Reproductive biology of the protogynous hermaphrodite Achoerodus viridis (Labridae) from south-eastern Australia

Achoerodus viridis (Pisces:Labridae) was sampled over two years at Little Bay, NSW, Australia, and comparative material was taken from a site 4.5 km away at Cape Solander. Population structure and gonadal structure showed that A. viridis was protogynous and monandric (i.e. no primary males were found). Histological sections of male gonads showed a gonadal lumen, general ovarian lamellar form and multiple sperm ducts running longitudinally through the gonad wall. Males dominated the larger size and age classes, whereas females predominated in the smaller size and age classes. The sex ratio of mature fish and the whole population was biased in favour of females. Individuals at both sites matured as females at 1(+)-2(+) years. Fish at Little Bay functioned as females at ages ranging from 8(+) to 18(+) years before changing sex at a size between 480 and 580 mm SL. Fish at Cape Solander may function as females for up to 18(+) years and change sex between 500 and 520 mm SL. Spawning occurred between July and October (1991-93).