Yuji Sakuma wrote:

Hello JR,

I am not sure that I understand the reasons for your opposition to trying to
restore disappearing natural runs with hatchery fish. These days, I
understand that hatchery stock, in order to maintain the purity of the gene
pool for a given river, is produced using eggs and milt from wild fish
returning to that river . From what I hear, hatchery fish do have a higher
early mortality than stream bred fish because despite having the same genes,
they will be less well adapted to wild conditions initially. However, if
they do manage to survive say, a year, it seems to me that they should be
the same in every way as stream-bred fish of the same age. Am I missing
something here? Sure, I too would like to see steelhead runs restored by
returning the environment to what it was a couple of centuries ago but let's
face it, that's not going to happen.


There are places where what you say is true and that if runs are to be
reestablished, hatchery fish must be used. However, there are many
places where natural fish can re-establish healthy runs on their own.


Using the milt and eggs from the wild fish returning to the river is the
best way if man must interfere. However, since man is choosing which
fish will have offspring, instead of the environment, we are likely to
be inadvertently selecting for specific traits. Because such an
unnaturally high number of artificially inseminated eggs will survive,
far fewer fish are needed and are being chosen to contribute to the gene
pool. Since many fish in the stocking would have died in the wild for
one reason or another before they would have reached "stocking" size,
the selection bias is even more pronounced.

Willi