Hook, Line and Sinker
Imagine trying to keep track of tens of thousands of research subjects, each one slightly different and constantly evolving.
That’s what Paul Venturelli does; his research in fish ecology and population dynamics helps set policies to keep freshwater fisheries sustainable, in Minnesota and beyond.
“Regulations are about when to fish, what to keep and how many,” says the assistant professor in the Department of Fisheries, Wildlife and Conservation Biology. “A fish is not just a fish, even within a species. There’s male vs. female, big or small, time of year. All of those factors are in play. “
Freshwater fisheries account for about one-eighth of all fish caught worldwide each year, but compared to salt-water areas, little data are collected on these fisheries. For example, Minnesota has so many lakes, ponds, rivers and creeks that the resource is highly divided and distributed. “This makes understanding and managing fish a huge challenge, because there is no one-size-fits-all solution,” he says.
“Southern Minnesota, northern Minnesota, close to the Cities or hard to access…they’re all different.”
“We can’t manage population-by-population, so we set up statewide regulations and then adjust as problems emerge, like with Mille Lacs,” he says. Venturelli is part of a blue-ribbon 17-member panel advising the state Department of Natural Resources on the declining walleye population in Mille Lacs Lake. “This results in crisis-hopping and a long list of special regulations.”
Venturelli believes that we can do better. “Our fisheries depend a lot on temperature,” he says. Fish in warmer waters can sustain more fishing than fish in colder waters, because warm water promotes faster growth and early reproduction. In Minnesota, that means regulations that work for a southern lake may not translate well up north.
Venturelli’s team is using temperature data to develop sustainable fishing regulations across the landscape, and then accounting for things like the availability of food and habitat. “The idea is to develop tools that agencies like the DNR can use to identify best practices in a given area,” he says.
Adding to the complexity of fisheries management: key information is often lacking because anglers don’t have to report when and where they fish. “Most of us do it for fun. It’s not our job so we don’t have to report effort and catch the way that commercial fisheries do,” he says. But anglers can, if they choose to: a smartphone app called iFish Forever that Venturelli helped develop last year allows anglers to report details of their catches, data that will be used to help to improve fisheries management.
Venturelli grew up near a Canadian river and has always loved to fish. In graduate school, he was introduced to the technical aspects of fisheries management “and that was it for me. I love this.”
“This is a resource that we’re struggling to quantify,” he says. “Recreational fishing is socio-economically important, especially in Minnesota, and freshwater fisheries help to feed the world. But we know relatively little about these fisheries. There are a lot of questions that need to be answered.”