Reproductive biology and ecology of red porgy, Pagrus pagrus, in the northeastern Gulf of Mexico

Douglas A. DeVries
National Marine Fisheries Service, SEFSC, Panama City Laboratory, 3500 Delwood Beach Road Panama City, FL 32408; Phone: (850) 234-6541 Fax: (850) 235-3559 Email: devries@bio.fsu.edu

The objective of this study is to determine why red porgy Pagrus pagrus may be highly sensitive to exploitation. In September 1999 the red porgy fishery in the U.S. South Atlantic Bight (SAB) was closed because of substantial declines in landings, a 99% decline in recruitment between 1973 and 1997, and a 97% drop in total spawning biomass. South Carolina biologists recently documented decreases in size at maturity and size at transition since the early 1970's. I am focusing on the reproductive traits and ecology of the lightly-fished northeastern Gulf of Mexico population, and will compare them with those of the severely overfished SAB population. The size distributions of 321 hook and line-caught males and 676 females were typical for a protogynous species; median sizes were 236 mm Fl for females and 267 mm for males, and only 17% of females were >=275 mm, versus 40% of the males. Transitional fish (n=17) were collected during March-August, ranged from 200 to 287 mm, and made up 1-5 % of the fish sampled. The overall proportion of males was 0.32, but this value varied with size and depth - 0.03 below 201 mm FL, 0.21 at 201-250 mm, 0.45 at 251-300 mm, 0.59 at 301-350 mm, and 0.82 above 350 mm. The proportion was lowest in the shallowest sites - 0.18 in the 20 m zone - and ranged from 0.22 to 0.38 between 30 and 90 m. GSI data indicated peak spawning in January but some activity occurring from December through March.