Fisheries: Science, raising, stocking
Certain waters in Michigan are stocked with fish as part of an evolving science to bolster natural fisheries, attract anglers and preserve a way of life.
Fisheries science is relatively new, and has changed considerably since the 1920s, Department of Natural Resources Fisheries biologist Tim Cwalinski said. Scientists focused their efforts on raising and stocking fish in lakes and rivers, even species that might not need the help.
Now, stocking decisions are based on more scientifically rigorous standards, Cwalinski said. In the last 40 years, biologists started to use fish community surveys, and the DNR spends more effort on better understanding the water bodies it stocks. Rather than raising lots of fish and stocking them all over, the DNR focuses on a smaller number of species in certain lakes and streams.
“We don’t raise bluegills, that’d be like raising mosquitoes,” he said. “We raise trout and salmon, because where we stock some of these things they typically don’t reproduce or wouldn’t reproduce to create a sustainable, justifiable fishery.”
Salmon go into the Great Lakes, which have their own unique situation and management goals. Inland lakes and streams get other species, like walleye, trout and muskellunge, Cwalinski said. Some lakes get walleye because natural reproduction is at an all-time low. Biologists check stocking records and use fisheries surveys and angler data to see if stocking is having any effect.
“You can look back and see where biologists have stocked walleye for a couple of years and they just didn’t take,” he said. “Well, I’m not going to reinvent the wheel. I’m not going to try to force something that just didn’t work.”
Biologists have to consider whether stocking is needed, and what effects it will have on a lake or stream, Cwalinski said. They also consider whether a water body can support a species. While muskies do well in Lake Winyah’s warm, brown waters, trout need clear, cold and clean water. Many other factors, like oxygen content and the presence of predator species, are considered.
Black Lake, in Cheboygan and Presque Isle counties, saw a collapse in natural walleye reproduction, Black Lake Association President Virgil Smith said. With the help of a local anglers group, the lake association has supplemented DNR stocking efforts by adding 20,000 fall fingerlings for the past five years. The DNR puts in hundreds of thousands of fingerlings in the spring, adding 192,561 in June 2012.
After walleye reproduction collapsed some time in the 2000s, biologists tried to determine why, Smith said. Several theories were offered, like zebra mussels impacting the food web, but no definitive answers were found. At the same time, the state stepped up efforts to save the lake’s walleye fishery through stocking.
“I’m hearing good reports, people are catching a lot of walleye, and they’re also catching a lot of sub-legal walleye,” he said. “We’re presently going to evaluate the situation and determine if we need to continue stocking.”
Fall surveys of young-of-the-year walleye have shown little natural reproduction in Black Lake so far, Smith said.
Prior to the collapse, it wasn’t uncommon to see 20 or 30 boats on Black Lake, Smith said. The walleye fishery was a huge draw, and its collapse hurt the area’s economy. As the fish are starting to come back, so too are the anglers.
To raise these stocked fish, the DNR draws on seven hatcheries around the state. Martha Wolgamood manages the Wolf Lake State Fish Hatchery near Kalamazoo, overseeing the rearing of steelhead and muskies, among other species. Different hatcheries have different capabilities, she said, and each one gets requests from biologists for fish to stock at certain locations. This, combined with other factors, determines how much of which species a hatchery will raise.
Some species are stocked after a short stay at the hatchery, while others, like lake and brown trout, take 18 months, Wolgamood said. Hatcheries take steps to make sure the fish are disease-free before they’re stocked, disinfecting the eggs after they’re taken and inspecting the fish before they leave.
The state spends about $9 million annually on its stocking efforts, DNR Fisheries Division Production Manager Gary Whelan said. These efforts pay off, generating at least $300 million in economic activities.
The DNR gets help raising walleye in the Alpena area from an angler group. Each spring for the past 23 years, Thunder Bay Walleye Club volunteers work at James Pond in Green Township, club member Carl Kelly said. It’s a manmade pond on Thunder Bay River’s south bank, filled with river water and 300,000 walleye hatchlings. This year, they successfully raised 196,000 walleye fingerlings, with 42,000 going into Beaver Lake.
“We’re the walleye club, and the DNR’s rearing walleye fingerlings, so it was just a natural fit,” he said.
Once fish are stocked, the DNR needs help from anglers to determine if their efforts are working, Cwalinski said. Not all anglers report what they catch.
“That’s actually one of the worst things they can do,” he said. “They should call us and tell us, ‘Hey, this program works, we’re catching fish over here,’ and not only when they’re not catching something.”