Effects of artificial and natural materials ropes as substrates for settling and metamorphosis of pediveliger pearl oyster, Pinctada maxima (Jameson, 1901)

Abstract

A study aimed at investigating the effects of four different materials ropes as substrates for settling and metamorphosis of tropical oyster, Pinctada maxima, pediveligers was conducted at laboratory scale. The number of pediveligers attached and metamorphosed on each substratum were counted at the termination of the experiment. Increment in shell length during settling and metamorphosis was also measured. Settling and metamorphosis were analyzed using One-Way ANOVA with substratum as the main effect. Two-Way ANOVA with time and substratum as the main effect on growth was also tested. The results showed that the settling and metamorphosis of pediveligers were affected by the substratum. The number of settled and metamorphosed pediveligers on polypropylene rope, natural ropes of Arenga pinnata and Cocos nucifera was significantly higher than on the bottom of Pyrex glasses. No significant difference between numbers of larvae settled on polypropylene and natural ropes of A. pinnata and C. nucifera appeared. A significant effect of time, but not of substratum, on growth occurred. Overall, settling and metamorphosis of P. maxima pediveligers larvae were strongly affected by artificial and natural ropes, while metamorphosis occurred haphazardly on the Pyrex glass. Growth occurred after settling and metamorphosis.