Ecophysiological model of growth and reproduction of the black pearl oyster, Pinctada margaritifera: potential applications for pearl farming in French Polynesia

A model of bioenergetics of the black pearl oyster (Pinctada margaritifera) was built to simulate growth, reproduction and spawning in suspended cultu re at field sites in Takapoto lagoon (French Polynesia). This model was bas ed on allometric scaling of physiological functions and scope for growth (S FG) calculations. The input functions were clearance rate (CR, 1 day(-1)), retention efficiency (RE, %) for each kind of particle encountered in suspe nded matter, pseudofaeces and faeces productions (PF and F, mg C day(-1)), excretion and respiration rate (U and R, mg C day(-1)). The assimilated car bon (i.e., SFG, mg C day(-1)) was partitioned to the three internal state v ariables (somatic tissue, shell and gonad) according to the asymptotic incr ease of the reproductive effort (ER, %) with the age. Given organic and min eral particulate matter in suspension in lagoon water (POM and PIM, mg L-1) and assuming that the taxonomic composition of POM was fairly constant thr oughout the year, the model predicted annual evolution of total tissue weig ht (W-Tissue, g dry weight), shell weight (W-Shell, g DW) and gonad weight (W-Gonad, g DW) of pearl oysters at various ages. Data on tissue and shell growth, but also on gonad development of cultivated pearl oysters, acquired in 1997-1998 in Takapoto lagoon, were used to validate the model outputs. Results of the simulations indicated that the P. margaritifera growth model provided realistic growth trajectories for shell, somatic tissue and gonad , for pearl oysters aged from 1 to 4 years.