Wednesday, February 1st, 2023
Wednesday, February 1st, 2023

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Anglers asked to watch for fin-clipped salmon and trout

Charlevoix, Mich. – From where came the chinook salmon or
steelhead trout you just beached, netted, or boated? The nose
knows.

Well, not the nose exactly, but in many cases, the snout. It’s
in some fish snouts that wire tags have been implanted, bearing
information important for several studies under way by the DNR and
others. It’s called the Coded Wire Tag (CWT) program.

And to determine whether there’s a wire in the snout of your
catch, you need to look elsewhere, specifically to the other end of
the fish.

Chinooks and steelhead with only the adipose fin (the small fin
just ahead of the tail along the top edge of the fish) removed have
the wires installed.

That’s more than 15 million trout and salmon since 1990 that
were grabbed in the hatchery (usually the Platte River or Wolf Lake
hatcheries), injected with a wire denoting when and where it is to
be planted, and relieved of their adipose fins before being
released.

Anglers can’t tell if their catch is “wired,” but they can tell
if the fin is missing. If that’s the only one gone (different fins
are clipped for different studies), it’s a CWT participant. And the
information you provide by turning in a head or snout, and adding
information on the catch, can help improve fishery management.

Dave Clapp, manager of the DNR’s Charlevoix Fisheries Research
Station, said studies using “wired” fish have provided solid info
for fishery managers.

“We’ve used information from Coded Wire Tag studies to evaluate
net pens, compare strains of steelhead, and compare stocking in
northern and southern parts of the lakes,” he said.

Net pens, for example, have been found to be one-and-one-half to
two times better than direct releases of fish, Clapp said, in
returns to anglers. That’s balanced a bit by the increased risk of
having all the fish in one pen if a storm or other catastrophe
looms.

Germane to a discussion of tags is the fact that you can only
compare net pens to direct plants if you can identify their
products years later.

These kinds of things are more than just scientific interest;
they affect the catch in anglers’ coolers and on stringers.

Traditional fin-clipping identifies a fish as being
hatchery-reared, and some variety is possible to add information.
But nothing is as refined as the coded wires, with which biologists
have been able to distinguish among three different plants of the
same species at three places on the Grand River, for example. “It’s
pretty amazing,” Clapp said.

Currently, about eight DNR employees work at the two hatcheries
for about one month, wire-tagging and fin-clipping 20,000 to 50,000
fish per day.

The agency is exploring opportunities with the U.S. Fish and
Wildlife Service to use automated, trailer-housed tagging
facilities that could reduce the manpower to two.

“If that happens, we would probably tag every fish that goes
into the Great Lakes,” Clapp predicted.

How can you help? If you catch a trout or salmon missing only
the adipose fin, remove the head, or at least the portion of the
snout where the CWT should be located by cutting from behind the
eyes to the back corner of the mouth.

Place the snout in a plastic bag and freeze it, making sure you
record the date it was caught and the nearest port or identifiable
location to the catch, the length of the fish, and, if possible,
its weight. Add your name, address, phone number, and email so
researchers can follow up if needed.

A printable CWT data form makes that easy; it’s available online
at:
http://www.michigan.gov/documents/coded_wire_tag_form-PR8550_35853_7.pdf
.

Your best bet is to put the information card in a small plastic
bag, seal it, and place it within a larger bag with the snout. That
ensures the two will stay together, and that the card will be
readable when the whole thing thaws.

Then, take the head or snout to a CWT head drop site, a list of
which can be found on the DNR web site at
http://www.michigan.gov/documents/coded-wire-tag-drop-sites-July-2006_165267_7.pdf
,
or by calling the Charlevoix Fisheries Research Station office at
(231)_547-2914.

For your trouble, you’ll receive a letter telling you where and
when your fish was released, and its age when you caught it.

At Charlevoix, researchers and technicians will thaw the snout,
use a wand detector to roughly locate the tag, then slice the snout
in two. The half that contains the wire will be sliced again – and
on it goes until the wire is exposed, when it can be removed and
examined under a microscope for its information.

So far, more than 75,000 of the wire tags have been recovered,
said Clapp, who heads up the program based at the Charlevoix
Fisheries Research Station.

But that’s a less than a 1 percent return. Is it enough?

“It depends on the study,” Clapp said, “but in general, these
numbers are large enough to work for us.”

He’s making an extra push for angler help this year because
budget restraints have kept him from hiring part-timers, often
college students, to “head-hunt” at popular angling ports.

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