Populations of wild steelhead have declined from historical levels in the Columbia and Snake rivers. Some stocks in the upper Columbia River are listed as endangered, and some in the Snake and Middle Columbia rivers are listed as threatened. The Columbia River Inter-Tribal Fish Commission (CRITFC) and the Nez Perce Tribe are conducting a project titled Kelt Reconditioning and Reproductive Success Evaluation Research. The goal of the project is to develop novel steelhead restoration approaches. One approach to increase natural production of steelhead is to utilize their iteroparous life history. This project is a collaborative study to investigate methods to increase adult steelhead returns by utilizing the post-spawn life stage by reconditioning kelts.
The study area includes collection and holding sites within the Snake River Basin. Trapping and fish collection primarily occur at the Lower Granite Dam (LGR) Juvenile Fish Facility (JFF). Holding, treatment and evaluation primarily occur at Dworshak National Fish Hatchery (DNFH). Additional experiments and laboratory analysis will occur on the campus of the University of Idaho.
The project schedule begins with set-up and operation of the holding facility at DNFH in early January followed by air- spawning of steelhead adults at DNFH beginning in late January or early February. In-river migrant kelts are collected at LGR from March through June and transported to DNFH for holding. Kelt reconditioning and monitoring activities at DNFH are conducted following the first collection of fish through September.
The LGR-JFF redirects migratory fishes away from the dam. Kelts are diverted across the separator to a temporary adult holding tank. During this temporary holding, fish are PIT tagged, and the general condition of each kelt is assessed. Candidates for reconditioning are separated into a final holding tank; all others are returned to the river. To minimize fish holding time, every one or two days, fish selected for reconditioning are transferred from the final holding tank to DNFH using tank trucks.
In addition to the post-spawned out-migrating steelhead collected at LGR, approximately 150 air-spawned steelhead from DNFH will be reconditioned. The air-spawn method gently expels eggs from the female without harming her. Low pressure compressed air is injected into the body cavity just above the pelvic fin using a hypodermic needle. As the air fills the body cavity, eggs are forced out and into a collection bucket. Fish selected for this method must be carefully examined for ripeness to insure that no (or very few) eggs remain in the fish. Once spawned, these fish are transferred to the kelt tanks.
Kelts are held in four 15’ circular tanks fitted with anti-jump containment curtains. Soon after transfer, fish are presented with feed. Considerable effort and creativity is needed to insure these fish initiate feeding for both somatic growth and gonad development. Regularly, a host of physiological data is collected. Blood hormone levels, body lipid measurements, as well as weight, color and behavior are used to track their health and development.