The effect of irradiance on the survival and growth of abalone postlarvae Haliotis fulgens fed Navicula incerta.
Survival and growth of Haliotis fulgens postlarvae (11 days old) were evaluated at four irradiance levels: 6, 24, 47 and 75 microensteins m-2 s-1 (µE). Experimental vessels were 1-l containers supplied with aeration and seawater flow. Four replicates per treatment were considered. Postlarvae were fed Navicula incerta, a cultured benthic diatom. Survival and growth rates were evaluated for 28 days. Shells were counted to determine mortality and shell size was determined by digital analysis of video recorded images. The highest survival (89.4% after 28 days) and growth rates (37.1 µm day-1) were found at 6 µE, whereas the lowest survival (3.5%) and growth rates (21.1 µm day-1) occurred at 47 µE. These results suggest that light conditions may have a dramatic effect on the success of abalone postlarval culture.