Wisconsin study focuses on thriving Green Bay whitefish population
GREEN BAY, Wis. — Fishing guide J.J. Malvitz is more than happy to do a bunch of extra paperwork if it will mean keeping a bountiful whitefish population in the waters of Green Bay.
“If we’re using this resource as a business, I’m fine reporting my catches,” said Malvitz, 25, who has operated a fishing guide business out of Sturgeon Bay for the last eight years. “If there’s anything we can do as conservationists and stewards of this resource, so future generations have the opportunity to experience Green Bay, I’m chips-in. I want to help as best as I can.”
Reporting will be a new requirement for guides this ice-fishing season, the Green Bay Press-Gazette (http://gbpg.net/2hPtHVJ ) reported. The state Department of Natural Resources will host a public informational meeting on the new rule at 6 p.m. Monday at the Brown County Public Library, 515 Pine St., Green Bay. Recreational ice fishermen won’t have to do anything differently; the new reporting rule applies only to holders of guide licenses.
Whitefish have always populated the waters of Green Bay, but for some reason, while their numbers have been dwindling in most places in the Great Lakes in recent years, they have been thriving in Green Bay, where they provide world-class sport fishing during ice fishing season, according to the state Department of Natural Resources.
“Whitefish have always been there, but it’s unprecedented to this level,” said Scott Hansen, DNR fisheries biologist. “Around 2007, 2008, it really took off. It’s not something we’ve seen anywhere else on Lake Michigan or the other Great Lakes. They catch whitefish, but not to these levels.”
Commercial fishermen have been taking whitefish for years, but 10 years ago, it was unusual for an angler to come up with one, because whitefish just wouldn’t take a hook.
“But two things changed,” Hansen said. “There was an increased abundance of spawning whitefish in Green Bay proper and, primarily, the west shore tributaries, and they’re feeding on different foods now.”
That makes them more likely to take a hook, which is good news for ice fishermen.
Green Bay has been the subject of so much bad ecological news, from phosphorus runoff and an alarmingly large “dead zone,” apparently caused by that runoff, to the introduction of invasive species. Invasive species have been blamed for the reduction of whitefish in most Great Lakes waters, but, for some reason, the Green Bay whitefish population has adapted, Hansen said.
“Historically, they fed on a shrimp-like critter called the Diporeia, an invertebrate that has been pretty much extirpated from Lake Michigan, most likely from the mussel invasion, the quagga and zebra mussels,” Hansen said. “Whitefish are benthivores, that is, bottom-feeders, and when the Diporeia disappeared, the whitefish had to search for something else.”
While most of the Great Lakes have become nutrient-poor, Green Bay remains productive, with vibrant algal blooms and a solid food chain, with good forage production for small minnow species, Hansen said.
“That seems to be what’s sustaining the whitefish, allowing them to pull off good years of production still,” he said.
Ironically — because it was the invasive species that harmed them in the first place — whitefish have been surviving off invasive species. They’ve been eating mussels and round gobies, for example.
“They’re probably doing the same thing in other parts of Lake Michigan, but what could be missing is the food supply for their earlier stages,” Hansen said. “They don’t just hatch out of the egg and start feeding on gobies or mussels. They have to have components in their diet to get them from one stage to the next. They start with zooplankton in the water column, then move on to bigger bugs, and then maybe they get big enough to handle small fish.”
Commercial and sport fishermen are seeing the thriving population with their takes, but where fish biologists are seeing the whitefish population boom is at the spawning level.
“In the Menominee River, there’s only about 2 miles or so of river before you hit the dam in Menominee-Marinette, and they’ll all be packed in that one area,” Hansen said of the spawning whitefish. “We’re seeing that on the Fox and the Peshtigo, too, although there’s a lot more river. We tagged a bunch in 2010 in the Menominee River and every one of those except one was recovered in Green Bay proper, not Lake Michigan, which suggests that fish that spawn in the Menominee River stay in Green Bay, as far as we know.”
There’s a lot that biologists don’t know about the whitefish population. They rely on things like tagging to try to determine whether Green Bay is gaining all of everyone else’s whitefish or whether it is simply supporting its own burgeoning population. And even judging what that population is or what the effects of commercial and sport fishing have on that population is tough, without hard data.
That’s where the new reporting could help. The DNR has done random creel surveys, in which they randomly check sport fishermen and see how they’re doing. This will be a lot less random. Most ice fishermen don’t work with guides, and Hansen said he doesn’t know how many guides are working the ice of Green Bay in a given season, but there probably are several, and each could provide data captured from the many individual fishermen they serve.
Malvitz, for example, typically will have as many as 10 shacks on the ice on any winter weekend. His reports and those of other guides will help Hansen come up with more accurate estimates of the whitefish population and the impact of a single season on that population.
Malvitz said he suspects some guides might complain about the new requirement.
“You tell some old salty charter captain that what he’s done for 30 years he’s now got to do differently, obviously there’s going to be some kickback,” Malvitz said. “But there’s no ‘this might happen, or it might not.’ You’re required to do this now, so grumbling and complaining is not going to help.”
But whitefish angling is a spectacular sport, and anything that’ll keep it thriving is OK with Malvitz.
“Whitefishing offers anglers a lot of action,” he said. “You get a really good fight, because you’re in 60 to 70 feet of water. That’s the draw. Rather than going out and sitting on a 5-gallon bucket and catching two or three a day, you can have a great time on the ice, catching your limit of 10 fish in a couple of hours and catching and releasing the rest.”