Re. Crabtree et al., MATURATION AND REPRODUCTIVE SEASONALITY IN BONEFISH, ALBULA-VULPES, FROM THE WATERS OF THE FLORIDA KEYS, Fishery bulletin, 95(3), 1997, pp. 456-465
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.