eggs. He suggested a winter pupping period. 

 Clark and von Schmidt (1965) recorded only a 

 single female (76 cm) in 9 yr of shark research off 

 Sarasota, Fla. Dahlberg and Heard (1969) re- 

 ported the capture of 30 individuals from July 

 through September 1968 off Georgia. Of these, 29 

 were between 52 and 94 cm. The other specimen 

 (144 cm) was probably the only mature indi- 

 vidual, although there was no mention of sex or 

 reproductive development. Hoese and Moore 

 (1977, appendix 5) listed C. isodon as a spring 

 through fall spawner based on collections of 

 juveniles at Port Aransas, Texas. Compagno 

 (1978), in his review of the species, assigned this 

 species to the genus Carcharhinus. 



During longlining operations in the northern 

 Gulf of Mexico in summer 1978, a gravid 

 female and two males were collected off Dauphin 

 Island, Ala. On 2 July 1979 one male and one 

 female were collected in the mouth of Mobile Bay. 

 With so few reports of mature C. isodon, these 

 captures will serve to better define the reproduc- 

 tive life history of this species. 



On 5 June 1978 the gravid female ( 139 cm) was 

 collected by longline in water about 5 m deep, 

 approximately 1 km southwest of Sand Island, a 

 small barrier island approximately 5 km south of 

 the east end of Dauphin Island. The shark carried 

 four embryos ranging from 49 to 51 cm. These 

 appeared to be near-term pups. There were two 

 pups in each uterus, each positioned with the 

 head toward the anterior end of the uterus. Each 

 pup was enveloped by a membrane which was 

 filled anteriorly with a translucent yellow fluid. 

 Each had a highly vascularized placenta attached 

 to the posterior portion of the uterus, and the 

 connecting umbilical cords measured 20.6-30.0 

 cm. Where an umbilical cord attached to a 

 placenta there were three saclike extensions con- 

 taining a small amount of clear fluid. In earlier 

 embryonic stages of other species of carcharhinid 

 sharks these sacs contain the remaining uncon- 

 sumed portion of the yolk (Gilbert and Schlernit- 

 zauer 1966). The left uterus contained two males; 

 the right uterus one male and one female. The 

 pups and jaws of the female were deposited in the 



Table i.- 



Item 



-Measurements (centimeters; methods after Bass et al. 1973) of the gravid female Carcharhinus 



isodon and the four pups. 



Gravid 

 female 



Pup no. 1 

 male 



Pup no. 2 

 male 



Pup no. 3 

 male 



Pup no. 4 

 female 



Total length 

 Fork length! 

 Standard length 

 Snout to: 



Dorsal 1 



Dorsal 2 



Pectoral fin 



Pelvic fin 



Anal fin 



(^outh 

 Mouth breadth 

 Between nostrils 

 Eye diameter 

 Gill lengths: 



No. 

 No. 

 No. 

 No. 

 No, 



Dorsal 1 height 



Dorsal 1 base 



Dorsal 1 free margin 



Dorsal 2 height 



Dorsal 2 base 



Dorsal 2 free margin 



Anal height 



Anal base 



Anal free margin 



Pectoral height 



Pectoral base 



Pectoral free margin 



Pelvic anterior margin 



Pelvic distal margin 



Uppper caudal length 



Lower caudal length 



Interspace base dorsal 1 to origin dorsal 2 



Interspace base dorsal 2 to caudal pit 



Origin of pectoral to origin of pelvic 



Origin of pelvic to origin of anal 



Weight (g) 



178 



