Anyone who has followed government news during the past few days knows that tinkering with fishing rules — hunting rules too, for that matter — can be touchy business in Minnesota.
The politics of outdoor sport are one thing.
The scientific aspects of managing fish and animal resources are quite another.
A new perspective on the latter suggests we could do a better job.
The strategy of setting quotas — say, six walleyes in possession on a given day — needs rethinking, says the report of a new study by prominent University of Minnesota ecologist Craig Packer and researchers at the University of Guelph in Ontario, the Norwegian Institute for Nature Research and the Center for Conservation Biology in Trondheim, Norway.
A more effective strategy for ensuring continued supply of the prey would be to limit the number of days allowed for hunting and fishing, the researchers concluded from the study reported this month in the journal Science.
Quotas generally are based on harvests from previous years, the researchers said.
They “don’t consider population fluctuations caused by disease outbreaks, harsh weather and other variables that affect animal abundance from year to year,” Packer said in a statement about the study.
“Hunters and fishermen can work harder to make their quotas when desirable species are scarce,” he said. “The extra pressure can cause populations to collapse.”
Packer has long studied the impact of trophy hunting on lion populations in Africa and cougars in the United States. That work helped to inspire the current research.
The scientists developed a model based on mass action assumptions about human behavior and current hunting and fishing regulations. They tested the model using data from three populations of white-tailed deer and moose from Canada and Norway over a 20-year period.
One of the interesting points the researchers make is that hunters and anglers tend to choose spots based on word of mouth, which travels slowly. By the time a good fishing hole becomes well known, the number of lunkers at that spot already may be shrinking. Thus, anglers need to work harder and longer to reel in their limits.
That vicious cycle ultimately can diminish the species to the point where it is threatened with extinction.
“It can take decades for large animal populations to recover from collapses, as we know from our disastrous experience with cod stocks off the coast of Newfoundland,” said John Fryxell one of the researchers from the University of Guelph. “We need to make strategic long-term changes to make a difference.”
The study was general, and it did not speak to the intricacies of fishing and hunting regulations in Minnesota where wildlife managers can monitor wildlife populations and adjust limits accordingly.
The general conclusion, though, was that setting limits on the amount of time spent hunting could best protect fragile populations.