Contemporary versus historical estimates of king mackerel (Scomberomorus cavalla) age and growth in the U.S. Atlantic Ocean and Gulf of Mexico

• Autores: Katherine E Shepard, William F. Patterson III, Douglas A. DeVries, Mauricio Ortiz
• Localización: Bulletin of Marine Science, ISSN 0007-4977, Vol. 86, Nº. 3, 2010, págs. 515-532
• Idioma: inglés
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• Resumen

  • King mackerel, Scomberomorus cavalla (Cuvier, 1829), is an economically important coastal pelagic fish in United States waters of the Atlantic Ocean (Atlantic) and Gulf of Mexico (GOM). In this study, von Bertalanffy growth functions (VBGFs) were fitted to size-at-age data collected from eastern GOM (n = 1447) and Atlantic (n = 869) populations in the summers of 2006 and 2007 from fishery-dependent and fishery-independent sources (GOM females: L(infinite) = 124.5 cm, k = 0.256, t 0 = -0.173 yr; GOM males: L(infinite) = 92.2 cm, k = 0.353, t 0 = -0.166 yr; Atlantic female: L(infinite) = 111.6 cm, k = 0.464, t 0 = 0.506 yr; Atlantic males: L(infinite) = 98.9 cm, k = 0.510, t 0 = 0.502 yr). Results from likelihood ratio tests indicated contemporary VBGFs were significantly different between sexes and populations. Differences in growth between contemporary and historic samples were tested in two ways. First, results from likelihood ratio tests indicated a significant time effect among VBGFs fit to fishery-dependent samples from three time periods (1977-79, 1986-92, and 2006-07). Second, results from analysis of variance indicated sex-specific differences existed in size-at-age for ages 2-10 between contemporary and historic data. The GOM population, which has experienced an estimated 2.5-fold increase in spawning stock biomass (SSB) since the early 1990s, displayed a decline in size-at-age for ages 2-7, while the Atlantic population, which has experienced an approximately 45% decline in estimated spawning stock biomass (SSB) over the same time period, displayed an increase in size-at-age for ages 4-10. These trends are most likely due to density-dependent responses to changes in population size.