STIMULATION OF SPAWNING IN THE MUSSELS, MYTILUS EDULIS LINNAEUS AND MYTILUS CALIFORNIANUS CONRAD, BY KRAFT MILL EFFLUENT

¹ Yaquina Bay Laboratory, Department of Fish and Game Management, Oregon State University, Corvallis, Oregon

1. Kraft mill effluent is a very effective material in stimulating spawning in the mussels M. edulis and M. californianus. Bay mussels obtained at all times of the year and sea mussels during January and February from the Oregon coast spawned within 24 hours after exposure to 4% KME. The gametes so obtained were viable and capable of fertilization, as shown by the artificial fertilization and development of eggs to the shell stage.

2. Electrical stimulation of intact mussels was also shown to stimulate spawning, but was not as effective as KME.

3. Mechanical stimulation, such as scraping the shells, or changing the water in which the animals were maintained, was only slightly effective in stimulating spawning. Stimulation associated with the partial opening of the valves was more effective in this regard.

4. Possible explanations for the mechanism of spawning in mussels are discussed.