Abstract

Epinephelus morio (red grouper) commercial fishery is the most important in Yucatan. This study seeks to provide new information on rearing conditions for red grouper, which can serve as an alternative to fishing. Using hook and line, 141 red grouper juveniles were caught, from April 20th to August 22nd 2007, at Sisal Yucatan Mexico. All individuals were kept alive in an aerated 0,5 m3 container, vented if needed, and carried to the UMDI-UNAM facility, where they were weighed and placed randomly in eight outside seawater tanks. Groupers were fed with trash fish for two months, until adapted to captivity. To minimize cannibalism and aggression groupers were graded into three size groups: small: 27.3 (± 3.06 cm); medium: 34.3 (± 1.74 cm) and large: 45.9 (± 3.42 cm), and reared in 19.63 m2 tanks (5 m diameter and 0.85 m deep), with constant seawater influx and airflow. Fish densities varied from 15.47 to 83.03 g/m2 depending on the size group. All individuals were fed a balanced humid pellet (55.6% protein, 4.9% lipids, 34.5% carbohydrates and approximately 4% vitamins and minerals, 3 times a week. In order to determine the individual growth rate each grouper was tagged using VIE (Visible Implant Elastomer tags), measured and weighed every 39 days and then sacrificed gradually throughout a year (until August 2008). Mean individual weight at the beginning of the study was 0.57 kg attaining a mean weight of 1.9 kg per fish, a year later. Daily growth rate was 3.64 g/fish. There were significant differences in weight between sampling (Kruskal- Wallis; H= 143.111; p ? 0.05), between growth rate in time (Kruskal- Wallis; H = 46.39, p ? 0.05) and between the food consumption rate (t = 2.58006; p ? 0.05).

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