Washington State and the Columbia River system mark the southern extent of the current distribution of sockeye salmon in North America. In 1992, the Washington Department of Fish and Wildlife (WDFW) and the western Washington Treaty Indian Tribes identified nine separate sockeye salmon stocks in the state. Lake Washington sockeye (3 stocks) and Columbia River sockeye (2 stocks) are the state's two largest runs of this species. Both runs have supported popular fisheries in past years. Because of intense public interest in the outlook for sockeye fishing, the following web pages will provide updated sockeye counts for Lake Washington (Ballard Locks) and for the Columbia River dams, along with a variety of other information on the management and life histories of these sockeye runs.
Sockeye salmon generally spawn in streams that are tributaries to large
lakes. These streams can vary in type, ranging from small tributaries
to large mainstem rivers and side-channels. Additionally, some sockeye
stocks spawn along the shorelines of lakes. Spawning of various sockeye
stocks begins as early as August and some stocks can extend spawning into
February. Those sockeye spawning from August through October need adequate
stream flows to provide proper spawner distributions on the spawning grounds.
All sockeye require extensive, quality spawning riffles for optimum production.
Successful egg and alevin survivals are dependent on clean spawning gravels
and low to moderate winter stream flows. Sockeye eggs and fry can be negatively
impacted by high flows during the fall and winter incubation period. The
erosion and downstream movement of spawning gravels is a major cause of
egg and alevin losses, and severe flooding can cause mortalities exceeding
90%. Land use practices and natural events that introduce substantial
amounts of silt into spawning streams affect sockeye intergravel survivals
by reducing the permeability of the gravel, which can affect the survival
of incubating eggs and alevins by interfering with the delivery of oxygenated
water and the removal of metabolic wastes. Channelization and bank armoring
reduces the amount, quality, and diversity of sockeye spawning areas by
narrowing and deepening the stream channel. Those sockeye that spawn on
lake shores need access to undisturbed shallow water shorelines, and clean
gravels with upwelling ground water.
|Cedar River sockeye salmon male (top) and female (bottom) in spawning
The sockeye fry migrate downstream to the deep waters of nursery lakes
upon emergence from spawning sites from January through June, at a size
of approximately 25 to 32 millimeters (1.0 to 1.25 inches). At this small
size, sockeye fry are vulnerable to predation by other fishes and birds,
and survivals can be lowered substantially by aggregations of natural
or artificially produced predators. Nearly all juvenile sockeye in Washington
State rear in lakes for 1 year, and continue to be subjected to predation
by other fish species. They also face competition for available food resources
with other fish. The production of food organisms is particularly important
at this life stage because faster growth rates can increase the survival
of the young sockeye.
Sockeye smolts emigrate to sea in spring at a length of approximately
4 - 6 inches and are subjected to intense predation by a variety of fish
and bird species. Squawfish and trout have been identified as especially
significant predators during this outmigration life phase, and gulls and
grebes are some of the significant avian predators of sockeye smolts.
The freshwater/saltwater transition zone provided by estuary habitat
can be important to the success of sockeye smolts. A natural, productive
estuary provides the food resources necessary for the smolts to transit
the area, and can offer refuges from numerous fish and bird predator species.
In the near shore and open ocean environments, predation by fish, birds,
and marine mammals, and competition for food resources with other fish
species affects growth and survival of sockeye salmon. Most of the estuaries
in Washington have been altered by changes including channelization, dredging,
diking, filling of wetlands and tidal areas, and degraded water quality.
This alteration and/or loss of estuarine habitat by factors such as urbanization,
agriculture, forest land management, and industrial and water resource
development has been extensive. These habitat modifications tend to reduce
the overall amount of habitat, and reduces the general productivity of
estuaries (and food production), which limits overall utility of these
areas for sockeye rearing.
Ocean growth and survival of all species of Pacific salmon can be affected
by periodic warm water events (El Niño) in local waters, and by
cyclic changes in ocean conditions in the North Pacific Ocean. Returning
sockeye will have spent 2-4 years at sea upon returning to their natal
spawning grounds, with the majority returning in June and July as 4 year
old fish at an average weight of about 5 pounds.