Programme général de recherche sur la nacre. Écophysiologie de l'huître perlière, approche des relations entre la croissance de l'huître Pinctada margaritifera et le milieu dans le lagon de Takapoto

A study of pearl oysters Pinctada margaritifera growth and mortality was done on a monthly basis between June 1990 and September 1991 in Takapoto atoll (Tuamotu archipelago). Meanwhile, sampling parameters representative of bivalves food showed a remarquable spatial stability whithin the lagoon. The amplitude of temporal variability varied in the order of some days. Carrying capacity appears low : energetic content of particulate material in waters is about 2 joules/liter, ten times lower than in temperate areas. On the opposite, seasonal effect is reduced and particulate food is always available. Oysters rearing conditions were appropriate during the studied period with a low mortality rate and a regular growth in size (from 97 mm to 136 mm). Pearls oysters regularly used the available energy without accumulating tissue reserves. Gonad maturation was continue during the year with a strong variability between individuals. Growth of reared oysters was faster than the growth of natural stock oysters. Two kinds of methods for a optimized management of pearl oyster culture are presented : regular acquisition on growth, rearing stocks and environnement data and direct determination of carrying capacity by analytic methods