WISCONSIN DEPARTMENT of Natural Resources fisheries biologist Zach Lawson discusses walleye growth rates Tuesday in Mercer during a talk on the health of the Turtle Flambeu Flowage’s fishery. The talk was part of the “Conservation on Tap” lecture series.

By RICHARD JENKINS
rjenkins@yourdailyglobe.com

MERCER, Wis. – Those who fish the Turtle Flambeau Flowage should largely be pleased with the state of its fishery, according to Wisconsin Department of Natural Resources fisheries biologist Zach Lawson.

Lawson provided an update on the health of the flowage’s fishery and the results of an extensive survey of the water’s fish populations at the Pines restaurant in Mercer  Tuesday as latest talk in the annual “Conservation on Tap” lecture series.

Lawson said the survey, which ran through most of 2016 and wrapped up in 2017 was very resource intensive.

“This is a huge, huge survey that only gets done once every 10 years. With a body of water like the Turtle Flambeau Flowage, we just don’t have the resources to be out there all day, every day,” Lawson said. “So to be able to do a survey out there on the flowage – a body of water of that size – is very difficult to organize, so we’re very glad everything went well.”

The survey confirmed the 13,500-acre body of water is home to a very diverse fishery; made up of healthy numbers of predators, panfish and forage base.

A variety of methods – including fyke nets, PIT tags, gillnets and electrofishing – were used to look at the actual fish, and a creel survey was conducted to see what species anglers were targeting.

By taking over a year to complete, Lawson said those conducting the survey were able to study a number of different fish species – including walleye, musky, smallmouth bass, lake sturgeon and various panfish species – as well as fish in different stages of their life cycles.

One thing the survey showed is that while the flowage has a relatively low density of panfish in it, the panfish that are there are generally a good size – with Lawson saying pumpkinseeds were 7-inches on average, blue gill averaged 8-inches and crappies averaging 10-inches.

These sizes were partially the cause of one of the survey’s most surprising conclusions – the sharp rise in anglers targeting panfish.

“The creel survey noted 30 percent of our anglers out on the flowage these days are targeting panfish, which is a huge change change from years past,” Lawson said. “In past creel surveys, we noted 0 to 5 percent (targeting panfish).”

The increase in anglers targeting panfish inadvertently reflects another key point in the survey – several years of low walleye production.

“Historically, the Turtle Flambeau has been, for the last 30 years on record, has been four to five adult walleye per acre. I think now we’re at 2.8 (walleye), so there has been a decline – and we picked that up in the creel survey, our anglers are responding to that and aren’t targeting walleyes as much,” Lawson said. “It’s still the largest sought after fish in the flowage, but effort has come down.”

The walleye population is still healthy Lawson reassured the audience, it’s just lower than in past years.

In 2010, and in 2013 or 2014, the flowage had poor walleye production. This was the same time period that featured several “wonky” springs, where ice-out either came late or early and likely impacted walleye spawning levels.

These low population years create gaps in the overall walleye population, which have become more noticeable as the fish grow into three to six year old fish and become increasingly targeted.

Lawson told the Daily Globe after his talk while it can’t be known for certain the weather impacted walleye populations, it’s hard to believe there wasn’t some impact given the correlation and the importance of water temperature to walleye.

He also said the walleye fishery may return to its previous size as recent years have delivered healthy walleye populations and it appears the current levels are the bottom of the population valley.

“The good thing is, while we’ve had a few very poor walleye year classes, 2016 was one of the highest year classes we’ve documented. While we’ve had a few gaps, reproduction is not gone,” Lawson said. “… We still have strong reproduction, it’s just not quite as frequent. We still have a strong adult population, it’s just not quite as high as it was.”

He said the flowage remains a “world-class walleye fishery,” with great habitat and there isn’t any reason to think the walleye populations won’t rebound.

Moving forward, Lawson said the DNR is likely to continue focusing on the continuing improvement of the flowage’s walleye population, which is expected to have the added benefit of maintaing the panfish population in its current state.

“I would say (there are) two … take-home points from the comprehensive survey, and that is that most of the species are basically right where we want them to be – quality density and quality size,” Lawson said. “The only pieces that are kind of moving are the panfish levels and the walleye levels. If we can improve walleye density a little bit, and improve size structure of the walleye population a little bit, then we’d have it made. Then I don’t think anybody could ask for anything more.

“In doing that, we’d keep the panfish populations in check, right where they are right now. If we can get on top of the walleye population … that should keep the panfish at still moderate levels, instead of exploding and having a ton of small panfish.”

The next “Conservation on Tap” lecture will be Aug. 8 and feature a talk on Wisconsin pollinators.