Outdoors / Sports

DNR exploring 'adaptive management' plan to increase size of panfish

One of my favorite public sculptures in Wisconsin is a 15-foot-tall rendition of a bluegill near Onalaska, the "sunfish capital of the world."

It represents both the exaggerated fish of our dreams and the magnitude of our actual love for panfish.

The healthy handful of panfish species -- including bluegill, black crappie, pumpkinseed sunfish and yellow perch -- are typically the smallest fish Wisconsin anglers pursue.

But they are arguably the state's most important category of fish.

Panfish are native, abundant, prolific, relatively easy to catch, highly nutritious and great table fare.

Beyond that, they are a "gateway" to the outdoors.

Think back on your angling life. What type of fish did you first catch? If you're like me and the majority of other anglers, you answered "panfish."

And in most waters of the state, anglers can pursue panfish 365 days a year with a daily bag limit of 25 fish.

Panfish are the most-caught fish in Wisconsin, according to a statewide mail survey conducted by the Department of Natural Resources. Of the 88 million fish anglers reported catching in Wisconsin in the 2006-'07 license year, two-thirds (57.7 million) were panfish.

Significantly, panfish are also the most kept. Anglers reported keeping 25.7 million (45 percent) of the panfish they caught.

The popularity results in a predictable downside -- high angling pressure and harvest leaves most lakes with reduced panfish size structure.

The DNR has been taking a hard look at the issue of panfish management for the last several years. It conducted angler surveys, reviewed research and held public meetings.

If it were merely a matter of managing for larger panfish, the strategy would be simple. Bag limits would be slashed statewide, perhaps in combination with protections for larger fish.

But surveys showed only partial support for such a broad change.

"We know we have to balance the social with the biological," said Jon Hansen, leader of the DNR's panfish team. "While about half of anglers would support changes, the other half are happy with the fishing they have now for panfish."

The agency announced its next step in Wisconsin panfish management -- a proposed study of modified harvest regulations on 110 lakes with poor panfish size structure. The lakes were identified by fisheries biologists and angler surveys as having smaller than average fish, good growth rates and high fishing pressure.

Hansen said panfish can have a small size structure for two reasons: stunting or overharvest.

In the first case, there are too many panfish and too few predator fish. The growth rate of the panfish slows and few, if any, reach large size.

The second reason, however, is more common. Creel surveys show anglers statewide have a significant impact on panfish populations, keeping most bluegills 6 inches or longer and many crappies 8 inches or longer.

Research in Wisconsin has revealed how long it takes for a bluegill to reach "keeper" size.

Al Niebur, fisheries biologist in Waupaca County, extracted bones from bluegills in nine lakes in central Wisconsin over the last four years. Analysis of the otoliths found on average a 6-inch bluegill was 4.4 years old, a 7-inch fish was 5.3 years old and an 8-inch bluegill was 6.8 years old.

Niebur found a limited number of bluegills 9 inches or longer; the fish were up to 11 years old. It's clear it takes a long time to grow a bluegill with "shoulders."

And in lakes farther north with lower productivity and shorter growing seasons, it takes even longer to get to those sizes.

In its proposed study, the DNR would randomly try one of three regulations on lakes identified as having good growth rates but poor panfish size structures.

The regulations would be either: a total of 25 panfish but no more than 10 of any species (25/10); a total of 15 panfish but no more than five of any species (15/5); or a total of 25 panfish but no more than five of the sunfish (bluegill and pumpkinseed, for example) may be over 7 inches in length (25/5 over 7 inches).

The 25/5 over 7 inches option primarily is targeted at reducing harvest of big bluegills.

"The goal of all of these proposals is to increase the average size of bluegill and crappie on select lakes that are currently overharvested," Hansen said.

In southeastern Wisconsin, the study waters would include: Bohners Lake in Racine County; Paddock Lake in Kenosha County; Tripp Lake in Walworth County; and Big Cedar, Little Cedar and Silver lakes in Washington County. Notable waters proposed elsewhere in the state include Butternut Lake in Ashland County, Three Lakes Chain in Oneida County, Dairyland Flowage in Rusk County and Little St. Germain and Kentuck lakes in Vilas County.

Hansen said the DNR wants to hear what the public thinks about the proposal. If there is support, the agency likely would include the 110 study lakes in a proposed fisheries rule change at the 2015 spring hearings.

The study would then occur on the selected lakes for about six years before results would be known. If one treatment outperformed the others and was accepted by anglers, it could then be used on more lakes. Hansen said it was part of an "adaptive management" approach.

"It's exciting to apply this to panfish, an important part of our Wisconsin fisheries that hadn't been getting as much attention as some other areas," Hansen said. "I'm looking forward to seeing how the proposal is received."

(c)2014 Star Tribune (Minneapolis)

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Distributed by MCT Information Services

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