CARIDEAN SHRIMPS ASSOCIATED WITH THE SLIMY SEA PLUME (PSEUDOPTEROGORGIA-AMERICANA) IN MIDSUMMER AT GUANA ISLAND, BRITISH-VIRGIN-ISLANDS, WEST-INDIES

Fifty-one slimy sea plumes (Pseudopterogorgia americana Gmelin, 1791) were sampled for caridean shrimps at Guana Island, British Virgin Isla nds, during one week in July 1992. Sampling depth ranged from 3-22 m. Nine species were collected: Hippolyte nicholsoni Chace, 1972; Latreut es sp.; Neopontonides chacei Heard, 1986; Perclimenes cf. patae Heard and Spotte, 1991; Periclimenes cf. pauper Holthuis, 1951; Periclimenes sp.; Pseudocoutierea antillensis Chace, 1972; Tozeuma cf. cornutum Mi lne Edwards, 1881; and Trachycaris rugosa (Bate, 1888). A total of 1,4 18 specimens (including fragments) was obtained. The number of shrimp species per gorgonian ranged from 1-5; one gorgonian harbored 156 shri mps. The 2 predominant species, N. chacei and H. nicholsoni, occupy di fferent mean depths (12.6 and 8.2 m, respectively). Sexual dimorphism assessed with Mann-Whitney U-tests was not apparent in the specimens o f N. chacei (P > 0.05), but females of H. nicholsoni were significantl y larger than males (P < 0.001). Minimum carapace length (CL, the tip of the rostrum to the posterior dorsal margin of the carapace) at whic h male N. chacei acquire a single appendix masculina spine is 1.25 mm; male H. nicholsoni can acquire a single spine at 0.9 mm CL. Histologi cal sections of male N. chacei showed that shrimp with 0 or 1 spine ar e least likely to be mature. Female N. chacei can become ovigerous at 1.9 mm CL and female H. nicholsoni at 1.2 mm CL. The taxonomic status of 5 of the 9 species collected is uncertain.