Red Snapper: Ecology and Fisheries in the U.S. Gulf of Mexico

Red Snapper in the Northern Gulf of Mexico: Age and Size Composition of the Commercial Harvest and Mortality of Regulatory Discards

David L. Nieland, Andrew J. Fischer, M. Scott Baker, Jr., and Charles A. Wilson, III

doi: https://doi.org/10.47886/9781888569971.ch20

Abstract.—Red snapper Lutjanus campechanus were sampled from commercial landings from the Gulf of Mexico (GOM) off Louisiana from October 2001 to May 2004. Fork length (FL), eviscerated weight, otoliths (both sagittae), and sex determinations were taken from 2,900 specimens; FL was subsequently converted to total length (TL) with the equation TL = 1.073 (FL) + 3.56. Red snapper ages (N = 2,867) estimated from counts of opaque annuli in otoliths ranged from 1 to 14 years; however, the vast majority (97.7%) of these were ages 2 to 6 years and the modal age was 3 years. Total lengths among 2,897 specimens ranged from 278 to 940 mm, modal TL was 400 mm, and 98% of all specimens were less than 600 mm TL. We also investigated the fate of red snapper regulatory discards (individuals <381 mm [15 in] TL) during 16 trips on working commercial vessels; over two-thirds of 4,839 red snapper assigned among four discard fate categories (ranging from alive and vigorous to dead) were returned to the water either in moribund or dead condition. Among 399 potential discards retained for age and length analyses, 86% were between 12 and 15 in (305–381 mm) TL and 85% were 2 years of age. The minimum size regulation appears to do little to protect juvenile red snapper from commercial fishing mortality. Heavy red snapper mortality, which begins as bycatch mortality in shrimp trawls, continues as discard mortality at sub-legal lengths when they first recruit to the offshore fishing grounds, and persists as harvest mortality among the youngest legal year- and size-classes. If the minimum size limit is intended to provide a respite from such mortality, a reconsideration of the utility of the minimum length regulation in the commercial harvest of red snapper may be warranted.