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Sagittal otoliths from 534 red grouper, Eplnephelus morlo, were collected from recreational and commercial fisheries of the eastern Gulf of Mexico In 1979·1981 (236 fish) and 1991·1992 (298 fish). Age estimations for the two collections were made In 1991·1992 from the surface and transverse sections of these otoliths. Also, estimates of back-calculated size at age (using the final annulus present at time of capture following Lea's (1910) method were made for these collections. Red grouper were larger In size at capture at age and back· calculated size at age In 1991-1992 than In 1979·1981. The respective von Bertalanffy growth parameters were: 1979·81 Loo = 78.9, K = 0.1778, t0 = 0.8259 1991·92 Loo = 92.6, K = 0.1588, t0 = 0.9323 where Loo Is mean maximum attainable total length In centimeters, K Is growth coefficient, and t0 Is hypothetical age In years at which fish would have zero length. The red grouper, Epinephelus morio, is a demersal marine fish that is abundant in the eastern Gulf of Mexico. It inhabits the Florida shelf from nearshore to depths of at least 110 m. Edges of reefs and areas of low-relief limestone bottoms are favored habitats for this' serranid (Bullock and Smith, 1991). This species is a protogynous hermaphrodite (Moe, 1969). Separation of red grouper from an amalgamation of groupers in fishery landings statistics did not occur until 1986. The 1989 landings indicate that about 67% (3.3 million kg) of the commercial grouper landings and about 29% (1.9 million kg) of the recreational grouper landings consisted of this species (Goodyear and Schirripa, 1991). Age composition of the landings is vital to the determination of the status of the stock and to provide management advice. We present here a comparison of the age and size composition of red grouper in the fishery in the eastern Gulf of Mexico from two time periods, 1979-81 and 101 1991-92. Previous information on age-size structure of this species was reported for the 1960s for the Florida west coast (Moe, 1969) and for 1972-88 for the U.S. Atlantic coast (Stiles and Burton, ms). We follow the same pattern of study as that of Johnson et al. (1993) for the gag, Mycteroperca microlepis. MATERIALS AND METHODS The red grouper fisheries (recreational and commercial) of the eastern Gulf of Mexico (Louisiana to Key West, Florida), were sampled from April1979 to August 1981 (period henceforth referred to as T1) and February 1991 to October 1992 (T2). These fisheries are mainly hook and line with some long line fishing. Body length was measured at the time of sampling in mm fork length for 254 fish in T1 and in either mm or em total length, or mm fork length, for 321 fish in T2. Collection, treatment, and processing of otoliths, as well as analysis of the data 1 Johnson and Collins: Age-Size Structure of Red Grouper, (Epinephelus morlo), from the Published by The Aquila Digital Community, 1993 102 Johnson, A. G. and L. A. Collins were the same as those of Johnson et al. (1993).

Age-Size Structure of Red Grouper, (Epinephelus morlo), from the Eastern Gulf of Mexico