932 BULLETIN OF MARINE SCIENCE. VOL. 31. NO.4, 1981 the study period the salinity of the Coral Gables Waterway site was consistently higher than that of the Snapper Creek site, and was probably more favorable to the occurrence of the polychaetes, bryozoans, and mollusks on which the gobies fed. Length of the digestive tract as measured from esophagus to anus is expressed by the linear regression: Y = -10.257 + 1.136X, where Y is digestive tract length in millimeters, X is standard length in millimeters, n = 48, r = 0.88. The length of the digestive tract is slightly less than the standard length. Results indicate that the crested goby feeds on a great variety of food items and is an opportunistic feeder. Kinch (1979) remarked on the variety of food items consumed by crested gobies from Marco Island, Florida, and Odum (1970) reported the species as omnivorous, though his specimens from the North River estuary, Florida, contained primarily mangrove-derived material. Plant material is appar- ently an important, though not necessary, food of the crested goby; Kinch (1979) found little plant material in specimens he examined. Small crustaceans and other benthic or algae-associated invertebrates are also of great importance. The varied diet is probably an adaptive advantage, particularly in areas with fluctuating salinity and accompanying floral and faunal changes.

ACKNOWLEDGMENTS

This study was completed in partial fulfillment of the Master of Sciences degree of the Rosenstiel School of Marine and Atmospheric Science, University of Miami, and was supported by an R. Maytag Fellowship. I wish to thank my committee members, D. P. de Sylva, C. R. Robins, and D. R. Moore for their guidance and critical comments, and J. Garcia Gomez for his help in identifying digestive tract contents,

LITERATURE CITED Darcy, G. H. 1978. Ecology of the crested goby, LopllOgobius cyprinoides (Pisces: Gobiidae), in southern Florida. M.S. Thesis, Univ. Miami, Coral Gables, Fla. 267 pp. Kinch, J. C. 1979, Trophic habits of the juvenile fishes within artificial waterways-Marco Island, Florida. Contrib. Mar. Sci. 22: 77-90, Odum, W. E. 1970. Pathways of energy flow in a South Florida estuary. Ph.D. Dissert., Univ. Miami, Coral Gables, Fla. 162 pp.

DATE ACCEPTED: July 28, 1980.

ADDRESS: Rosenstiel School of Marine and Atmospheric Science, University of Miami, 4600 Rick- enbacker Causeway. Miami, Florida 33149.

BULLETIN OF MARINE SCIENCE. 31(4): 932-934. 1981

CNIDARIAN PREY OF THE SNAILS CORALLIOPHILA ABBREVIATA AND C. CARIBAEA (: ) IN DISCOVERY BAY, JAMAICA

Alan C. Miller

The gastropod Coralliophila is known to be associated with and to prey upon members of the phylum Cnidaria (Ward, 1965; Robertson, 1970; Miller, 1972; Ott and Lewis, 1972; Kitting, 1975; Hadfield, 1976; Patton, 1976). The ability of these gastropods to insert the proboscis either through the prey's body wall or down the oral opening of an individual polyp (Ward, 1965; Miller, 1972) SHORT PAPERS AND NOTES 933

Table I. The associations of Coralliophila spp. with species of Cnidaria in Discovery Bay. The number of times an association was observed in the field is noted under each gastropod species and the general location is given

Coralli· Coral/i· ophila ophi/a Cnidaria abbreviata caribaea Lo~tion

Scleractinia Acropora pa/mata (Lamarck) I 2 bay (S.E.) A. cervicornis (Lamarck) 5 reef crest (N.W.) Agaricia agaricites (Linnaeus) 22 reef crest and forereef (N.W.); bay (S.E.) Helioseris cllclillata (Ellis & Solander) bay (S.E.) Siderastrea siderea (Ellis & Solander) I bay (S.E.) S. radians (Pallas) 2 I bay (S.E.) Porites astreoides Lesueur 2 2 bay (S.E.) P. porites (Pallas) I ] bay (S.E.) Favia fragum (Esper) 2 bay (S.E.) Dip/oria clivosa (Ellis & Solander) 2 bay (S.E.) D. labyrinthiformis (Linnaeus) 2 bay (S.E.) D. strigosa (Dana) 5 bay (S.E.) Montastraea annu/aris (Ellis & Solander) 28 forereef (N .W.); bay (S.E.) Dichocaenia stokesii Milne-Edwards & Haime I forereef (N.W.) Mussa angll/osa (Pallas) I bay (S.E.) Mycetophyllia /amarckana Milne-Edwards & Haime bay (S.E.) Gorgonacea Briareum asbestinllln (Pallas) 10 reef crest (N.W.); bay (S.W.) Erythropodium sp. bay (S.E.) Pseudop/exallra sp. reef crest (N. W.) Zoanthidea Zoanthlls sociatlls (Ellis) 8 bay (S.E.) Corallimorpharia Ricordea florida Duchassaing & Michelotti 4 5 bay (S.E.) Rhodactis sanctithomae (Duchassaing & Michelotti) I bay (S.E.) allows these snails to feed on a wide range of cnidarian prey. Although some authors have identified a few prey species of Coralliophila in the Caribbean (Robertson, 1970; Miller, 1972; Ott and Lewis, 1972; Hadfield, 1976), an extensive listing of prey species has not been published. This paper presents a list of cnidarian species preyed upon by Coralliophila abbreviata (Lamarck) and C. caribaea Abbott in Discovery Bay, Jamaica (Table 1). The counts of snail-cnidarian associations were made subtidally (1-25 m depth) during July and August, 1970, along two transects (about 150 m long) in the southeastern section of the bay and by casual survey elsewhere in the bay. The occurrence of one or more snails around an individual cnidarian was counted as a single association. Single individuals or small groups of the snails found with scleractinian corals, the zoanthid Zoanthus sociatus, and the encrusting gorgon ian Briareum asbes- tinum usually live on the fringes of the colonies. Those living in aggregations of the corallimorpharians Rhodactis sanctithomae and Ricordeaflorida are attached to the substratum among individual polyps. Coralliophila caribaea on erect gor- gonians is found attached to dead patches on individual branches or at the base of the colonies. When approached underwater slowly, some individual snails can be found with their proboscis extended in the feeding position. 934 BULLETINOFMARINESCIENCE,VOL.31, NO.4, 1981

Although not all of the 62 species of Scleractinia found in Jamaica by Goreau and Wells (1967) were examined, Coralliophila in Discovery Bay was found in these surveys to feed upon 16 species (C. abbreviata, 14 spp.; C. caribaea, 6 spp. (Table 1)). Only seven of the 83 associations with Scleractinia in this study were with branching corals (Acropora cervicornis and Porites porites) and one of the eight coral prey of C. abbreviata in Barbados (Ott and Lewis, 1972) was branching (A. cervicornis). There appears, therefore, to be a preference for as- sociations with coral species that have massive, plate-like, or encrusting growth forms. The reason for this is unknown, but perhaps the base of branching coral colonies is not extensive enough to attract Coralliophila compared to the large perimeter provided by the other coral growth forms. Even though the diets of C. abbreviata and C. caribaea have some overlap (both eat Scleractinia, Zoanthidea, and Corallimorpharia (Table I», C. abbreviata prefers scleractinian prey (2 x 2 contingency table; X2 = 46, P < 0.00]). Only C. caribaea was found eating Gorgonacea, as found in other studies (Robertson, 1970; Kitting, 1975; Hadfield, ]976). Due to the limited extent of this study, it is certain that additional cnidarian species can be added to the prey list by examining different habitats and cnidarian species. It would be interesting to investigate how the apparent partitioning of prey between C. abbreviata and C. caribaea is maintained.

ACKNOWLEDGMENTS

This work was supported by the Discovery Bay Marine Laboratory, Discovery Bay, Jamaica, and the Organization for Tropical Studies. I thank Dr. J. Lang for identifying the cnidarians and Dr. S. Lawrenz-Miller for diving assistance.

LITERATURE CITED Goreau, T. F., and J. W. Wells. 1967. The shallow-water Scleractinia of Jamaica: revised list of species and their vertical distribution range. Bull. Mar. Sci. 17: 442-453. Hadfield, M. G. 1976. Mollusks associated with living tropical corals. Micronesica 12: 133-148. Kitting, C. L. 1975. The impact of mollusks feeding on some West Indian gorgonians. Bull. Amer. Malacol. Union 41: 73. Miller, A. C. 1972. Observations on the associations and feeding of six species of prosobranch gastropods on anthozoans. (Abstract). Pages 4-5 in G. J. Bakus, ed. Marine studies on the north coast of Jamaica. Atoll Res. Bull. 152. Ott, B., and J. B. Lewis. 1972. The importance of the gastropod Coralliophila abbreviata (Lamarck) and the polychaete Hermodice carunculata (Pallas) as coral reef predators. Can. J. Zool. 50: 1651-1656. Patton, W. K. 1976. associates of living reef corals. Pages 1-36 in O. A. Jones and R. Endean, eds. The biology and geology of coral reefs. Vol. III, Bio. 2. Academic Press, London. Robertson, R. 1970. Review of the predators and parasites of stony corals, with special reference to symbiotic prosobranch gastropods. Pac. Sci. 24: 43-54. Ward, J. 1965. The digestive tract and its relation to feeding habits in the stenoglossan prosobranch Coralliophila abbreviata. Can. J. Zool. 43: 447-464.

DATE ACCEPTED: December 30, 1980.

ADDRESS: Department of Biology, California State University, Long Beach, California 90840