Warm Springs National Fish Hatchery
Pacific Region
 
 

The Hatchery's Role in Restoring Fish Populations

SIMULATING A NATURAL ENVIRONMENT - SALMON RETURN - SPAWNING - INCUBATION - NURSERY TANKS - OUTDOOR RACEWAYS - SMOLT RELEASE

The Confederated Tribes of the Warm Springs realized long ago the need to restore the fishery resource, not only for the benefit of Indians, but for everyone.  The Warm Springs National Fish Hatchery was started as a cooperative effort to make more fish available on the Columbia, Deschutes, and Warm Springs rivers.  Each year young Chinook salmon are released into the Warm Springs River to replenish and restore fish populations.

The hatchery provides a safe environment for the development of eggs, fry, and fingerlings. Controlled conditions allow the hatchery staff to mimic growing conditions of wild fish. In the past attempts were made to rear the fish as large as possible but there was a concern that this approach may create a competitive advantage over wild fish. This practice is no long employed.

Simulating A Natural Environment

The hatchery simulates the salmon's natural growing environment by providing clean, cold, water.  Fresh river water enters the hatchery and is filtered before being pumped to the various tanks and ponds.  Large debris, such as leaves and twigs, are removed by a series of grids and screens. Smaller debris is removed in sand filters, and harmful bacteria and other organics are killed as the water passes through ultraviolet lights. Fish Barrier on the River and Ladder Entrance into the Hatchery

Salmon Return

Salmon rearing begins with adult spring Chinook returning upstream from April through August.  The hatchery barrier dam requires all fish to climb the fish ladders into the hatchery, where wild and hatchery fish are separated.  Wild fish are released above the hatchery barrier, while hatchery fish, identified by tags, remain in holding ponds until ready to spawn.  Holding ponds are kept at 50º F, since warm water causes the fish to spawn too soon.  Because river temperatures rise above 60º F in the summer, chillers cool the water before it is pumped to the holding ponds.

Spawning

Spawning begins in August and continues weekly through September.  The broodstock - adult fish used for spawning - in the holding ponds are moved to the spawning area where hatchery biologists remove eggs from the females and fertilize them with milt from the males. To gather enough eggs to restock the river at optimum level, up to 700 adult fish are needed for spawning.  When available, 10 percent of the wild salmon coming through the hatchery are added to the hatchery boodstock to retain genetic traits.

Incubation

The fertilized eggs are poured into incubation trays.  Clean, cold, oxygen-rich water is pumped through the tray stack, which holds 6,250 eggs per tray.  Optimum water temperature for proper growth at this stage is 50º F.  Winter river temperatures drop to freezing, so water is heated by boilers before being pumped through the trays.  By late October eyes of the developing embryos can be seen through the egg shells, and in late December and January eggs hatch into sac fry

Nursery Tanks

In December and January fry are transferred to nursery tanks and fed a prepared diet high in fish protein.  The hatchery water is warmed to increase feeding activity and speed up the growth process.

Coded-Wire Tagging Spring Chinook Salmon at Warm SpringsOutdoor Raceways

By March, fry develop into fingerlings and are put into the outdoor raceways after being acclimated to cooler outside temperatures.  In April and May, hatchery fingerlings are tagged with a coded wire tag in the snout and an adipose fin clip to distinguish them from wild fish.   Most young salmon stay in the raceways to develop until the following spring, although some early developers are ready to migrate in the fall.

Smolt's Journey from Warm Springs to the OceanSmolt Release

At about 16 months of age, fingerlings have developed into smolts and are ready for migration.  Each year approximately 750,000 smolts are released into the Warm Springs River and join wild smolts on their journey to the Pacific Ocean, where they will feed and grow for 1 to 4 years before making their return to the Warm Springs River to spawn, continuing the salmon's life cycle.

 

 

Last updated: July 16, 2013

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