On 2004-02-07 11:04:31 -0700, Chas Wade
said:

"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.


Yuji,

JR is right on the money here, but you are too. The problem os that only
some of the hatcheries actually take wild fish for their brood stock. Most
of the rivers have two distinct runs of fish, the early run is the hatchery
fish, they are smaller, and the descendants of hatchery fish first
introduced from other rivers many years ago. The later run natives are the
vestige if the original stock and need to be protected.

I don't think the problem is that hatchery steelhead (bred from wild stock)
have inferior genetics at conception. They have the same genetics as wild
fish. The problem is that they're raised "in bulk," protected from the
vissicitudes of nature, such as predators, weather, and disease, until
they're smolts., and then they're released. They haven't gone through the
culling that they're wild cousins endure, so they have inferior genetics
when they're released.

IMO, of course. I'm just an armchair fisheries biologist. :-)

-----------------------------------------------------
Cut "to the chase" for my email address.