P.C. Southgate, J.J. Taylor, M. Ito-1998
Asian Fisheries Science, 10(3): 265-268
Abstract:
This paper reports on two experiments in which the effect of egg density on hatch rate of pearl oyster Pinctada maxima (Jameson) and P. margaritifera (L.) larvae was determined. Fertilized eggs were stocked at densities of 10, 20, 30, 40, 50 and 100/ml for P. maxima and 10, 20, 30, 50, 100 and 150/ml for P. margaritifera. After 24 h, the number of D-stage veliger larvae was assessed and survival was calculated. Highest survival was shown at an egg density of 10/ml for both P. maxima (82.5%) and P. margaritifera (93.2%). Lowest survival was shown at a density of 100/ml for both P. maxima (74.1%) and P. margaritifera (79.4%). However, for both species, there was no significant difference in survival between densities of 20 and 50 eggs/ml or between 30 and 100 eggs/ml.
(Aquaculture Department, James Cook University of North Queensland, Townsville, Queensland 4811, Australia)