Eric Engbretson, U.S. Fish and Wildlife Service
To the layperson or ichthyological initiate, fishing might seem like a simple, if not time-consuming, series of tasks: Find water. Cast line. Wait. Reel in fish. But in-the-know anglers understand that, in many cases, somebody is putting in plenty of hours to keep that prized pond, stream or lake full of healthy, desirable fish.
Despite the best efforts of managers in Michigan’s Upper Peninsula, two popular brook trout fisheries there have succumbed to overpopulation by stunted yellow perch. In response, the Michigan Department of Natural Resources has announced plans to reclaim Bullhead and Dillingham lakes in hopes of restoring trout populations.
“We did a survey in spring 2013 with our netting gear to try to evaluate some of our brook trout stock,” said Cory Kovacs, a fisheries biologist with the Michigan DNR. “In that survey, we found lots of stunted yellow perch, 3 to 4 inches — pretty undesirable by anglers.”
As for the trout, things weren’t looking so great.
“We only found brook trout that were stocked in that given year. In Bullhead, we only found one brook trout, 6 to 7 inches,” Kovacs said. “What that’s telling us is we didn’t get any carryover.”
Both Dillingham and Bullhead were known as good trout fisheries, the former having been stocked with brook trout since the 1950s. Bullhead has stocked the fly fisherman’s favorite for the last 20 years or so, serving as an unsuccessful rainbow trout and splake fishery before 1993. So what led to the recent population upset?
The perch, it seemed, were outcompeting the brook trout for forage resources. Removing them was a clear solution, but netting a segment of the population significant enough to restore balance was simply out of the question. That would take more time, money and human resources than the DNR could muster.
Instead, the DNR decided on a far more efficient — albeit somewhat controversial — method of eliminating the unwanted perch. Sometime in the third week of October, Michigan’s DNR Fisheries Division field crews will treat the lakes with rotenone. The chemical will eradicate fish populations in the lakes, while leaving unharmed any reptiles, amphibians, birds or mammals.
While Kovacs understands why some might have a negative knee-jerk reaction to such an operation, he insists that the treatment is four to five times cheaper than netting, well-established in fishery management, and totally safe (unless you’re a fish).
“The concentrations we’re using are pretty low,” Kovacs said. “It would only stay in the environment for a couple of days depending on the temperature of the water.” The only concern, he noted, would be for the applicator, but he asserts that they’ll be well-protected with personal protective equipment.
Following the rotenone application, any affected fish will die and float to the surface. There, they’ll make welcome meals for any of the lakes’ enterprising scavenger species, whether turtle, bird or even human. Kovacs said that some people have expressed interest in taking the fresh carcasses home for dinner.
“I would just caution folks if they’re going to come eat [the fish]. It’s not the rotenone that I’d be concerned about, but the bacteria that infect the fish after they die,” Kovacs said. “They could be floating for four or five days.”
Bullhead and Dillingham lakes will be restocked with brook trout next year as part of their normal annual cycle. The outcome, Kovacs said, should be every angler’s simple pleasure:
“The benefits are hopefully more big fish.”