Algal-induced spawning in the marine mussel<i>Mytilus californianus 4</i>

Abstract

Abstract The characteristics of algal-induced spawning of the marine mussel Mytilus californianus were studied. Exposure of mature individuals to culture suspensions of the unicellular alga Pseudoisochrysis paradoxa elicited copious and synchronous release of gametes. Alkaline conditions were necessary to make the animals responsive to the spawning stimulus provided by the algae. The filtered, cell-free fraction of the algal suspensions also stimulated spawning, suggesting that an active principle is secreted into the culture media by the algae. A key requirement for the development of an efficient and economically viable molluscan mariculture program is the capability to induce copious, synchronous spawning of gravid individuals. This procedure should be easily managed and have no deleterious effects on the gametes, fertilization, or the ontological development of the animals. Miyazaki [1] induced spawning in male oysters by exposing them to an extract of green algae. Recently it was reported that the marine mussels, M. californianus, could be induced to spawn by exposing them to cultures of the marine algae, P. paradoxa [2], This paper summarizes our efforts to characterize this spawning response of mussels to high concentrations of cultured marine algae. Keywords: Mytilus californianusspawningalgaepH dependence