Evaluation of pearl oyster (Pinctada maxima) spawning using natural and artificial induction methods to increase the seed production

Abstract

The increasing pearl jewelries production leads to an increasing demand for pearl oyster (Pinctada maxima) seeds of certain sizes. The induction spawning method is an important factor in producing pearl oyster seeds. This study aimed to evaluate natural and artificial induction methods for pearl oyster spawning using wild and farmed broodstocks to determine efficient seed production. Treatments applied were natural spawning induction of wild and farmed broodstocks (A), natural spawning induction of farmed broodstocks (B), and artificial induction of farmed broodstocks (C). After spawning completed, reproductive performances of the pearls for each treatment were observed with parameters of total number of eggs, number of hatching eggs, and the hatching rate. Pearl oyster seeds were reared for 43 days and fed twice a day with a mixture of phytoplankton. At the rearing stage, we observed the morphology, number, size, and survival of larvae. Natural spawning induction with wild male and farmed female broodstocks showed the highest total number of eggs (32,000,000 eggs) and the highest hatching rate (25%) compared to natural induction and artificial induction with all farmed broodstocks. However, natural spawning induction of wild male and farmed female broodstocks showed higher survival and normal seed growth to the spat stage compared to other spawning induction methods.