By Jeff Dankert

Winona Daily News

Lake City, Minn. (AP) Dozens of golden sauger and walleye lay
tangled in nets piled inside large galvanized steel tubs. Other
fish were there, like gizzard shad, channel catfish, redhorse,
white bass and freshwater drum. But what mattered most to the state
fisheries workers gathered in a garage in Lake City were the sauger
and walleye.

Dressed in rubber garments, standing around a large worktable,
Minnesota DNR workers processed the fish. They were completing
their annual gill net sampling of Lake Pepin, the biggest pool in
the Upper Mississippi River.

Two men extracted fish from the nets. Workers at the table
measured length and weight, determined sex, and extracted scales
and otoliths.

Every fish has otoliths, except most anglers know these as the
“lucky stones” in drum, or sheepshead. They are inner ear organs.
And, like fish scales, they reveal fishes’ age and growth rate,
which was the central focus of the work.

Kevin Stauffer, area fisheries manager, said they began taking
otoliths a few years ago to check their accuracy in aging fish
using scales.

“They match up pretty well,” he said.

Lake Pepin’s walleye and sauger have phenomenal growth rates,
Stauffer said. Walleye and sauger born in the boom year of 2001, a
year of a massive flooding, are already 18 to 20 inches long. In a
large northern Minnesota lake, those same-aged walleye would be
only 13 to 14 inches long, Stauffer said.

“It’s never been better,” he said.

The crew expected to process 1,200 fish by the end of the
checkup. Each 250-foot net catches, on average, 30 sauger and eight
walleye. This ratio is typical of a river more sauger than walleye,
Stauffer said.

John Hoxmeier, DNR large lakes specialist, said Pepin’s walleye
and sauger reach a maximum age of 6 to 7 inches.

“We really don’t have a lot of old fish in the system,” he said.
“They grow fast, die young.”

Abundant gizzard shad and emerald shiners form a strong
foundation for Lake Pepin’s walleye and sauger growth, Stauffer
said.

“We have an incredible forage base,” he said.

That forage also supports first-year fish, key to their
survival.

“The bigger they get before they go into winter the better their
survival will be,” Stauffer said.

The workers set five, 250-foot long gill nets, varying the
locations each day. Walleye encounter the net, swim alongside it,
try to find an opening and attempt to swim through the
diamond-shaped gaps. The net goes past their gills but not over the
thick midsections, and the fish can’t back out or swim through.

The sampling method kills the fish, and workers would have to
kill them anyway to extract the otoliths. However, the DNR releases
uncommon species, such as a 13-inch lake sturgeon and 29-inch
paddlefish.

The DNR assesses most Minnesota lakes once every five years, but
the DNR targets selected large lakes, like Pepin, for annual
checkups.

“We can follow the year-classes through,” Stauffer said. “You
have a better running picture of what’s out there.”

The crew sets nets every morning at pre-chosen sites, so each
year’s sampling is the same. They use global positioning data to
make sure they use the same ones every time.

“Of course Dale has run them so long that he can drive to them
without the GPS,” said Al Schmidt, DNR warm water streams
specialist.

Dale Sogla grabbed another fish.

“Walleye, 17.9, male, 2.3,” he said. Hoxmeier cut the walleye
open and Dan Dieterman deftly pulled out the little bone with
tweezers and placed it into a numbered vial.

For more than 30 years, Sogla has worked for the state on Lake
Pepin fisheries. He says the lake is “loaded” with walleye and
sauger.

“But we also have a wonderful catfish population, and smallmouth
and largemouth bass populations,” he said.

Sogla is an avid fisherman, working both ends of fishery
management.

“There are a lot of big fish out there,” he said.

Sogla anticipates retiring in a couple of years, but until then,
he leaves the office work to others.

“Office jobs are…,” he said, paused, smiled, and finished his
sentence, ” OK.”

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