High energy diets and high feed rates used in salmon hatcheries can cause early sexual maturation in male salmon. Early maturing male salmon may stay in freshwater and spawn at an early age rather than migrate to the ocean to feed for months or years. Because of this, these fish are usually smaller than males that mature at a later age and can also negatively affect freshwater ecosystems through increased predation and competition for limited resources. Consequently, studies have been conducted at Pacific Region NFHs to determine whether restricted feeding can reduce early male maturation in salmon. Physiologists at Abernathy are assisted with these projects by measuring plasma levels of 11-ketotestosterone (an indicator of male sexual maturation) in hatchery salmon that are fed different amounts of feed. A project like this could result in alternative feeding practices which reduce premature male maturation rates at salmon hatcheries.
Research