REPRODUCTIVE AND TROPHIC ECOLOGY OF THE SOLDIERFISH MYRIPRISTIS-AMAENA IN TROPICAL FISHERIES

Squirrelfish of the genus Myripristis are valued in small-scale fisher ies throughout much of the tropics. The life history and species biolo gy of most of these soldierfishes is poorly known. For the brick soldi erfish, M. amaena, in Hawaii and Johnston Atoll, we found that sexual maturity for both sexes was reached between 145 and 160 mm standard le ngth at about six years of age - a large fraction of the apparent maxi mum size and lifespan. Fecundity was relatively low and increased as t he fifth power of body weight. Spawning peaked from about early April to early May, and a secondary peak occurred in September. Myripristis amaena is a nocturnal predator, feeding mostly on meroplankton, especi ally brachyuran crab megalops, hermit crab larvae, and shrimps, but al so taking a variety of benthic prey. In pristine fish communities, hol ocentrids were abundant, quantitatively important (often dominant) ree f predators and prey. Myripristis amaena (and probably other common an d important soldierfish) seems to be relatively long lived (at least 1 4 years), slow growing, and late maturing. The populations suffer cons iderable natural predation and depend mainly on the largest and oldest fish for reproduction. Heavy, unregulated fishing of these soldierfis h, especially at prereproductive size, may severely reduce populations .