Abstract

Epinephelus morio (red grouper) is the most important grouper species in southern Gulf of Mexico, contrib-uting from 1999 to 2009 with 58% to 61% (% gutted weight) of total captured volume. CPUE data shows grouper land-ings decline from 19,886 tonnes (T) in 1972 to 6,212 T in 2011. Red grouper is considered as near threatened spe-cie by IUCN and its fishery overexploited and in danger of collapse. During 1996 - 1999, 420 red groupers were cap-tured using long line by artisanal and industrial Mexican fishing fleets. Otoliths were up through the gills-removed, al-cohol cleaned and stored dry. Age determination was performed by assigning annuli based on the number of opaque zones from the otolith core to the otolith margin, in left sagittae thin sections. Individuals ranged in size from 39.0 - 89.0 cm (LF) and in age from 2 - 14 years. Age-7 fish were the most numerous in the sample (N = 106), followed in fre-quency by age-6 (n = 99), age-8 (n = 51) and age-5 (n = 45), representing 71.6 % of total specimens. Young fish with age-2 and age-3 (each one n = 1) and older fish with age-13 and age-14 (n = 3, n = 1, respectively) were poorly repre-sented. Edge-type analysis confirmed the formation of a single growth annulus per year, recording the smallest marginal increment values between July (0.6241 mm) and August (0.64421 mm). The relationship between furcal length and age was described by von Bertalanffy growth model: LF= 79.49[1- exp (0.18 (t -0.997))].

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