Sheridan: Forecasting the fishery for Penaeus duorarum 



753 



Hannah (1993), and references cited therein), and 3) 

 changes occur in the database used to make predic- 

 tions. In time, new environmental, biological, or fish- 

 ery conditions are encountered. For example, the 

 database for the Tortugas pink shrimp fishery now 

 reflects (directly or indirectly) results of massive 

 seagrass mortality in Florida Bay which began in 

 1987, a prolonged drought in south Florida during 

 1989—91, and the four worst fishing years on record. 

 None of these factors would have influenced the first 

 forecast model derived in 1987, and assessment of 

 that model indicated it would have been a failure if 

 used in most future years. Even the durable Texas 

 brown shrimp forecast, first released to the public in 

 1962 and accurate within ±20% of actual landings 

 for 22 of its first 29 forecasts, was modified in 1994 

 to reflect the changing nature of the Galveston Bay 

 live bait shrimp fishery after 1980. 2 



Incorrect fishery forecasts can have negative eco- 

 nomic impacts on fishermen and processors (Bocking 

 andPeterman, 1988; Walters, 1989), especially if the 

 fishery in question is actively regulated on a short- 

 term basis like the salmonid fisheries of the north- 

 eastern Pacific. The penaeid shrimp fisheries of the 

 U.S. Gulf of Mexico are managed to prevent the har- 

 vest of undersized shrimp (Gulf of Mexico Fishery 

 Management Council, 1981; Klima et al., 1986). 

 Shrimp management strategies are assessed annu- 

 ally and are accomplished by seasonal closure of Fed- 

 eral and state waters off Texas and by areal closure 

 of shallow Federal waters off southwest Florida. Flex- 

 ible, in-season adjustments are possible but rare, and 

 to date shrimp management has not been altered in 

 response to forecasts of high or low harvests. As yet, 

 no assessment of the utility and economic effects of 

 either pink shrimp or brown shrimp forecasts have 

 been made among members of the fishing community. 



This study indicates that landings of Tortugas pink 

 shrimp might be forecast reliably with some advance 

 knowledge of environmental conditions and abun- 

 dance of juvenile pink shrimp in nursery areas. 

 Cause-effect relationships are not yet known, and 

 mechanisms describing pink shrimp responses to 

 predictor variables need to be determined through 

 experimental analyses. 



Acknowledgments 



The following people provided data and information 

 that made this study possible: Frank Patella, NMFS, 

 pink shrimp catch and effort statistics; David 

 Sikkema and George Schardt, ENP, hydrological data 

 and manuscript review; James Tilmant and Michael 

 Robblee, National Biological Survey, juvenile pink 



shrimp densities and manuscript review; and Steacy 

 Hicks, James Hubbard, and Briah Connor, NOS, tide 

 gauge data. Charles Caillouet, Geoffrey Matthews, 

 Thomas Minello, and James Nance provided insight- 

 ful reviews of the manuscript, as did three anony- 

 mous reviewers. 



Literature cited 



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



1980. Postlarval shrimp {Penaeus) in the Florida Keys: spe- 

 cies, size, and seasonal abundance. Bull. Mar. Sci. 30:21- 

 33. 



Barrett, B. B., and M. C. Gillespie. 



1973. Primary factors which influence commercial shrimp 

 production in coastal Louisiana. Louisiana Wildl. Fish. 

 Comm. Tech. Bull. 9:1-28. 

 1975. 1975 environmental conditions relative to shrimp 

 production in coastal Louisiana. Louisiana Wildl. Fish. 

 Comm. Tech. Bull. 15:1-22. 

 Barrett, B. B., and E. J. Ralph. 



1977. 1977 environmental conditions relative to shrimp 

 production in coastal Louisiana along with shrimp catch 

 data for the Gulf of Mexico. Louisiana Dep. Wildl. Fish. 

 Tech. Bull. 26:1-16. 

 Baxter, K. N., and L. F. Sullivan. 



1986. Forecasting offshore brown shrimp catch from early 

 life history stages. In A. M. Landry Jr. and E. F. Klima 

 (eds.), Proceedings of the shrimp yield prediction workshop, 

 p. 22-36. Texas A&M Univ. Sea Grant Publ. TAMU-SG- 

 86-110, College Station, TX. 

 Berry, R. J., and K. N. Baxter. 



1969. Predicting brown shrimp abundance in the north- 

 western Gulf of Mexico. FAO Fish. Rep. 57:775-798. 



Bocking, R. C, and R. M. Peterman. 



1988. Preseason forecasts of sockeye salmon {Oncorhynchus 

 nerka): comparison of methods and economic consider- 

 ations. Can. J. Fish. Aquat. Sci. 45:1346-1354. 

 Browder, J. A. 



1985. Relationship between pink shrimp production on the 

 Tortugas grounds and fresh water flow patterns in the 

 Florida Everglades. Bull. Mar. Sci. 37:839-856. 

 Caillouet, C. W., and D. B. Koi. 



1981. Trends in ex-vessel value and size composition of re- 

 ported annual catches of pink shrimp from the Tortugas 

 fishery, 1960-1978. Gulf Res. Rep. 7:71-78. 



Cargo, D. G., and D. R. King. 



1990. Forecasting the abundance of sea nettle, Chrysaora 

 qumquecirrha, in the Chesapeake Bay. Estuaries 13: 

 486-491. 

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



1966 Migrations and geographic distribution of pink 

 shrimp, Penaeus duorarum, of the Tortugas and Sanibel 

 grounds, Florida. U.S. Fish Wildl. Serv., Fish. Bull. 65: 

 449^59. 



1970. Synopsis of biological data on the pink shrimp 

 Penaeus duorarum duorarum Burkenroad, 1839. FAO 

 Fish. Rep. 57:1499-1538. 



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



1986 Distribution, seasonal abundance, and ecology of ju- 

 venile northern pink shrimp, Penaeus duorarum. in the 

 Florida Bay area. U.S. Dep. Commerce, NOAA Tech. 

 Memo. NMFS-SEFC-161, 84 p. 



