Use of tropical microalgae as food for larvae of the black-lip pearl oyster Pinctada margaritifera

Abstract

This study determined the nutritional value of tropical microalgae for black-lip pearl oyster ( Pinctada margaritifera, L.) larvae. One-day old larvae were fed the flagellates Pavlova salina, Pavlova sp., TISO and Micromonas pusilla in binary and ternary combinations in Experiment 1. In a second experiment, umbo-stage larvae were fed the best binary combinations from Experiment 1 with the addition of one diatom species ( C. muelleri, Chaetoceros sp. or Skeletonema sp.) per combination. The best two ternary combinations (flagellates only) from Experiment 1, Pav. salina/ Pavlova sp./TISO and TISO/ M. pusilla/ Pavlova sp., were also assessed in Experiment 2. In Experiment 1, greater growth rate was shown by larvae fed the ternary combination of Pavlova sp./ Pav. salina/TISO followed for the binary combination of Pavlova sp./ M. pusilla; however, larvae fed Pavlova sp. as a mono-specific diet performed as well as those fed the ternary combination of Pavlova sp./ Pav. salina/ M. pusilla ( P = 0.001). The addition of a diatom to microalgae diets composed of flagellates resulted in increased growth rates and survival of umbo-stage P. margaritifera larvae when compared to combinations without a diatom (Experiment 2). The results showed that Pavlova sp. supported a high growth rate of D-stage P. margaritifera larvae which was equivalent to that of larvae fed plurispecific diets. For umbo-stage P. margaritifera larvae, the best growth rate was achieved when the binary combination of Pavlova sp. and C. muelleri was used. Based on these results, Pavlova sp. and Pavlova sp./ C. muelleri are recommended as diets for D-stage and umbo-stage P. margaritifera larvae, respectively.