NOTE Carlson: Occurrence of neonate and luvenile Charchannus plumbeus in the northeastern Gulf of Mexico 



391 



prey and bycatch from intense commercial shrimping 

 operations that occur in the area surveyed at the 

 mouth of the Apalachicola River. 



The absence of gravid females in the survey does 

 not preclude the presence of a pupping and nursery 

 area. Females may be pupping farther inshore or 

 offshore from the sampling area, at times when sam- 

 pling did not occur or sampling gear may have had 

 reduced efficiency at capturing larger sharks. Female 

 sharks are reported to move into Chesapeake Bay to 

 pup when water temperatures reach 18-20^C 

 (Grubbs, 1996), and most sampling in this study be- 

 gan in April when water temperatures were usually 

 above 20"C. In addition, mature female sandbar 

 sharks are large (>1800 mm TL; Sminkey and 

 Musick, 1995) and it is likely that they were able to 

 avoid the sampling gear. 



Neonate sandbar sharks (<age 1) usually reside 

 in primary nursery areas where they were born 

 through the first summer (Pratt and MersonM; thus 

 it is unlikely that individuals captured in this area 

 underwent significant migrations from another area. 

 The paucity of tag and recapture information in the 

 Gulf of Mexico also complicates understanding of the 

 geographical and seasonal distribution of neonate 

 and juvenile sandbar sharks. Future research should 

 be focused on further delineation and annual moni- 

 toring of hypothesized nursery areas for sandbar 

 sharks and on increasing ongoing tagging efforts. 



Acknowledgments 



Thanks are given to L. Trent who began determin- 

 ing the distribution of sharks in the northeastern 

 Gulf of Mexico in 1992. B. Blackwell, N. Lewis, and 

 M. Miller helped with sampling. E. Cortes and D. 

 DeVries suggested valuable improvements on an 

 earlier version of this manuscript. This research was 

 funded by NOAA/National Marine Fisheries Service/ 

 Highly Migratory Species Office and the Southeast 

 Fisheries Science Center, National Marine Fisher- 

 ies Laboratory, Panama City. 



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