ralph heidecke

Is this an interesting thread or just a lot of nonsense?

http://forum.fishbc.com/index.php?showtopic=16019

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peter charles

GL steelhead all originated from stockings taken from Pacific rivers.
Genetically, they're still steelhead. Everything else is sophistry.

Peter

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rw

The problem with that reasoning is that steelhead and rainbows are the
same species, Oncorhynchus mykiss (formerly Salmo gairdneri).

"Steelhead" aren't distinguished from rainbow trout by genetics. They're
distinguished by behavior -- migrating to the sea. The question should
actually be: "Are the Great Lakes seas?" I don't think so, because
they're fresh water. YMMV.

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peter charles

They migrate, we just left out the salt.

Peter

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ken fortenberry

Anadromous or potadromous the same genetically identical
species of fish is born in a river, lives in a sea and
returns to the *same* river to spawn. The ones in the
Pacific watersheds are there by the grace of god, the
ones in the Great Lakes are there by bucket biology.
Other than that, they're the same.

In my ain't never been humble opinion.

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wolfgang

Oh?

Wolfgang

asadi....

Lord have mercy, land of Goshen..
Shades of gray out on that ocean....
don't you dare take that boat out to sea...

john

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bob patton

//snip//

How about them that migrate up Snowbird creek from Santeetlah lake?

:-)

Bob

jr

What distinguishes steelhead from resident rainbows is not that they
migrate, or even that they migrate to salt water, but rather that they
undergo the process of smoltification (ugly word, but there you are).
Smoltification produces specific, major physiological and morphological
changes that are unmistakable.

Even in the PNW there are native populations of O. mykiss that migrate
from their natal streams to lakes in order to feed/live and then return
to the same streams to spawn, but do not smolt before the initial
migration. These are clearly "resident" rainbows, despite their
potadramous life histories. Great Lakes steelhead, on the other hand,
do smolt, and the process of smoltification quite obviously produces
essentially the same morphological changes that it produces in PNW
steelhead. I assume that the physiological changes are quite similar.

It's a bit of a mystery, I suppose, just *why* GL steelhead smolt, given
that at least one "goal" of smoltification in PNW fish (adaptation to
living in salt water), is not "needed." Still, the fact that they do
undergo the process clearly makes them, to my mind anyway, steelhead.

JR

peter

Forgot about the smolting -- the other characteristic is their large
size. Resident bows never grow very large even in rivers rich with
forage, while GL steelhead can reach 20 lbs. I'm also curious if our
lake run browns are imitating sea trout for they reach very large sizes
also.

One interesting adaptation going is happening outside of Whiteman's
creek, one our best steelhead nurseries. (No hatchery fish in the
Grand system except for U.S. strays.) For whatever reason, some
steelhead are not migrating to the lake, but are staying in the river
instead. These residents don't attain anything close to the size of
their steelhead parents. I'm wondering if we're seeing the
steelhead-to-resident transformation going on. Probably these resident
fish failed to smolt properly. Just guessing, but probably there are
"non-smolt" genes in the rainbow genone that result in non-reproducing
fish in an anadromous environment but result in successful resident
fish in a landlocked or potadromous situation.

I could imagine a siutation in the past where geologic change has cut
off a rainbow population from the ocean, producing the "resident"
strain. Then more geologic change reopens the waterway to the ocean,
allowing anadromous fish to mix with the landlocked residents,
introducing the "non-smolt" gene into the genone. Then all it takes is
a favourable situation to allow this strain to emerge in any later
population. Just a guess mind you, but it seems plausible.