Numerous measures have been implemented on the Columbia River to improve downstream survival of salmonids (Oncorhynchus spp.).
Salmonids pass up to nine hydroelectric projects on their migrations to the ocean. Piscivorous (fish eating) birds specifically feed on disoriented smolt passing downstream through hydroelectric projects. Smolt pass through the Mid-Columbia in April, May and June. We conduct behavioral analysis and non-lethal hazing activities from our research vessel in dam tailrace areas. These activities significantly deter avian predation on salmonids passing through the Mid-Columbia.
Juvenile salmonids are reared in large ponds at hatcheries throughout the Mid-Columbia. These fish attract piscivorous birds such as blue herons, kingfishers, mergansers and cormorants. We perform behaviorial analysis and non-lethal hazing activities throughout the fall, winter and spring periods to reduce predation rates within local hatchery ponds. Results show that this service dramatically decreases predation rates.