307 



Abstract— The gray snapper {Lutjanus 

 griseus) is a temperate and tropical 

 reef fish that is found along the Gulf 

 of Mexico and Atlantic coasts of the 

 southeastern United States. The rec- 

 reational fishery for gray snapper has 

 developed rapidly in south Louisiana 

 with the advent of harvest and sea- 

 sonal restrictions on the established 

 red snapper iL. campechanus) fishery. 

 We examined the age and growth of 

 gray snapper in Louisiana with the 

 use of cross-sectioned sagittae. A total 

 of 833 specimens, (441 males, 387 

 females, and 5 of unknown sex) were 

 opportunistically sampled from the 

 recreational fishery from August 1998 

 to August 2002. Males ranged in size 

 from 222 to 732 mm total length (TL) 

 and from 280 g to 5700 g total weight 

 (TW) and females ranged from 254 to 

 756 mm TL and from 340 g to 5800 g 

 TW. Both edge analysis and bomb 

 radiocarbon analyses were used to 

 validate otolith-based age estimates. 

 Ages were estimated for 718 individu- 

 als; both males and females ranged 

 from 1 to 28 years. The von Berta- 

 lanffy growth models derived from 

 TL at age were L, = 655.4ll-e [ -°- 23((| l| 

 for males, L, = 657.3{l-el-° 21l "l| for 

 females, and L , = 656.4)l-e [ -° 22 " l| l 

 for all specimens of known sex . Catch 

 curves were used to produce a total 

 mortality (Z) estimate of 0.17. Esti- 

 mates of M calculated with various 

 methods ranged from 0.15 to 0.50; 

 however we felt that M=0.15 was the 

 most appropriate estimate based on 

 our estimate of Z. Full recruitment to 

 the gray snapper recreational fishery 

 began at age 4, was completed by age 

 8, and there was no discernible peak 

 in the catch curve dome. 



Age, growth, mortality, and 



radiometric age validation of gray snapper 



{Lutjanus griseus) from Louisiana 



Andrew J. Fischer 



Coastal Fisheries Institute 



School of the Coast and Environment 



Louisiana State University 



Baton Rouge, Louisiana 70803-7503 



E-mail address: afischeigilsu.edu 



M. Scott Baker Jr. 



North Carolina Sea Grant 

 UNC-W Center for Marine Science 

 5001 Masonboro Loop Rd 

 Wilmington, North Carolina 28409 



Charles A. Wilson 



Louisiana Sea Grant College Program 



Louisiana State University 



Baton Rouge, Louisiana 70803-7507 



David L. Nieland 



Coastal Fisheries Institute 



School of the Coast and Environment 



Louisiana State University 



Baton Rouge, Louisiana 70803-7503 



Manuscript submitted 19 September 2003 

 to the Scientific Editor's Office. 



Manuscript approved for publication 



20 November 2004 by the Scientific Editor. 



Fish. Bull. 103:307-319 12005). 



The gray snapper {Lutjanus griseus), 

 commonly referred to as the mangrove 

 snapper, is a temperate and tropical 

 reef species that is found along the 

 southeastern Atlantic coast of the 

 United States from North Carolina 

 to Bermuda, throughout the Gulf of 

 Mexico (GOM), and south to Brazil 

 (Johnson et al., 1994; Allman and 

 Grimes, 2002). Gray snapper are 

 fairly common along the Louisiana 

 coast and are usually associated 

 with complex structures such as oil 

 and gas platforms, artificial reefs 

 and other hard bottom substrates. 

 In 1991 restrictions were put on the 

 recreational red snapper (Lutjanus 

 campechanus) fishery; these restric- 

 tions coincided with a rapid expansion 

 of the gray snapper fishery in south 

 Louisiana. Recreational anglers now 

 typically target gray snapper once 

 they have reached their bag limit of 

 red snapper; thus peak gray snap- 



per landings generally coincide with 

 the red snapper recreational season 

 (April-October). As a result, recre- 

 ational landings of gray snapper in 

 Louisiana have increased exponen- 

 tially from 3.25 metric tons (t) in 1983 

 to 175 t in 2002 (NMFS 1 ). Currently 

 there is a 305 mm (12 inches) mini- 

 mum size and a recreational bag limit 

 of 10 fish/person/day for gray snapper 

 in the GOM. 



Some background information is 

 available for gray snapper in the 

 southeastern United States, mainly 

 from south Florida. Scientists have 

 reported on early life history (Ruth- 



1 NMFS (National Marine Fisheries 

 Service). 2003. Fisheries Statistics 

 and Economics Division. Unpubl. 

 data. Website: http://www.st.nmfs. 

 gov/pls/webpls/MF_ANNUAL_LAND- 

 INGS. RESULTS. [Accessed 25 August 

 2003.] 



