Weather issues inhibit walleye pond production

By Steve Griffin Field Editor

Midland, Mich. — At first blush, losing half your rearing
ponds’ usual production of young walleyes sounds like trouble.
Coping with an output one-fifth of last year’s sounds
catastrophic.

But when multiple, weather-induced failures at several of the
ponds ringing Saginaw Bay resulted in just 400,000 fish ready for
plant-out, DNR district fisheries biologists Jim Baker consoled
himself with the knowledge that this is a year in which fish from
those ponds just aren’t as critical as other years.

Rearing ponds have long been linked with the fortunes of Saginaw
Bay’s walleyes. It was the drainable rearing pond, dried each year
so its nutrients could be restored, that two decades ago provided
the millions of fish that have rebuilt the

Saginaw Bay’s walleye population – and its nationally renowned
fishing.

But there are signs that those restored walleyes are now
handling reproductive duties pretty well themselves.

The past two years have seen bumper crops of fish on the bay,
Baker said, with a whopping 80 percent of those walleyes the result
of natural spawning, not hatchery and pond production.

Anglers are consistently reporting oodles of walleyes just below
the 15-inch legal minimum. Soon, they’ll be 15 inches and longer –
and fry-pan bound.

There’s no sign that natural reproduction is falling off,
either.

Getting credit for bigger walleye numbers has been the shrinking
number of alewives, a forage fish that competes with walleyes and
perch, eats some of them, and makes up a big portion of the diet of
chinook salmon.

Since alewives have all but disappeared, walleyes and yellow
perch “have taken off like a shot,” Baker said.

The DNR, in cooperation with local fishing clubs, this year
operated rearing ponds at Sugar Springs, Tawas City, Au Gres,
Auburn, Kawkawlin, and Fish Point, and in Genessee County.

Fisheries technicians collect eggs and sperm from mature
walleyes making spring spawning runs up the Tittabawassee and other
rivers, mix them and hatch fry at DNR hatcheries, then plant tiny
fish in rearing ponds. The fast-growing fish, which a biologist
once described as little more than “a pin with two eyes” when
transferred to the ponds, are planted-out just a few weeks later
when they reach lengths of about 2 inches.

But rearing ponds aren’t always successful.

“We know that we’re always pushing the envelope on ponds, making
them as productive as possible,” Baker said in a phone interview
with Michigan Outdoor News.

But in early June, Baker said, there came a hot spell that
resulted in a generous bloom of algae, which uses sunlight as it
manufactures oxygen.

A period of overcast skies then killed off these organisms,
though, and their decomposition consumed dissolved oxygen from pond
water, instead.

The result? Young walleyes suffocated. Baker said ponds in other
districts suffered similar losses.

Last year the ponds produced a record 2.1 million walleyes.
Typical production, Baker said, is more like 750,000. This year?
Just 400,000.

Baker said that may not make much difference to anglers.

Not everyone agrees.

“It’s definitely going to hurt the fishery,” said Rod Marr, of
Breckenridge, president of the Saginaw Bay Walleye Club, in a
Saginaw News story carried by the Associated Press. “It depends a
lot on how much natural reproduction we get.”

Besides Saginaw Bay, pond-reared walleyes are used to stock
inland lakes.

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