Wolfgang wrote:

"rw" wrote in message
nk.net...


Producing hatchery fish -- even ones bred from wild stock -- doesn't
change the genes...


Yes, it does. Every environment has its mutagens. No two are the same.

That's true, I suppose, but it's a very small effect over just one
generation, and probably not even measurable because sustainable
mutation rates are low. Most short term variation in genetics (by far)
comes from sexual reproduction and the resulting combination of alleles,
and not from mutation. That's Biology 101.

The point I was making, if you can just stop wanking for a moment, is
that hatchery production affects the genetics of populations, if not
(very much) the actual genes themselves.

I'm not as alarmed about hatchery production of steelhead and salmon as
some people are. I don't doubt that hatchery production adversely
affects the gene pool (from our point of view as fishermen), but the
real problem is habitat loss and degradation. Hatcheries should be seen
as temporary, stop-gap measures. If the habitat were somehow magically
restored to its pristine condition (not likely) and hatchery production
were stopped, the population genetics of fish would return to a "normal"
wild state in a few generations, under normal wild selection pressures,
as long as the underlying genetic diversity hadn't been lost.

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