Spawing induction and larval rearing of the giant clam, Tridacna maxima in Chuuk Lagoon, Micronesia

Abstract

The giant clam (Tridacna spp.) is a tropical bivalve in high demand for bio industry materials using protein sources, aquarium biomaterials and decorative sources from shells. Due to the recent increase in demand, overfishing is taking place in major habitats around the world, and it has been designated as an vulnerable species. Therefore, production by aquaculture is required for stable resource management and to respond to market demand of bio materials. The purpose of this study was to establish the production system of indoor environment for spawning and early larval rearing in Tridacna maxima. It carried out the spawning induction by injecting macerated gonad as a dropper to inhalent siphon in a rectangular FRP tank (approximately 1 ton scale). We could be gained about 307×104±16.54 egg individuals from 12 adult bivalves. In general, it have been conducted spawning induction in tropical bivalve by the methods as the sun dry, raised watertemperature etc. The method of stimulation using by gonad solution is considered effective for spawning induction in giant clam. The methods of spawning induction should be selected an efficient method according to the conditions. It takethe 10~14 days reached at the stage of metamorphosis from stage of fertilized eggs. during the larval rearing, it was supplied the Isocrysis aff. galbana, Chaetoceros simplex, and Tetraselmis suecica which mixed at a ratio of 3: 3 4. At a