Wisconsin regulators work to balance big bass with lots of them

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Wisconsin regulators are challenged with balancing angler demand for high catch rates and big largemouth bass. Image: Jonathan Hansen

Biologist Jonathan Hansen with a largemouth bass at Lake Wingra, Wisconsin. Regulators are challenged to balance demand for high catch rates and big fish. Image: Tom Cichosz

By Holly Drankhan

Largemouth bass nibble on a variety of fishing lures.

But Wisconsin anglers were still surprised in recent years to find a growing number of the olive-green fish tugging on their lines.

From 1992 to 2011, angler catch rates increased by half a fish per hour in the northern third of the state, according to research conducted by the Wisconsin Department of Natural Resources and the University of Wisconsin — Madison. Electrofishing data also confirmed an increase in relative abundance for both adult and juvenile largemouth bass, according to the study recently published by the American Fisheries Society.

This is not necessarily bad news, said study author Jonathan Hansen, a fisheries biologist for the Wisconsin Department of Natural Resources, or DNR. The bass are doing better than ever and provide good fishing opportunities in waters with few other sportfish.

But one concern is that largemouth bass may be competing with and eating the young of another popular sportfish — walleye. In waters where largemouth bass numbers are climbing, walleye numbers dropped by nearly half a fish per acre from 1990-2011.

Largemouth bass are fun to catch, making them great for children new to fishing. Image: Jonathan Hansen

Ada Hansen with one of the largemouth bass that are fun for children new to fishing to catch. Image: Jonathan Hansen

Another concern is that largemouth bass grow more slowly in crowded waters, according to the study. In the 20 years that the population increased, the average length of six-year-old bass decreased by more than an inch.

This relationship between size and abundance makes it difficult for state agencies to balance anglers’ demands, said study author Greg Sass, a Wisconsin DNR program supervisor. Some want high catch rates while others want large fish for trophies.

“If you have too many out there, then your growth rate is going to decline,” Sass said. “If you have too few, then you lose catching opportunities.”

The Wisconsin DNR is attempting to change largemouth bass fishing regulations to encourage greater collection without removing too many large fish, Sass said.

For example, the state recently removed a catch-and-release mandate during spawning season that was intended to protect reproducing males that stay in shallow waters to guard eggs and fry. Their aggressive behavior makes them more likely to attack fishing lures and be pulled away from their offspring, Hansen said.

However, research since the mandate was enacted in the 1980s shows that fishing during spawning does not negatively influence population numbers. Wisconsin anglers can now catch and keep bass during the spawning period.

In a number of Wisconsin lakes with growing numbers of largemouth bass, the 14-inch minimum length limit was removed in 2011. Fish size and abundance for the next decade will be compared to fish in lakes with the limit left intact.

Fish managers are also testing new ways to bring walleye numbers back to normal. These include reducing the number of walleye that can be caught each day, increasing the minimum length for keepers and stocking juvenile fish in the fall.

Factors other than government regulations influence both species. They may explain why western Minnesota reported a surplus of largemouth bass, despite not enforcing a minimum length limit, Hansen said.

One factor are anglers who release fish even if they are not required to. Anglers generally like to eat walleye when they catch them but release largemouth bass, Hansen said.

Wisconsin DNR surveys found that while non-mandated angler release rates for walleye decreased by almost 20 percent, rates for largemouth bass went up from 80 percent in 1980 to a steady 96 percent since 2005.

The state agency is encouraging anglers to keep their catch in lakes where bass are abundant.

“We are trying to be careful, because we don’t want to send the messages that bass are evil and we should kill them all. That’s not true,” Hansen said. “But on a much smaller scale we are saying, ‘Don’t feel bad about keeping a few small bass for a meal.’”

Climate change may also affect fish populations. Environmental trends such as warmer, clearer waters with more plant growth may favor largemouth bass while discouraging walleye, Hansen said.

State regulators must take constantly-shifting ecosystems and social demands into account as they form policies that balance the scales — both for the fish and those who enjoy reeling them in.

Related story: New Michigan regs allow year round catch and release of bass

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