Reproduction in the camouflage grouper (Pisces: Serranidae) in Pohnpei, federated states of Micronesia

Abstract

Reproduction in the camouflage grouper, Epinephelus polyphekadion (Bleeker, 1849) was determined from 1073 individuals collected during a July 1997 pilot study and a 14-mo period in 1998-99 in Pohnpei, Micronesia, with a view to understanding sexual pattern and reproductive seasonality and to inform fisheries management. Gonadosomatic indices, combined with histological analyses of gonads, show that fish spawn during a two consecutive month period between February and April, and that gonad maturation occurs 1-2 mo prior to spawning. Sexual pattern was unresolved: histological examination of 677 individuals revealed no fish undergoing transition from functional female to functional male, although direct development of some males from juveniles is suggested and males were significantly larger than females. Mean relative fecundity was estimated to be 1350 oocytes g-1 gonad-free body weight, actual fecundity increased linearly as a function of body weight and fecundity is determinate within each aggregation period. Females spawned an average of 83 ± 17% of their vitellogenic oocytes per month, with repeat spawning by individual females during a single aggregation period.