A q u a cu ltu r e,16 (1 9 8 9 ) 4 3 -5 6 43 Elsevier S cien ce Publishers B .V ., Am sterdam -P rin ted in T h e N etherlands Larval and Juvenile Rearing of Black-Lip Pearl Oyster, Pinctada margaritifera (Linnaeus)K IN T R O D U C T IO NThe black-lip pearl oyster, P inctada m argaritifera (Linnaeus), is one of the three valuable species of pearl oyster for the cultured pearl industry of the world, the other two being P. m axim a (Jameson) and P. fucata (Gould). In India, P. m argaritifera is second in importance, after P. fucata. Its distribution is limited to the Andaman and Nicobar Islands ( Alagarswami, 1983); however, stray oysters may occasionally be collected from the Gulf of Mannar. The re source is not substantial in the islands; it is not exploited for the shell or the pearl, but collected by the Nicobarese for food. As a species native to the is-0044-84 8 6 /8 9 /$ 0 3 .50

A quaculture, 34 (1 9 8 3 ) 2 8 7-30 1 T he Indian pearl oyster Pinctada fucata w as spawned in the laboratory and the larvae w ere successfully reared to spat setting under tropical con dition s. T h e larve grow s through the straight-hinge, u m bo, eye sp ot and pediveliger stages in the pelagic phase b efore m etam orphosing to plantigrade and setting on a substratum as spat, and these stages are described. Large differences were n oticed in larval grow th w ithin and betw een fou r rearing experim ents. Isochrysis galbana was used as standard fo o d th roughou t larval rearing at a cell concentration range 8 0 -350/jul. Spatfall occu rred on day 24-32 o n a variety o f substrata. The highest density o f 4 .7 1 /cm * was observed on fibreglass tank b o tto m . G row th o f P. fucata larvae appears to be a step fu n ction , and that o f spat u p to 13 weeks describes a curvilinear form . IN TR O D U C TIO NFollow ing the developm ent o f techniques fo r farming o f pearl oyster Pinctada fucata and production o f cultured pearls in India (Alagarswami, 19 7 4 ), it became im portant to breed the species artificially as the popula tions in the natural beds display drastic fluctuations (Alagarswami and Qasim, 1973). Spat collection in inshore areas and bays yields only small quantities which com prise several species o f pearl oysters with a low per centage o f P. fucata (Alagarswami, 19 7 7 ). M ethods fo r controlled spawn ing o f pearl oyster were developed earlier (Alagarswami et al., 1980a) and larval rearing cou ld be carried o u t only up to the straight-hinge stage (Ala garswami et al., 1980b). Subsequently success has been achieved in produc tion o f pearl oyster spat in the experiments described in this paper.The few works on breeding o f the Japanese pearl oyster (Kobayashi, 0 0 4 4 -8 4 8 6 /8 3 /$ 0 3 .0 0