A TAG AND RECAPTURE STUDY OF GAG, MYCTEROPERCA MICROLEPIS, OFF THE SOUTHEASTERN U.S.

Abstract

During 1995–1999, 3876 gag, Mycteroperca microlepis (Goode and Bean, 1879), were tagged off the southeastern U.S. from North Carolina to southern Florida, pri marily from commercial fishing vessels. Prior to release, the swim bladder of tagged fish was deflated with a 16-gauge hypodermic needle. Approximately 11% of the tagged fish were recaptured. Many gag (36%) moved 185 km. Most of the gag that moved > 185 km were tagged off South Carolina and recaptured off Georgia, Florida, and in the Gulf of Mexico. Gag tagged at depths of 20–40 m showed the greatest degree of movement while gag tagged in deeper water appeared to be relatively sedentary. Recapture rate was greatest for gag tagged off southern Florida and gag tagged off Georgia and Florida were generally recaptured near the same area that they were tagged. Recapture rate declined with increasing depth of capture of tagged fish. Depth-related mortality of degassed fish was estimated to range from 14% at 15 m to 95% at 95 m. Recapture data from 1996–1997 for gag tagged in 1996 provided an estimate of fishing mortality = 0.27. The length of gag tagged was related to depth, with significantly larger individuals occurring in water deeper than 35 m. It was estimated that 3.6% of the gag tagged during 1995–1999 were male. The mean length of gag tagged and depth of capture was greatest during the spawning season (February–April) suggesting that commercial fishermen may have targeted spawning aggregations. The gag, Mycteroperca micropelis (Goode and Bean, 1879), is a long-lived, protogy nous hermaphroditic grouper that is of considerable commercial and recreational importance along the southeastern Atlantic coast of the U.S. and in the Gulf of Mex