Hatcheries

To mitigate the decimation of wild salmon runs caused by construction of dams and over fishing, the U.S. Fish and Wildlife Service yearly deposits billions of salmon eggs and young, propagated in nurseries, into natural breeding grounds and constructs fish ladders for the upstream journey of mature salmon. However, hatchery-raised salmon are often not the best solution to recovering natural production. The issue is largely one of scale and management practices. Large production hatcheries can help improve fishing, but can also cause some real problems for native populations. Smaller scale genetic conservation and recovery hatcheries can avoid many of the problems of the large production hatcheries. Sometimes they are the best, or only way to conserve a dwindling population. Some problems with hatchery fish include the following: They have aggressive feeding habits. This means, unlike wild salmon that spend most of their time in deep water or under cover, hatchery raised salmon spend most of their time at the water’s surface looking for food . As a result, hatchery-raised salmon consume  the food that wild salmon need. At the same time, this aggressive feeding makes hatchery salmon more vulnerable to predators because they stay near the surface. Problems are created if hatchery salmon compete with wild salmon in creeks and rivers. If the hatchery salmon are released as “smolts” (having entered the hormonal change that triggers their instinct to go to sea). They do not eat much, and for coastal short-run salmon, like coho, they reach the ocean in a few days. At sea, competition between hatchery and wild salmon seems to be less of an issue. Another problem is that hatchery salmon usually have less genetic diversity than wild salmon. This can lead to lowered resistance to disease and other environmental hazards. Hatcheries can minimize this effect by using breeding programs that maximize the genetic diversity of the fish they produce.

hatchery

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