MATURATION AND REPRODUCTIVE SEASONALITY IN BONEFISH, ALBULA-VULPES, FROM THE WATERS OF THE FLORIDA KEYS

We examined 528 bonefish to estimate length and age at sexual maturity and to describe seasonal patterns in gonadal development. These fish ranged from 21 to 702 mm fork length (FL) and were collected in South Florida waters from 1989 to 1995. Gonads of 437 bonefish were examined histologically, and gonadosomatic indices (GSI) were calculated for 4 49 bonefish. Male bonefish reached 50% sexual maturity (the predicted size and age at which half the individuals are expected to be sexually mature) at 418 mm FL (95% confidence interval 393-443 mm) and an age of 3.6 years (95% confidence interval 3.3-3.9 years). Females reached 50% sexual maturity at 488 mm FL (95% confidence interval 472-504 mm) and 4.2 years (95% confidence interval 3.9-4.6 years). Lengths and age s at 50% maturity for males and females were significantly different. The smallest sexually mature male was 425 mm FL, and the smallest sexu ally mature female was 358 mm FL. The youngest sexually mature male wa s 3 years old, and the youngest sexually mature female was 2 years old . Gonadal activity was seasonal and peaked during November-May. Vitell ogenic oocytes were present in ovaries in every month except August an d September and were most abundant during November-May. Median GSI's w ere greatest during November-May and least during July-September for b oth males and females. No fully hydrated ovaries or postovulatory foll icles were found, therefore we could not estimate spawning periodicity or batch fecundities. Total fecundity ranged from 0.4 to 1.7 million oocytes and had a significant positive relation to fish weight. The ab sence of fully hydrated ovaries and postovulatory follicles in the bon efish we sampled suggests that bonefish spawn outside the traditional shallow-water (<2 m) fishing grounds in the Florida Keys.