638 



Fishery Bulletin 92(3). 1994 



ally, environmental conditions in the nursery area, 

 e.g. spring temperature and salinity (with related 

 factors such as rainfall, river discharge, and meteo- 

 rological conditions; Gaidry and White, 1973; Barrett 

 and Gillespie, 1975; Zein-Elden and Renaud, 1986; 

 Childers et al., 1990) are thought to be important 

 influences on production. Biological factors such as 

 predation and secondary production have also been 

 postulated to influence yield (Hunter and Feller, 

 1987; Gleason and Wellington, 1988; Minello et al., 

 1989). Postlarval indices have been used with some 

 success in predictive models that incorporate envi- 

 ronmental variables and indices of juvenile shrimp 

 abundance (Sutter and Christmas, 1983; Baxter et 

 al., 1988). We have been unsuccessful in efforts to 

 produce a model for brown shrimp production using 

 data from consectutive years, although our postlar- 

 val index may be useful in the future. 



Undoubtedly many factors influence the produc- 

 tion of P. setiferus populations, but recent studies 

 have demonstrated that commercial harvest of P. 

 setiferus can be modeled (Lam et al., 1989) and ap- 

 parent spawner-recruit relationships have been de- 

 scribed in South Carolina (Lam et al., 1989) and in the 

 Gulf of Mexico ( Nance and Nichols, 1988;Gracia, 1991). 

 Our study demonstrates that monitoring off! setiferus 

 postlarvae can be a reliable indicator of harvest. 



Expanded sampling effort, i.e. more locations and 

 increased numbers of samples, would perhaps yield 

 more statistically significant results than were ob- 



tained at a single location in our study. These data 

 do, however, represent one of the longest-term stud- 

 ies of postlarval penaeid recruitment to date. In ad- 

 dition to contributing to our overall understanding 

 of penaeid shrimp population dynamics, our baseline 

 monitoring effort may be useful as a management 

 tool for predicting harvest and providing advice on 

 optimal times for flooding coastal impoundments for 

 extensive aquaculture. 



Acknowledgments 



Numerous individuals have contributed to this study, 

 notably C. Bearden, C. Boardman, C. Farmer, L. 

 Leseman, and T. Read. M. Clise assisted with data 

 preparation and K. Swanson prepared the map. E. 

 Wenner and B. Stender reviewed the manuscript. 



Literature cited 



Aldrich, D. V., C. E. Wood, and K. N. Baxter. 



1968. An ecological interpretation of low temperature 

 responses in Penaeus aztecus and P. setiferus 

 postlarvae. Bull. Mar. Sci. 18:61-71. 

 Allen, D. M., J. H. Hudson, and T. J. Costello. 



1980. Postlarval shrimp {Penaeus) in the Florida 

 Keys: species, size and seasonal abundance. Bull. 

 Mar. Sci. 30:21-34. 

 Anderson, W. W. 



1970. Contributions to the life histories of several 

 penaeid shrimps (Penaeidae) along the South At- 



