Federal biologists say that cutting hatchery production could help protect wild salmon

It is an argument for removing dams as well.

For many years biologists have known that hatchery fish effect the fitness of wild fish through competition and interbreeding. Hatchery fish don’t have the selective pressures that wild fish do so are less fit to survive in the wild. Because of this, when hatchery fish breed with wild fish the progeny are less suited to survive in the wild affecting the overall survival of wild fish.

Hatchery fish are also larger and more aggressive than wild fish and compete with them for food further limiting the success of wild fish. Being more aggressive makes hatchery fish more vulnerable to predators, a trait that you don’t want to transfer to wild fish. Hatchery fish also stray more so they can interbreed with runs which are managed to be exclusively wild such as the Middle Fork of the Salmon River.

In the case of steelhead, hatchery fish virtually flood the habitat with stray fish, a situation that almost ensures that hatchery fish will interbreed with wild fish in places where it is not intended.

I think the report mentioned is more of an argument for removing dams than it is for reducing hatchery production because, due to the impacts of lower numbers of fish in the short term like economic and biological impacts, you can’t reduce hatchery production without increasing the success of wild fish reproduction. The only way to increase wild fish production to such a degree will be to remove dams.

Federal biologists say that cutting hatchery production could help protect wild salmon
By Scott Learn, The Oregonian

Posted in endangered species act, Fish. Tags: , , , , . Comments Off on Federal biologists say that cutting hatchery production could help protect wild salmon

Anandromous fish from hatcheries have poor survival rates.

“Steelhead turned out by hatcheries quickly evolve into a kind of swimming livestock with a poor chance of surviving in the wild and may carry their inferior traits into wild populations that biologists are trying to save, a new study of fish in Oregon’s Hood River has found.”

Read the rest of the story: Hatchery fish found to be poor at survival. A study indicates steelhead are so bad at surviving that they are little help to wild runs. By Michael Milstein. The Oregonian.