2019 Volume 85 Issue 3 Pages 321-330
Walleye pollock Gadus chalcogrammus were reared indoors from egg to adulthood in order to record their life history in a controlled rearing environment. Next, a laboratory experiment using the reared fish was conducted to examine the relationship between the adults' feeding conditions and the quantity and/or quality of spawned eggs. The hatchery-reared fish spawned spontaneously for the first time at age 2 years. The fish were fed at two ration levels (to satiation or 25-50% of the satiation amount) for periods of 8 months prior to and during the first-time spawning season. The relative egg production (number of spawned eggs per female somatic weight) was similar between the two groups. The diameters of eggs spawned by fish fed to satiation were larger than those spawned by fish fed on the low ration. Laboratory experiments using hatchery-reared walleye pollock are useful for examining the quantity and quality of spawned eggs in relation to the biological characteristics (e.g. age, standard length, nutritional status and recruit/repeat spawner) of adult fish.
