Diversity and recruitment of penaeoid shrimps (Crustacea : decapoda) at Bear Cut, Biscayne Bay, Florida, USA

Postlarval and juvenile penaeoid shrimps were collected with moored channel nets at Bear Cut, a tidal pass between the Atlantic and Biscayne Bay, Flor ida, from January through December 1994. Results show a much higher number of species than in previous reports. Among juveniles, Metapenaeopsis spp., which comprised five species, was the most abundant and diverse genus. Two of them, M. martinella and M. hobbsi, constitute new records for North Amer ican waters. Despite the abundance of Metapenaeopsis spp., neither small ju veniles (CL <2.0 mm) nor larger adults (CL >12.5 mm) were caught at Bear Cu t. The genus Farfantepenaeus was represented by the pink shrimp, F. duoraru m, and the pink spotted shrimp, F. brasiliensis, in a proportion of 2:1. Mo nthly mean densities of the juvenile penaeoids Farfantepenaeus spp., Metape naeopsis spp., Sicyonia spp., and Rimapenaeus constrictus showed a seasonal pattern. Densities were lowest between May and October, and highest betwee n December and February. A two-factor repeated-measures ANOVA of density by depth and tidal period showed that depth does not have a significant effec t on the density for any of the juvenile taxa, but the effect of the tidal period is highly significant (alpha = 0.05). The reverse result was obtaine d for Farfantepenaeus spp, postlarvae; depth effect was significant but not tidal period. F. duorarum and F brasiliensis juveniles exhibited the great est carapace length in January and February, when the highest density of sh rimps were leaving the Bay. Farfantepenaeus spp. postlarvae showed a bimoda l distribution with peaks in March and November.