Sunday, February 12, 2012

At Pymatuning Lake, Hearty Walleyes Stocked In 2009 Are Reaching Legal Size

Sunday, February 12, 2012
Above, Pennsylvania Fish and Boat Commission
 biologist Gary Smith holds a sauger-walleye crossbreed,
 a saugeye, left, and walleye, right.
A successful plan is a beautiful thing, especially when the story grows from an apparent failure.

In 2001, electro-fishing surveys conducted by the Ohio Department of Natural Resources and Pennsylvania Fish and Boat Commission charted a disturbing decline in walleye numbers on jointly managed Pymatuning Reservoir. In 2005, surveys counted no walleyes in the lake -- zero -- and anglers reported a catch rate of one for every 30 hours of fishing.

But by 2011, DNR netting surveys showed the walleyes had bounced back to healthy population levels, and those stocked in 2009 were near or over the 15-inch legal size. Angler surveys reported one walleye caught every 1.3 hours -- unofficially some fishermen were boating three per hour.

Biologists in both states predict outstanding walleye fishing at Pymatuning in 2012.
The dramatic changes at the 14,000-acre impoundment are the result of natural cycles and a progressive wildlife management approach on both sides of the state line -- a scientific method in which actions were taken, analyzed, reconsidered and improved until the desired impact was achieved.

Matt Wolfe, a fisheries biologist at Ohio DNR, will explain the Pymatuning walleye recovery and assess this year's fishery at 7:30 p.m. Wednesday and 6:30 p.m. Thursday at the Allegheny Sport, Travel and Outdoor Show at the Monroeville Convention Center at Monroeville Mall.
"Once we noticed a problem, we realized that in a lake the size of Pymatuning, there was only one thing we could control -- what we were stocking," said Wolfe, who grew up in Jeannette, Westmoreland County, and briefly worked for the Fish and Boat Commission.

With little natural walleye reproduction, in the late 1980s DNR and PFBC began stocking millions of inexpensive and easy-to-raise half-inch walleye fry. A large percentage of vulnerable fry routinely succumb to predation, weather and water conditions, but enough seemed to be surviving until the 2000s.

It's still unclear what changed at Pymatuning resulting in the elimination of an entire year-class of an important predator. Water quality was good and no over-fishing occurred -- suspected causes include unusually high predation, a decline in the health of zooplankton that fry eat, or both.

Following the walleye's population collapse, Ohio switched management tactics, stocking only hatchery-grown fingerlings of 1 to 2 inches. Pennsylvania followed suit, continuing to stock some fry.

In recent years, tons of rock reefs and 100 wooden crib structures were dumped onto the muddy, decaying bottom of Pymatuning Lake, improving a small portion of habitat.
"The fish we're seeing now are mostly the result of stocking, not natural reproduction," said Wolfe. "It's probably about 20 percent natural, 10 percent from the fry that survived and the rest from the fingerlings, which really seemed to take hold in the lake. In fall netting surveys, we found a large number of fish from that 2009 year class."

That year, excess walleyes from Pennsylvania hatcheries were added to the planned stockings. Fish and Boat biologist Tim Wilson, who is not part of this week's walleye seminars, said from a wildlife management standpoint it would be unwise to continue stocking at 2009 levels despite the positive results.

"We've had respectable survival from other years, as well," he said. "You don't want to oversaturate the population to the point where we affect the growth rate. I'm not sure it would be good to have that number every year."

Wilson said Pennsylvania continues to stock some fry, despite limited results, "with hopes that things [could] return to the days when we could stock fries only. We'd like to go back to that, but so far survival has favored fingerlings."

Wolfe said he hopes his talk will "give anglers hope," and recommended bottom-bouncing worm harnesses at Pymatuning Reservoir. Mild winter conditions may encourage walleyes to spawn early this year.

"Once they're done spawning in mid-April through June, that's the time to hit that 2009 year-class," he said.

Pennsylvania's new rule permitting three rods per angler went into effect Jan. 1. Ohio restricts anglers to two fishing rods, but will permit three rods on Pymatuning at the March 1 start of that state's license year.

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