4, and 2 ppt was 99.2%, 97.8%, 83.8%,
63.4%. and 40.2%„ respectively. Figure 3 exhibits tlie
effect of salinity challenge on 22-day-old postlarval sur-
vival. The Kruskal-Wallis test detected significant differ-
ences in overall survival due to salinity . Significantly lower
survival was detected for animals transferred from 32 ppt to
4 and 2 ppt salinity (Mann-Whitney U-lest). Survival of
animals exposed to 4 ppt was lower than survival of animals
exposed to 8 ppt. Survival was also lower for animals
exposed to 8 ppt than for animals exposed to 16 ppt. There
was no significant difference in survival percentage be-
tween PL-22s transferred to 32 ppt (control) and those
transferred to 16 ppt.

Survival of postlarvae after 24 hours exposure was
generally higher at all salinities than after 120 hours expo-
sure. Statistically significant differences for time of expo-
sure are also indicated on Figure 3.

Salinity Acclimation

Effect of acclimation to lowered satin ity on survival of 22-
day-old postlarvae

Figure 4 compares the survival of shrimp acclimated to
lower salinities at two temperatures. The Kruskal-Wallis
test failed to delect differences in survival due to salinity at
a temperature of 16°C. However, differences were de-
tected at Uic higher temperatures where shrimp displayed a
greater sensitivity to salinity (Maim-Whitney U-tests de-
tected lower survival at 2 ppt than at 16 ppt).

Effect of salinity acclimation and temperature on
growth rate

Postlarval P. vannamei grew fastest at higher leinpera-
mres (Figure 5). The two-way nested analysis of variance
delected greater final weights for shrimp reared at 30X
than those at 16°C. Animals mainiained at 28-30°C were
nearly twice as large as those grown at I6^C.

There were no statistically detectable differences in
growth among shrimp maintained at the four salinities.
However, the greatest final weights were attained in tlie
intermediate salinities (8 and 4 ppt) at both temperatures.

Interestingly, there were large differences between
shipments of shrimp in overall performance. Animals in
experiment 2 (30X) reached 1 g in both 8 ppt and 4 ppt

418

Ogle FT AL.

Salinity (ppt)

Figure 1. Survival of salinity shock by 8-day-old and 22-day-old postlarval Penaeus vannameL Asterisks denote
statistically signitlcaiit dilTerences in survival between shrimp of tbe two ages.

2 . 4 . 8 . 16 . 32 .

Salinity (ppt)

Figure 2. Survival of salinity shock by 8-day-old postlarval Penaeus vannamei for 24 and 120 hour exposures.
Salinities sharing a line are not statistically different from one another. Asterisks denote statistically significant
differences in survival between shrimp exposed for 24 hours or 120 hours at each salinity.

Effects of Salintty on Postlarval Pesaeus vannamei

419

2 . 4 . 8 . 16 . 32 .

Salinity (ppt)

Figure 3. Survival of salinity shock by 22-day-old postlarval Penaeus vannamei for 24 hour and 120 hour exposures.
Salinities sharing a line are not statistically difTerent Trom one another. Asterisks denote statistically significant
differences in survival between sbrioip exposed for 24 hours or 120 hours at each salinity.

Salinity (ppt)

Figure 4. Effects of temperature on survival of 22-day-old postlarval Penaeux vannamei acclimated to low salinity.
There are no statistically significant differences among salinities for shrimp maintained at 16°C. For shrimp
maintained at 28°C and 30°C, salinities sharing a letter are not statistically different from each other.

420

Ogle et al.

m 30C
□ 16 C

Salinity (ppt)

Figure 5. Final weights of Penaeus vannamei grown for 30 days at two temperatures* There is a statistically
significant difference between the temperatures, but there are no signiHcant differences due to salinity at either
temperature.

seawater. Animals grown in both 16 ppl and 2 ppi seawater
ai 30®C failed to attain a size of I g. Animals from a
different shipment of shrimp grown at 28'’C demonstrated
negligible growth at any salinity and therefore were ex-
cluded from the growth rate analysis.

Discussion

Our results on Uie tolerance of postlarval P. vannamei
to rapidly-lowered salinities are consistent witli oUier stud-
ies of penaeids. Zein-Eldin and Aldrich (1965) report lower
survival of P. az(ecus when exposed to reduced salinilies
for more than 24 hours. Biesiot (1975) noted that 22-day-
old F. aziecus were more tolerant to challenge by low
salinity than lO-day-old postlarvae. In studies on four
penaeid species. Mair (1980) found that as shrimp became
older and increased in size, their salinity preferences al-
tered and they were apparently able to adjust more readily
to lower salinities.

In our studies, posilarvae of P. vannamei had greater
observed survival at 24 hours than at 120 hours. The differ-
ences in survival at a particular age which we noted
between 24 hours and 120 hours are due to lime of expo-

sure. The survival rale (deaths per hour) is no different at 24
hours than at 120 hours, even though the total number of
deaths was greater at 120 hours for each salinity and age.

There was a great deal of variability in survival among
the different shipments of posilarvae tested. Ability of
postlarvae to withstand stresses is known to vary considera-
bly and is apparently correlated with overall performance
in aquaculture settings. In fact, postlarvae collected from
full seawater in the wild in Ecuador which are destined for
shrimp culture ponds are subjected to a three -minute brack-
ish water stress lest bath (15 ppt) to assess their vigor
(Maugle, personal communication). A simple salinity
stress test was used by Tackacn el ai. (1989) to evaluate
nulritional differences for three si>ecies of penaeids includ-
ing P. vannamei.

Although we were unable to d etect statistically signifi-
cant differences in growth rate attributable to salinity, the
greatest observed growth rales occurred at 8 and 4 ppt
salinities. In a commercial setting, P. vannamei slocked
into nursery ponds are expected to achieve a size of 1 g in
30 to 50 days (Shleser and Folleil 1984). The growth of
shrimp at30°C in this study was acceptable by this criterion
at salinities of 8 and 4 ppt. Growth at 16°C was below this
criterion at all salinities. Zein-Eldin and Griffith (1969)

Effects of Salinity on Postlarval Penaeus vannamei

421

have shown lhal P. an ecus and P, seiiferus posUarvae were
adversely alTecled by low salinities when held at low lem-
peratures. Stunner and Lawrence (1989) found that a
combination of high salinity and high temperamre had an
adverse effect on production of P, vannamei posUarvae.

As with survival » growth of P. vannamei under labora-
tory conditions is highly variable and often unpredictable
(Ogle 1 992). The lack of growUi in the group of shrimp held
at28^C was probably not due to temperature, but indicative
of the variabil ily of the animals^ Olin and Fast ( 1989) tested
P. vannamei and P. monodon posilarvae in acclimation
studies. When different groups of posilarvae were tested
under the same conditions, there appeared to be significant
differences in growUi among the groups. This points out the
critical need for using as many replicates as possible when
designing aiid performing experiments on .shrimp growth
and survival.

Even though greatest growUi was found in waters with
salinities of 8 and 4 ppt, percentage survival was better at
16 ppt. We feel that posU^al .shrimp would have a higher
survival rate if stocked into lower salinity ponds (between
1 6 and 8 ppt) as PL-22s rather than PL-8s. We do not know
if the additional cost of holding the shrimp for the added 1 2
days would offset the cost of additional postlarvae.

Acknowledgments

The authors wish to express their appreciation to
Annette Barrett, Leslie Christmas, Ken Stuck, and Bill
Trimble for data collection and Vicki Crain for typmg. This
research was supported in part by the Cooperative State
Research Service of the U.S. Dept, of Agriculture through
Grants 85-CSRS-2-2538 and 88-38808-3319.

Literature Cited

Biesioi, P. 1 975. Saliniry tolerance of postlarval brown shrimp
Penaeus aziecus in relation to age and acclimation salinity.
MS thesis. Bowling Green Slate University, Ohio. 63 pp.

Chung, K.S. 1980. A note on salinity preferences of Penaeus
brasiliensis. Bull. Jap. Soc. Sci. Fish. 46(3):389.

Chauvin, W.D. 1983. Ecuador shrimp moves to second largest
export. The Fish Boat 28(8):4l, 66-70.

Garston,G. 1986. Personal correspondence. Aquaculture Digest
lL8.3g.p.20.

Gunter, G. 1961. Habitat of juvenile shrimp (family Penaeidac).

42(3): 598-600.

Gunter, G. and W.E. Shell, 1958. A study of an estuarine area with
water-level control in the Louisiana marsh. Proc. of Louisi-
ana Acad. Sci. 2l :5-34.

Gunter, G., J. Y. Christmas and R. Kilicbrew. 1964. Some
relations of salinity lo population distributions of motile es-
luarine organisms, with special reference lopenaeid shrimp.
Ecology 45( 1 ) : 1 8 1 - 1 85.

Huang, H I. 1983. Factors affecting the successful cullurc of
Penaeus stylirosiris and Penaeus vannainei at an csluarinc
power plant site; temperature, salinity, inherent growth
variabiUty.damsclfly nymph predation, population density
and distribution, and polyculturc. Ph.D dissertation. Texas
A&M University, College Station, Texas. 221 pp.

Maugle, P.D. 1990. Personal communication. P.O. Box 476,
Sandcrslome, Rhode Island. 02874.

Mair, J. McD. 1980. Salinity and water type preferences of four
species of postlarval shrimp {Penaeus) from West Mexico.
J. Exp. Mar. Biol. Ecof. 45:69-82.

Ogle, J.T, 1989. The giowlh of cultchlcss CrassosJrea virgintca
spat at Biloxi Bay, Mississippi using different methods of
culture. Gulf Res- kept. 8(2):173-179.

Ogle, J.T. 1992. Variability in growth of postlarval P. vannamei.
Gulf Res. kept, 8(4):423.426.

Olin, P.G, and A.W. Fast. 1987. Acclimation to pH and salinity
of postlarval Penaeus nvarginatus and Penaeus vannamei in
tropical aquaculture ponds. Absl. J. World Aquacul. Soc.
18(1);I7A.

Olin, P.G. and A W. Fast. 1989. Acclimation of postlarval
Penaeus vannamei and Penaeus monodon to abrupt change
in salinity and Icmpcralure. Absi. J. World Aquacul. Soc.
20(1):60.

Raj, R.P. and P.3.S. Raj. 1982. Effect of salinity on growth and
survival of three species of pen acid prawns. Proc. Synip.
Coastal Aquaculture 1:236-243.

Shlcscc,RA.andL.F.FoUcL 1984. Research and development in
maturation and production of penaeid shrimp in the Western
Hcraisplrerc. Proc. 9th and 10th. U.S. -Japan Meeting on
Aquaculture NOAA Tech. Repi. NMFS 16:57-60.

Sturmcr, L.N. and A. Lawrence. 1989. Salinity effects on Pe~
naeus vannamei production in nursery and growoul ponds,,
/. World Aquacul. Soc, 20(1):73A.

Tackaerl, W., P. Abelin, P. Legcr and P. Sorgcloos. 1989. Stress
resistance as a criterion lo evaluate quality of postlarval
shrimp reared under different feeding procedures. Shrimp
Plantation 89. IB Brazilian ShrimpConference, October 16-
20 19$9. Joaa Pessoa - P.B.- Brazil, pp, 393-403.

Wulff, R. 1987. Rumblings in Arizona. Aquaculture Digest
12.11.7, p. lo-n.

Zcin-Eldin, Z.P. 1963. Effcclof salinity on growth of postlarval
penaeid shrimp. Biol. Bull 125(1): 188- 196.

Zein-Eldin, Z.P. and Aldrich, D.V. 1965. Growth and survival of
posilarvae Penaeus aztecus under controlled conditions of
temperature and salinity. Biol. Bull. 129 (1); 199-21 6.

2^in-EIdjn, Z.P. and G.W. Griffith. 1969. An appraisal of the
effects of salinity and temperature on growth and Survival of
postlarval pcnacids. F AO Fish, kept, 3(57): 1015- 1026,

Gulf Research Reports

Volume 8 | Issue 4

January 1992

Variability in Growth of Postlarval Penaeus vannamei

John T. Ogle

Gulf Coast Research Laboratory

DOI: 10.18785/grr.0804.08

Follow this and additional works at: http:/ / aquila.usm.edu/ gcr

Part of the Marine Biology Commons

Recommended Citation

Ogle, J. T. 1992. Variability in Growth of Postlarval Penaeus vannamei. Gulf Research Reports 8 (4): 423-426.
Retrieved from http://aquila.usm.edu/gcr/vol8/iss4/8

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Gulf Research Reports. Vol. 8. No. 4, 423-426. 1992

Manuscript received October 1, 1990; accepted Janaary 18. 1992

VARIABILITY IN GROWTH OF POSTLARVAL VANNAMEl

JOHN T. OGLE

GuJf Coast Research Laboratory, P.O. Box 7000, Ocean Springs, Mississippi 39564

ABSTRACT This note reports the average size of Penaeus vannamei postlarvae held under a variety of conditions for
approximately 30 days. Fifteen separate and independent rearing trials were completed over several seasons. Extreme growth
variations were noted, with significent differences existing in eight of the 26 replicates. Significant differences were noted
for treatments in seven of the 12 studies. Shrimp ranged in size from an average of 0.01 to 3.08 g after a month of culture.

Introduction

Commercial aquacultun; in the Americas typically in-
volves culture of the South American while legg^ shrimp.
Penaeus vannamei, in earthen or plastic-lined nursery
ponds (Stunner and Lawrence 1987). Postlaivae stocked
into nursery ponds are expected to achieve a 1 g size in 30
to 45 days. After this nursery period, the juveniles are
stocked into large earthen growout ponds.

The use of nursery ponds increases the feed efficiency
for the postlarvae and provides belter inventory control for
the stocking of production ponds. Extending the growing
season is one advantage of using nursery ponds in the
United States. Eluring the colder months, shrimp culture
may be started indoors under controlled conditions. At the
Gulf Coast Research Laboratory (GCRL), rearing trials of
postlarvalP. vannamei were conducted under a variety of
conditions. Results of those independent trials are pre-
sented ha-e.

Materials and Methods

P. vannamei posUarvae obtained firom a number of
commercial and research hatcheries in the United Stales
and abroad were reared at GCRL. Most studies utilized 113
L, all-glass aquaria stocked with 30 animals each( 108/m^).
Several 1 .5 m diameter by 1 .5 m deep kalwall tanks (Solar
Components Corp., Manchester, New Hampshire), rectan-
gular tanks (0.96m x L9mx0.3m) L84m^andapond(683
m^) were also used in some of the studies as noted. Shrimp
were stocked at densities ranging firom 100/m^ to 4,000/m^.

Outside studies utilized aquaria or tanks exposed to
full sunlight. Tanks placed under a roofed porch received
indirect sunlight With the exception of one location study
in a shed, aquaria maintained indoors were routinely kept
at 28®C under constant light supplied by six 40-walt fluo-
rescent bulbs. One study used additional 30-wau lighting
directly over each aquaria and Fucus sp. algae. Another

study used 15-watt lighting over each aquaria and GraciT
(aria sp. algae. Illumination provided by six seven-watt
bulbs of three colors (red, green and blue) and a combina-
tion of the three colors were utilized in one study. The
aquaria were wrapped in black plastic to shield them firom
incidenial light. A study on substrates used five plasdc
screens suspended longitudinally in each of three tanks,
while GracUlaria sp. algae was used as the substrate in
three additional tanks. A production trial was conducted in
a pond containing floating round cages constructed of 500
micron plastic screen with a volume of 1 mL A final study
utilized three aquaria outside and three aquaria inside
plumbed into a common water source. The aquaria were
placed in water baths which also shared a common water
source. Tliree additional aquaria indoors were not plumbed
into the common water system, but shared the indoor water
bath.

Aeration was provided by a single airstone to all
treatments with the exception of the pond. A prepared
commercial postlarval diet (Zeigler Bros, Inc., Gardners,
Pennsylvania) was used in all treatments and shrimp were
fed ad libitum. All studies utilized water of 16 ppl salinity.
Artificial seawater prepared from aged tap water and a
commercial sea salt was used in all aquarium studies.
Natural sunlight and natural bay water were used in the
kalwall tank and pond studies. The posUarvae (PLs), IG to
36 days old, weighed several milligrams at Uie time of
stocking. After the growth period, all shrimp were har-
vested, counted and individually weighed to Uie nearest
milligram on an electronic balance. Numbers were aver-
aged and a standard deviation calculated. Significance (a =
0.01) between replicates and between treatments for each
study were calculated using analysis of variance (ANOVA),
Shrimp growth was expected to increase fourfold after one
month. Therefore, growth was not deiermined in percent
increase but reported as final wet weight

Genaal categories of variability included producUon.
polyculture, light, algae, substrate, source of PLs, feeding
rate, water depth and indoor versus outdoor locaUons.

423

424

Ogle

Results

Growth was extremely variable, resulting in a final
average size after 30 days from 0.01 g to 3.08 g (Table 1).
Significant differences existed in eight of 26 replicates and
seven of 12 treatments. Production trials resulted in sizes
of 0.37 (Study A) and 0.10 g (Study N). A feeding trial
resulted in a final size of 0.07 and 0.09 g (Study D).
Polyculture resulted in sizes of 1.32 (Study E) and 0.28 g
(Study F). The use of various colored lights resulted in
sizes of 0.04 and 0.05 (Study I). It was interesting to note
that the shrimp held under green light turned a deep blue
color. The use of a macioalgae substrate and additional
light resulted in sizes of 0.1 4 (Study K) and 0,72 g (Study
L). The use of substrate screens resulted in a size of 0.29 g
(Study M). Animals obtained from differem sources achieved
sizes ranging from 0.0 1 (Study G) to 1 . 16 g (Study H). The
growth at three water depths ranged from 1 .02 in the 5 ft
depth to 1 .34 g in the 3 ft depth (Study B). A comparison
of inside with outside growth resulted in an outdoor size of
1 . 18 g (Study C) and 0.48 g (Study Final sizes of shrimp
from inside static» inside flowing and outside flowing tanks
were 0.81, 0.98 and 1. 13 g (Study O), Best growth was
recorded for animals held in the 683 pond (Study J).
Shrimp held in cages in the pond reached a size of 1 .20
when fed and 1 .24 g when unfed. Animals stocked directly
into the pond grew to a final size of 3.08 g (S tudy J). Shrimp
in four of the 2 1 inside treatments ( 1 9 %) achieved a size of
1 g, while shrimp in eight of the 11 outside treatments
(73%) achieved 1 gin size. The maximum size achieved by
shrimp in the four treatments held under the roofed porch
was 0.47 g.

In the kalwell study (Study B), temperature ranges
were similar in the 5 ft (80^96 F) and 3 ft (81-96 F) depth,
but fluctuated more in the 1 ft (78-98 F) depth. In the study
which compared location (Study C), water temperatures
ranged from 73-100, 75-85 and 70-86 F for tanks located
outside, under a porch and inside a shed, respectively. In
the final study (Study O), the inside flowing and outside
flowing aquaria generally maintained the same tempera-
tures, whereas the inside static aquaria generally ranged 2
to 9 degrees lower.

Discussion

The animals placed in natural pond water showed
remarkable growth. Leber and Pruder( 1988) demonstrated
a growth factor present in high density culture systems that
promotes growA gieaterthen 1.5 g/wk in production ponds.
They showed that this water, when pumped indoors, still
induced good slirimp growth. It should be noted that when
aiumals from Study B were harvested and restocked into

the kalwall tanks, they also showed remarkable growth, in-
creasing in size by 3.29 g during an 1 1-day period.

Direct statistical comparisons between trials were not
possible due to differences in initia] age, tank type, light
source, seawater type ai)d temperature. However, empiri-
cal comparisons are discussed. For all factors, examples
can be found for both good and poor growth.

Shrimp ^owth is highly variable among groups of
animals (Olin and Fast 1989), and even within the same
group of animals. While this has been demonstrated by the
significant differences reported in eight of the replicates
with identical conditions, this is not always the case. Ani-
mals from four different sources (two different sources for
each study) cultured under the same conditions within the
same study achieved poor growth in Study G (0.0 1 g) and
good growth in Study H (1.16, 1 .14 g).

Animals cultured outside generally grow better than
animals grown inside. Eight of the 1 1 outside treatments
achieved a size greater than 1 g, while only four of the 21
inside treatments achieved a size greater than 1 g. This was
contradicted in the polycultuie Studies E and F. The
shrimp cultured inside in Study E achieved a size greater
than 1 g, while the shrimp cultured outside in Study F grew
to a maximum size of 0.48 g. However, there was a signifi-
cant difference in three of the four treatments in Studies E
and F. All shrimp were held in aquaria without filuaiion at
a density of 108 m^ for 30 days. Although there was a
difference in posilarvae age at the lime of stocking, age
does not appear to be the determining factor. The shrimp
in Study H surpassed the 1 g size expected in a nursery
system while the posilarvae in Study G showed negligible
growth even though the animals were twice as old at the
lime of slocking (PL- 12 vs PL-24, respectively). Also, the
shrimp in Study H achieved the same size as the shrimp
cultui^ without snails in Study H, even though Study £
animals were three limes as old (PL-36 vs PL-12). In all
three studies, postlarvae were held inside in aquaria for 30
to 32 days at a density of 108 m^.

In these studies, all treatments that were located out-
doors tended to be warmer than the 28°C temperature of
indoor tanks. The shallower water depth used for the
kalwell tank.s also resulted in warmer temperatures. Aq-
uaria placed outdoors tended to grow algae which may have
conditioned the water or served as a supplemental feed
source. The final study attempted to eliminaie the influ-
ence of these factors by circulating both the culture water
and the baUi water. Temperatures and algae growth were
the same for both the inside and outside flowing tanks, and
no significant differences were noted for shrimp sizes. Sig-
nificant differences in growth of shrimp in the inside
replicates were noted. TTieiefore, the role of natural sun-
li^t per se has not been demonstrated.

Variabd-tty in Growth of Postlarval PEffAEUS vannamei

425

Table 1

Nursery growth of Penaeus vanaamei under a variety of conditions

Study

Location

Tank

Type

Biter

Density

An*

Age

PL

Duntim

Days

Rep

No.

Sorviva]

Percent

Slat

X Size

g

SD

A. production

outside

kal

□one

274

20

33-35

3*

,39.7

0.37

0.126

B, 5*

outaide

kal

ncoe

108

26

31

1

19.0

a

1.01

0.338

3* depth

outside

kal

ume

108

26

32

I

99.0

b

1.34

0.335

r depth

outside

kal

none

108

26

32

1

81.0

a

1.14

0.395

C. location

outside

tk

none

100

23

29-32

1

43.8

a

1.18

0.389

porch

tk

none

100

13

35

1

69.2

b

0A7

0.159

inside

tk

none

100

23

32

1

51.5

c

0.65

0.248

D. 1% feed

inside

aq

dynaflo

108

14

32

3

68.3

a

0.07

0.061

10% feed

inside

aq

dynaflo

108

14

32

3

85.0

a

0.09

0.073

E. snails

inside

aq

none

108

36

32

3*

96.0

a

1.32

0.357

no snails

ionde

aq

none

108

36

32

3

88.0

b

1.16

0.380

F. rauUd

outside

aq

none

108

24

30

3*

93.3

a

0.28

0.146

no mullet

outside

■q

none

108

24

30

3*

98.9

b

OM

0.166

0. source:

f^niviso

inside

dynaflo

108

24

30

3

82.2

A

OjOI

0J019

GuaiajuabuJ

inside

*q

dynaflo

108

24

30

3

97.8

a

0.01

0.006

R souice;

Oceanic InaL

inside

aq

none

108

12

30

2

88.0

A

1.16

0J48

GCRL

inside

aq

none

108

12

30

2

61.6

■

1.14

0.540

I. lights:

grceci

iiudde

aq

dynaflo

108

-

30

3

67.0

a

0.05

0.040

red

inside

aq

dyniHo

108

-

30

3

76,0

s

0.05

0.027

blue

inside

aq

dynaflo

108

-

30

3

73.0

a

0.04

0.021

mixod

inside

aq

dynaflo

108

-

30

3

75.0

a

0.05

0.033

J. cage/fed

outside

pd

none

108

22

32

3*

73.3

a

1.20

0.542

cage/imfed

outside

pd

none

108

22

32

3

55.7

a

1.24

1.173

pend

outside

pd

none

"■

22

32

1

—

b

X08

0368

K. bare

inside

aq

none

108

..

30

1

7.0

a

0.02

0.019

with algae

inside

aq

ncme

108

-

30

1

75.0

a

0.06

0.045

algae/Iighi

inside

aq

none

108

--

30

1

110,0

b

0.14

0.067

L. bare

inside

•q

none

108

-

30

3

90.0

0.49

SNA

with light

inside

aq

none

108

-

30

3

90.0

0.41

algae/light

inside

aq

none

108

-

30

3

90.0

0.72

SNA

SNA

M. substrate:

screens

poich

tk

none

1635

10

37

3*

59.3

a

0.29

0.170

aigao

poich

Ik

none

1635

10

37

3

52.9

a

0.35

0218

N. production

porch

tk

exchange

4000

10

30

2

58.0

0.10

0.033

O, static

inside

•q

none

108

12

30

3*

107.0

a

0.81

0.485

Howing

inside

aq

none

108

12

30

3*

58.0

ab

0.98

0.702

(lowing

outside

aq

none

108

12

30

3

2Z2

b

1.13

0.679

denotes Fcplicatea dial are significaDtly different

liealmeata abaxing the same letter are not significaiitly differenl

SNA— sample not analyzed

kal - Kahvell tank l.S s 5 foot diameter^ aq • aqaaritun 0.279 & 3 gal; tk ■- tank 0.96-m x 1.9-in z 0.3 m; pond 683

inside - 24-h canataxU illumination; outside • full sunlight; porch ' under cover with natural sunlight
Smdy I used six seven-watt lights (red, green, blue and mixed) with aquaria wrapped in black plastic.

Study J used Fucus spu algae and 30-watt lighting

426

CkH£

Acknowledgments

I wish to thank Leslie Christmas, Vicki Crain, Kathy and to Dr. Terry McBee for statistical analyses. Research
Beaugez and Robert Westbrook for help in collecting data was supportedby USD ACSMR Giants 2-2537 and 2-2538.

Literature Cited

Leber, K.M. and G,D, Rrudcr. 1988. Using experimental micro-
cosms in shrimp research: the growth-enhancing effect of
shrimp pond water. 7. World AquacuU. Soc. 19(4): 197-203,
Olin, P.G. and A.W. Fast, 1989. Acclimation of postlarvae
Penaeus varmamei and Peruieus nwrtodon to abrupt changes

in salinity and temperature. Abst, /. World AquacuU. Soc.
20(1);60A-61A.

Shumer, L.N. and A.L. Lawrence. 1987, Intensive pond manage-
ment strategies for nursery production of Penaeus varmamei
juveniles, Abst,/. World AquacuU. Soc. 18(1):28A,

Gulf Research Reports

Volume 8 | Issue 4

January 1992

The Effect of Salinity on Spawning Frequency of Penaeus setiferus in Aquaria

John T. Ogle

Gulf Coast Research Laboratory

DOI: 10.18785/grr.0804.09

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Part of the Marine Biology Commons

Recommended Citation

Ogle, J. T. 1992. The Effect of Salinity on Spawning Frequency of Penaeus setiferus in Aquaria. Gulf Research Reports 8 (4): 427-429.
Retrieved from http://aquila.usm.edu/gcr/vol8/iss4/9

This Article is brought to you for free and open access by The Aquila Digital Community It has been accepted for inclusion in Gulf and Caribbean
Research by an authorized editor of The Aquila Digital Community. For more information, please contact Joshua.Cromwell(Dusm.edu.

Gu^ Research Reports, VoJ. 8. No. 4, 427-429, 1992

Manuscript Received June 29, 1992; accep*^ August 31, 1992

THE EFFECT OF SALINITY ON SPAWNING FREQUENCY OF
PENAEUS SETIFERUS IN AQUARIA

JOHN T. OGLE

Gu^ Coast Research Laboraiory, P.0, Box 7000, Ocean Springs, Mississippi 39564

ABSTRACT Penaeus setiferus were matuiedand spawned in asm all 120 L tank system in the absence of males. No significant
differences in the number of shrimp that spawned or the time required to spawn were delected for shrimp held at salinities
of 20, 25 or 30 ppt in cither natural or artificial seawater. The earliest that spawning occurred was an average of 17 days past
ablation and as late as 28 days past ablation. None of the shrimp held in artificial seawater at 20 and 25 ppt spawned in the
same molt cycle in which they were ablated, while one third of the shrimp held in natural seawater did.

Introduction

Interest in culture of marine shrimp has increased
dramatically in the last decade. In 1980, 2% of the world’s
shrimp were fanned in ponds. In 1991, fanned shrimp
provided 28% of the world’s shrimp supply. The major
Umiditg factor lo further development is the hatchery
production of postlarvae or seed (Rosenbeny 1991). The
production of seed by controlled sexual maturation of
captive broodstock has been possible for marine shrimp
since 1975. Experimental data on penaeid shrimp matura'
tion and reproduction have been reviewed by Muthu and
Laxminarayana (1982), Primavem (1985), Chamberlain
(1985), Bray and Lawrence (1992), and Browdy (1992).
Conditions represenling the “industry standard’ ’ for matu-
ration of Penaeus vannamei from commercial facilities
have been documented by Ogle (1991a), It is the general
recommendation of those reviews that clear, clean, ocean
seawater of 28-32 ppt be utilized for maturation. Few sites
can provide these conditions, compelling more thanhaJf of
the maturation facilities to use some percentage of recircu-
lation (Ogle 1991a). The salinity of the natural seawater
available to the Gulf Coast Research Laboratory is gener-
ally much lower than the 28-32 ppi recommended for
maturation. Therefore, the addition of artificial salts to the
natural seawater is often required (Ogle 1992).

In an attempt lo experimentally determine the salinity
requirements for maturation and spawning of P. setiferus,
the following study was conducted.

Materials and Methods

A small lank maturation system as described by Ogle
(1991b) was utilized. Six systems containing six aquaria
each with a volume of 120 L were utilized. Three systems
contained natural seawater and three systems contained
artificial seawater. Salinities of 20, 25 and 30 ppl were
tested with both natural and artificial seawater. Bay water

from Davis Bayou m Ocean Springs, Mississippi with a
salinity of 25 ppt was heated to 80®C to achieve a 30 ppt
salinity through evaporation for use in the three natural
seawater systems. This water was then adjusted with weU
water as required to achieve test sal iniiies. For the artificial
seawater systems. Marine Environment (San Francisco,
California) artificial sea salt was dissolved in well watCT
and adjusted to the required test salinities.

Female shrimp collected from the wild were held at 30
ppl and 28°C un^ they had achieved a minimum size of
30 g before being ind ividually placed in an aquarium in one
of the six systems. The shrimp placed m the aquaria system
had never been matured. Aiuinals were held at 28°C,
exposed toa 14L: lOD photoperiod and fed a shrimp grower
ration (2:ciglef, Gardners, Pennsylvania) until they molted.

After molting, the diet was changed to frozen Maine
bloodworms, squid and an artificial maturation pellei (Rangen,
Buhal, Idaho). Animals were fed three limes daily and
water temperature and salinity were recorded. Tanks were
cleaned d^y by siphoning debris from the bottom of the
aquaria. Five days after molting , animals were unilaterally
ablated by eyestalk enuculaiion. Egg collectors were
placed on taiiks containing ablated animals and checked
daily. Subsequent molts and lime to spawning were re-
corded. If the animals failed to spawn after four molt
cycles, they were discarded. After spawning, animals were
replaced with other shrimp from the holding system. As
many as 14 shrimp and as few as 7 shrimp were u.sed in the
six systems. For each female, the number of days past
ablation until the time of spawning was recorded. This data
from each system was analyzed using ANOVA. The
percent spawning was analyzed using a G-tesu

Results

There were no significant differences in the number of
animals that spawned or the time required to spawn be-
tween P. setiferus at each of the salinities 20, 25 or 30 in

427

428

Ogle

either the namral or aitiflcial seawater. The fewest spawns
were recorded for animals held at 25 ppi, while the most
spawns recorded occurred at 20 ppt; both were natural
seawaters (Table 1). Highest mortality was recorded for
animals held in 20 ppl artificial seawater and least mortal-
ity for animalsheld in 30 ppt natural seawater. The earliest
spawning occurred seven days past ablation in 20 ppl
natural seawater. The latest spawning occurred 58 days
past ablation in artificial seawater of 25 ppl. In two of the
systems containing natural seawater at 20 ppl, the average

days past ablation was 17. while at 25 ppt the average days
past ablation was 28. Even though it appears that best
results were obtained for 20 ppt natural and 30 ppt artificial
waters, the results were not significantly different No
shrimp in the artificial water withsah'niiiesof20and 25 ppt
spawned during the same molt cycle in which they were
ablated. In comparison, 33% and 38% of the shrimp in the
natural seawater of 20 and 25 ppt spawned during the same
molt cycle in which they were ablated, respectively.

TABLE 1

Effect of Salinity on Maturation and Spawning of P, set^ferus in Aquaria

SPAWN

Molt Cycle % Average

Seawater Salinity No Days Past

Type

ppl

Spawn %

Spawn %

Dead %

Number

Ist

2nd

3id

Ablation

SE

20

46

28

36

11

0

80

20

27

7.2

Artificial

25

64

14

22

14

0

56

44

24

4.26

30

50

30

20

10

20

60

20

19

3.74

20

73

9

18

11

38

38

24

17

4.48

Natural

25

43

43

14

7

33

33

33

28

5.70

30

54

36

10

11

17

50

33

22

4.16

Spawns in the same moll cycle as ablation are 1 si molt cycle.

Discussion

F. setiferus are thought to spawn in 60 feet of water
offshore in Louisiana during May and June when salinities
are 34-36 ppl (Lindner and Anderson 1956). Joyce and
Eldred (1966) reported the spawning of F. setiferus inshore
at or near inlets. Bray, ei al, (1982) caught large numbers of
mated F. setiferus off Port Aransas, Texas at asalinity of 34
ppl. Marifanns operated with mated females fished from
Apalachicola Bay, Florida, but no salinities were reported.
Continental Sea Farms, a maturation facility in Florida,
utilized water collected at 22-28 ppt and adjusted to 28 ppt
salinity. Other reported salinities for maturation of F.
setiferus are 30.5 to 37. 1 ppt, Johnson and Fielding (1956);

44 ppt, Conte, et al (1977); 22 to 30 ppt, Brown, et al,
(1979); 24 to 29 ppt, Lawrence et ah (1980); 30 to 36 ppt,
Chamberlain (1988); and 25 to 32 ppt with an average of
26.9 ppt.Browdy and Sandifer (1991).

The results rejxjtted here are encouraging and demon-
strate ihaiF, setiferus can be artificially induced to mature
and spawn in lower salinity and artificial seawaters. This
may allow production of F. stf/z/ez-wsin areasof low salinity
and will provide a savings for those facilities utilizing
artificial seawater. Further research should be conducted
to d^eimine the discrete effects of salinity on mating and
egg viability.

Salinity Effects on Spawning of Pe^aevs sehfervs

429

Acknowledgments

Appreciation is expressed to Dr, Jeffrey Lotz, prin-
ciple invesiigaior, for statistical analysis, Casey Nicholson
and Cherie Heard for data collection and daily operation.

and Kathy Beaugez for help in manuscript preparation.
This project was funded by U.S. Dept of Agriculture
Grants 85-(SRS -2-2537) and 85-(SRS-2-2538).

Literature Cited

Bray, W.A., G.W. Chamberlain and A.L. Lawrence. 1982. In-
creased larval production oiPenaeus setiferus by artificial
insemination during sourcing cruises. J. World Maricul.
Soc, 13:123-133.

Bray, W. A. and A.L. Lawrence. 1992. Reproduction of Pena^us
species in captivity. Chapter 5, pp. 93-169, In: A. Fast and
L.J. Lester (eds,). Marine Shrimp Culture: Principles and
Practices. Elsevier. 1992.

Browdy, C, 1992. A review of the n&pioductive biology of
Penaeus species: Perspectives on controlled shrimp matura-
tion systems for high quality nauplii production. Pp. 22-51 .
In; J. Wyban (cd.). Prvc. Special Session on Shrimp Farm-
ing. World Aquacul. Soc., Baton Rouge. Louisiana. 301 pp.

Browdy, C.L. and P.A. Sandifer. 1991. Individual institutional
progress rcpoils - WaddeU Maricultuie Center, U .S, Marine
Shrimp Farming l^ogram Progress Report, Vol. 1. CSRS
U.S. Dept. Agriculture, pp. 34-57,

Brown, Jr., A., J. MeVey, B.S, Middleditch and A.L. Lawrence.
1979. Maturation of white shrimp {Penaeus setiferus) in
captivity. Proc. World Maricul. Soc. 10:435-444.

Chamberlain, G.W. 1985. Biology and control of shrimp repro-
duction. In: G.W. Chamberlain, M.G. Haby andR.J. Migct
(csds.). Texas Shrimp Farming Manual. Texas Agricultural
Extension Service publication of invited papers presented at
the Texas Shrimp Farming Workshop. 19-20 Nov. 1985,
Corpus Christi, Texas, III1-II141.

Chamberlain, G.W. 1988. Stepwise investigation of environ-
mental and nutritional requirements for reproduction of
penaeid shrimp, Ph.D. dissertation. Texas A&M Univ. 210

pp.

Conte, F.S„ M.J. Duronsicl, W.H. Clark and J.C. Parker. 1977.
Maturation of Penaeus siylirostris (Stempson) and Penaeus
setiferus (Linn.) in hypcrsaline water near Corpus Christi,
Texas. Proc, World Maricul. Soc. 8:327-334.

Johnson, M.C. and J.R. Fielding. 1956. Propagation of the white
shrimp (Penaeus setiferus) in captivity. Tulane Studies in
Zool 4:175-190.

Joyce, Jr., E.A. and B. Eldred. 1966. The Florida shrimping
industry. Florida Bd. Conserv., Educ. Scr. No. 15. 47 pp.

Lawrence, A.L.; Y. Akamine; B.S. Middleditch; G. Chamberlain
and D. Hutchins. 1980. Maturation and reproduction of
Penaeus setiferus in captivity, Proc, World Maricul. Soc.
11:481-487.

Lindner, M.J. and W.W. Anderson. 1956, Growth, migradons,
spawning and size distribution of shrimp Penaeus seri/erus.
Fish, Bull. 106 from Fish. Bull,, U.S. Fish and Wildlife
Service, vol, 56, 645 pp.

Muthu , M.S , and A . Laxminaray ana, 1 982 . Induced maturation of
penaeid prawns - a review. Proc. Symp. Coastal Aquacul.
Part 1, Prawn Culture. Mar. Biol. Assn. India, pp, 16-27.

Ogle, J.T. 1991a. Maturation of Penaeus vannamei based upon a
survey. Gulf Res. Kept. 8(3):295-297.

Ogle, J.T. 1991b. Design and operation of a small tank system for
ovarian maturation and spawning of Penaeus vannamei.
Gulf Res. Rept. 8(3):285-289.

Ogle, 1992. Design and operation of the Gulf Coast Research
Laboratory penaeid shrimp maturation facility I. Penaeus
vannamei. Gulf Coast Res. Lab. Tech. Kept, No. 4. 41 pp.

Primavera, J.H. 1985. A review of maturation and reproduction
in closed thely cum pcnacids. In: Y. Taki, J.H. Primavera and
J.A. Llobrcra (cda.). Proc. Istlnternat.Cor^. on the Culture
of Penaeid PrawnsiShrimps. SEAPDEC , Iloilo City. Philip-
pines, pp, 47-64.

Rosenbeny , R. 1 99 1 . World Shrimp Farming 1991. Aquaculture
Digest 9434 Kearny Mesa Road, San Diego, California.

Gulf Research Reports

Volume 8 | Issue 4

January 1992

A Note on the Fine Structure of Myoskeletal Junctions in Acartia tonsa Dana (Copepoda^
Calanoida)

Harold D. Howse

Gulf Coast Research Laboratory

William E. Hawkins

Gulf Coast Research Laboratory , William.Hawkins^usm.edu

Harriet Perry

Gulf Coast Research Laboratory , Harriet.Perry^usm.edu

DOI: 10.18785/grr.0804.10

Follow this and additional works at: http:/ / aquila.usm.edu/ gcr

Part of the Marine Biology Commons

Recommended Citation

Howse, H. D., W. E. Hawkins and H. Perry. 1992. A Note on the Fine Structure of Myoskeletal Junctions in Acartia tonsa Dana
(Copepoda, Calanoida). Gulf Research Reports 8 (4); 431-434.

Retrieved from http:// aquila.usm.edu/gcr/vol8/iss4/10

This Article is brought to you for free and open access by The Aquila Digital Community. It has been accepted for inclusion in Gulf and Caribbean
Research by an authorized editor ofThe Aquila Digital Community. For more information, please contact Joshua.Cromwell^usm.edu.

Gulf Research Reports. Vol. 8, No. 4, 431-434, 1992

Manuscript received January 15, 1992; acceded March 20, 1992

A NOTE ON THE FINE STRUCTURE OF MYOSKELETAL JUNCTIONS IN
ACARTIA TONSA DANA (COPEPODA, CALANOIDA)

HAROLD D. HOWSE, WILLUM E. HAWKINS,

AND HARRIET M. PERRY

Gulf Const Research Laboratory, P. O. Box 7000, Ocean Springs, Mississippi 39564

Introduction

The endoskeleion of ihe calanoid copepod, Calanus
finmarchicus, and its muscle attachments were described
by Ixiwe (1935). She reported that the endoskeleion in C,
fintnarchicus consists of two tendinous endostendtes and
chitinous cxoskelclal ingrowths to which muscles are at-
tached. Howsc (I960) noted attachments of the main
muscles of the thorax to ihe exoskeleion in Acariio tonsa.

Bouligand (1962) described the ultrastructure of muscle
attachments to cuticle in three species of freshwater cope-
pods of the genus Cyclops, Raymoni et al (1974) de-
scribed the fme structure of muscle attaclunents to cuticle
in C.finmarchicus.

Inlormation of the internal anatomy of marine cope-
pods remains sparse. Therefore, we thought it worthwhile
to focus our observations on the attachmenLs of muscle to
exoskelelal ingrowths in A. tonsa.

Materials and Methods

Live specimens of Acartia lonsa Dana were fixed
overnight in cold phosphate-buffered 3% glularaldehyde
(pH 7 ,2), washed in cold 0.1 M phosphate buffer (pH 7.2)
with 5% sucrose for two hours, and post-fixed in phos-
phate-buffered 1% osmium leiroxide (pH 7.2) for two
hours (Millonig 1961). The specimens were embedded in
a Maraglas-CardoHte mixture according to the method of
Freeman Sc Spurlock (1962). Ultraihin sections were cut
and doubly stained with uranyl acetate and lead citrate for
electron microscopy. These sections were examined and
photographed with a Siemens Elmiskop I A. electron micro-
scope.

Results and Discussion

Lowe (1935) reported that the muscles in C. fin-
marchicus are attached to the chitinous exoskelelal in-
growths (CEI) by tendinous comieclions, and that the
endosieniites are attached to the exoskeleton by “groups of
ectodermal tonofibrils.” Furihennore, she slated that
some of the chitinous ingrowtiis serve only as attachments

for muscle and ‘ ‘may be regarded as trueapodeines compa-
rable with those wliich Manton (1928) has described in
Hemimysis as being formed by the gradual sinking in of the
attachment of a group of muscle.'’ The muscle attach-
ments to Uie exoskeleton that we observed in Acartia
appear to fit this criterion for apodemes. Lowe (1935)
stated that iheendostemiies provide support for the muscles
of the antennae and mouth parts. The chitinous ingrowths
from the exoskeleion provide attachments for the remain-
ing somatic muscles.

Raymoni et al, (1974) described muscle attachments
in C. fimtar Chius to a tendon: "^Arising from this are fine
tubules which become grouped together into electron-
dense bundles of fibers with loss of the tubular appear-
ance.’ ’ They staled that these fibers bridge a narrow space
and insert “...into the cuticle as lonofilamenis which can be
seen with diminisliing density for practically die full thick-
ness of the cuticle.” Further, they found no specialized
tendinous aitachinenls in some areas. However, the sar-
colemma of the muscle cell is apposed to the hypodermal
membrane. But there are no tubular fibers in the hypoder-
mis or lonofilaments penetraiing the cuticle.

vSlighi variations occur in the diameter of microtubules
(MT) among different species. Tliey are over 280 A in
diameter in the brown shrimp, Penaeus aztecus (Talbot el
al, 1972), about 210 A in diameter in the horseshoe crab,
Limulus polyphemus (Sherman 1974), 240 A in the crab,
Carcinus maenus (Roosnerand Sherman 1976) and about
230 A in the insects, Calpodes eihitus and Rhodi/ius prolixs
(Lai-Fook 1967).

Acartia epidermal cells (lendinal cells, TC) are inter-
posed between the chitinous exoskelelal ingrowth (apo-
deme) and the muscle cell (Figs. 1 J23) where they form the
lendo-skeletal junction with the former and the myo-
lendinal junction wiili the latter. The gap of the myo-
lendinal Junction is from 160 to 230 A in width (Fig. 1),
narrower than a similar gap in the copepod, Cletocampius
retrogressus, in which it is 400 A (Gharagozlou-van Gin-
neken and Bouligand 1 973), and in F. anemoniae in which
it is 300 to 400 A wide (Brigg, 1979). A similar gap in die
barnacles. Baiatvus impro^kus and B. halanodk^y ranges
from 250 to 700 A depending upon the region (Koulish
1973). The membranes of the cells forming the gap in
Acartia are electron-dense but no desmosomes or other

431

432

Howse et al.

Figure 1. Section through an epidermal tendinal cell (TC) interposed between the distal end ofa muscle cell (MC) anda chilinous
exoskeletal ingrowth (CF*1). The microtubules (MT) are shown in langitudinal view, most of which arc bent. Note the several
layers of chitin (arrowhead) in the center of the CEI. G-glycogen; lA.-itTemovahle artifact; Nu-nucleus; P>plasmalemma.
X 43,500.

Figure 2. Higher power view of the MT as they attach to cuticular projections, and the lonofibrils (TF) penetrate and ramify
within the CEI. X 104,400.

Myoskeletal JuNcnoNs IN A. Tons A

433

Figure 3. Section of an obliquely attached epidermal tendinal cell (TC) to the exoskeletal chitinous ingrowth (CEI). MC-muscle
cell; SR'Sarcoplasmic reticulum, X 58,000.

Figure 4. TraD5verse view of the microtubules (MT). Note desmosomal attachment ofMTs to chitinous knobs (CK) and their
uniform distribution throughout the cytoplasm. Note the intermediate junction (arrowhead) between the tendinal cell and an
adjacent epithelial cel) (EC2). C£l-chltlnou$ exoskeletal ingrowth. X 58,000.

Figure 5. Transverse vie w of the MTs and large chitinous knobs (CK) Indenting the apical plasma membrane of the epidermal
tendinal cell. CEl-chltlnous exoskeletal ingrowth. X 108,000.

434

Howse et al.

specialized junctions occur.

The cytoplasm of iheTCs mAcartia contain numerous
MTs that are about 230 A in diameter and extend from their
insertion in the basal end of the TC to their insertion in the
apical region (Figs. 4,5). The MTs are larger than those in
Cyclops in which they are 125 to 150 A in diameter
(BouUgand 1962) and in the cyclopoid copepod, Paran-
ihessius anemoniae, in which they are 200 A in diameter
(Briggs 1979). In Acartia they are dispersed but closely
associated throughout the cytoplasm (Fig. 1). They form
groups, each of about 800 A in diameter, and become elec-
tron-dense where they attach by hemidesmosomes to cu-
ticular projections that form invaginations in the apical
region of the TC (Fig. 2). In some areas, the attachment of
the TC to the cuticle is marked by chiiinous knobular
projections that arise from the cuticle. They vary in diame-
ter up to 1200 A (Fig. 5). The microtubules ofiheTC attach
to the chiiinous knobs by hemidesmosomes (Figs. 2,5). In
other areas, the TC appears to be attached to the cuticle by
lonofibrils that pass from the core of the invaginations
deeply into the cuticle. This finding differs from that in C.
fmniarchicus which in some areas lack lonofibrils and the
muscle cell attaches directly to the innermost layer of the
cuticle (supra cil.). In other areas, tonofibrils span a narrow
space (Raymoni el al. 1974), and in Cyclops (Bouligand,
1962) there is a space between the epidermal cell and Uie
cuticle through which the tonofibrils cross. In C. maenus,
cuiicular rods tvise from the cuticle and insert into conical
invaginations of the lendinal cell (Roosner and Sherman
1976). Similar groups in Cyclops consist of about 10
tonofibrils (Bouligand 1962), and in P, anemoniae they

form electron-dense fibers of about 400 nm in thickness
(Briggs 1979). The TFs that attach the TC to the cuticle are
0.08 um m diameter in C. ethUus and 0.05 to 0.22 pm in R.
maenus (Lai-Fook 1967).

In one of our preparations, the MTs are bent, a configu-
ration that may reflect the relaxation or severance of the
proximal end of the muscle (Fig. 1).

Close association be( ween adjacent TCs occur nearthe
CEI (Fig. 4) . The TCs are nucleated and contain pockets of
glycogen (Figs. 1,3). The plasmalemma of the adjacent
cells are electron-dense and are separated by a gap of about
140 A which is bisected by electron-dense material form-
ing iniermediale junctions.

The chiiinous projections and knobs provide a finn
anchor for the TC, the microtubules of which may contrib-
ute powerful tensile strength to enable the cell to withstand
the force of muscle contraction (Lai-Fook 1967). The
tendinal cell not only provides a strong tendinous attach-
ment for the muscle to theexoskelelon, but may also absorb
the shock of contraction in this constantly .swimming and
highly active organism. Neither the chemistry of the
lonofibrils nor their functional mechanisms are known, but
Dustin (1978) Stated that they appear to have a me-
chanical role (in leiusion)..,'"

Acknowledgments

We gratefully acknowledge the assistance of Gene
Brown and Gina Brown in the preparation of iliis report.

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Bouligand. Y. 1962. Les uhrasnuc lures du muscle slric cl dcses
attaches au squcletle chez les Cyclops (Crustactis Cop«Spo-
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Dustin. P. 1978. Microtubules. New York: Springcr-Verlag.
Briggs, R. P. 1979. Fine structure of musculature in ihecopcpod
Paranihessius anefftoniue Chun. Biol. Bull. 157; 1 12-124.
Gharagozlou-van Ginneken,!. D. and Y. Bouligand J973. Ultras-
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Howse, H. D. 1960. The Internal Analomyof a Marine Copepod,
Acartia tonsa. Thesis Collection, University of Southern
Mississippi. Hattiesburg, Mississippi.

Koulish.S. 1973. Microtubules and muscle attachment in the
integument of the Balanidac. J . Morphol. 140:1-14.
Lai-Fook, J. 1967. The structure of developing muscle insertions
in insects. J. Mo/pAo/. 123:5 03-528.

Lowe, E. 1935. On the Anatomy of a Marine Copepod. Calanus
finmarchicits (Gur\ncrus). Trans. Roy. Soc. (Edinb.) 58:561-
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Manlon. S. M. 1928. On the embryology of a Mysid crustacean,
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Raymont, J. E. G„ S. Krishnaswainy, M. A. Woodhouse, and R.
L. Griffin. 1974. Studies on the fine structure of Copepoda,
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Rossner, K. L. and R. G. Sherman. 1976. Organization of skclcl.'il
muscle insertion in the crab Carcinusrnaenas. Trans. Amer.
Micros. Soc. 95: 46-55.

Sherman, R. G. 1974. Muscle attachments in horseshoe crab
walking legs. Biol. Dull. 146: 88-99.