long period. Van Engel (1958) reported that 

 mating of C. sapidus began in early May and 

 continued into October in the Chesapeake Bay. 

 After hatching, the larvae passed through a 

 number of zoeal stages and a megalops stage, 

 before they had the form of a crab. Also, 

 Van Engel reported that the zoeal form lasted 

 about a month, during which time it molted 

 at least four times. Hopkins (1944) suggested 

 that there may be a fifth stage zoea, and 

 Snodgrass (1956) reported that perhaps there 

 was a sixth stage zoea preceding the mega- 

 lops stage. In the laboratory, Costlow and 

 Bookout (1959) observed ttiat C. sapidus had 

 seven zoeal stages and one megalops before it 

 reached the first crab stage. An eighth zoeal 

 stage was sometimes observed but usually did 

 not complete metamorphosis to the megalops. 

 Development to the megalops required a mini- 

 mum of 31 days and a maximum of 49 days. 

 The megalops stage lasted from 6 to 20 days 

 depending on the salinities used. 



reports (Anderson and Gehringer, 1957a, 1957b, 

 1958a, 1958b, 1959a, 1959b, and 1959c; Ander- 

 son, Gehringer, and Cohen, 1956a and 1956b). 

 Biological methods and procedures and other 

 pertinent information were given in those 

 reports. 



To examine the plankton samples from the 

 Gill cruises for Callinectes larvae a 40-ml. 

 subsample was taken from each sample 

 (table 2). Then, three 4-ml. aliquots were 

 taken from each subsample, and the Ca//iraec«es 

 larvae removed with the aid of a binocular 

 microscope. The number of larvae at each 

 stage was recorded and stored for future 

 reference. Finally the larvae in each 4-ml. 

 aliquot were combined. Identification of 

 Callinectes type larvae was based on Costlow 

 and Bookout (1959) and unpublished work by 

 the Bureau of Commercial Fisheries Biologi- 

 cal Laboratory, Beaufort, N.C. 



To obtain information on the spawning season 

 and the number of larval molts of Callinectes 

 crabs and to determine the offshore distribu- 

 tion and abundance of the larval forms in the 

 areas cruised by the Bureau of Commercial 

 Fisheries research, vessel Theodore N. Gill, 

 we examined the plankton collected by that 

 vessel on nine cruises over a 2-year period, 

 1953-54. This study is a part of an investiga- 

 tion by the Bureau of the blue crab C. sapidus 

 along the South Atlantic coast of the United 

 States. 



METHODS 



OCCURRENCE OF Callinectes LARVAE 



Early stage Callinectes zoeae were more 

 common than the advanced stage zoeae, though 

 all eight stages and the megalops were pres- 

 ent. The most productive sections for the com- 

 bined larval forms were Matanzas and Jack- 

 sonville, Fla. ; Savannah, Ga.; Charleston, S.C.; 

 and Cape Fear, N.C. (fig. 2). The number of 

 larvae at each stage in each area in the com- 

 bined 4-ml. aliquots, is listed in table 3 by 

 cruise and station number. The east-west 

 distribution of larvae at each stage is listed 

 in table 4 by month with temperature, salinity, 

 and depth of capture ranges. 



The basic station plan for all cruises of the 

 Gill has 80 regular stations between Jupiter 

 Light (Florida Straits) and Cape Hatteras 

 extending from near the beaches to beyond 

 the axis of the Gulf Stream and 9 special 

 stations farther offshore (fig. 1). The regular 

 stations were 20 miles apart on the east-west 

 line, 40 miles apart in the north-south direc- 

 tion, with some stations established inshore 

 between the east-west lines. Nine cruises 

 were made from January 1953 to December 

 1954; all varied from the basic plan (table 1). 

 The physical oceanographic, biological, and 

 chemical data were published in a series of 



In general, larger numbers of early stage 

 zoeae were collected near the beaches with a 

 progression to advanced stage zoeae occurring 

 20 and 40 miles offshore, and the megalops 

 in greatest numbers were 40 or more miles 

 offshore (figs. 3 and 4). In Florida and Georgia 

 early stage zoeae and the megalops were 

 collected each month, while late stage zoeae 

 were collected only from April to October 

 (fig. 5). In South Carolina and North Carolina 

 early stage zoeae were collected from May to 

 December, late stage zoeae from July to 

 September, and megalops from January to 

 December (fig. 6). 



