by Michael A. Kallok
At age 57, Lyle Swanson caught the trophy northern pike he had been chasing for most of his life.To do it, he hiked for hours through deep snow, drilled ice holes with a hand auger, and endured two nights of subzero temperatures in a tent.
Watch a video of DNR fisheries research aimed at learning more about the importance of thermal habitat for pike.
"I was getting old. I wanted to catch that 20-pound fish, a 40-incher," Swanson says. After decades of striking out on easier pike waters, Swanson joined a group of younger men, including his son, Shane, on a trek seven miles deep into the Boundary Waters Canoe Area Wilderness. There, Swanson hooked his trophy on Basswood Lake.
Trophy pike aren't intrinsically hard to catch. The challenge in Minnesota is finding one, according to Rod Pierce, a DNR fisheries biologist who has studied Esox lucius for more than two decades.
Since the 1940s, large pike have become increasingly uncommon in the state's waters. The reason for their scarcity is simple: Trophy pike end up on the wall. Large pike (fish longer than 24 inches) end up in frying pans. And to produce trophy-sized pike, a lake needs large pike.
A 15-year DNR study of 23 lakes with special regulations shows that protecting some pike from harvest can maintain or restore a lake's population of large pike.
Like any long-lived, slow-growing fish species, northern pike are vulnerable to overharvest. It takes three to five years for a pike to reach 24 inches. If a pike is really lucky and survives for 10 years, it can grow to 35 inches or longer, says Pierce. Studies of pike population density in Minnesota lakes show that pike 24 inches or longer make up a very small part of a typical population, according to Pierce. For every 100 acres of water, researchers found pike less than 20 inches are very abundant—more than 800 on average. That same water probably holds only 60 pike longer than 24 inches.
A long-running big-fish contest sponsored by Fuller's Hardware Store and Tackle Shop in Park Rapids illustrates the steady decline of large northern pike in Minnesota. DNR researchers examined contest records including 29,541 pike entered from 1930 to 1987. They discovered the average weight of those pike entered in the contest shrank from 10.1 pounds in the 1930s to 6.8 pounds in the 1980s.
The liberal 25-pike-a-day limit of 1920 had been reduced to a three- fish bag limit by 1948. Despite this stricter limit, big pike entries began a decades-long nosedive after the 1950 season, when close to 300 trophy pike were measured and weighed at Fuller's store. By the 1980s, fewer than 100 big pike were being entered in the contest annually.
Big Fish, Little Fish
Healthy fish populations are comprised of fish of a wide range of ages and sizes. Because pike generally reach sexual maturity by age 2, the absence of older, larger fish in a population doesn't limit natural reproduction—as long as the lake has adequate spawning habitat. With angling pressure focused on fish longer than 20 inches, a lake will have an overabundance of small pike. Special regulations are designed to protect older, larger northern pike. But because pike are slow-growing, increasing the population of larger pike takes time. These graphs compare trap net data from different years on Medicine Lake near Bemidji. Data from 1988, the year before special pike regulations took effect, shows an overabundance of pike less than 20 inches. The most current trap net data, from 2002 and 2003, shows how the number of larger pike increased after 14 years of special regulations.
Not everyone is happy with the new special regulations on pike. Dark-house spearers, who have no sure way to judge the size of a fish underwater, either have to be very conservative in targeting pike on lakes with slot limits or find another place to spear. "We came up with this large, amorphous goal of improving opportunities to catch large pike, while at the same time maintaining both harvesting and spearing," DNR fisheries biologist Rod Pierce explains. "If you look at these two things, they look like conflicting goals. Fortunately, in Minnesota we're blessed with a huge northern pike resource—one that should be able to provide opportunities for everyone. The main issue, then, is determining how many lakes should be set aside with special regulations, and where those lakes should be located."
In lakes with good natural reproduction, the fishery can afford harvest of fish less than 20 inches, Pierce says. But creel surveys have shown that anglers aren't as willing to take smaller pike home. And common pike-angling methods, using large lures and bait, are effective at catching larger pike. A DNR study of seven northern Minnesota lakes found that, on average, anglers harvested more than 20 percent of the population of large pike annually.
In response to Minnesota's lack of large pike, the DNR launched a study in 1989 to examine whether special regulations could produce more large pike in Minnesota lakes. The study experimented with several types of length limits that restricted which pike anglers could keep. For example, a slot limit of either 20 to 30 inches or 22 to 30 inches was implemented on five north-central lakes (all pike within the slot had to be released). Three of the five lakes showed increased populations of large pike during the study. Medicine Lake near Bemidji, which received a protected slot of 22–30 inches, fared particularly well. From 1989 to 2003, the fishery's proportion of pike longer than 20 inches increased from 7 percent to 39 percent.
Steve Addler, who has owned Cedar Rapids Lodge on Medicine Lake for 24 years, promoted the regulation to guests. And after a few years, his guests started catching and releasing more large pike. The proof hangs on a wall inside the lodge where guests post measurements of memorable pike they let go.
Before the slot was introduced, guests were catching lots of smaller pike but only one or two fish over 30 inches in an entire season, according to Addler. Seven years after the slot went into effect, at least one 30-inch pike was caught every week. In 2007 the slot was changed to 24–36 inches, and today guests regularly catch pike longer than 36 inches, he says.
"Basically the fish have grown up," Addler says. "We think it's really helped fishing, and it's helped our business too." On some large lakes, traditional hot spots for trophy pike, the DNR established slot limits to protect populations that already had larger-sized pike. Lake of the Woods got a 30–40 inch protected slot, and Mille Lacs received a 26–36 inch slot. For comparison, researchers also studied Lake Winnibigoshish and Leech Lake, which received no special protection for pike.
Monitoring at Lake of the Woods showed the slot limit increased the population's proportion of fish over 30 inches by 9 percent. Modest improvements in size structure were observed at Mille Lacs, while the population of large pike on Winnibigoshish and Leech lakes decreased.
After more than a decade of analyzing the experimental pike regulations, the DNR reached a conclusion: Special regulations can produce bigger pike. In 2002 DNR fisheries directors set special pike regulations for some lakes based on their potential to produce large or trophy-sized pike.
For lakes with the greatest potential to produce trophy pike (low pike population density and good habitat), the DNR designated a 40-inch minimum length limit to protect pike until they approach trophy size. For southern Minnesota lakes with limited spawning and nursery habitat but low population density, the DNR prescribed a 30-inch minimum. For lakes with few large pike but abundant smaller pike, the DNR designed a 24–36 inch protected slot. The slot allows anglers to keep small pike but protects these medium-sized fish so they can grow larger.
"[These] regulations were sent to fisheries managers around the state with the idea that they would look at pike populations in their area and pick out some lakes that could benefit from the regulations," Pierce says.
In 2003, following public input meetings, the DNR added special regulations to 70 lakes around the state. Most lakes were given a 24–36 inch protected slot limit.
Today 106 of the 3,351 Minnesota waters containing pike have special regulations. With the exception of Olmsted County, no special pike regulations have been added since 2008, when the final draft of Minnesota's Long Range Plan for Muskellunge and Large Northern Pike Through 2020 was published. The plan called for special pike regulations on up to 125 waters. But public comments were divided. Some people didn't think the plan went far enough to protect pike; others thought it was too restrictive.
"We ended up with very different opinions about what pike fishing should look like in Minnesota," Pierce says. While the science of managing pike has improved greatly since the 1950s, Pierce says the social dimension of pike management remains tricky, largely because Minnesotans target pike for different reasons: Some prize trophy pike; others angle to take home a meal; and some enjoy the hard-water pursuit of dark-house spearing for northern pike.
"That's where the social issues come into play," Pierce says. "Regulations reduce harvest in order to increase the numbers of larger pike, and not everybody agrees that reduced harvest is a worthwhile tradeoff."
The DNR has contracted with the University of Minnesota to survey pike anglers and spearers to get a clearer picture of what they want.
But it's already clear that many Minnesotans want trophy pike. Plenty of anglers will drop big bucks on a flight to a remote Canadian resort where hooking a toothy behemoth is just short of guaranteed. And some Minnesota anglers, like Lyle Swanson, want to catch a trophy pike in their home state.
"A lot of big pike come from out of the country," says Swanson, whose prize pike from Basswood Lake measured 40 inches. "I wanted one from Minnesota. Mine was made in the U.S.A."