Morphological Characteristics of Early Life History Stages of the Blue Crab, Callinectes sapidus Rathbun, from the Northern Gulf of Mexico with a Comparison of Studies from the Atlantic Seaboard

Abstract

Zoeae, megalopae, and early crab stages of Callinectes sapidus Rathbun, 1896 were described from the northern Gulf of Mexico (nGOM). Observations during this study were based on larvae reared in the laboratory through the early crab stages and on megalopae and early crab stages collected in the wild. Gulf of Mexico data are compared with similar information for the southeast Atlantic coast of the United States. Size and setation of C. sapidus larvae reared from nGOM stocks were different than those in published descriptions of larvae reared from Atlantic populations. Seasonal differences in size were noted in both reared and wild caught specimens. Zoeal stages I, II and III of larvae cultured in the spring were larger than corresponding larvae hatched in the summer/fall. Data sets on zoeal stages IV and V were incomplete; however, seasonal differences in measurements on all structures tended to be smaller in the summer/fall reared larvae. No seasonal differences were observed for the sixth and seventh zoeal stages, megalopal stage and first crabs. Spring reared larvae had higher survival rates when reared at optimal temperature (25°C) and required fewer zoeal stages (6) to reach the megalopal stage. Megalopae and first crabs collected from the plankton exhibited distinct seasonal variations and were larger in the spring than in fall.