Scientists concerned about Lake Superior's declining cisco (lake herring) population

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MARQUETTE, Mich. (WLUC) - Scientists from the Great Lakes region are meeting in Marquette to discuss Lake Superior's shrinking population of cisco, which are also called lake herring.

The Lake Superior Technical Committee, which is part of the Great Lakes Fishery Commission, is comprised of U.S., Canadian and Tribal agencies in the Great Lakes Region.

The committee meets bi-annually.

Much of the three-day meeting will focus on the declining population of cisco.

"The job of agencies that are here at this meeting today is to determine what the population sizes are [for cisco], what are sustainable quotas and then ultimately to implement those quotas for commercial and recreational and subsistence fisheries," said Seth Moore, Director of Biology and Environment with the Grand Portage Band of Lake Superior Chippewa.

While cisco numbers have been declining since 2006, scientists said it's hard to know why.

"In the fisheries, it's rarely ever one factor that you can put your finger on that's causing a decline," said Cory Goldsworthy, Fisheries Supervisor at the Minnesota Department of Natural Resources.

One possibility has to do with the climate.

"Ice cover has been known to be an indicator of successful recruitment, so when there's good ice cover on Lake Superior, typically we'll see a year-class, or a good recruitment event for that year," Goldsworthy said. "With warming climate, we're seeing less ice cover."

It's important to get cisco numbers back up so scientists efforts to rehabilitate the lake trout population can continue.

"Herring are an important prey base, or prey fish, for lake trout and other predators in Lake Superior, so we're really concerned since we've rehabilitated lake trout populations in Lake Superior," Goldsworthy said. "We really want to make sure that there's an ample forage base, or food supply, for them. For sport anglers especially, lake herring are an important species."

Scientists will also discuss sea lamprey management, lake trout rehabilitation efforts, splake stocking and lake sturgeon at the meeting.

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