DNR Resumes Full-Scale Walleye Production
April 21, 2011
After a number of years of reduced production and stocking of walleye, the Department of Natural Resources' hatchery system is going all in once again.
Walleye production at state fish hatcheries was slashed after viral hemorrhagic septicemia (VHS) was discovered in Michigan waters of the Great Lakes system. A disease that was first identified in Europe and affects a large variety of species, VHS kills fish by causing internal bleeding. And although the most spectacular example of VHS in Michigan waters occurred in 2006. when an estimated 2,000 to 4,000 muskellunge succumbed to the disease in Lake St. Clair and the Detroit River, a number of walleye died from VHS in Lake Erie as well.
So rather than risk contaminating the state's hatchery system, or spreading VHS into new waters, Fisheries Division dialed down walleye production, waiting for a breakthrough in egg disinfection techniques. That time has arrived; new disinfecting techniques make it safe to bring wild walleye eggs into the hatchery system. The DNR has ramped up walleye production accordingly.
A number of DNR Fisheries Division personnel were on hand at the Muskegon River below Croton Dam in the waning days of March and early April to collect eggs and milt from walleyes for the hatchery system. The crew had a goal of collecting and fertilizing 50 million eggs this year - an eight-fold increase over the last two years.
Egg-take went off without a hitch.
"Everything went well," said fisheries technician supervisor Ed Pearce. "We ended up with a little more than 60 million eggs - so we are in good shape."
As usual, a fisheries crew used an electro-shocking rig to collect walleyes from the Muskegon River. The fish were brought to the ramp at Pine Street, where the public was invited to watch the process. Fisheries staffers checked the females for ripeness; those that were ready to spawn were stripped of their eggs. The eggs were mixed with milt from the males, transferred into buckets, and then placed in a tight-meshed pen in the river where the eggs hardened. The fertilized eggs were then transferred to the Wolf Lake State Fish Hatchery.
The next phase, hatching out those eggs and transferring them to rearing ponds, will be just a little more problematic. Fisheries managers believe they'll be able to attain about 80 percent of maximum production this year.
"We have a number of ponds that we operate around the state, both state-owned and private ponds, which we operate cooperatively with other sport fishing groups," explained fisheries biologist Jim Dexter. "A lot of these ponds have been fallow for several years now. It takes some amount of work to get them back up to production standards."
The breakthrough on VHS disinfectants didn't happen until winter, Dexter said.
"By the time the decision was made to go to full production, it was too late to get started rehabilitating those ponds in time for this season. A lot of the ponds have dike systems that haven't been maintained or repaired in years. We have ponds that need some concrete work. And there are some drainable ponds where the brush and trees are growing up out of the bottom because they haven't been cut in years."
Nonetheless, fisheries staff is optimistic production will at maximum levels by next year.
"We currently have 17 active partnerships, with organizations spread across the state, which help us rear walleyes," Dexter said. "That's a good thing. We now have an opportunity to reevaluate all of our walleye stocking programs. It may not be necessary to utilize every pond that we've used in the past. If you think back on it, is a lot of our walleye production used to go into Saginaw Bay. We don't stock Saginaw Bay any more. So we may be able to get the production from those ponds - which are larger ponds - and take care of our needs.
"So it's not imperative that we have 100 percent of our ponds back in production. We may not need them all."
Walleye are among the most popular cool-water game fish in Michigan, prized both for their sporting characteristics and as table fare. Numerous walleye fisheries have been developed over the years by stocking hatchery-raised fish into lakes and rivers. Biologists believe production will be high enough this year to stock all of the waters that are managed with hatchery walleyes. Walleyes will be stocked in waters in the Lake Superior Basin for the first time in several years.
Fisheries staffers will take additional eggs from Little Bay de Noc this spring, which will be incubated and hatched at the Thompson State Fish Hatchery in the Upper Peninsula.
Most of the walleyes used in the Muskegon River egg-take operation were returned to the river, though a few were sent to Michigan State University for disease testing.
By 2012, the DNR's walleye production should be hitting on all cylinders.