AGE, GROWTH, AND REPRODUCTION OF THE RED SNAPPER, LUTJANUS CAMPECHANUS, FROM THE ATLANTIC WATERS OF THE SOUTHEASTERN U.S.

摘要

Otoliths and gonadal tissue were taken from red snapper collected from fishery-independent and fishery-dependent sources between Cape Lookout, North Carolina and Key West, Florida during 1979-2000. The mean size of red snapper from fishery-dependent samples was 594 mm TL and ranged from 70-976 mm TL. Fish sampled with fishery-independent gear had a significantly smaller mean TL (426 mm, range = 121-866 mm) than fishery-dependent samples. The mean size of red snapper was significantly smaller in the 1980s when compared to the 1990s, regardless of gear type. Mean marginal increment analysis showed that opaque zone formation is annual with deposition occurring from June through August. The age range for fishery-independent samples was 1-22 yrs with a mean age of 3.1 yrs, and 1-45 yrs with a mean age of 4.2 yrs for fishery-dependent samples. Von Bertalanffy growth curves revealed that red snapper from commercial catches approach asymptotic size at around age 10, however, no asymptote is apparent for those fish sampled with fishery-independent gear. The overall sex ratio for red snapper was not significantly different from the expected 1:1, regardless of gear type. The smallest mature female was 287 mm TL and the largest immature female was 435 mm TL, with an estimate of length at 50% maturity (L50) of 378 mm TL. The smallest mature male was 200 mm TL and the largest immature male was 378 mm TL, with an L50 for males of 223 mm TL. Histological examination of the gonads indicated that female red snapper were in spawning condition from May through October, with a peak between June and September. The gonadosomatic index (GSI) for females ranged from a low of 0.35 in November and December to a high of 2.67 in June. Males were found to be in spawning condition throughout the year.