Determination of the optimum concentration of eggs and spermatozoa for the production of normal larvae in Pecten maximus (Mollusca, Lamellibranchia)

Abstract

1. The scallop Pecten maximus (L.) can be conditioned in the laboratory to produce ripe gametes at times other than its normal spawning seasons. 2. The spawning stimulus consists of taking the scallop out of water for a period of approximately 2 h. Spawning occurs within 2 to 4 h of re-immersion in water. 3. More larvae and a higher proportion of normal larvae are produced by eggs incubated at low density levels. 4. The higher sperm concentrations produce fewer larvae and higher percentages of abnormal larvae than the lower concentrations. 5. Eggs incubated at 7 per cm2 bottom area produce very few abnormal larvae but large numbers of normal larvae can be produced more efficiently by incubating at a density level of 700 eggs per cm2 although a higher percentage of abnormal larvae must be tolerated. © 1970 Biologischen Anstalt Helgoland.