Sciences marines : recherche et développement

Abstrait

Optimization of Fertilization Success in the Bivalve Mollusk Tivela mactroides under Laboratory Conditions

Yajaira García de Severeyn, Ana Villasmil, Héctor Severeyn, Félix Morales and Marynes Montiel

With the objective to produce seed in an aquaculture facility it was studied under laboratory conditions, the effect of sperm concentration and contact time between gametes to optimized fertilization success of the bivalve mollusk Tivela mactroides. Mature ovocites and spermatozoids gotten through gonads dissection of adult mature male and female clams were artificially combined to produce fertilization. Solutions of 5.5×106 ovocites were fertilized with 10 different sperm concentrations. Results indicate that the percentage of succeed fertilization was low, highly variable and relying on the sperm concentration. The maximum mean percentage of fertilization was 22% between 1.3×107 and 1.7×107 spermatozoid/ml. A strong fall in fertilization success was observed at sperm concentrations lower than 106 spermatozoid/ml. The time lapsed after the first contact for fertilization that produced the highest fertilization rate was three hours, at sperm concentrations higher than 107 spermatozoids/ml. The highest fertilization percentage found in this study falls between the ranges reported for other bivalve mollusk species.