Determination of optimum light intensity for larval rearing of sea bass and tiger grouper for aquaculture

Asian seabass Lates calcarifer and tiger grouper EpinepheJus Juscogttatus larvae hatched with immature sensory organs, however their sensory organs developed rapidly after hatching. Their eyes had only cone cells in their retinae until commencement of the metamorphosis. Seabass larvae got rod cells in their retinae at 12-day-old, and tiger grouper larvae got rod cells at 25-day-old. Then, retinomotor responses occurred in their retinae, which were the dark adaptation and the light adaptation. The retinomotor responses of both species of larvae occurred between 0.1 Ix and Ilx. Feeding experiments showed that both species of larvae ingested Artemia with high ingestion rates under 10 Ix and above. However, Asian seabass larvae ingested Artemia with lower rates or almost none under 1 Ix and below. Tiger grouper larvae also ingested Artemia with high ingestion rates under 10 Ix and above, but the tiger grouper larvae ingested the Artemia with considerably high rates under even 1 Ix and below. The larval rearing experiments showed that Asian seabass larvae survived with high rates under 10 Ix and above, and tiger grouper larvae showed high survival rates under 100 Ix and above. Therefore this study recommends the light intensities for larval rearing without phytoplankton that are from 10 Ix to 1000 Ix for Asian seabass, and from 100 Ix to 1000 Ix for tiger grouper larvae