Chas-
Since you seem to be in the know on Bull trout and Dollies. Can you clarify
something for me?
I have always been told that the only difference between a Dolly and a Bull
was that the Dolly was "sea run"
(similar to the rainbow/steelhead)
Are there actual detectable genetic differences?
I have never heard of the anal adipose alignment identification what are the
other identifiers but it seems a very sketchy
way of calling a bull a bull and then implanting it?

thanks
t.


"Chas Wade" wrote in message
news:TEfUb.180283$nt4.779001@attbi_s51...
After my discussion with the ranger a couple weeks ago, he got back to
me with an email introducing Sam Brenkman, a biologist for the Olympic
National Park. I'm not sure if Sam is in charge of the bull trout
migration analysis, but he's certainly in the thick of it. He called
me back today, and we talked for half an hour about the bull trout in
the Olympic National Park. I'll try to hit the interesting parts of
that discussion without being too long winded about it.

Next Tuesday from 7:00 to 8:00 at the Olympic National Park Visitor
Center Sam will be giving a talk about his work with more details.
That is the visitor center above Port Angeles on the road to Hurricane
Ridge. I'm going to try to be there.

It turns out that there are no Dolly Varden in the main rivers that
drain to the coast. There's an isolated population above Sol Duc
falls, and one other location I can't remember now, but all the
"dollies" we catch in the Hoh, Queets, Quinalt, and the rest of the
costal rivers are actually bull trout.

They practiced the surgery to implant the radio tags on hatchery fish,
and then captured and tagged 82 bull trout on several of the west coast
rivers. None of those fish have died from the implant. Four of the
radios failed and a few fish were killed by fishermen. The tagging was
done about two years ago, and the fish have been wandering all over the
Washington coast. One fish migrated over 40 miles downstream in less
than two days, following the flood waters out to sea. Upstream
migration is slower, the fish hold in one place for several days and
then move on up. I don't know how much in one day.

Field identification isn't perfect, but Sam says that if you fold the
anal fin back towards the tail and line up the tip with the tip of the
adipose fin, a bull trout has the anal fin longer, and the dolly varden
has a shorter fin. All the fish they implanted were verified as bull
trout. They haven't identified a single dolly varden in the Hoh,
Queets, or Quinalt system.

Every year, I think in September, Sam and three other biologists
snorkle down the South Fork of the Hoh doing a bull trout survey. They
work together for two or three days when the water is clear, and count
the bull trout they see. Their highest count was 236 fish in 13 miles
of the river. This should be in the middle of the upstream migration,
and has him concerned about the numbers of fish in the river. He's
hoping that the radio tags will show them where the fish spawn, and
make it possible for them to do a more careful population count.

Oh, Sam also said he was a bit concerned when they put signs up all
over the rivers describing the tagging process. His name and phone
number were on the signs. He was afraid there'd be a flood of calls
from fishermen. It turns out my call is the first one he's gotten. He
was genuinely glad I called and in no hurry to get rid of me.

That's it for now,

Chas
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