curred during the breeding period. The female released approximately all of her ripe eggs in a single spawning, which lasted less than 20 seconds. Spawning involved one female and one or more males in midwater of the tank. Just after release of eggs by a female, one or a few males followed the female and spread sperm on the eggs using tail beats. The eggs and milt slowly sank to the bottom. The spawning behavior of Pacific cod differed from the single-pair spawning characterized by ven tral mounting and multiple spawning over a several day period seen in walleye pollock and Atlantic gadid species.