Life History of the Gray Triggerfish from the Southeastern United States

Jennifer L. Moore
Grice Marine Biological Laboratory, University of Charleston, 205 Fort Johnson Rd., Charleston, SC 29412; 843 / 762-5425; moorej@mrd.dnr.state.sc.us

A life history study of gray triggerfish from the southeastern United States was conducted from 1992-1997 as part of the Marine Resources Monitoring Assessment and Prediction Program (MARMAP) of the South Carolina Department of Natural Resources. A total of 1,210 gray triggerfish were collected for use in age determination and reproductive analysis. Monthly samples were obtained from fishery-independent and commercial sources to allow for comparison between gear types. The first dorsal spine was sectioned (1 mm) for ageing. Marginal increment analysis verified the annual nature of increment formation, and determined that annuli were deposited in summer. Fish collected from the commercial fishery were significantly larger than fish from MARMAP samples for ages 1-4, regardless of sex. Males were significantly larger than females for both gear types. Reproductive biology was examined using histological techniques. Spawning condition in females was determined by the presence of post-ovulatory follicles (POF's), and spawning season was found to occur in summer, with a peak in July. Gonadosomatic Index was calculated, and a peak in June and July corresponded with the presence of POF's. Males appear to be in spawning condition year round.