Perch kills dampen a great start to season
Written by Toledo Blade   
Tuesday, 30 May 2006 03:12

If timing is everything, then news last week of extensive kills of highly prized yellow perch in central Lake Erie could not have come at a worse time - right on the eve of the unofficial kickoff of the summer fishing season on Memorial Day weekend.

The presence of thousands of dead perch washing up on beaches from Lorain to Mentor has the sport and commercial fishing industries shuddering in dismay and fisheries biologists scrambling for answers.

At the same time Lake Erie tourism and sport fishing promoters are hurrying to reassure the public that it is OK both to fish and eat fish.

The Ottawa County Visitors and Convention Bureau, for example, recently disseminated a fishing promotional packet, with photographs of fine walleye catches, in apparent hopes of countering any potential undue concerns about fishing on Lake Erie.

All of which is occurring amid some phenomenal spring fishing, perhaps the best in nearly 20 years.

It also is occurring on the heels of a massive, abnormal kill of tens of thousands of freshwater drum, or sheepshead, in early May in western Lake Erie, up to several thousand muskellunge in muskie-rich Lake St. Clair and its connecting rivers, and a huge if not unwelcome dieoff of pesty round gobies in eastern Lake Ontario earlier this spring.

"We're still thrashing, trying to determine whether there is some massive disease-component to this," stated Gary Isbell, executive administrator of fish management and research for the Ohio Division of Wildlife. "We're trying to find out why this is out-of-ordinary."

Roger Knight, Lake Erie program manager for the state wildlife division, is trying to head off irrational concern over the kills. "It's kind of painting a picture that disease is a big player."

But he was quick to point out that disease outbreaks in fish, though on a smaller scale, are not uncommon in the spring and they usually dissipate as the water warms.

For one thing, in spring many species of fish are concentrated for spawning, and the proximity alone among individuals ups the ante for spreading trouble.

"My sense is, this is all going to pass," assured Knight. As for the problems with the recent yellow perch dieoffs, tests of samples are under way. "We will know definitely by the end of next week."

He added that no significant walleye kills have been seen so far. Some reports of distressed "whirling walleye" could not be documented by state fisheries crews that set out to confirm them.

"The big point is, there is not a human health risk. Fish diseases are not transmittable to humans. If you are catching healthy fish and cooking them thoroughly, you're fine."

A virus known as viral hemorrhagic septicemia, or VHS, only recently was confirmed as responsible for the big sheepshead kills earlier. It is the same virus known to have killed sheepshead in Lake Ontario's Bay of Quinte in 2005.

VHS also was found in a muskie caught on the Michigan side of Lake St. Clair a year ago. But Curt Newman, Lake Erie basin coordinator for the Michigan Department of Natural Resources, said that the source of this spring's muskie kill still is uncertain. "We have not had cultures confirmed for anything," he said adding that it will be at least next week before laboratory analyses are completed.

A bacterial infection called muskie pox commonly, or Piscirickettsia scientifically, irrupted on Lake St. Clair last year. It is not considered harmful to humans. The disease first was confirmed in the lake's muskies in 2002, and the MDNR has been researching solutions since.

After perch washed ashore in central Lake Erie, an aerial survey by a state wildlife pilot showed that the plumes of dead fish could be traced back to commercial trapnet boats working central Lake Erie. But by week's end state fisheries managers were backing away from implicating the fishermen in the abnormal kill.

Trapnets generally are worked so that fish can be hauled up live and sorted, with commercially undersized fish and non-target species to be thrown back alive. Perch already under stress from an infection, however, may lack enough vitality to survive the trapnet operation.

Knight said that a certain small percentage of fish can be expected to die from trapnetting. "That always happens." But the problem this year goes way beyond what may be considered normal. He added that commercial netters have invited state fisheries crews on board their boats to observe.

Jeff Herr, a trapnetter based in Jerusalem Township, also volunteered to collect and share samples of yellow perch with federal fisheries authorities for testing. "We have a batch right now that the U.S. Fish & Wildlife Service is sending in," he said from his boat, en route to dock from a haul, Friday afternoon.

Herr noted that the commercial netters took the initiative - "we contacted them. Their concerns revolve around possible impacts on the health of the fishery, their businesses, and public perceptions toward eating fish. Some of the perch in the sample he was turning in, Herr said, "have open sores and white gills. They're not right. We've been seeing this now for the better part of three weeks."

But he added that trapnetting is not suddenly behind the big perch kills. "The only problem we have with survival rates of discarded fish is with white perch." Those, he said, are nonnative invasive species that may not be well adapted to the lake in any case. As for yellow perch, he said that trapnetters have been releasing undersized fish for years without seeing such dieoffs.

"This all started with dead fish. There is no way, if we were killing all those fish, that they would end up on the beach at Fairport Harbor. Dead fish would not float that long."

Bob Collins, president of the Lake Erie Charter Boat Association, remains somewhat suspect about the trapnetting, having seen aerial photos of the scenes around the boats. "We could literally see the trail of fish behind them."

But he was quick to add, "our concerns are everyone's concerns. To me it sounds like it's in the biologists hands now." He said that he would like to be relieved of any worries that might affect interest in sport fishing or consuming fish.

The MDNR's Newman agreed with Knight's view that the central Lake Erie perch problem may diminish naturally. "We get fish kills every year - that's normal. The lake warmed up pretty quickly [this spring].

"My concern is that people are going to worry.''

He noted that even though up to several thousand muskies may have been lost this spring, those are only a small fraction of the population in the St. Clair system.

"It's still going to be terrific [muskie] fishing. The system arguably is home to the highest densities of muskies anywhere.''

Overall, Newman added, "if it is up to me I'd say, 'go fishing.' "

 
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