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Alternate Title

Distribution, Abundance, and Age Structure of Red Snapper (Lutjanus campechanus) Caught on Research Longlines in U.S. Gulf of Mexico

Abstract

Two pilot surveys were conducted in the northern Gulf of Mexico (Gulf) to determine the feasibility of sampling red snapper (Lutjanus campechanus) populations in offshore waters with bottom longline gear. The first pilot survey off Mississippi-Alabama was conducted in May 1999 and yielded a total of seven snapper from 60 stations. The second pilot survey was off Texas in June 2000 and yielded a total of 76 snapper from 44 stations. The catch per unit effort was 0.12 red snapper/100 hook hr [coefficient of variation (CV) = 0.54] in 1999 and 1.73 red snapper/100 hook hr (CV = 0.21) in 2000. Otoliths were removed from all collected red snapper, and ages were assigned with an average percent error of 3.71%. Red snapper from the 1999 survey ranged from 405 to 873 mm total length (TL) (545 mm TL median) and from 3 to 19 yr (median age 5 yr). The red snapper from Texas ranged in size from 380 to 903 mm TL (755 mm TL median) and ranged in age from 3 to 53 yr (median age 11 yr). Based on the results of the pilot surveys, expanded longline surveys targeting red snapper were conducted in 2001 and 2002; these surveys yielded 86 snapper and 75 snapper, respectively. The 2001 snapper ranged from 427 to 950 mm TL (770 mm TL median) and from 3 to 37 yr (median age 12 yr). The 2002 snapper ranged from 409 to 950 mm TL (815 mm TL median) and from 4 to 44 yr (median age 13 yr). Twelve red snapper were captured in the eastern Gulf (east of the Mississippi River), and their ages ranged from 3 to 19 yr (median age 6 yr). The 232 red snapper that were caught in the western Gulf ranged in age from 3 to 53 yr (median age 12 yr). A difference in catch rates by depth was also noted with most red snapper captures occurring in the 55-92 m depth range.

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