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NSRAA has doubled chinook production at Medvejie Hatchery by utilizing an innovative approach that combines existing capability, experience with saltwater net pen rearing and some recent information on successful rearing of salmon in net pens in lakes. Hatchery smolt production capacity is limited by the fish's requirements for freshwater and space: demands which increase as the fish grow. Thus, a hatchery can produce large numbers of small fish, but relatively small numbers of large fish.
The key to expansion of capacity is to find other ways of growing fish that do not substantially impact the water and space demands at the hatchery. One example is NSRAA's Deer Lake project where small coho are planted in a lake and left to forage on zooplankton until they are ready to migrate to sea. The hatchery provides the means to incubate and rear the fish for a short time until they can be planted in the lake. The numbers of coho produced this way are at least ten times greater than would be possible by relying on the hatchery for the full rearing period.
Chinook fry are reared in freshwater net pens in Green Lake each summer, then transferred to saltwater net pens at the hatchery in early October. The chinook will spend the winter in the saltwater pens and be released as smolt the following spring. In 1998, the first group of fry was introduced into the lake. This group was about 400,000 fry. The project went to full production in 1999 with 1.1 million fry going into Green Lake net pens. Adults from the project began to return in 2001. Full adult production for the project began in 2003, with Green Lake fish contributing to all major adult age classes.
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