Reproductive biology of a large, aggregation-spawning serranid, Epinephelus fuscoguttatus (Forsskål): management implications
Abstract:The reproductive biology of Great Barrier Reef populations of the long-lived grouper Epinephelus fuscoguttatus (brown-marbled grouper or flowery cod) was investigated using histological analyses. Evidence provided by gonad morphology and age-based demographics suggested monandric protogynous hermaphroditism. Younger age groups contained only immature and mature females, and all males were above the size and age of 100% female maturity, consistent with secondary males derived from mature females by adult sex change. Fishing records confirmed that spawning aggregations of this species and the co-occurring Epinephelus polyphekadion (camouflage grouper) are sometimes targeted on the Great Barrier Reef. Sampling data revealed strong spawning seasonality for E. fuscoguttatus, with a relatively narrow annual spawning period (November to January). The temporal pattern of reproductive activity within the spawning period, based on occurrence of near spawning ovaries (containing hydrated oocytes), indicated spawning events may occur throughout much of the lunar cycle and only partly coincide with seasonal fishing closure periods on the Great Barrier Reef. The results indicate that protection would be enhanced by a longer seasonal closure.
Document Type: Regular Paper
Affiliations: 1: School of Marine and Tropical Biology, James Cook University, Townsville, QLD 4810, Australia 2: Antarctic Climate and Ecosystems CRC, University of Tasmania, Private Bag 80, TAS 7001, Australia 3: Australian Fisheries Management Authority, P. O. Box 7051, Canberra Business Centre, ACT 2610, Australia
Publication date: September 1, 2007