i et ISSN 0038-3872 SOUTHERN CALIFORNIA ACADEMY OF SCIENCES BULLETIN Volume 87 a: Number 1 BCAS-A87(1) 1-48 (1988) APRIL 1988 Southern California Academy of Sciences Founded 6 November 1891, incorporated 17 May 1907 © Southern California Academy of Sciences, 1988 OFFICERS Robert G. Zahary, President Camm C. Swift, Vice-President Hans M. Bozler, Secretary Takashi Hoshizaki, Treasurer Jon E. Keeley, Technical Editor Gretchen Sibley, Managing Editor BOARD OF DIRECTORS 1986-1988 1987-1989 1988-1990 Daniel M. Cohen Larry G. Allen Sarah B. George Takashi Hoshizaki Hans M. Bozler Margaret C. Jefferson Gerald Scherba Allan D. Griesemer Susanne Lawrenz-Miller Camm C. Swift Peter Ls Haaker John D. Soule Robert G. Zahary June Lindstedt-Siva Gloria J. Takahashi Membership is open to scholars in the fields of natural and social sciences, and to any person interested in the advancement of science. 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Date of this issue 6 May 1988 Bull. Southern California Acad. Sci. 87(1), 1988, pp. 1-11 © Southern California Academy of Sciences, 1988 Organisms of a Subtidal Sand Community in Southern California James G. Morin, Jon E. Kastendiek,' Anne Harrington, and Noel Davis? Department of Biology, University of California, Los Angeles, California 90024 'Present address: Biology Department, University of California, Los Angeles, California 90024 ?Present address: Chambers Consultants and Planners, 2933B Pulman Street, Santa Anna, California 92705 Abstract. —A long-term study of a subtidal sand community on the exposed coast of California has revealed a highly structured, diverse assemblage of macroscopic, epifaunal organisms. It is dominated by a few species of relatively large, long- lived suspension feeders, particularly the sand dollar Dendraster excentricus. Along the depth gradient from 2.6 m to 13.1 m there are three faunal zones with the sand dollars occupying most of the middle zone. The community is composed of about 45 common species; the seaward zone has the greatest diversity and number of predators. Nearly 90 invertebrate and more than 30 fish species were recorded during the study. The subtidal nearshore regions of the southern California coastline are domi- nated by long stretches of uninterrupted sand bottoms. Within these habitats there often occur immense beds of the sand dollar Dendraster excentricus. The distri- bution of these beds has been documented in detail by Merrill and Hobson (1970) and also discussed by others (Parks 1973; Dexter 1978; Cameron and Rumrill 1982). The dynamics of these beds have been extensively studied by Morin et al. (1985). The general organization of soft-substrate communities in southern Cal- ifornia has also been addressed by Fager (1968), Davis and VanBlaricom (1978), Oliver et al. (1980), Kastendiek (1982), and VanBlaricom (1982). Despite the unstable, dynamically changing nature of the substrate that occurs in the shallow sandy subtidal, the associated animal assemblages tend to be highly structured and show complex interactions between the physical and biological components of the environment (Morin et al. 1985). The present paper provides a thorough documentation of the macroscopic epifauna and some of the infauna that regularly occur in and around a representative sand dollar bed in southern California. Methods The observations presented here were collected from March 1970 to January 1975 by scuba diving at a variety of locations along Zuma Beach (118°50’W, 34°01'N), 35 km northwest of Los Angeles, California. However, most of the data were collected from two transects located 0.4 km apart and ranging in depth from 1 2 SOUTHERN CALIFORNIA ACADEMY OF SCIENCES 2.6 m (MLLW) and 13.1 m (Morin et al. 1985). Each transect was permanently marked at its ends by stakes placed 180 m apart along the bottom and perpen- dicular to shore. One transect was displaced 30 m seaward relative to the other so that the combined transect length was 210 m. Censuses of macroscopic epi- fauna (>5 mm) and visible infauna were accomplished by counting individuals within a one-meter wide path along each five-meter interval of a polypropylene line that was attached to the stakes just before each census. Sand dollar densities were determined from counts of individuals found within a 0.1 m7? ring blindly tossed at regular intervals along the transect. Less abundant organisms were cen- sused from counts of transects that were 10 m wide along the entire distance of 180 m. The observations reported here are derived from 65 complete transects, 28 partial transects, and a total of 208 dives encompassing about 554 person- hours of underwater surveying. Other details of our methods are reported in Morin et al. (1985). Results The subtidal sand bottom off Zuma Beach is divisible into three distinct zones (Fig. 1): (1) the shoreward zone (2.6-—6.4 m depth [MLLW]), which is dominated by the Pismo clam TJivela stultorum and the sea pansy Renilla kollikeri, (2) the middle or sand-dollar zone (6.4—9.1 m depth [MLLW]), which is dominated by the sand dollar Dendraster excentricus, and (3) the seaward zone (9.1-13.1 m depth [MLLW]), which is dominated by the sea pen Stylatula elongata, the sea pansy Renilla kollikeri, the sea star Astropecten armatus, and the tube worm Diopatra ornata (see also Morin et al. 1985). Nearly 90 macroscopic invertebrate species and over 30 fish species were encountered during the study (Table 1). Detailed information on the distributions, frequencies and abundances, relative locations, and particular features of all these organisms is given in Table 1. Discussion The shallow subtidal sand habitat at Zuma Beach in southern California is composed of a rich assemblage of epifaunal organisms capable of survival in shifting sediments and buffeting sands. Among all the organisms we encountered during our study, over two-thirds were permanent, resident sand dwellers, and about one-quarter were transients from distant rocky habitats; the remainder occur in both types of habitats. Similar to reports of most rocky subtidal habitats (e.g., Pequegnat 1968), the sand community at Zuma Beach is dominated, in both numbers and biomass, by suspension feeding organisms, particularly Dendraster excentricus, Renilla kollikeri, Stylatula elongata, and Tivela stultorum (Table 1 and Morin et al. 1985). All of these species are relatively large, long-lived sus- pension feeders and thus represent an enormous permanent standing crop that is relatively stable, but with low rates of turnover and productivity (Morin et al. 1985). Because of the instability of the substrate, attached plants, and hence herbivores, are virtually absent from this habitat. Carnivores, however, are com- mon but occur in relatively low densities, and fall into two major categories: highly motile species and creepers. Highly motile carnivores (e.g., the decapods Cancer gracilis, Randallia ornata; the fishes Citharichthys stigmaeus, Pleuronich- thys coenosus, Hypsopsetta guttulata) can tolerate substantial surge and thus occur throughout all zones (Table 1). It is only in the relatively calm seaward zone (at ORGANISMS OF A SUBTIDAL SAND COMMUNITY yydaq (S4a}aw U!) ‘poyelas3exa SI 9[BOS [POILIOA “(UMOYS 10U SoYsy) SOUOZ [BOIZOTOIQ UTE 90141 94) WOT sa1Idads UOWIUWIOD aU} JO ¢] BUIMOYS PIUIOJI[ED ‘YoRog ewuINZ JO W0O1}]0q pues [epNqns MOT[eYs 91 JO UOTIONS PazI[AIS “| “314 SNUIDSINAIG 1A{SOS/of ox WUILION URLIODONS IP SIYOWIO UHIIAOLS I MM SNIINUBIXS JA{SOIPUIG EF (MAIN BDDJINS) WAIOL/N{S D/AALL @ (M8IN APIS) WNLOL/N{S D/BALL f} DIIUSOJI/OI DUIWS yy ‘joosueI] 9Y) UO | 9UOZ JO PIeEMaIOYS = § :S$191UNODUD SBI] 01 189}8913 JO JOPIO I19Y) UI PoIsT] Ie PIAtasqo UsEq aARY SaTdads 9Y] B19YM SOUOZ 5 (a 01 |S ‘€9q) daispludiu ‘g “(FO |S ‘ERA) SNIDJOU sdyIyoOg “(S OL F EVA) SyVIMaA “ (§ 01 F ‘EA) Man sXyIyoIUOANa]d ‘(§ 1 A ‘“E%RA) SNNIaa skaydosvd {S$ Or q ‘€wq) vwo}s vuissojsoddiy ‘(a ‘—) “ds snywusudys “(q ‘—) snjpsouanul sdyjyriuavdsor§ (€10'O F 9ZO'O “14sIU 1e | INQ | “—) pIDIINs DUaDAdIOIS ‘(\YystU 1e J Inq [ ‘—) 4ojdn7 DaJIYD “(110'0 F 610°0 UO PasoJUNODUA) satoeds B1PY q ‘syeyiqey djay pue YO1 Ul UOWIWIOD jsOU “‘JUoTSURPIT, = + ‘(S361 ‘Je 19 ULIO| UT ¢ 9IQeI OSTe 99S) sUONeLIeA UONL[Ndod (1v94 p) WHI} BuO] SOJBOIpU] = x (SQ6I ‘Te 19 ULIOY Ul Z BIqQeI OSTe 99S) DATJOB AT[UINISON = x ‘(SQ6] ‘Je 19 UOJ UT | 9IQuI OSTe 99s) JUBPUNGe AT[eUOSRIg = f -eore APMIS OY} UTYIIM SIATP 9} JO %7 UY} DIOUI UO pa}da}ap eUNeKyUT aIQIsIA ATTerIed pue euneyjids (ui ¢<) dIdOdsoO1DvU [][e SOpNou] - cee a a HO RE A a SS SE ee d v9r0'0 + 8£60°0 LY = DIIDA SAYIYIIDUDG 1y43Iu Aq ynoYysnosy} ‘Aep Aq sul] Jns Jesu d 0980°0 + 9070 89 S ,lunajuasav uodososdsada d 96700 + 8€1 0 VL = SnIDIANf UOposaUDYy ouTy Jans vou d ¢rvL0'0 + 11800 18 Ny SNJDINPUN SNYAAIINUAWY JOWIUINS Ul UOWUWIOD 9IOUI q 90L0°0 + vEl'0 8°8 Lecae sdazo01mn] snpouds d 8ITO0 + Ivs'0 6 TI = SNIDAYIDII XDAQDIDADG [[e} Wey) JoWIUWUNS UI UOUTUIOD dow S17 s9P~£0'0 + 0960'°0 €7 — SNIMUAO{YDI SAYIYINDVADT $d o8190°0 + 0970 Sle as pvjniins vjyjasdosdA yy a a a a ee s]USUWOD jove1]sqns (W'a"Ss = X) (awIAep) ,I9U0Z qeSd100d§ 0} Jo0dso1 dAIp Jod uses JOquUINN pues quia SOATP JO uOT}ISOg 93e]U99 -19g eee ‘panunuod “| Ge ORGANISMS OF A SUBTIDAL SAND COMMUNITY “SUIIOJ 9ATIOB A[[PUINIOOU OY} UT 1YSIU 1e SoIdeds oY] JO UOTIISO”g = ( ) “aJBIISGNS 9} DAOGL WOT I[QISIA 10 posodxe jou AT[ensn ‘;eunejuy = | ‘posodxa Wistue3i0 ay} Jo JUNOUIe po}IWIT] e ATUO YIM pue pues oI UI poJOYyoUe JO paLing AT}soul BUIaq Inq pajeloosse ajeNsqng = |S ‘pues oy} UI poloyoue Jo poting Ajied ose ing pesodxs ATIsour BZUI9q Inq po}eloOsse a}eIISqNS = § ‘aye1sqns dy} UO ZuNsol ‘jeuneyidg = q *BUI}SOI AT[PULIOU JOU ‘ZUIWIWIMS ‘oIse[sg = ‘pues UI poling Aqjeried oq Ae a}¥IISsqns PI[OS Inq ‘auIeS = |V ‘a}eIISQNS PI[OS B 0} poyoeie pue [euneyidg = Vv, ‘gye[NoTed 01 JUONboIUT 00} = — °, ‘SOAIP Qpl JO SIseq UO pole[No[ed = x “SOSNSUID ZY ‘SNILMJUIGIXA AAISDAPUIG *L (S861 ‘[e 19 ULIOJ UI g “SY OsTe 9as) pouTUTeXd (‘a°qG) aIsPipUag QOI Jed poyorne sapoeuseqg Jo Jaquinu sy} se possoidxo pu sesnsusd /€ -Oj1NA SIIIv_ “9 “(S861 [B19 ULIOJ Ul ¢ “BY OSTe 9as) pouTUIexa (‘a'q) dajsDApUag OO] Jod paysene safoeuseqg Jo Jaquinu ay} SB posso1dxo puk SesNsUsd 6 snoyfiond snunjpg ° (S861 ‘[e 19 ULIOJ[ Ul € “BY OSTe 99S) pL 61 “Go4 Ul OZO puke snsUsd [/6] ‘G24 94} Ul PCE = N -Sosnsuad QI :VJDU4O pajvdoiq “sosnsuso 77 ‘Mayo v1IAID “Ploy oy} Ul B[QeYSINSUNSIpUI e1oUDS ‘sasnsusd / | :PauUIquIOS (aepluljnueduiey J) puynuvduyyD pue vjjauaaoT “Ply oy} Ul s[qeYsINsuNsIpur sordeds :sasnsusd Q/ :pautquios ‘dds v1jaq—Q isasnsuao [eloads BULINp poArosqgo Ssioquinu = 7 (¢9) A[UO s}OOsURI] SULINP PoAJOsqO SIoquINU =O [WO d1v puL (66I ‘[e 19 ULIOJ] UI g PUL ¢ “SBI OSTL 99S) SUT} DY} JO %OZ< Uses satdads 10J 1d99x9 SOAIP Bp] INoge jo SOBPIDAB OY} Be SIOQUINNA, » ‘S30 DAIP UI PopsOdaI JOU AT[eNsn puke psArJosqo ApJU9}}IUI9}UT = J ‘payeunsaiapun A[qeqoid si souepuNqe oy} Jey} OS Aep sy) 3ULINp pasodxa Ajoreq 10 Teunejuy = y “S30 DAIP UI P9}OU jOU UdJO Inq (%(¢ <) poJoJUNOSUS AfJUaNbeI{ = 4 ‘QAIp Jad Udas I9QUINU dY} UI PIA[OAUI SOI9Z JO IOQUINU 9} JO UONVOIPUT Ue JAIZ PUB SAAIP Sp] INOGe WOIJ UdZP} Iv $93P]UDIINd p ‘yidap wl ¢] 01 9°7 {(€—-]) SOUOZ [[e UT SINd90 ‘pa}oLNsaI A[IeIJI JON = — ‘yidop WI ¢] < ‘preMeBaS dy} 0} JOISURI) BY] puosDg = g aNatwH ‘ponunuoy “] 319eL 10 SOUTHERN CALIFORNIA ACADEMY OF SCIENCES depths >9.1 m), where sand movement and surge become negligible, that creeping carnivores and scavengers (e.g., the asteroids Astropecten verrilli, Luidia foliolata; the gastropods Armina californica, Polinices altus, Megasurcula carpenteriana) become common (Table 1). Thus, this deeper zone also has the greatest number of species. Merrill and Hobson (1970) made an extensive survey of sand dollar beds along the coast of western North America from Eureka, California south to Bahia de Todos Santos, Baja California, Mexico. From sand habitats south of Point Con- ception, California they reported about 53 species of organisms associated with sand dollar populations from the outer-coast (Merrill and Hobson 1970—table 4, p. 613). Of these 53 species, we recorded about three-quarters (38 species) within our study area at Zuma Beach. We have, however, observed all of the other 15 species in other locations either near the ends of the 6 km-long sand dollar bed at Zuma Beach or at nearby locations. Furthermore, 10 of the 15 are listed by Merrill and Hobson as occurring only in some beds and surrounding areas; thus they may be rare or absent within our study area. The differences between the two studies are probably due to: 1) fluctuations in the population densities between the two study periods, 2) differences in habitats (Merrill and Hobson studied a much broader range of habitats and bottom configurations while the habitat in the present study was much more homogeneous), and 3) some infaunal organisms not being systematically sampled in either study. In addition, misidentification is always a possibility. The combined species numbers from Merrill and Hobson (1970) and our study (see also Morin et al. 1985) yields a very large, diverse macrofauna of over 135 species that live on or near these subtidal sand surfaces. And this list does not include the rich and diverse (although low biomass) infaunal and meiofaunal populations that occur in these kinds of habitats (Dexter 1978; Smith 1981; VanBlaricom 1982). From all of these studies it is clear that southern California subtidal sand habitats contain a highly structured, zonally organized community, dominated by specialized organisms whose populations are dynamically modu- lated through complex interactions with the physical environment and with one another. Acknowledgments We thank the other divers who contributed to collecting the data. These include D. Crandall, D. Costa, R. Vance, and M. Tarttelin. For numerous discussions, comments and criticisms we thank T. Ronan, R. Vance, R. Fay, M. Shulman, E. Hobson, and J. Vallee. We acknowledge the help of the Los Angeles County Lifeguards for the use of their physical data and their concern for our safety. This research was supported in part by USPHS Grant NS 09546 and University Re- search Grants to J.G.M. Literature Cited Cameron, R. A., and S. S. Rumrill. 1982. Larval abundance and recruitment of the sand dollar Dendraster excentricus in Monterey Bay, California, USA. Mar. Biol. 71:197-202. Davis, N., and G. R. VanBlaricom. 1978. Spatial and temporal heterogeneity in a sand bottom epifaunal community of invertebrates in shallow water. Limnol. Oceanog. 23:417-427. Dexter, D. M. 1978. The infauna of a subtidal, sand-bottom community at Imperial Beach, Cali- fornia. Calif. Fish Game 64(4):268-279. ORGANISMS OF A SUBTIDAL SAND COMMUNITY 11 Fager, E.W. 1968. A sand-bottom epifaunal community of invertebrates in shallow water. Limnol. Oceanog. 13:448-464. Kastendiek, J. E. 1982. Factors determining the distribution of the sea pansy, Renilla kollikeri, in a subtidal sand-bottom habitat. Oecologia 52:340-347. Merrill, R. J., and E. S. Hobson. 1970. Field observations of Dendraster excentricus, a sand dollar of western North America. Amer. Midl. Nat. 83:585-624. Morin, J. G., J. E. Kastendiek, A. Harrington, and N. Davis. 1985. Organization and patterns of interactions in a subtidal sand community on an exposed coast. Mar. Ecol. Prog. Ser. 27:163- 185. Oliver, J. S., P. N. Slattery, L. W. Hulberg, and J. W. Nybakken. 1980. Relationships between wave disturbance and zonation of benthic invertebrate communities along a subtidal high-energy beach in Monterey Bay, California. Fish. Bull. 78:437-454. Parks, N. B. 1973. Distribution and abundance of the sand dollar Dendraster excentricus off the coast of Oregon and Washington. Fish. Bull. 71:1105—1108. Pequegnat, W. E. 1968. Distribution of epifaunal biomass on a sublittoral rock reef. Pac. Sci. 22: 37-40. Smith, A. L. 1981. Comparison of macrofaunal invertebrates in sand dollar (Dendraster excentricus) beds and in adjacent areas free of sand dollars. Mar. Biol. 65:191-198. VanBlaricom,G.R. 1982. Experimental analyses of structural regulation in a marine sand community exposed to oceanic swells. Ecol. Monog. 52:283-305. Accepted for publication 21 January 1987. Bull. Southern California Acad. Sci. 87(1), 1988, pp. 12-18 © Southern California Academy of Sciences, 1988 Foraging Patterns of Yellowjackets, Vespula pensylvanica, in an Artificial Flower Patch Harrington Wells! and Patrick H. Wells? ‘Faculty of Biological Science, The University of Tulsa, Tulsa, Oklahoma 74104 ?Department of Biology, Occidental College, Los Angeles, California 90041 Abstract. — Vespula pensylvanica, yellowjackets, were attracted to artificial flower patches, made repeated foraging trips, and returned on successive days. We ob- served the foraging patterns of Vespula pensylvanica in blue-yellow color-dimor- phic and clove-peppermint odor-dimorphic artificial flower patches, with variable sucrose molarities and volumes, as previously used to study honey bees. Yel- lowjackets foraged randomly in color-dimorphic patches regardless of reward volume or odor. When one morph provided 1.5 M sucrose, the other 2.5 M sucrose, vespulid wasps foraged randomly. When one morph provided 1.5 M sucrose, and the other flower morph 0.75 M sucrose, yellowjackets visited ran- domly but only drank the richer solution. In odor-dimorphic monochromic patches yellowjackets foraged randomly. Introduction Vespulid wasps, like honey bees and bumble bees, are social hymenopterans. Their diets are more diverse than those of bees, but often include nectar gathered from flowers (Akre et al. 1980; Ross 1983). In fact, when studying foraging patterns of honey bees (Wells et al. 1981, 1983; Wells and Wells 1983, 1984, 1985, 1986), vespulid wasps (yellowjackets), often ventured into the artificial flower patches and foraged there for extended periods. This led to the systematic observation of yellowjacket foraging patterns in color- or odor-dimorphic artificial flower patches under conditions comparable to those used to study honey bees. Experiments were designed to compare yellowjacket foraging to that of honey bees by testing the null hypotheses of random visitation to flower morphs by vespulid wasp foragers, uniform visitation (all foragers exhibit similar behavior) by yellowjacket foragers, and unchanging behavior by individual yellowjackets under the following conditions: 1) each flower, blue and yellow, provided a full load of scented sucrose solution; 2) each flower presented a smaller volume of reward so that a yellowjacket had to visit many flowers per trip from the nest to harvest a full load of scented sucrose solution; 3) unscented rewards were provided in both colors of a dimorphic flower patch; 4) flowers were provided that were odor-dimorphic and monochromic; 5) one color flower had a higher quality reward than the other color flower in a dimorphic flower patch. Methods Yellowjackets, Vespula pensylvanica, were studied at Switzer’s Picnic Area in the Angeles National Forest 35 km north of Occidental College, Los Angeles, on 12 FORAGING OF YELLOWJACKETS 13 Highway 2. Yellowjackets which had been scavaging at the picnic area readily began to forage on the artificial flower patch. Each yellowjacket involved in the experiment was given an individually recognizable paint dot on its thorax or abdomen. The yellowjackets were not traced to their nests, therefore, they may not have all come from a single colony. Foraging patterns of yellowjackets harvesting sucrose solution from an artificial flower patch were recorded under five experimentally controlled conditions with N = 5 in each experiment. Observation periods were of two hours duration from 11:00 a.m. to 1:00 p.m., and were the only times we provided food or exposed the vespulid wasps to artificial flower patches. The artificial flower patch used was of a previously published design (Wells et al. 1981). In that system a “‘flower’’ was defined as a piece of 6 mm clear plexiglass 30 mm square on a pedicel 90 mm long, with a 3 mm x 5 mm feeding well (a “nectary’’) in one corner of the upper surface. The bottom surface of each flower was painted with either No. 1208 blue or No. 1214 yellow Testors enamel. The grids used had 36 flowers, arranged on a brown background board in a Cartesian coordinate system. Flower colors or odors were arranged randomly by the use of a table of random numbers, and random arrangements were changed between and during experiments as a control for the possible use by vespulid wasps of flower position as a foraging cue. A modified pipette was used to dispense the sugar solution. Each flower and the background board were washed after each trial. In the color-dimorphic flower patches equal numbers of blue and yellow flowers were randomly arranged to form a grid of 36 flowers, spaced at 75 mm. In the odor-dimorphic patches, thirty-six flowers were all of one color, spaced at 150 mm rather than 75 mm, and two different scents were randomly distributed among them, one scent per flower. Chi-square statistics were used to test the null hypotheses of random visitation and uniform visitation. The General Exact Test (Wells and King 1980) was used to test for change in behavior of individual foragers. Condition 1. Each blue or yellow flower provided a surplus of scented reward. Each of the 18 yellow and 18 blue flowers of a color-dimorphic flower patch was provisioned with 100 ul of 1.25 M sucrose, scented at the rate of 200 uwml/1 with oil of clove. Flowers were refilled after visitation by vespulid wasps, so that yellowjackets could obtain a full load by visiting only one flower per trip to the artificial flower patch. Yellowjackets were individually marked as they first visited the flower patch. Foraging patterns were recorded during two-hour observation periods on three successive days. Condition 2. Each blue or yellow flower provided a smaller volume of scented reward so that yellowjackets visited several flowers on each trip from the hive in order to obtain a full load of nectar. On the day after the condition | experi- ments, the same set of yellowjackets was offered a flower patch in which each of the 18 blue and 18 yellow flowers was provisioned with 10 ul of 1.25 M sucrose, scented at the rate of 200 ul/1 with oil of clove. Flowers were refilled after visitation by wasps. Foraging patterns were recorded during a two-hour observation period. Condition 3. Unscented rewards were provided in a color-dimorphic flower patch. Each of 18 yellow and 18 blue flowers of a color-dimorphic flower patch was provided with 10 ul of 1.25 M unscented sucrose solution. Flowers were 14 SOUTHERN CALIFORNIA ACADEMY OF SCIENCES Table 1. Vespula pensylvanica visitation to artificial flower patches containing 100 ul clove-scented (200 l/l) 1.25 M sucrose rewards in each of 18 blue (B) and 18 yellow (Y) randomly arranged flowers. Yellow- Day 1 Day 2 Day 3 Total jacket # B Y B Y B Y B Y 1 13 12 13 16 5 9 31 37 2 8 10 10 14 4 5 22, 29 3 11 3 16 5 9 10 36 18 4 — — 9 7 11 8 20 15 5 — — 7 6 9 4 16 10 6 — — 5 7 2 4 7 11 7 _ — 1 5 3 5 4 10 Total 32 25 61 60 43 45 136 130 refilled as emptied. A new set of yellowjackets (different from those observed under conditions | and 2) visited the flower patch during two-hour observation periods on two successive days. The wasps were individually marked upon first visit to the flower patch, and their choices of flowers recorded. Condition 4. Two differently scented rewards were provided in a uniformly colored flower patch. Thirty-six blue flowers were provisioned with 100 ul 1.25 M sucrose solution, 18 scented at the rate of 200 ul/1 with clove oil and 18 scented with 200 ul/1 oil of peppermint. The scented rewards were randomly distributed in the flower patch. A new set of yellowjackets (different from conditions 1, 2 or 3) was marked and foraging patterns recorded for each vespulid wasp during two- hour periods. Whenever flowers were depleted they were refilled with rewards of the original scent. Condition 5. One color flower provided a higher quality reward than the other in a dimorphic flower patch. A final set of yellowjackets different from those observed in conditions 1, 2, 3 or 4 was marked and their foraging patterns recorded as they visited a patch of 18 blue and 18 yellow flowers. Yellow flowers were provisioned with 100 ul 2.5 M and blue flowers with 100 ul 1.5 M clove-scented sucrose solutions. Flowers were refilled as emptied. Foraging patterns were re- corded during a two-hour observation period. A second experiment was performed the next day, using the same set of vespulid wasps, with yellow flowers provisioned with 0.75 M and blue flowers with 1.5 M clove-scented sucrose solutions. Flowers were refilled as emptied. Foraging pat- terns were recorded during a two-hour observation period. Results Condition 1. Each blue or yellow flower provided a surplus of scented reward. Foraging patterns of yellowjackets in a color-dimorphic flower patch when each blue and each yellow flower provided a surplus of scented reward are shown in Table 1. Yellowjackets foraged homogeneously (day 1: x? = 4.0, df = 2, P > 0.10; day 2: x? = 10.1, df = 6, P > 0.10; day 3: x? = 4.8, df = 6, P > 0.50; thus n.s. any day), which is to say they all exhibited the same foraging behavior. Further- more, flower visitation appeared to be random with respect to color (day 1: x? = 4.8, df = 3, P > 0.10; day 2: x? = 10.1,.df = 7, P > 0.10; day 3: x? = 4.9, df= 7, P > 0.50; thus n.s. any day) and yellowjackets individually did not change behavior between days (GET: H, unchanged behavior, P = 0.9 in each case). FORAGING OF YELLOWJACKETS 15 Table 2. Vespula pensylvanica visitation to artificial flower patches containing 10 ul clove-scented (200 pl/1) 1.25 M sucrose rewards in each of 18 blue (B) and 18 yellow (Y) randomly arranged flowers. Yellowjackets are the same as those in Table 1. Yellowjacket # B Y¥: Total 1 16 9 25 2 7 13 20 3 13 16 29 4 11 10 21 5 15 7 22 6 7 9 16 7 15 13 28 Total 84 UY 161 Yellowjackets sometimes visited more than one flower during a trip to the flower patch, even though each flower always provided a surplus of reward. In- dividuals were easily disturbed by movements of other foragers or by the ob- servers, but after taking flight would return to another flower, not necessarily of the same color. All changes in color of flowers visited were recorded and are included in Table 1. Condition 2. Each blue or yellow flower provided a small volume of scented reward. Forging patterns of yellowjackets in a color-dimorphic flower patch in which each flower provided only 10 ul of scented reward are shown in Table 2. At this volume of reward per flower, yellowjackets visited several flowers during each trip to the flower patch (X = 5.6). Visitation again was random (x? = 7.4, df = 7, P > 0.25; n.s.) with respect to color and wasps did not differ significantly in their behavior (x* = 7.1, df = 6, P > 0.25; n.s.). Behavior can be seen to be unchanged from condition 1. Condition 3. Unscented rewards were provided in a color-dimorphic flower patch. Foraging patterns of yellowjackets in a color-dimorphic flower patch with all flowers provisioned with a surplus of unscented reward are shown in Table 3. Yellowjackets did not forage homogeneously (x7 = 14.7, df = 4, P < 0.01) when under condition 3. However, individuals 1, 3, 4 and 5 foraged homogeneously (x? = 0.93, df = 3, P > 0.75; n.s.) and randomly (x? = 1.32, df = 4, P > 0.75; n.s.), whereas yellowjacket 2 exhibited a preference for blue flowers. As in condition 1, wasps often visited more than one flower during a trip to the flower patch. All changes in color of flowers visited were recorded and are included in Table 3. Table 3. Vespula pensylvanica visitation to artificial flower patches containing 100 ul unscented 1.25 M sucrose rewards in each of 18 blue (B) and 18 yellow (Y) randomly arranged flowers. Yellowjacket # B Y Total 1 15 14 29 2 25 4 29 3 7 11 18 4 4 6 10 5 3 3 6 Total 54 38 92 16 SOUTHERN CALIFORNIA ACADEMY OF SCIENCES Table 4. Vespula pensylvanica visitation to artificial flower patches containing 18 flowers with 100 ul clove-scented (C) 1.25 M sucrose rewards, and 18 flowers with 100 ul peppermint-scented (P) 1.25 M sucrose reward. Flowers were randomly arranged. All were blue. Yellowjacket # C P Total 1 9 10 19 2 8 3 11 3 8 11 19 4 3 Vl 10 5 5 5 10 Total 33 36 69 Condition 4. Two differently scented rewards were provided in a uniformly colored flower patch. Foraging patterns of yellowjackets visiting an odor-dimor- phic monochromic flower patch are recorded in Table 4. As in conditions | and 3 yellowjackets often visited more than one flower during a trip to the flower patch. All changes in odor of flowers visited are included in Table 4. Foragers were homogeneous in this behavior (x7 = 4.3, df = 4, P > 0.25; n.s.), and visited flowers randomly with respect to scent (x? = 4.4, df = 5, P > 0.50; n.s.). Thus, yellowjacket foraging in an odor-dimorphic flower patch was identical to the general foraging behavior in the color-dimorphic experiments. Condition 5. One color flower provided a higher quality reward than the other in a dimorphic flower patch. As in conditions 1, 3 and 4, foragers sometimes visited more than one flower during a trip to the flower patch. All changes in flower color visited were recorded and are included in Tables 5 and 6. When the blue flowers of a dimorphic patch provided 1.5 M and the yellow flowers 2.5 M clove-scented sucrose the foraging patterns recorded in Table 5 were observed. Yellowjacket foraging was both homogeneous (x? = 2.8, df = 4, P > 0.50; n.s.) and random (x? = 2.8, df= 5, P > 0.50; n.s.) with respect to color. Foragers visited and drank the rewards from both yellow (2.5 M reward) and blue (1.5 M reward) flowers. When the blue flowers again were provided with 1.5 M and the yellow flowers 0.75 M of clove-scented sucrose, foraging patterns of these same yellowjackets were as shown in Table 6. Yellowjacket flower visitation was both homogeneous (x? = 4.0, df = 4, P > 0.25; n.s.) and random (x? = 5.3, df = 5, P > 0.25; n.s.) with respect to color. Foraging pattern was not quantitatively different from that recorded in Table 5. Behavior of the yellowjackets in the last experiment (Table 6) was qualitatively different from that in all the other experiments. Only yellowjacket No. 3 (Table 6) drank the 0.75 M sucrose solution provided in the yellow flowers. The other yellowjackets tested it then moved to another flower (yellow or blue), drinking only when encountering the 1.5 M sucrose provided in the blue flowers. However, yellowjackets never learned not to test the flower color with lower molarity reward in either condition of experiment 5 (Tables 5 and 6). Discussion Yellowjacket nectar foraging appears to be significantly different from the be- havior reported for honey bees under similar conditions. Honey bees when for- aging on an artificial flower patch composed of pedicellate blue flowers and yellow FORAGING OF YELLOWJACKETS 17 Table 5. Vespula pensylvanica visitation to artificial flower patches containing 18 blue (B) flowers with 100 ul 1.5 M sucrose and 18 yellow (Y) flowers with 100 ul 2.5 M sucrose reward. Flowers were randomly arranged and all rewards contained clove-scent (200 ul/I). Yellowjacket # B Ye Total 1 10 5 15 D 9 12 21 3} 12 11 23 4 7 10 17 5 3 4 7 Total 41 42 83 flowers, randomly arranged, are each remarkably constant to one color or the other, but not all to the same color (Wells et al. 1981, 1983; Wells and Wells 1984). Honey bees are also individually constant to odor when two scents are randomly dispersed among uniformly colored pedicellate artifical flowers (Wells and Wells 1985). In these studies on honey bees, individually constant foraging in a patch of dimorphic pedicellate flowers persisted even when the flower morphs provided unequal qualities, volumes, or frequencies of reward. Individual con- stancy also persisted when distribution of morphs was patchy, rather than random (Wells et al. 1986). Color-dimorphic flat flower patches which allow bees to walk, rather than fly from flower to flower, however, elicit a different behavior from honey bees. In- dividual honey bees foraged at random among alternative flower types when an artificial inflorescence had identical rewards in all flower morphs, and foraged optimally under conditions involving some reward differences (Waddington and Holden 1979; Wells and Wells 1984). Bumble bees and wasps were reported to forage inclusively in artificial inflo- rescence-type flower patches (Real 1981). Foraging behavior of bumble bees on flat flower patches, like that of honey bees, is also variable. Inequalities of molarity and/or frequency of reward between morphs can result in “‘optimal diet’’ or ““minimal uncertainty” patterns of foraging (Real 1981). Complex flower patches, those involving three flower morphs (white, blue and yellow), demonstrated that, not only does honey bee foraging behavior vary in differing environments (Wells and Wells 1984), but that within a single flower patch individual bees foraged differently. Bees visited either both blue and white flowers, and foraged in an optimal diet manner between these two morphs, or Table 6. Vespula pensylvanica visitation to artificial flower patches containing 18 blue (B) flowers with 100 wl 1.5 M sucrose, and 18 yellow (Y) flowers with 100 ul 0.75 M sucrose reward. Flowers were randomly arranged and all rewards contained clove-scent (100 l/l). Yellowjackets are the same as those in Table 5. Yellowjacket # B We Total 1 13 5 18 2 8 10 18 3 16 10 26 4 8 8 16 5 5 6 11 Total 50 i HOO 89 18 SOUTHERN CALIFORNIA ACADEMY OF SCIENCES visited only yellow flowers. Those visiting blue and white rarely visited yellow, and those visiting yellow rarely visited blue or white flowers. Thus, individual constancy behavior acted as a superstructure, while optimal foraging occurred within subsets of flower morphs (Wells and Wells 1986). Behavior of yellowjackets gathering nectar, on the other hand, did not involve individually constant foraging. Furthermore, yellowjackets often failed to take a full load of nectar from a flower when it was available. Finally, unlike bees, yellowjackets would not drink low molarity rewards (0.75 M) when encountered in a dimorphic pedicellate flower patch involving unequal rewards provided by the blue and yellow flowers. However, the yellowjackets did not learn to avoid a flower morph containing the lower molarity reward. Inability to distinguish the color difference between flower morphs does not appear to be the reason for continued visitation, without drinking the reward, to the lower reward-yielding flower morph. A yellowjacket in experiment 3, for example, did not forage ran- domly; rather, it predominantly visited blue flowers. Although not strictly optimal behavior, since foraging time was not minimized, yellowjackets did maximize caloric gain by drinking only the 1.5 M, not the 0.75 M sucrose solution in our second unequal quality experiment. Evolutionary history differences may explain the differing foraging behaviors of yellowjackets and honey bees. Honey bees coevolved with angiosperms as primary pollinators (narrow diet). Yellowjackets evolved as predators and scav- engers. The social structure of bees and wasps may be merely a convergent char- acteristic. Use of nectar, in fact, may be a relatively recent addition to the diets of socialized wasps so that little coevolution has occurred between species of yellowjackets and plants. Literature Cited Akre, M. E., A. Greens, J. F. MacDonald, P. J. Landolt, and H. G. Davis. 1980. Yellowjackets of America north of Mexico. U.S. Dep. Agric. Handb. 552. 102 pp. Real, L. A. 1981. Uncertainty and pollinator-plant interactions: the foraging behaviour of bees and wasps on artificial flowers. Ecology 62:20-26. Ross, K.G. 1983. Studies of the foraging and feeding behavior of yellowjacket foundresses, Vespula (Paravespula) (Hymenoptera: Vespidae), in the laboratory. Ann. Ent. Soc. Amer. 76:903-912. Waddington, K. D., and L. R. Holden. 1979. Optimal foraging: on flower selection by bees. Amer. Nat. 114:179-196. Wells, H., and J. L. King. 1980. A general “exact test’? for N x M contingency tables. Bull. So. Calif. Acad. Sci. 79:65-77. , and P. H. Wells. 1983. Honey bee foraging ecology: optimal diet, minimal uncertainty or individual constancy? J. Anim. Ecol. 52:829-836. ,and . 1986. Optimal diet, minimal uncertainty and individual constancy in the foraging of honey bees, Apis melifera. J. Anim. Ecol. 55:881-836. ,and D. M. Smith. 1981. Honeybee responses to reward size and colour in an artificial flower patch. J. Apic. Res. 20:172-179. , and 1983. Ethological isolation of plants 1. Colour selection by honeybees. J. Apic. Res. 22:33-44. , and D. Contreras. 1986. The effects of flower morph frequency and distribution on recruitment and behaviour of honey bees. J. Apic. Res. 25:139-145. Wells, P. H., and H. Wells. 1984. Can honeybees change foraging patterns? Ecol. Ent. 9:467-473. , and 1985. Ethological isolation of plants 2. Odour selection by honeybees. J. Apic. Res. 24:86-92. Accepted for publication 22 June 1987. Bull. Southern California Acad. Sci. 87(1), 1988, pp. 19-30 © Southern California Academy of Sciences, 1988 Recruitment, Distribution, and Feeding Habits of Young-of-the-Year California Halibut (Paralichthys californicus) in the Vicinity of Alamitos Bay-Long Beach Harbor, California, 1983-1985! Larry G. Allen Department of Biology, California State University, Northridge, California and Southern California Ocean Studies Consortium, California State University, Long Beach, California Abstract. — Distribution, recruitment, and feeding habits of young-of-the-year (YOY, <80 mm SL) California halibut were investigated during the spring and early summer months of 1983-1985 in shallow water (O-6 m) near Alamitos Bay- Long Beach Harbor. YOY halibut were most abundant in fully-protected waters; semi-protected waters contained one-half to one-quarter the number of YOY halibut. No YOY halibut were collected at the exposed coast site. Newly recruited halibut ranged from 8 to 12 mm SL and were approximately 20 to 29 days old. Gammarid amphipods, mysids, teleosts, and harpacticoid copepods were the major food items of YOY halibut. Recruitment was signifi- cantly greater in 1983 and 1984 than in 1985 (catch-per-unit-effort in 1983 > 1984 > 1985). Introduction The California halibut (Paralichthys californicus) is a major commercial and sport species in California. Commercial landings of halibut have steadily declined since recording began (Frey 1971). The commercial catch of halibut has declined since 1915, exhibiting progressively decreasing peaks in the 1930’s, 1940’s, 1960’s, and early 1980’s. Although the catch rose in 1981 (to 1.2 million pounds), it dropped off again in 1982 through 1984 (R. Collins, California Dept. of Fish and Game unpubl. data). Gill-netting pressure has increased (especially in southern California) over the last three to four years which may account, in part, for the slightly higher catches and subsequent decrease in landings. The “‘El] Nino” event of 1982-1983 may also have had an impact on commercial catches through a northward shift in the distribution of adults. Catches from sport landings of California halibut showed a similar pattern to the commerical landings from the 1940’s until about 1972 when the minimum size limit of 22 inches was put into effect. Thereafter, sport catch has remained very low. This trend may be best explained by the fact that sport boat fishing for halibut is no longer profitable and generally has been curtailed. The most probable explanations for the overall decline include over-exploitation of adult stocks by commercial fishing and de- struction and alteration of nursery habitats (Plummer et al. 1983). Although the actual status of the current halibut fishery is under debate, it seems clear that population levels are depressed relative to historical levels. Despite its 1 Contribution No. 55 to the Southern California Ocean Studies Consortium. 19 20 SOUTHERN CALIFORNIA ACADEMY OF SCIENCES historical importance to the commercial and sport fishery, until recently little has been known about the life history and ecology of California halibut. Frey (1971) summarized some of the information up to 1970 on the life history of California halibut. California halibut range from Long Beach, Washington to Magdalena Bay, Baja California with both the center of the commercial fishery and population center being from central California to northern Baja. Frey (1971) reported that halibut spawn in shallow water (9-20 m) from February to July. Halibut are relatively long-lived (up to 30 yr) females growing faster and attaining larger sizes than males. Males mature at about 2-3 years while females mature later at a much larger size (4-6 years). Some notable errors by Frey (1971) include the statement that halibut eggs are demersal and that settlement of juveniles occurs as early as June. Based on the information gathered since 1970, it is known that halibut eggs are planktonic like their larvae and settlement can occur as early as February. Additionally, the aforementioned depth range of spawning in California halibut may not be entirely correct and is currently being investigated using egg data (R. J. Lavenberg, LACMNH pers. comm.). A study by Haaker (1975) presented information on younger stages of California halibut occupying the bay/estuarine environment of Anaheim Bay, California. He found that halibut in the year classes of 0 to 2+ primarily occupied the bay and presented information on growth, diet, movements, parasites, and some limited information on recruitment of YOY into the bay. Plummer et. al. (1983) presented valuable data on food habits in juvenile and adult halibut from open coast locations in the vicinity of San Onofre-Oceanside, California. These authors also summarized existing information on both the diet of halibut and on the habitats of the critical young-of-the-year (YOY) stage. They speculated that YOY halibut occur primarily in embayments along the California coast (see table 3, Plummer et al. 1983) and not in shallow coastal waters. Reliable information on the spawning and the distribution of eggs and various larval stages of California halibut is only now becoming available. It has been known for some time that halibut spawn in nearshore, coastal waters primarily from February—July (Frey 1971; Gruber et al. 1982). However, the actual depth range of spawning is not known at this time. The planktonic eggs of halibut have recently been identified and information on their distribution within the nearshore waters should be forthcoming (R. Lavenberg pers. comm.). Halibut larvae were first described by Ahlstrom and Moser (1975) and have been recently distinguished (Ahlstrom et al. 1984) from the larvae of fantail sole (Xystreurys liolepis) within a limited size range. Planktonic larval stages (<10 mm SL) occur throughout the water column, mainly over 12—45 m bottom depths within approximately 2- 5.5 km of shore in the San Onofre-Oceanside region (Barnett et al. 1984 and unpubl. rep.). Larger larvae occur closer to shore. Halibut larvae are most abun- dant in the plankton in the San Onofre-Oceanside region during March-September (Barnett et al. 1984). Plummer et al. (1983) suggested that halibut larvae probably metamorphose in coastal water and migrate into embayments. The western At- lantic congener, Paralichthys dentatus, spawns offshore in coastal waters and larvae probably move into estuaries after metamorphosing nearshore (Smith and Daiber 1977). A similar species from the western Pacific, Paralichthys olivaceus, shows a similar pattern of life history in Japan (Minami 1982). Further, ichthyo- plankton surveys of several bays and estuaries in southern California have shown CALIFORNIA HALIBUT IN ALAMITOS BAY-LONG BEACH HARBOR 21 ... Los Angeles S Alamitos Bay Oceanside Long Beach Harbor 1 Nautical Mile Sunset Beach \ Fig. 1. Location of sampling stations within the study area near Alamitos Bay-Long Beach Harbor. halibut larvae to be rare within the bays themselves (White 1977; Horn and Allen 1980; Leithiser 1981). Although information on various aspects of the life history and ecology of California halibut is rapidly becoming available, little was known about the critical young-of-the-year stage prior to this study. This gap in information and the hy- potheses about the distribution of early life history stages presented by previous authors (primarily Plummer et al. 1983) served as the impetus for the current study. The purpose of this paper is to present information on the young-of-the- year stage (<80 mm SL) of the California halibut based on a three-year study (1983-1985) primarily in the area of Alamitos Bay-Long Beach Harbor, Califor- nia. Specifically, this paper presents information on: 1) length frequencies and recruitment (1.e., settlement from the plankton) during 1983-1985; 2) estimated growth rates); 3) age-length relationships; 4) food habits; 5) patterns of distribution; and 6) recruitment success during the three years of the study. Methods and Materials Study Sites Sampling was carried out primarily in the vicinity of Alamitos Bay-Long Beach Harbor in 1983-1985 (Fig. 1). Supplemental sampling was carried out in 1984 in the vicinity of San Onofre-Oceanside which served as a comparison site (Aqua Hedionda, near Carlsbad, California, Oceanside Harbor, and five open coast sites 22 SOUTHERN CALIFORNIA ACADEMY OF SCIENCES 10 km apart). At each location specific areas were ranked according to overall exposure to marine weather/swell influence. Embayment stations (Alamitos Bay and Aqua Hedionda) were designated as fully protected habitats. Long Beach and Oceanside harbors were designated as semi-protected habitats. Open coast sites were considered to be exposed habitats (Sunset Beach and five other sites from San Clemente to Oceanside). Sampling Procedure Sampling gear and effort varied over the three years of the study in an attempt to increase sampling efficiency and to satisfy the requirements of various funding agencies. In all three years, small seines were utilized to sample shore stations within Alamitos Bay. The seine used measured 4.9 m x 1 m and consisted of 2 mm knotless, nylon mesh. In 1984, non-shore sampling was carried out using a 2 m beam trawl consisting of 2 mm knotless, nylon mesh. This method was found to have limited use in soft-substrate areas. Subsequently, in 1985, the non-shore stations were sampled with a 2 m otter trawl consisting of 4 mm mesh in the wings and 2 mm mesh in the bag. The otter trawl sampled effectively over all substrates encountered. Seine samples from each of the three years of the study consisted of at least three replicates on each sampling date. The seine was hauled parallel to shore for 10 m and then pivoted straight onto the shoreline. This method of sampling covered approximately 65 m? per haul. A total of 78 seine hauls were made in the three years. Otter trawl and beam trawl samples were deployed and retrieved in an identical manner. Five replicate, three minute tows were made randomly at each station with both the beam trawl (1984; N = 45) and the otter trawl (1985; N = 105) towed behind a 5 m Boston Whaler. The stations, as previously mentioned, corresponded to fully-protected, semi-protected, and exposed habitats at depths of 3-6 m. Beam trawl stations in the San Onofre-Oceanside area were sampled using an 8 m vessel (Raden). Sampling in the Alamitos Bay region was carried out at approximately two- week intervals from 4 May to 27 July in 1983 (5 dates), 12 April to 20 June in 1984 (4 dates) and 13 March to 24 July in 1985 (8 dates). Supplemental sampling in the area of San Onofre-Oceanside was carried out on 13-15 June and 25 June 1984. Surface temperature and salinity were recorded at each station using a Hydrolab sensing device, a bucket thermometer and an AO refractometer. Bottom tem- perature and salinity were recorded using the Hydrolab unit. All halibut caught in the seines or trawls were counted and measured alive on shore or on board the boat. In 1985, subsamples of at least ten individuals per date were either placed on ice for preliminary age determination or preserved in 10% formalin for later gut content analysis. Abundance of other fish and invertebrate species in the hauls was also noted. In the laboratory, otoliths were dissected out and read using a light microscope. Growth rings were read in the sagittae of 10 individuals between 14 and 45 mm SL. We assumed that all rings represented daily growth checks. Gut contents were examined for 67 individuals from the field subsamples which ranged in size from 7 to 77 mm SL. Digestive tracts were removed under a stereo- CALIFORNIA HALIBUT IN ALAMITOS BAY-LONG BEACH HARBOR 23 12 April1984 ‘'? 10 April 1985 N= 23 8 N=18 4 May 1983 N = 31 & 17 May 1983 12 15 May 1984 15 May 1985 5 N = 36 N = 28 N=5 3 8 2 4 TG 4 5 4 £ 4 Oo 20 20 — 4 ‘ ® 6-4 1 June 1983 i 6 June 1984 29 May 1985 r= N=61 N=15 N=14 = 1275 12 = 8 a-| 4 ral 14 June 1983 =| 20 June 1984 12 June 1985 S N=50 2 N=11 N=3 a 4 10 20 30 40 59 60 70 80 10 20 30 40 50 60 70 80 10 20 30 40 50 60 70 80 Size Classes (5 mm intervals) Fig. 2. Length frequency histograms for four comparable sampling dates in each year of the study, 1983-1985. Size classes are depicted in 5 mm intervals. dissecting microscope, opened up, and the contents emptied into a petri dish. Items were identified to the lowest possible taxon and counted. The sorted items were then placed in aluminum pans, dried to a constant weight in a 50°C oven, and then weighed on an analytical Mettler balance to the nearest 0.001 g. Statistical Procedures Relative growth rates were determined for all three years by comparing the mean lengths of halibut for each sampling period. Age-length relationships were determined by least-squares linear regression. Gut content data were summarized as percent frequency of occurrence (F), percent number (N), percent dry-weight (W), and by calculation of the Index of Relative Importance. IRI (Pinkas et al. 1972) was calculated as follows: IRI = (N + W)F. Food habit data were compiled separately for all individuals (N = 67), and for individuals =20 mm SL (N = 29), and for individuals 20-77 mm SL (N = 38), since the most noticeable shift in diet occurred at approximately 20 mm SL. Differences in the distribution of YOY halibut among the three types of habitats (locations) in the Alamitos Bay area were analyzed using Friedman’s non-para- metric method for randomized blocks (Sokal and Rohlf 1969). Data from 1984 beam trawls and from 1985 otter trawls were analyzed separately. A comparison of recruitment success between the three years of the study was based on replicate small seine hauls collected from the shore within Alamitos Bay. Catch-per-unit-effort (CPUE) for each sampling date within each year was 24 Table 1. Year 1983 1984 1985 Fig. 3. — SOUTHERN CALIFORNIA ACADEMY OF SCIENCES YOY halibut mean length and growth rates for four comparable dates in 1983, 1984, and 1985 in Alamitos Bay. Date 4 May 17 May 1 June 14 June 12 April 15 May 6 June 20 June 10 April 15 May 29 May 12 June 80 60 40 Percent Number 20 X length (mm) 21.30 19.67 21.26 29.17 21.48 30.32 44.86 62.33 19.75 19.20 26.50 47.00 N YOY a2 S:E: halibut 6.82 31 3.47 36 1.64 53 3.63 47 3.05 23 7.45 17 8.97 14 5.93 a 6.31 18 11.37 4 11.58 16 17.01 3 Paralichthys californicus 7Tmm 50 mm SL) YOY halibut. Distribution Among Locations The general patterns of distribution for 1984 and 1985 were virtually identical in the Alamitos Bay area, although the location difference in 1984 was not sta- tistically significant (x7[2] = 3.17; P ~ 0.22) due to low sample size, but was significant in 1985 (x?[2] = 8.36; P < 0.05). Comparison sampling in 1984 near San Onofre-Oceanside yielded a nearly identical pattern of distribution between the three locations (protected, Aqua Hedionda, CPUE = 2.3; semi-protected, Oceanside Harbor, CPUE = 0.4, and exposed, five open coast stations, CPUE = 28 SOUTHERN CALIFORNIA ACADEMY OF SCIENCES 0.04). The greatest concentration of YOY halibut in the Alamitos area occurred in fully protected waters (CPUE of 2.1 in 1984 and 1.2 in 1985) (Fig. 6). The semi-protected habitat contained between one-half and one-quarter the concen- tration of YOY halibut. Recruitment of halibut was not observed in the exposed, open coast habitat off Sunset Beach. In 75 trawls taken in the exposed, open coast stations in both the Alamitos and San Onofre-Oceanside areas, only one YOY halibut (35 mm SL) has been captured in the 3 to 6 m depth range. No new recruits were ever collected in these exposed areas. Recruitment Success As indicated by the length frequency plots (Fig. 2), recruitment success varied greatly in the three years of the study based on small seine data from Alamitos Bay. Seine CPUE (+2 S.E.) was highest in 1983 (4.6 + 1.6) followed by 1984 (3.1 + 3.4) and 1985 (0.1 + 0.1). A comparison among the three years showed these differences in CPUE to be highly significant x7[2] = 11.83; P < 0.005). Discussion Feeding Habits Young-of-the-year halibut exhibited a marked ontogenetic shift in diet. Recently recruited (<20 mm SL) halibut fed mainly on small, substrate-oriented prey such as harpacticoid copepods and small gammarid amphipods. YOY halibut larger than about 20 mm SL appeared to shift to larger prey items which are probably less substrate oriented, including mysids, teleosts (principally gobies), and larger gammarid amphipods. As YOY halibut within Alamitos Bay get larger, teleost fishes become more and more important to their diet. Haaker (1975) found a similar pattern of dietary shift in young halibut from Anaheim Bay although the smallest halibut he examined were in the 40-50 mm SL range. Young halibut in Anaheim Bay shifted ontogenetically from small crustaceans and gobies initially to an almost exclusively piscivorous diet in older specimens. Plummer et al. (1983) examined the stomach contents of 336 Cali- fornia halibut (109 to 689 mm SL) trawled from 6 to 30 m depths off San Onofre and near Oceanside. The gut contents were dominated by northern anchovies (Engraulis mordax) and large mysids (notably Neomysis kadiakensis). Smaller halibut (<250 mm SL) mainly contained mysids. Larger individuals (>300 mm SL) mainly contained northern anchovy and other juvenile and adult fishes. It seems clear that halibut from most habitats exhibit a shift in diet according to size. They feed first (<100 mm SL) on small benthic crustaceans, and as they increase in size, larger prey are incorporated into their diet. Large mysids and small fishes become increasingly important in the diet of medium (100-300 mm SL) size fish. Finally, larger fishes are the almost exclusive prey of larger halibut (>300 mm SL). Halibut occurring in bays probably encounter a different range of prey items in different abundances than those in nearshore areas. Haaker (1975) found gobies to be important food items from YOY halibut in Anaheim Bay. However, Plum- mer et al. (1983) determined that mysids were important in the diet of juvenile halibut from coastal waters. From the present study, it was evident that YOY halibut of equivalent size were feeding on different prey items in Alamitos Bay CALIFORNIA HALIBUT IN ALAMITOS BAY-LONG BEACH HARBOR 29 as compared to YOY in Long Beach Harbor. YOY halibut within Alamitos Bay contained mainly harpacticoids, gammarids, and gobies, while those of compa- rable size in Long Beach Harbor contained mostly mysids which were abundant in the area. Recruitment and Distribution Halibut were recruited at sizes ranging from 8 to 12 mm SL in the Alamitos Bay area. This corresponds to an age of between 20 and 29 days based on the preliminary age-length relationship determined by examination of otoliths. If this aging is accurate, the planktonic larval period of halibut is, therefore, somewhere in the realm of 20 to 29 days after hatching. No significant correlation between water temperature and the appearance of new recruits was evident in any of the three years of the study. In 1985, new recruits were sampled at temperatures ranging from 16.4°C to 22.9°C. Recruitment was sporadic and appeared to be independent of temperature in the nursery areas, at least in 1985. Water temperatures during the sampling times varied little in both 1983 (18.3-19.5°C) and 1984 (19.2-21.9°C). This study has provided the first direct evidence in support of the view set forth by Plummer et al. (1983), that young-of-the-year California halibut occupy “‘em- bayments”’ almost exclusively. The results of the present study clearly show that in the area of Alamitos Bay YOY halibut recruit successfully to and are found only in protected or semi-protected waters. Concentrations of YOY halibut are greatest in the protected water within Alamitos Bay. This pattern may be consistent for the entire Southern California Bight since an almost identical pattern of dis- tribution for YOY halibut was found independently in the San Onofre-Oceanside area further south in southern California. A model of YOY halibut distribution based on these findings states that “‘re- cruitment of halibut will occur anywhere that there are relatively calm waters (protected or semi-protected) and these areas will be nursery areas for the young- of-the-year halibut.”’ Calm waters might include not only bays/estuaries and har- bors, but also the leeward sides of points and islands. This general, verbal model allows predictions to be made of where YOY halibut should recruit and occur. These predictions can be tested by sampling for YOY halibut with appropriate gear in areas in question at the correct time of year. The variable recruitment success of YOY halibut among the three years in the study area is intriguing but, as yet, cannot be explained. The most successful recruitment of the three years based on CPUE was 1983, followed by 1984 with a sporadic, ‘““medium”’ recruitment, and by 1985 witha sporadic, light recruitment. A few of the many possible explanations include: 1) general oceanographic con- ditions off the Alamitos Bay area were very different in the three years, 2) pro- ductivity within this nearshore area possibly varied, 3) the El Nino event of 1982- 1983 had some effect on halibut populations, 4) stronger net transport upcoast in 1983 may have brought more potential recruits into the area from southern waters, and 5) fishing pressure on spawning adults offshore of general Alamitos Bay area in the form of gill-netting may have had an effect over the last three years. Whatever the reason, it is clear that some event or events strongly influenced the recruitment success and/or the larval survivorship in the Alamitos Bay-Long Beach Harbor area for the three years, 1983-1985. 30 SOUTHERN CALIFORNIA ACADEMY OF SCIENCES Acknowledgments I gratefully acknowledge my students, Lucienne Bouvier, Robert Jensen, Rhon- da Murotake, and Robert Scott for their field and laboratory assistance during the course of the study. Without their conscientious assistance the project could not have been completed. I also want to thank Jim Cvitanovich and Danny Warren, who operated the Southern California Ocean Studies Consortium (SCOSC) whaler, for their diligence and support. Chris Onuf, John Zoeger, and Jon Sloan were most helpful with several field collections. Milton Love (Occidental College) performed the preliminary aging of the halibut based on otolith ring counts. Steve Caddell, Ed DeMartini, John Hunter, and Milton Love reviewed and provided valuable comments on this paper. This study was funded in part by the Depart- ment of Biology and the School of Science and Mathematics, California State University, Northridge, by the Marine Review Committee (MRC) of the Cali- fornia Coastal Commission, and by the Southern California Edison Company. I gratefully acknowledge their financial support. The MRC does not necessarily accept the results, findings, or conclusions of the portion they funded stated herein. Literature Cited Ahlstrom, E. H., and H. G. Moser. 1975. Distributional atlas of fish larvae in the California current region: flatfishes, 1955-1960. Calif. Coop. Oceanic Fish. Invert. Atlas 23. —., K. Amaoka, D. A. Hensley, H. G. Moser, and B. Y. Sumida. 1984. Pleuronectiformes: development. Jn Ontogeny and Systematics of Fishes. Am. Soc. Ich. Herp., Spec. Publ. No., 1:640-970. Barnett, A. M., A. E. Jahn, P. D. Sertic, and W. Watson. 1984. Distribution of ichthyoplankton off San Onofre, California, and methods for sampling shallow coastal waters. U.S. Fish. Bull., 82(1):97-111. California Dept. of Fish and Game, unpubl. data. Frey, H. W., ed. 1971. California’s living marine resources and their utilization. Calif. Dept. Fish Game, 148 pp. Gruber, D., E. H. Ahlstrom, and M. M. Mullin. 1982. Distribution ofichthyoplankton in the Southern California Bight. Calif. Coop. Oceanic Fish. Invest. Rep., 23:172-179. Haaker, P. L. 1975. The biology of the California halibut, Paralichthys californicus (Ayres), in Anaheim Bay. Jn The Marine Resources of Anaheim Bay. (E. D. Land and C. W. Hill, eds.), Calif. Dept. Fish Game, Fish Bull., 165:137-151. Horn, M. H., and L. G. Allen. 1980. Ecology of fishes in Upper Newport Bay, California: seasonal dynamics and community structure. Calif. Dept. Fish Game, Mar. Res. Tech. Rep. 45, 106 pp. Leithiser, R. M. 1981. Distribution and seasonal abundance of larval fishes in a pristine southern California salt marsh. Rapp. P.-V. Reuns. Cons. Int. Explor. Mer., 178:174-175. Minami, T. 1982. The early life history of a flounder, Paralichthys olivaceus. Bull. Jap. Soc. Sci. Fish., 48:1581—1588 (In Japanese, with English abstract). Pinkas, L., M. S. Oliphant, and I. L. K. Iverson. 1972. Food habits of albacore, bluefin tuna, and bonita in California waters. Calif. Dept. Fish Game, Fish Bull. 152, 105 pp. Plummer, K. M., E. E. DeMartini, and D. A. Roberts. 1983. The feeding habits and distribution of juvenile-small adult California halibut (Paralichthys californicus) in coastal waters off northern San Diego County, CalCOFI Rep., 24:194-201. Smith, R. W., and F. C. Daiber. 1977. Biology of the summer flounder, Paralichthys dentatus, in Delaware Bay. U.S. Fish., Buil., 75:823-830. Sokal, R. R., and F. J. Rohlf. 1969. Biometry. W. H. Freeman and Co., 776 pp. White, W. S. 1977. Abundance, diversity and seasonality of the ichthyoplankton of Newport Bay, California. M.A. Thesis, Calif. St. Univ., Fullerton. Accepted for publication 18 December 1986. Bull. Southern California Acad. Sci. 87(1), 1988, pp. 31-34 © Southern California Academy of Sciences, 1988 Research Notes Records of Mugil curema Valenciennes, the White Mullet, from Southern California Mugil cephalus Linnaeus, the striped mullet, has a cosmopolitan tropical and warm-temperate distribution and is the only mugilid listed from Californian waters (Eschmeyer, Herald and Hammann 1983; Fitch and Lavenberg 1971; Hubbs, Follett and Dempster 1979; Miller and Lea 1972, 1976). Striped mullet are rel- atively common in estuaries and lagoons south of Pt. Conception and occasionally range as far north as San Francisco Bay (Reilly and Sakanari 1982). They were once abundant in the Salton Sea and remain a common fish in the lower Colorado River where they are utilized as a food fish (Minckley 1973; Moyle 1976). White mullet, Mugil curema, are similar to striped mullet in that they occur in tropical shelf waters shallower than 200 meters over sand and mud substrata, at times in brackish and freshwater, but are unknown north of Magdalena Bay on the outer coast of Baja California. Mugil curema occurs in both the tropical Pacific and Atlantic off the Americas. In recent years marine biologists and fishermen have suspected that a second species of mullet might occur in the bays and estuaries of southern California. On 20 August 1982, 13 mullet were collected by beach seine in upper Newport Bay, Orange Co., by John Sunada of the California Department of Fish and Game (CDFG). On 11 May 1983, eight mullet were collected in Bolsa Bay, Orange Co., by Eric Knaggs also of the CDFG. Although both collections were initially iden- tified as Mugil cephalus, they seemed atypical. These fish were turned over to the Natural History Museum of Los Angeles County (LACM). The Newport Bay fish are catalogued as LACM 44375-1; 13: 155-192 mm standard length (SL). Of the eight Bolsa Bay specimens, two were preserved (LACM 43461-1; 2: 226-238 mm SL) and six were skeletonized by maceration (LACM 43461-2 through 7; 6: 223-237 mm SL). The specimens from both collections were in extremely poor condition and their specific determination was not confirmed until the acquisition of a similar mullet from south San Diego Bay on 25 May 1985. We identified this specimen as Mugil curema Valenciennes, the white mullet, and recognized it as conspecific with the material from Newport and Bolsa bays. The San Diego Bay mullet (LACM 44108-1; 293 mm SL), was taken in a gill net set by Luigi Sanfilippo, a commercial mullet fisherman, who speculated it was not the striped mullet he usually caught. Additional white mullet have since been taken by Mr. Sanfilippo. A minor fishery exists for mullet in San Diego Bay where these fish are sold fresh primarily for local consumption. Landings from this fishery since 1980 have varied from 19,000 (1984) to 45,000 (1980) pounds per year. Diagnostic characters that separate the various species of eastern Pacific Mu- gilidae have been presented by Ebeling (1957, 1961) and Chavez (1985). Super- ficially, striped mullet (=s) and white mullet (=w) are similar; however, the fol- lowing characters distinguish them: dorsal profile and cross section of head— blunt and depressed (s) vs. wedge-shaped and more rounded (w) (Figure 1); soft 31 32 SOUTHERN CALIFORNIA ACADEMY OF SCIENCES Fig. 1. Dorsal (upper) and anterior (lower) views of heads of: A. Mugil cephalus (LACM 44108- 2; 322 mm SL), and B. Mugil curema (LACM 44108-1, 293 mm SL); both taken in San Diego Bay on 25 May 1983. The lower figures are based on a cross section of the head taken at rear margin of eyes to emphasize differences in head shape, which is not so striking where the head meets the body. Scales both equal one centimeter. dorsal and anal fins—lacking scales (s) vs. densely scaled (w); tooth morphology — primary teeth simple and secondary teeth bifid (s) vs. all teeth simple (w); total anal fin elements—10 or 11 (s) vs. 12 or 13 (w); general body coloration—grey, distinctly striped (s) vs. silvery, faintly striped or unstriped (w). In addition, when fresh or observed alive underwater, white mullet have a yellower caudal fin, which has a blackened posterior margin that is lacking in striped mullet. Selected counts and measurements (in mm) for the San Diego Mugil curema (LACM 44108-1) are: Dorsal fin IV + 8; anal fin III, 9; pectoral fin (left) 17; vertebrae 12 + 12 = 24; total length 371; head length 70.2; pectoral fin length 40.4; pectoral axillary scale 18.2; anal fin base 42.0; longest anal fin ray 34.0. Two suppositions concerning the provenance of white mullet in California waters can be addressed. First, the capture of this species in 1982, 1983 and 1985, at the possible onset, during and immediately following the 1982-84 El Nino event may be directly related to the occurrence of warm water along Baja California and California. If so, Mugil curema might be expected to make its appearance off RESEARCH NOTES 33 California from those waters off southern Baja California and mainland Mexico only during anomalously warm-water periods, a pattern similar to round herring, Etrumeus acuminatus, and the southern subpopulation of Pacific sardine, Sar- dinops sagax, which made sudden appearances off southern California during the 1982-84 El Nino event (Lavenberg et al. 1986). In such cases occurrence could be associated with either movement of adults (responding to thermal gradients in the eastern Pacific (Simpson 1984a, b)) or to larval—prejuvenile transport. Larvae and prejuveniles of the genus Mugil are planktonic, primarily associated with neuston for a lengthy period (at least two months), and are common in the offshore waters of Baja California. Cowan (1985) has demonstrated that large scale variation in recruitment of sheephead, Semicossyphus pulcher, off California is consistent with annual oceanographic conditions. The early life history stages of sheephead are also planktonic and are subject to transport by currents. During the El Nino event of 1982-84 sheephead recruitment in southern California ap- peared to have been from southern populations (Cowan 1985). It seems to us that both means of transport are possible for Mugil, either as larval—prejuvenile dis- persion or adult movement. These two modes are not necessarily mutually ex- clusive. Second, we do not discount the possibility that M. curema historically has been a component of the bay fauna of southern California and has remained undetected because of its similarity to M. cephalus. Acknowledgments We would like to thank Luigi Sanfilippo for donating his mullet for study, John Sunada and Eric Knaggs (CDFG) for supplying the mullet from Newport and Bolsa bays and John Duffy (CDFG) who kindly made San Diego Bay material available and provided information on the San Diego Bay mullet fishery. We also thank Jeffrey Seigel and Richard Feeney for processing the fish for archiving at LACM. We thank Charles Haugen, Andrew Jahn and James Petersen for their reviews and comments. Literature Cited Chavez, H. 1985. Aspectos biologicos de las lisas (Mugil spp.) de Bahia de La Paz, B.C.S., Mexico, con referencia especial a juveniles. Invest. Mar. CICIMAR, 2(2):1-22. Cowan, R.K. 1985. Large scale pattern of recruitment by the labrid, Semicossyphus pulcher. Causes and implications. J. Mar. Res., 43(3):719-742. Ebeling, A. W. 1957. The dentition of eastern Pacific mullets, with special reference to adaptation and taxonomy. Copeia, 1957(3):173-185. 1961. Mugil galapagensis, a new mullet from the Galapagos Islands, with notes on related species and a key to the Mugilidae of the eastern Pacific. Copeia, 1961(3):295-305. Eschmeyer, W. N., E. S. Herald, and H. Hammann. 1983. A field guide to Pacific coast fishes of North America from the Gulf of Alaska to Baja California. Houghton Mifflin Co., Boston. 336 pp. + 48 plates. Fitch, J. E., and R. J. Lavenberg. 1971. Marine food and game fishes of California. Univ. California Press, Berkeley, 179 pp. Hubbs, C. L., W. I. Follett, and L. J. Dempster. 1979. List of the fishes of California. Occas. Pap. California Acad. Sci. 133, 51 pp. Lavenberg, R. J.,G. E. McGowen, A. E. Jahn, J. H. Petersen, and T. C. Sciarrotta. 1986. Abundance of southern California nearshore ichthyoplankton: 1978-1984. CalCOFI Rept., 27:53-64. Miller, D. J., and R. N. Lea. 1972. Guide to the coastal marine fishes of California. Calif. Dept. of Fish and Game, Fish Bull. 157, 235 pp. 34 SOUTHERN CALIFORNIA ACADEMY OF SCIENCES . 1976. Guide to the coastal marine fishes of California. California Fish Bulletin Number 157. Univ. California, Div. Agricultural Sci., 4065, 249 pp. Minckley, W. L. 1973. Fishes of Arizona. Arizona Dept. Fish and Game, Tempe. 292 pp. Moyle, P. B. 1976. Inland fishes of California. Univ. California Press, Berkeley. 405 pp. Reilly, C. A.. and J. Sakanari. 1982. Record of the striped mullet, Mugil cephalus, in San Francisco Bay. California. California Fish and Game, 68(4):190. Simpson, J. J. 1984a. El Nino-induced onshore transport in the California Current during 1982- 1983. Geophysical Res. Letters, 11(3):241-242. ——. 1984b. A simple model of the 1982-83 Californian “El Nino.” Geophysical Res. Letters, 11(3):243-246. Accepted for publication 22 June 1987 Robert N. Lea, Marine Resources Division, California Department of Fish and Game, Marine Resources Laboratory, Granite Canyon—Coast Route, Monterey, California 93940; Camm C. Swift and Robert J. Lavenberg, Section of Fishes, Natural History Museum of Los Angeles County, 900 Exposition Blvd., Los An- geles, California 90007. BIOLOGY OF THE WHITE SHARK Memoir #9 Papers from a symposium held by the Southern California Academy of Sciences. Contents include material on shark distribution, ecology, age and growth, visual system, hematology, cardiac morphology, feeding, temperature, heat production and exchange, and attack behavior. Make check or money order payable to Southern California Academy of Sciences, and mail to: SOUTHERN CALIFORNIA ACADEMY OF SCIENCES 900 Exposition Blvd. Los Angeles, CA 90007 I would like to order price of $22.50 per copy. copies of the “Biology of the White Shark” papers at the Enclosed is my check for $__________ . Please ship my order to me as follows: Name Address City a Ee ee ee States eee AD COVCNI SOCALSMEM9 Bull. Southern California Acad. Sci. 87(1), 1988, pp. 35-38 © Southern California Academy of Sciences, 1988 Digestion and Abnormal Expulsion of a Jackknife Clam Tagelus subteres by a Sandstar Astropecten armatus Sandstars of the widespread genus Astropecten, living on and under intertidal and subtidal sandy bottoms, are important predators of shelled molluscs, both gastropods and bivalves, as well as other organisms. Astropecten spp. do not possess grasping suckers on their tube feet. They swallow their prey whole carrying out digestion internally (Hyman 1955). If the prey are bivalves Astropecten then expels either ungaped (undigested), partially or fully gaped animals through the oral opening. Clearly the degree of digestion and the size of the bivalve will influence the ease with which an Astropecten will eliminate its prey in the normal manner. Prenant (1936) and Lems (1951) report that Astropecten irregularis are damaged by the swallowing of bivalves that became too large to handle after their valves gape following digestion of the soft tissues. Prenant collected an individual in which the pair of Donax trunculus valves were sticking symmetrically through the aboral wall of the sandstar with indications of regeneration of the aboral integument over the valve hinge. Lems found a number of Astropecten with worn spots on the aboral surface where valves of swallowed Donax vitatus pressed on the underside. In one individual the entire left valve and the dorsal portion of the right valve had punctured the aboral surface at an angle. Christensen (1970) is fairly convinced that the phenomenon cannot occur in a living Astropecten. He maintains that previous reports were made on dead and, in most cases, dried specimens. He also invokes his own observations, suggesting that he did observe the phenomenon although he gives no details. He does offer a drawing of a specimen of Astropecten irregularis, sent to him by Engel from Holland, showing the edge of the right valve of a gaped Donax vitatus poking through the aboral surface. Engel assumes and Christensen concurs that fissures in body walls of Astropecten spp. which have engulfed and digested large bivalves are postmortal in origin and have come about when sandstars have been washed ashore, died and dried in the sun during low tide. The sharp edges of one or both valves then perforated the shrunken skin of the sandstar. While there is no way to determine whether Engel’s specimen had a pre- or postmortal puncture, the photographs of Prenant’s and Lem’s specimens strongly suggest to me that ab- normal expulsion of gaped bivalves was occurring while Astropecten was alive. Corroboration of this possibility follows from the following account. I report an event in which one valve of a digested, fully gaped 46.5 mm long jackknife clam (Tagelus subteres [Conrad, 1873]) is ejected through the mouth of a 126 mm Astropecten armatus Gray, 1840 while the second valve is slowly forced through the stomach and aboral body wall. Since the valves gaped but remained hinged throughout the digestive process, they ultimately came to lie in a plane at right angles to the oral-aboral axis. The sandstar was unable to maneuver both valves through the oral opening; thus one was ejected orally and the other aborally while they were still hinged. Both valves were then forced through the side of the Astropecten, almost severing it in two. Over the following week the standstar tore 35 36 SOUTHERN CALIFORNIA ACADEMY OF SCIENCES itself into two parts, one with two arms and the madreporite, the other with three arms. The details are as follows: On 27 February 1983, during low tide, an Astropecten armatus showing a large, aboral bulge outlining the long axis of a jackknife clam was collected in lower Newport Bay, Orange County, California and transferred to a circulating seawater system at California State University, Northridge. Three days later I observed a cleaned valve of 7. subteres partially protruding through the oral opening of Astropecten. On the following day the edge of the second valve broke through the aboral wall while the first valve was completely out of the mouth but held there by the hinge. By 3 March the opposite end of the second valve was also through the aboral surface; the middle of the valve being covered by the epidermis (Fig. la). Astropecten actively cruised around the tray and reburrowed rapidly when placed on the surface of the sand. On the morning of 5 March the second valve was pushed through the remaining strands of aboral epidermis. Over the next two days the cleaned pair of valves was maneuvered through the side of the sea star, partially cutting it into two; a two-armed section with madreporite and a three-armed section. The partially rendered Astropecten was active throughout the day. Periodically one or another arm would be raised putting a tearing force on the wound. During 8 and 9 March the two-armed section was forced under the three-armed section as a shearing force was applied along the wound line. This behavior continued for the next four days as the tissue bridge between the sections narrowed. On 14 March the sections separated (Fig. 1b). Both sections of Astropecten remained active for the following month. During the middle of April the three-armed section died and disintegrated. The two- armed section regenerated slowly; three minute arms were present on 1 November. Shortly thereafter the animal died when the sea water system broke down. Christensen and Engel notwithstanding, a living Astropecten may expel at least one valve of a gaped bivalve through its aboral surface. It is difficult to generalize about the phenomenon. While Astropecten spp. may occasionally swallow large bivalves, most prey appear to be small. Gemmell, Hertz, and Myers (1980) found mostly small bivalve prey in A. armatus from the Gulf of California as did Wells, Wells, and Gray (1961) in A. articulatus from North Carolina. Of 1051 A. ir- regularis examined by Christensen (1970) 95% of the bivalves were 2.9 mm long or less. However, he does mention an 80 mm long A. irregu/aris normally expelling a 25.3 mm Macoma calcarea and a 32 mm long Cultellus pellucidus inside an A. irregularis of unstated dimensions. Ribi, Scharer, and Ochsner (1977) found 4. aranciacus ranging in size from 107 mm to 190 mm orally eliminating bivalves between 2 mm and 21 mm in length while A. bispinosus between 65 mm and 103 mm were similarly occupied with bivalves between | mm and 19 mm. In another study A. aranciacus averaging 152 mm expelled bivalve prey from | mm to 30 mm long with the majority measuring 10 mm or less (Ribi and Jost 1978). While Lems (1951) gives no measurements for his aborally protruded bivalve, Prenant (1936) does; the sandstar was 86 mm long and the clam 33 mm long. Where measurements permit, including the specimen sent to Christensen by Engel, I have calculated the length to length ratios of Astropecten and engulfed bivalves. Where aboral expulsion has occurred Astropecten is 2.7X or less the length of the bivalve. Where aboral expulsion is not indicated Astropecten is 3.1 Xx or more the length of the bivalve. Whether a critical size relationship determines RESEARCH NOTES 37 Fig. la. Aboral view of Astropecten armatus with both ends of one valve of Tagelus subteres protruding through the aboral epidermis. Fig. 1b. Aboral view of Astropecten armatus after separation of two and three-armed section. Madreporite (light circular area) visible in two armed section. Photographs reproduced from 35 mm Kodachrome slides. 38 SOUTHERN CALIFORNIA ACADEMY OF SCIENCES the incidence of abnormal expulsion will require additional measurements from natural events or from deliberate feeding experiments with large bivalves. This report is the first known of an Astropecten tearing itself into two parts in the process of expelling an unusually large, gaped bivalve. Regeneraton of the disk and three arms on the madreporite bearing two-armed section was underway while the three-armed section disintegrated prior to the system breakdown and the death of the sandstar. In the field I have occasionally observed A. armatus with one or two partially regenerating arms but never with a regenerating disk. However, distintegrating sandstars, either whole or in part, are not uncommon. Whether one can extrapolate from an event in the laboratory under relatively controlled, benign conditions to the field under natural, highly variable conditions is debatable at this time. Addendum On December 2, 1986, during low tide at the same location in lower Newport Bay, I collected a second living Astropecten armatus with both valves of a fully digested, gaped Tagelus subteres protruding through the aboral body wall while a short section of the left valve protruded through the mouth. The animal was established in a sea water tray in my laboratory and by December 8 had ejected both valves partially tearing itself into two parts. Its progress is being followed. Since the sandstar measures 120 mm through the longest arms and the jackknife clam 49.5 mm through its long axis, the length to length ratio is 2.4 and falls under the 2.7 ratio calculated above. Acknowledgments I wish to thank my colleage Dr. John Irving of the Foreign Languages Depart- ment, CSUN, for assistance in translating the article in the Dutch language. Literature Cited Christensen, A. M. 1970. Feeding biology of the sea star Astropecten irregularis. Ophelia, 8:1—134. Gemmell, J., C. M. Hertz, and B. W. Myers. 1980. Seastar predation on molluscs in the San Felipe Bay area, Baja California, Mexico. Festivus, 12:24—55. Hyman, L. B. 1955. The Invertebrates: Echinodermata Vol. IV. McGraw-Hill vii + 763 pp. Lems, K. 1951. Het problem van de gulzige zeesterren. Levende Nat., 54:14—-18. Prenant, M. 1936. Sur un curieux complexe d’Asterie et de Donax. Mem. Mus. Roy. Hist. Nat. Belg., Ser 3(2):413-414. Ribi, G., and P. Jost. 1978. Feeding rate and duration of daily activity of Astropecten aranciacus (Echinodermata: Asteroidea) in relation to prey density. Mar. Biol., 45:249-254. , R. Scharer, and P. Ochsner. 1977. Stomach contents and size-frequency distributions of two coexisting sea star species, Astropecten aranciacus and A. bispinosus with reference to compe- tition. Mar. Biol., 43:181-185. Wells, H. W., M. J. Wells, and I. E. Gray. 1961. Food of the sea-star Astropecten articulatus. Biol. Bull., 120:265-271. Accepted for publication 15 April 1985. Earl Segal, Department of Biology, California State University, Northridge, Cali- fornia 91330. Bull. Southern California Acad. Sci. 87(1), 1988, pp. 39-43 © Southern California Academy of Sciences, 1988 Abundance of Harbor Seals on San Miguel Island, California, 1927 through 1986 Harbor seals (Phoca vitulina richardsi; Shaughnessy and Fay 1977) haul out on all of the Southern California Channel Islands and breed at each with the possible exception of Santa Barbara Island (Stewart et al. in press). The number of seals observed on San Miguel Island (34°02'N, 120°22’W) has been, in general, con- sistently larger than that at any of the other islands (Stewart et al. in press). There seals haul out primarily on four sandy beaches on the north coast and three on the south coast (Stewart 1981la). The number of seals ashore varies during the day (peak numbers are ashore in early afternoon; Stewart 1981la, 1984) and the year (peak numbers are ashore in late May to early June, when seals are molting; Stewart 1981a, b; Stewart and Yochem 1984). Births occur from mid-February through mid-April, although most are in March, and nearly all pups are weaned by early May (Stewart 1981b). Bonnot (1928:30) observed three harbor seals on San Miguel Island in summer 1928. The few published data since then (i.e., Bartholomew and Boolootian 1960; Carlisle and Aplin 1966; Frey and Aplin 1970; Odell 1971) suggest they were uncommon on the Southern California Channel Islands prior to the 1970’s (Stew- art et al. in press). We report here our counts of harbor seals on San Miguel Island in late spring from 1973 through 1983 and use them to examine recent trends in abundance. Since individual seals do not haul out every day and because all seals are rarely, if ever, ashore simultaneously (Stewart and Yochem 1983; Yochem and Stewart 1985), the counts reported are minimal estimates of population size. However, we estimate absolute abundance using corrections derived from radiotelemetry studies (Stewart and Yochem 1983) and discuss the reliability of those estimates. Methods We made aerial surveys each year from 1973 through 1983, and in 1985 and 1986 in late May and early June between 1200 hr and 1500 hr when the greatest number of seals was expected to be hauled out (Stewart 1981b, 1984; Yochem and Stewart 1985). We made those surveys in a single or twin engine, high wing aircraft at altitudes between 150 m and 250 m and photographed seals with a 35 mm camera (hand held) and a 200 mm lens. Counts of seals were later made from black and white enlargements or from projected color imagery. We calculated observed instantaneous rates of increase (f) using the regression method (In number of seals regressed on time, where f is the slope of the regression line; Caughley and Birch 1971; Caughley 1977; McCullough 1982) and converted those exponential rates to finite races (A = e'), which are more appropriate for ‘‘birth-pulse” species (Caughley 1977:6; Eberhardt 1985) such as harbor seals. We estimated absolute abundance (X) and 95% confidence intervals as follows: 39 40 SOUTHERN CALIFORNIA ACADEMY OF SCIENCES X = N/A; 95% confidence interval = N/[(A) + (S.E.)(1.96)] where: N = the number of seals counted, A = average proportion hauled out during survey (= .64); S.E. = standard error of A (= .06): and A and S.E. are from Stewart and Yochem (1983). Results and Discussion The annual increase in seals hauled out in late spring averaged about 22% from 1958 (when the first systematic surveys were made) through 1976 (Ff = .20, R = .91; Fig. 1). Such a high rate of increase is uncommon among large mammals though there are a few well documented cases (e.g., Antarctic fur seals— Payne 1977; white-tailed deer— McCullough 1982; feral horses—Eberhardt et al. 1982: northern elephant seals— Cooper and Stewart 1983). Some pinniped populations increased rapidly on the Channel Islands and elsewhere after commercial harvests and bountied killings ended in the 1800’s and 1900’s (e.g., California sea lions and northern elephant seals— Stewart et al. in press; harbor seals—Scheffer 1928; Pearson and Verts 1970; Newby 1973; Brown and Mate 1983; Payne and Schnei- der 1984). Although harbor seals were occasionally killed on the Channel Islands during the early 1900’s (e.g., Cockerell 1938), they were never harvested or boun- tied to any extent. Their rapid increase in abundance in the 1960’s and 1970’s on San Miguel Island, and other Channel Islands (Stewart et al. in press) which are near the southern limit of the species’ range, may have resulted from relatively high immigration from recovering populations further north. We believe it un- likely, however, that rates of population increase in northern regions were high enough to sustain sufficiently high emigration to account for the increases in Southern California. Alternatively, combinations of high fecundity and low mor- tality of seals in Southern California during that period would have been required to account for the increases observed. Data are not available, however, to test those hypotheses. Harbor seal numbers continued to increase from 1976 through 1986 (fF = .05, R = .75) but much slower than previously, perhaps because of density-dependent influences on vital rates, entanglement and mortality of seals in fishing gear and marine debris (Stewart and Yochem 1985a, 1987) or changes in haul-out patterns acting singly or in combination. Mortality of seals in drift and set gill net fisheries has apparently increased recently in coastal waters of California (e.g., Hanan et al. 1986). The impacts of those mortalities on harbor seal abundance on the Channel Islands are, however, unpredictable. We estimated that there were about 1830 harbor seals in the San Miguel Island herd in 1987 (Fig. 1) but because the age and sex composition of seals ashore may vary seasonally (Yochem and Stewart 1987), this is probably an under- estimate. In addition, the accuracy of an estimate of absolute abundance (Fig. 1) is dependent on the consistency among years of the average proportion of seals hauled out and on the similarities of haul-out patterns on San Nicolas (where correction factors were derived) and San Miguel islands. Interpretations of recent trends in abundance based on counts are also sensitive to those influences, but there are few data available to examine temporal and geographic variability of RESEARCH NOTES 41 2 ae Bad, | 2 lal 2 ” =! 3 < 1.6 4 we 7) o & 1.4 4 o 8 5 1.2 4 i 2 15 = = oe S| 0.6 0.4 0.2 ry Al a OR Saale a al Ta ee 58 59 60 61 62 63 64 65 66 67 68 69 70 717 YEAR (1958-1986) Number of seals counted ® Derived abundance estimate Fig. 1. Annual peak counts and estimated absolute abundance (with 95% confidence intervals) of harbor seals on San Miguel Island, 1958-1986. haul-out patterns. On San Nicolas Island, the proportions of radio-tagged seals hauled out in afternoon in late May and early June were much smaller in 1983 than in 1982 (Yochem and Stewart 1985). Those differences may be related to differences in age and sex compositions of seals tagged in 1982 and 1983 or to the influence of the 1982/1983 El Nino Southern Oscillation event on seals’ behavior as evidenced by changes in their diet at San Nicolas Island in 1983 (Stewart and Yochem 1985b), or both. Accurate determinations of absolute abundance of harbor seals on the Channel Islands and elsewhere will require further studies of temporal, geographic, and habitat influences on the proportions of seals ashore. Acknowledgments We thank J. R. Jehl, Jr., C. F. Cooper, C. W. Fowler, T. R. Loughlin, J. Estes, and P. Boveng for their comments on the manuscript. Work of BSS and PKY was supported by USAF contract No. F04701-81-C-0018 and National Marine Fisheries Service contracts 81-IGA-284 and 83-ABC-00136. We thank the Chan- nel Islands National Park and Channel Islands National Marine Sanctuary pro- grams for their support of our research, Channel Islands Aviation for their service in conducting aerial surveys, and the personnel of Range Scheduling, Pacific Missile Test Center, for their help in issuing clearance to us to conduct surveys in the Pacific Missile Test Range. Aerial surveys were conducted under MMPA Marine Mammal Permits No. 71 and No. 341. 42 SOUTHERN CALIFORNIA ACADEMY OF SCIENCES Literature Cited Bartholomew, G. A.,and R. A. Boolootian. 1960. Numbers and population structure of the pinnipeds on the California Channel Islands. J. Mamm., 41:366-375. Bonnot, P. 1928. Report on the seals and sea lions of California. Calif. Div. Fish Game Fish. Bull., 14:1-62. Brown, R. F., and B. R. Mate. 1983. Abundance, movements, and feeding habits of harbor seals, Phoca vitulina, at Netarts and Tillamook Bays, Oregon. U.S. Fish. Bull., 81:291-301. Carlisle, J. G., Jr.,and J. A. Aplin. 1966. Sea lion census for 1965 including counts of other California pinnipeds. Calif. Fish and Game, 52:119-120. Caughley, G. 1977. Analysis of vertebrate populations. John Wiley and Sons, N.Y., 234 pp. , and L. C. Birch. 1971. Rate of increase. J. Wildl. Manage., 35:658-663. Cockerell, T. D. A. 1938. San Miguel Island, California. The Scientific Monthly, 46:180-187. Cooper, C. F., and B. S. Stewart. 1983. Demography of northern elephant seals, 1911-1982. Science, 219:969-971. Eberhardt, L. L. 1985. Assessing the dynamics of wild populations. J. Wildl. Manage. 49:997-1012. , A. K. Majorowicz, and J. A. Wilcox. 1982. Apparent rates of increase for two feral horse herds. J. Wildl. Manage., 46:367-374. Frey, H. W., and J. A. Aplin. 1970. Sea lion census for 1969 including counts of other California pinnipeds. Calif. Fish and Game, 56:130-133. Hanan, D.A., J. P. Scholl, andS. L. Diamond. 1986. Marine mammal/fisheries interactions: Analysis and mitigations in California fisheries. S. Calif. Acad. Sci. Ann. Mtng., San Bernardino, CA, 2-3 May 1986. McCullough, D. R. 1982. Population growth rate of the George Reserve deer herd. J. Wildl. Manage., 46:1079-1083. Newby, T. C. 1973. Changes in the Washington State Harbor seal population, 1942-1972. Murrelet, 54:4-6. Odell, D. K. 1971. Census of pinnipeds breeding on the California Channel Islands. J. Mamm., 52: 187-190. Payne, M. R. 1977. Growth of a fur seal population. Philos. Trans. R. Soc. Lond., Ser. B, 279: 67-79. Payne, P. M., and D. C. Schneider. 1984. Yearly changes in abundance of harbor seals, Phoca vitulina, at a winter haulout site in Massachusetts. U.S. Fish. Bull., 82:440-442. Pearson, J. P., and B. J. Verts. 1970. Abundance and distribution of harbor seals and northern sea lions in Oregon. Murrelet, 51:1-S. Scheffer, T. H. 1928. Precarious status of the seal and sea lion on our northwest coast. J. Mamm., 9:10-16. Shaughnessy, P. D., and F. H. Fay. 1977. A review of the taxonomy and nomenclature of North Pacific harbor seals. J. Zool., Lond., 182:385-419. Stewart, B. S. 1981la. Hauling patterns and molt in the harbor seal (Phoca vitulina richardsi) and their significance in monitoring populations on the Southern California Channel Islands. Proc. Fourth Bienn. Conf. Biol. Mar. Mamm. 14-18 Dec. 1981, San Francisco, CA, p. 110. —. 1981b. Seasonal abundance, distribution, and ecology of the harbor seal, Phoca vitulina richardsi, on San Miguel Island, California. M.S. Thesis, San Diego State University, San Diego, CA, 66 pp. —. 1984. Diurnal hauling patterns of harbor seals at San Miguel Island, California. J. Wildl. Manage., 48:1459-1461. ,and P. K. Yochem. 1983. Radiotelemetry studies of hauling patterns, movements, and site fidelity of harbor seals, Phoca vitulina richardsi, at San Nicolas and San Miguel islands, Cali- fornia. HSWRI Tech. Rept. 83-152, 25 pp. , and 1984. Seasonal abundance of pinnipeds at San Nicolas Island, California, 1980- 1982. Bull. Southern Calif. Acad. Sci., 83:121-132. , and 1985a. Entanglement of pinnipeds in net and line fragments and other debris in the Southern California Bight. Pp. 315-325 in Proceedings of the Workshop on the Fate and Impact of Marine Debris, 26-29 November 1984, Honolulu, Hawaii. (R. S. Chomura and H. O. Yoshida, eds.), U.S. Dept. Commerce, NOAA Tech. Memo., NMFS, NOCAA-TM-NMFS- SWFC-54. RESEARCH NOTES 43 , and 1985b. Feeding habits of harbor seals (Phoca vitulina richardsi) at San Nicolas Island, California, 1980-1985. Proc. Sixth Bienn. Conf. Biol. Mar. Mamm. 22-26 November 1985, Vancouver, B.C. , and 1987. Entanglement of pinnipeds in synthetic debris and fishing net and line fragments at San Nicolas and San Miguel islands, California, 1978-1986. Mar. Pollut. Bull., 18:336-339. , R. L. DeLong, and G. A. Antonelis. Jn press. Status and trends in abundance of pinnipeds on the Southern California Channel Islands. Proceedings of the Third California Islands Symposium, 2-6 March 1987, Santa Barbara, CA. Yochem, P. K., and B. S. Stewart. 1985. Radiotelemetry studies of hauling patterns, movements, and site fidelity of harbor seals (Phoca vitulina richardsi), at San Nicolas Island, California, 1983. HMRI Technical Report No. 86-189. , and 1987. Factors influencing haul-out behavior of harbor seals at the Southern California Channel Islands p. 39, Abstr. Third California Islands Symposium. Santa Barbara, CA. Accepted for publication 18 December 1986. Brent S. Stewart, Sea World Research Institute, Hubbs Marine Research Center, 1700 South Shores Road, San Diego, California 92109, George A. Antonelis, Jr., and Robert L. DeLong, NMML, NMFS, 7600 Sand Point Way, Seattle, Wash- ington 98115, and Pamela K. Yochem, Sea World Research Institute, Hubbs Marine Research Center, 1700 Shores Road, San Diego, California 92109 CALL FOR MANUSCRIPTS FOR BULLETIN After a number of years, we have finally depleted our large backlog of manuscripts. We can now publish manuscripts within six months of submission. Please send to Dr. Jon Keeley, Biology Department, Occidental College, 1600 Campus Road, Los Angeles, California 90041. Bull. Southern California Acad. Sci. 87(1), 1988, pp. 44-45 © Southern California Academy of Sciences, 1988 Pacific White-sided Dolphins (Lagenorynchus obliquidens) in the Sea of Cortez Leatherwood et al. (1984) reviewed data on distribution and movements of Pacific white-sided dolphins, Lagenorynchus obliquidens, in the eastern North Pacific (east of 180 degrees west longitude). The 1300 records they judged reliable, documented the occurrence of this species in coastal, continental shelf, and pelagic waters and from about 20 degrees to 61 degrees north latitude; the most northerly record, from Valdez, Alaska, in Prince William Sound, and the most southerly, from Islas Revillagigedos, Mexico, were considered extralimital. It was concluded that in the eastern North Pacific this species is primarily an inhabitant of temperate waters between about 23 degrees north latitude and the southern Alaskan coast. It undertakes pronounced movements north-south and inshore-offshore in var- ious areas and seasons. There are only a handful of verified records of white-sided dolphins from the southern Baja California peninsula (Leatherwood et al. 1984: fig. 7). Of those, the only ones indicating presence of this dolphin species in the Gulf of California (Sea of Cortez) are fishermen’s accounts from the 1960’s and early 1970’s of occasional sightings near Gorda Bank, in the mouth of the Gulf (Leatherwood et al. 1982). Heretofore, there has been no information indicating penetration very far into the Sea of Cortez. Table 1. Recent sightings of Pacific white-sided dolphins in the southwestern Sea of Cortez. Number of indi- Date Location viduals Observations 23 June 1981 Canal de San Lorenzo ca. 25 Seen 250 m from R.V. Ellen B. 24°23'N, 110°20'W Scripps. 25 April 1982 Canal de San Lorenzo ca. 100 Feeding in company of an adult California sea lion, Zalophus sp., identified by divers at <6 m distance. 28 April 1982 Canal de San Lorenzo 8-9 19 June 1982 Canal de San Lorenzo ca. 150 31 March 1983 Near Cabo San Lucas 3 M. Webber, M.V. Executive; 22°45'N, 109°50'W small animals. 15 April 1984 Canal de San Lorenzo ca. 200 Group included newborn calves. 20 February 1985 Between Isla Cerralvo and 5 K. Connally S/R/V Diamaresa Baja California (see Connally et al. 1985). 24°15'N, 110°05’W 23 February 1985 West of Isla Espiritu Santo 2 K. Connally S/R/V Diamaresa 24°30’N, 110°25’W (see Connally et al. 1985). 6 March 1985 Near Isla Danzante 15 S. Leatherwood, R/V Sea 25°50'N, 111°00’W World. 44 RESEARCH NOTES 45 Between June 1981 and March 1985, we and colleagues encountered white- sided dolphins on nine occasions between about Punta Gorda and Isla Danzante, in the southwestern Sea of Cortez (Table 1). The sightings were logged incidental to tourist activities or other research, so were not investigated in detail. All occurred between spring and early summer, part of the period (winter through spring) when the greatest number and variety of cetaceans appear to congregate in the Bay of La Paz (Aurioles and Munoz, unpublished data). ““Groups” contained 2 to over 250 individuals and were all over the narrow shelf separating the peninsula shores from the adjacent pelagic zone. Two groups (on 20 and 23 February 1985) were associated with the common dolphin, Delphinus delphis, a common association elsewhere. These two species are sympatric. Collectively, these records suggest that white-sided dolphins are not infrequent visitors, at least seasonally, to waters of the southwestern Sea of Cortez. Literature Cited Connally, K., S. Leatherwood, G. James, and B. Winning. 1985. A note on vessel surveys for whales in the Sea of Cortez, January through April, 1983-1985, and on the establishment of a data reporting center for the area. Document SC/37/0 25, presented to the IWC Scientific Committee, Bournemouth, England, 16 pp. Leatherwood, S., R. R. Reeves, A. E. Bowles, B. S. Stewart, and K. R. Goodrich. 1984. Distribution, seasonal movements and abundance of Pacific white-sided dolphins in the eastern North Pacific. Sci. Rep. Whales Res. Inst. 35:129-157. , W. F. Perrin, and W. E. Evans. 1982. Whales, dolphins, and porpoises of the eastern North Pacific and adjacent arctic waters: a guide to their identification. NOAA Tech. Rep., NMFS Circ. 444, 245 pp. Accepted for publication 24 September 1986. David Aurioles (1), Stephen Leatherwood (2), and Eduardo Munoz (1); (1) Centro de Investigaciones Biologicas de B.C.S., Apdo. postal 128, La Paz Baja California Sur, México, (2) Hubbs Marine Research Institute, 1700 South Shores Road, San Diego, California 92109 USA Bull. Southern California Acad. Sci. 87(1), 1988, pp. 46-47 © Southern California Academy of Sciences, 1988 Detonella papillicornis (Richardson) (Isopoda: Oniscidea: Scyphacidae) from Bolinas Lagoon, California Even though it has an extensive range, Detonella papillicornis (Richardson) has been only sporadically collected. The species was originally described by Rich- ardson (1904) on the basis of a single male (Schultz 1972) from Seldovia, Alaska. Fee (1926) collected an additional specimen of D. papillicornis at Hammond Bay in British Coiumbia, Canada. Lohmander (1927) reported and described four individuals from Bering Island, Russia, which were collected in 1897, and Hatch (1947) reported D. papillicornis from Ketchikan, Alaska, and Friday Harbor, Washington. See Van Name (1936) for a discussion of the species and early synonymy. Unfortunately, Richardson’s description of Detonella papillicornis was inac- curate in several respects (Lohmander 1927; Schultz 1972) and her figures were, as Lohmander put it, somewhat schematic, making it unlikely that new collections of D. papillicornis could have been recognized as such on the basis of Richardson’s description alone. This situation is evidenced by the fact that Verhoeff, on the basis of Richardson’s and Lohmander’s descriptions, erected a new species (De- tonella lohmanderi Verhoef) for Lohmander’s specimens, and suggested that D. papillicornis and D. lohmanderi probably belonged to different families (Verhoeff 1942). However, for the reasons put forth by Hatch (1947), and with the rede- scription of Richardson’s type specimen by Schultz (1972), and considering the fact that Richardson herself identified the Bering Island specimens (Lohmander 1927), there is no doubt that D. Johmanderi is a junior synonym of D. papillicornis. With Lohmander’s (1927) excellent description and illustration of D. papillicornis, and Schultz’s illustration of the whole animal (Schultz 1972), D. papillicornis is now adequately described and figured and easily recognizable. I collected a single female specimen of Detonella papillicornis (5 mm long) at Bolinas Lagoon in Marin County, California, on 30 May 1986, and an additional six specimens (3 females, lengths = 3.25, 3.00, and 2.50 mm; 2 males, lengths = 3.75 and 2.00 mm; and 1 juvenile, length = 1.25 mm) at the same site on 27 September 1986. None of the females was gravid. The female collected on 30 May had a distinctly orange colored body with reddish-orange eyes. The remaining specimens possessed black eyes and light brown body color as described by Rich- ardson (1904). All specimens were collected at the southern end of the lagoon at the high tide line. Specimens were found under rocks and gravel in grass and pickleweed. Other oniscids found at the site were Mauritaniscus littorinus (Miller), Armadilloniscus coronacapitalis Menzies, Armadilloniscus lindahli (Richardson), Armadillidium vulgare (Latreille), and Porcellio scaber Latreille. The “‘red eyed/red body” color morph of the specimen collected on 30 May is not uncommon in oniscids and has been previously reported in Armadillidium vulgare (Vandel 1945), Venezillo evergladensis Schultz (Johnson 1976), Porcellio scaber (Schultz et al. 1982), Porcellio dilatatus Brandt & Ratzeburg (Sassaman 46 RESEARCH NOTES 47 and Garthwaite 1980), and Mauritaniscus littorinus (Schultz et al. 1982). I have also observed this color morph in Trachelipus rathkei (Brandt). Lohmander (1927) considered Detonella papillicornis to have a subarctic dis- tribution. The collection of D. papillicornis from Bolinas lagoon in central Cali- fornia, which extends the range of this species 1150 km to the south, is clearly outside of the subarctic region. The oniscids of California have never been ade- quately collected, and accurate historical information on the species present in California and their distributions does not exist. It is thus impossible to say whether this southern collection represents a recent introduction of D. papillicornis into California or a natural part of the range of this species. Two individuals of Detonella papillicornis from Bolinas Lagoon have been deposited in the Santa Barbara Museum of Natural History (SBMNH 34871) and an additional two specimens have been deposited in the National Museum of Natural History (USNM 233301). I thank Floria Parker for help in collecting the specimens. Literature Cited Fee, A. R. 1926. The Isopoda of Departure Bay and vicinity with descriptions of new species, variations, and colour notes. Cont. Canad. Biol. Fish., N. S., 3(2):13-47. Hatch, M. H. 1947. The Chelifera and Isopoda of Washington and adjacent regions. Univ. Wash. Pub. Biol., 10(5):155-274. Johnson, C. 1976. Genetics of red body polymorphism in the isopod Venezillo evergladensis. J. Hered., 67:157-160. Lohmander, H. 1927. On some terrestrial isopods in the United States National Museum. Proc. U.S. Nat. Mus., 27:1-18. Richardson, H. 1904. Isopod crustaceans of the northwest coast of North America. Harriman Alaska Expedition, 10:213-230. Sassaman, C., and R. L. Garthwaite. 1980. Genetics of a pigment polymorphism in the isopod Porcellio dilatatus. J. Hered., 71:158-160. Schultz, G. A. 1972. A review of species of the family Scyphacidae in the New World (Crustacea, Isopoda, Oniscoidea). Proc. Biol. Soc. Wash., 84:477-—487. , R. L. Garthwaite, and C. Sassaman. 1982. A new family placement for Mauritaniscus littorinus (Miller) n. comb. from the west coast of North America with ecological notes (Crus- tacea: Isopoda: Oniscoidea: Bathytropidae). Wasmann J. Biol., 40:77-89. Vandel, A. 1945. Recherches sur la génétique et la sexualite des isopodes terrestres. IX. Recherches de génétique sur quelques oniscoides. Bull. Biol. France Belg., 79:168-216. Van Name, W. G. 1936. The American land and fresh-water isopod Crustacea. Bull. Amer. Mus. Nat. Hist., 71:1-535. Verhoeff, K. W. 1942. Zur kenntnis der Armadilliden und tiber Detonella (Scyphacidae). Zool. Anz., 138:162-174. Accepted for publication 17 April 1987. Ronald L. Garthwaite, Institute of Marine Sciences, University of California, Santa Cruz, California 95064 SOUTHERN CALIFORNIA ACADEMY OF SCIENCES ANNUAL MEETING MAY 6-7, 1988 CALIFORNIA STATE UNIVERSITY NORTHRIDGE with participation by American Cetacean Society « Desert Studies Consortium Southern California Association of Marine Invertebrate Taxonomists e Southern California Ichthyologists « Program Chairman: Dr. Larry G. Allen, Department of Biology, California State University, Northridge, CA 91330. Tel.: (818) 885-4569. 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All changes in galley proof attributable to the author (misspellings, inconsistent abbreviations, deviations from style, etc.) will be charged to the author. Reprint orders are placed with the printer, not the Editor. CONTENTS Organisms of a Subtidal Sand Community in Southern California. By James G. Morin, Jon E. Kastendiek, Anne Harrington, and Noel Foraging Patterns of Yellowjackets, Vespula pensylvanica, in an Artificial Flower Patch. By Harrington Wells and Patrick H. Wells 000000000... Recruitment, Distribution, and Feeding Habits of Young-of-the-Year Cal- ifornia Halibut (Paralichthys californicus) in the Vicinity of Alamitos Bay-Long Beach Harbor, California, 1983-1985. By Larry G. ATT CIs Bios ne ess Gn hos ir Sala RU RT) caret ae et Research Notes Records of Mugil curema Valenciennes, the White Mullet, from Southern California. By Robert N. Lea, Camm C. Swift, and Robert J. Lavenberg Digestion and Abnormal Expulsion of a Jacknife Clam Tagelus subteres by a Sandstar Astro- pecteniarmatuss. By Earl Segal tis. pee ee ES eae Abundance of Harbor Seals on San Miguel Island, California, 1927 through 1986. By Brent S. Stewart, George A. Antonelis, Jr., Robert L. DeLong, and Pamela K. Yochem Pacific White-sided Dolphins (Lagenorynchus obliquidens) in the Sea of Cortez. By David Aurioles, Stephen Leatherwood, and Eduardo Munoz 2.2 ee Detonella papillicornis (Richardson) (Isopoda: Oniscidea: Scyphacidae) from Bolinas Lagoon, Galifomiay, By“Ronald L. Garthwaite 2.222 LIBRARY APR - 2 1996 NEW YORK BOTANICAL GARDEN 12 19 31 35 39 44 46 COVER: Dendraster excentricus, a dominant sand dollar species of the subtidal sand community of the exposed coast of Southern California. Photograph submitted by authors, Morin, Kas- tendiek, Harrington and Davis. Page 1.