THE RÔLE OF CHEMICAL STIMULATION IN THE SPAWNING REACTIONS OF OSTREA VIRGINICA AND OSTREA GIGAS

Abstract

The discharge of eggs or sperm of the oyster is stimulated by the presence in the water of sexual products of the opposite sex. In the [female] oyster the latent period varies from 6 to 38 min. and is independent of the concentration of sperm. The spawning reaction of the [female] is followed by a refractory period lasting 2-5 days. In the [female] the latent period varies from 5 to 12 sec; the reaction is not followed by a refractory period. The active principle of sperm suspension does not pass through the collodion membrane, and is destroyed by heating for 15 min. at 55[degree] C. The active principle of egg suspension is soluble in the sea water and withstands boiling for 10 min. The chemical stimulation is influenced by the temp., which determines the lowest limit (20[degree] for O. virginica) below which the [female][female] fail to spawn, and supplies initial stimulus for the spawning of the [male].