|September 26, 2005
On September 7, 2005
program managers for the Redfish Lake Sockeye Salmon Captive
Broodstock Program completed one of their annual fish reintroduction
activities. Workers released 173 sockeye into Redfish Lake to spawn
naturally. Adult release is one of five strategies used to return
fish to the wild.
All adults released on September 7 were reared by NOAA Fisheries in
Manchester, Washington. The 173 adults released represent maturing
sockeye from brood years 2000, 2001, and 2002 (age-3 through age-5
fish). Six captive-reared sockeye received radio transmitters before
release to allow research biologists to monitor spawning behavior.
Snake River sockeye salmon Oncorhynchus nerka were listed as
Endangered under the U.S. Endangered Species Act in 1991.
Conservation experts have described Snake River sockeye salmon as a
prime example of a species on the threshold of extinction. In Idaho,
the lakes of the upper Salmon River represent the only potential
habitat for sockeye salmon.
Historically, five Sawtooth Valley lakes (Redfish, Alturas, Pettit,
Stanley, and Yellow Belly) supported sockeye. By 1962, sockeye
salmon were no longer returning to Stanley, Pettit, and Yellow Belly
lakes. Currently, only Redfish Lake receives a remnant run of
sockeye returning from the Pacific Ocean; between 1990 to 1998, only
16 wild adults returned to Redfish Lake.
Snake River sockeye salmon travel the longest distance (900 miles
one way) and to the highest elevation (almost 7,000 ft) of any
population of sockeye salmon in the world. In addition, they are the
most southerly population of sockeye salmon in the world.
Due to the precipitous decline of returning anadromous adults, the
Idaho Department of Fish and Game began the Snake River Sockeye
Salmon Captive Broodstock Program in 1991. The program generates
hatchery-produced eggs, juveniles, and adults for reintroduction to
Sawtooth Valley waters. Genetically diverse broodstocks remain in
the hatchery to supplement the fish that migrate to and from the
The reintroduction plan follows a "spread-the-risk" philosophy.
Progeny from the captive broodstock program are reintroduced to
Sawtooth Valley waters at different life stages using a variety of
release options including: 1) eyed-egg plants to in-lake incubator
boxes, 2) presmolt releases direct to lakes, 3) presmolt transfers
to net pens for in-lake rearing and release in Redfish Lake, 4)
smolt releases to the outlet of Redfish Lake and to the upper Salmon
River and 5) adult releases directly to lakes. All sockeye salmon
spawning and early rearing is conducted at the IDFG Eagle Fish
Hatchery and at NOAA Fisheries facilities in Washington State.
Juveniles produced from in-lake spawning will begin migrating
downstream toward the Pacific primarily as one year old smolts in
2007. Adults could return to Redfish Lake as early as 2009.
The program is coordinated by the Stanley Basin Sockeye Technical
Oversight Committee, a team of biologists representing the Idaho
Department of Fish and Game, the Shoshone-Bannock Tribes, the
National Oceanic and Atmospheric Administration (NOAA), and the
University of Idaho. The Bonneville Power Administration is the
coordinating and funding agency for Snake River sockeye salmon