Synopsis of the biology and ecology of Pomadasys argenteus (Haemulidae) in New Caledonia
Pomadasys argenteus (Forsskål, 1775) is a major commercial and subsistence species of shore fish in most of its range (East Africa to Fiji) but little information is available on its biology and ecology. The present study investigates the major biological and ecological traits of this species in New Caledonia, on the eastern border of its range. This species was mainly found in mangroves and to a lesser extent on nearby soft bottoms. Most of the fish were found in shallow waters (< 5 m), the deepest record being 28 m. Abundance varied within habitats through the year, with fish becoming more abundant on soft bottoms during the reproductive season, which occurs between July and December. The largest specimen was 42 cm FL and 1150 g. Females were more abundant (73% of the sexed population) and larger than males, the latter never exceeding 34 cm FL. Both sexes matured at the same size (16-18 cm). A higher proportion of females was found in the mangroves than on soft bottoms. However, the proportion of males and females ready to reproduce was similar in both habitats. Diet showed little diversity and was mainly composed of crabs and to a lesser extent shrimps, bivalves and annelids. Length-weight relationships varied between sexes, with males being slightly heavier than females of the same size. Growth was estimated by analyzing daily and seasonal otolith increments which were validated by a combination of methods. An asymptotic growth formula was fitted to the data: Length (mm FL) = 420*(1 – e-0.346*(age-0.161)), where age is given in years. Growth was found to be slower than in most other studies, except in Kuwait waters. There was no significant difference in growth between sexes.