Fishery Surveys

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Fishery Surveys

FYKE NETTING WITH THE WISCONSIN DNR
By Dave Neuswanger
Spring 2018

During the week starting Sunday, May 6, Wisconsin DNR crews from Fisheries Management (in Hayward) and Hatcheries (in Spooner) were busy setting and running fyke nets for multiple purposes in Lost Land and Teal lakes. Fishery Management Biologist Max Wolter enjoyed having members of QLIA help and learn how these operations are vital to science-based management. On Monday, May 7, QLIA Photo Editor Bryan Neuswanger of Keenai Photography was invited to join the Management crew for a morning of fyke netting and fish processing. The following sequence of photos will bring you into the boat with Bryan to observe the operation.

WDNR Fishery Technician Scott Braden (foreground) and Fishery Management Biologist Max Wolter (background) load a fyke net into their boat on Monday, May 7, 2018.
Approaching a fyke net set in the shallows overnight from May 6 to May 7. Nets were tended every 24 hours. Anglers were asked to give these nets a wide berth while fishing. All were marked with buoys and DNR flags.
Scott Braden lifts a fyke net to inspect the overnight catch.
The last hoop of the net is secured with large hooks and a custom slot welded into the bow of the net boat.
Scott found the “cod end” of the net loaded with fish that swam through the funnels overnight and became entrapped.
Max Wolter inspects the catch dipnetted out of the fyke net by Scott Braden.
Survey targets included black crappies and yellow perch, which were transferred to a large holding tank until they could be measured and released.
Abundant yellow perch were in the middle of their spawning season. Adult and juvenile perch are vitally important as prey for walleye, muskellunge, largemouth bass and northern pike.
Yellow perch deposit their eggs in long strands, which often are draped over submersed structure near shore (e.g., fallen tree branches) in order to keep the eggs well oxygenated off the mucky lake bed. More fallen trees in both Lost Land and Teal would increase the probability of survival of perch eggs. More young perch would improve growth rate and survival of young walleyes.
Max Wolter lowers a large walleye into the holding tank until it can be measured and released.
Scott Braden admires the largest walleye captured in the May 7 fyke nets. Any guesses on length?
The official measurement of this large female walleye was 29.6 inches — a trophy by almost any standard!
Fyke nets also capture muskellunge. These adults await donation of their eggs and milt before being released.
Crew members relieve a large female muskellunge of her first batch of eggs. She will develop more eggs for a second bout of spawning in the lake.
A sterile, stainless steel bowl is where little muskies are created. The eggs from each female are fertilized with milt from two or three males (to simulate real-world behavior and genetic diversity).
Each muskellunge used as broodstock for the hatchery in Spooner donates a small tissue sample for genetic analysis. Each donor fish also receives a PIT tag that can be scanned to identify and exclude it from repeat use in future years. This maximizes genetic diversity among hatchery products over time. Science matters!

SPRING 2018 FISHERY SURVEYS AND OPERATIONS
By Dave Neuswanger
Spring 2018

Spring of 2018 was an exceptionally busy time for Wisconsin DNR fishery management and hatchery workers on Teal and Lost Land lakes. Lake residents saw lots of activity that might otherwise have caused concern, but was only our dedicated natural resource professionals doing their jobs on behalf of the fishing public.

Shortly after ice-out, WDNR’s Hayward Fish Team led by biologist Max Wolter fished several large-framed fyke nets in Teal and Lost Land lakes in a scheduled quadrennial survey to monitor the status of walleye and northern pike populations. Nets were fished overnight and run for 2-3 consecutive days until Max obtained the data needed to characterize the current status (relative abundance and size distribution) of these important sport fish. (Summaries will be published in mid summer.) One end of each net was staked to the shoreline, and a “lead” was extended perpendicular to shore to depths of 5-8 feet where fish were funneled into a “pot” to await processing (measure and release). The deep end of each net was marked by a large WDNR buoy.

A fyke net set perpendicular to shore in early spring awaits a school of pre-spawn walleyes to follow the lead from shore into the rectangular pot, where funnels will entrap them overnight.
A nice pair of walleyes removed from a fyke net in Teal Lake in spring of 2010 by WDNR Fisheries Biologist Joe Krahn.

As water temperatures approached and exceeded 50F, WDNR’s crew from the Thompson Hatchery in Spooner spent a week or so running numerous fyke nets in Teal and Lost Land in order to collect and fertilize eggs of adult muskellunge. Eggs were fertilized on site and transported daily to Spooner for incubation and hatching. The fingerlings will be reared to 10-12 inches for stocking throughout northwestern Wisconsin in September.

Eggs being stripped from a 49.0-inch, 32.5-pound female musky by fish culturists from the Thompson Hatchery in Spooner.
A quart of fertilized eggs being prepared for shipment to the Thompson Hatchery in Spooner.

Teal and Lost Land are special because our near-shore habitats and fish communities are conducive to natural reproduction and recruitment (survival to first birthday) of muskellunge. No hatchery stockings are needed or desired here. Decades of broodstock collection from lakes with natural reproduction reveal no adverse impact associated with taking eggs (from females) and milt (from males) from a small proportion of the total adult population in these hatchery egg-take operations. The primary limitation to recruitment always comes long after hatching when juvenile muskellunge must “run the gauntlet” past hungry largemouth bass, northern pike, and even their parents. Yes, they are cannibals. Regardless of the number hatched, only a few lucky muskellunge ever survive to adulthood.

Retired WDNR Fisheries Team Leader Dave Neuswanger releasing a 51.0-inch, 40.9-pound female musky after she donated a quart of eggs to the Thompson Hatchery in Spooner.

While the Thompson Hatchery crew focused on fertilizing muskellunge eggs, Max Wolter and crew tagged and collected information from adult muskellunge, including growth rate data from previously tagged fish. He also obtained meaningful data from these mid-spring fyke nets on notoriously difficult-to-sample species such as black crappie and yellow perch. Max involved several QLIA members in these surveys. They will be acknowledged in upcoming reports.

Be prepared to bundle up if you volunteer to assist WDNR with spring fish sampling!

As water temperature rose from the upper 50s into the low 60s, WDNR’s Hayward Fish Team conducted nighttime electrofishing surveys in Teal and Lost Land lakes. (Because of its smaller size, Ghost Lake is on a longer rotation for these baseline fishery monitoring surveys.) Some lake residents undoubtedly say their 18-foot flat-bottomed “shocker boat” with long booms projecting off the bow (suspending metal electrodes) and lots of lights moving slowly along the shorelines where Max and crew collected literally hundreds of temporarily stunned fish to be measured, recorded, and released. Primary target species for assessment during those surveys were largemouth bass, smallmouth bass, rock bass, bluegill, pumpkinseed, natural hybrids between bluegill and pumpkinseed, suckers, troutperch, and juvenile walleyes and muskies.

WDNR ONLINE ANGLER SURVEY RESULTS
By Dave Neuswanger
May 2, 2018

WDNR Sawyer County Fishery Biologist Max Wolter is grateful for feedback received from Quiet Lakes anglers who participated in his April 2018 online survey. Max has summarized results from 59 respondents for whom fishing on Teal and Lost Land lakes (combined) is an important activity.

Max was interested in comparing his April 2018 survey results with data from a visioning session that I facilitated with 19 local stakeholders in June of 2006. The attached document (click on link below to view in separate window) presents two tables — one containing raw data from both surveys, and another summarizing those data with relative importance rankings.

Fish Species of Angling Interest in Teal and Lost Land lakes

Max and I were pleasantly surprised at the degree of concurrence between these two different polling methods. Walleyes were Number 1 in angling interest in both the 2006 visioning session and the 2018 online survey. Black crappies and muskellunge ranked either second or third depending on survey method, so both were very important. Smallmouth bass rounded out the top four species — all of which generated above average interest among anglers on Teal and Lost Land Lake in both surveys. There was a large gap in the level of sport fishing interest between the top four and the bottom four species (largemouth bass, bluegill, northern pike, and yellow perch) in both surveys.

This information, combined with other data on size and harvest preferences for each species, will serve as a guide to completion of a Fishery Management Plan for Teal and Lost Land lakes in the coming year.

SEPTEMBER 2017 ELECTROFISHING SURVEY RESULTS ON LOST LAND LAKE
By Dave Neuswanger
September 25, 2017

On Tuesday night, September 19, I was privileged to help WDNR with their annual fall evaluation of juvenile walleye survival on Lost Land Lake. Fisheries Biologist Max Wolter and Technicians Scott Braden and Evan Sniadajewski met me at the public boat ramp at dusk. After launching their electrofishing survey boat, we spent the next 5 hours traveling slowly through the shallows around the entire 8-mile shoreline, capturing electrically stunned fish for immediate processing and release. A few curious residents waved greetings from their docks, but we were unable to hear or respond to their questions or comments over the roar of the onboard generator. Survey results were disappointing in some respects, yet hopeful in others.

WDNR Fisheries Biologist Max Wolter (center right) prepares waterproof data tablet while WDNR Fisheries Technician Scott Braden (back left) checks out the controls prior to our nighttime electrofishing survey.

Survival of 6,955 walleyes stocked by WDNR in August of 2017 at an average length of 3.5 inches was very low. We captured only 9 fish 6-7 inches long that were either stocked in August or hatched naturally last spring (1.1 per mile of shoreline). Follow-up genetic analysis will reveal the origin of those few fish. Regardless, we have a very weak 2017 year-class of walleyes in Lost Land Lake. On the bright side, we captured 44 walleyes (5.5 per mile) between 10 and 14 inches long that probably originated as fingerlings stocked by WDNR in fall of 2015 at lengths of 6-7 inches.

Young walleyes like this one, hatched in 2017, were the primary target of our nighttime electrofishing survey on Lost Land Lake. But very few were captured.

We will never know exactly why the 3.5-inch walleyes stocked in August survived in such low number. But our fall electrofishing survey revealed there are still enough largemouth bass to have an impact as predators on and competitors with young walleyes. Max reported that our catch rate of largemouth bass 8 inches and longer was almost 9 per mile of shoreline. That is down from 17 per mile captured in spring of 2014 (spring data may not be comparable with fall data), but still too close to the 10-per-mile threshold for largemouth bass, above which some biologists (including the retired author of this post) believe juvenile walleyes will rarely survive to adulthood.

The largemouth bass we captured were quite robust, indicating they had plenty to eat in recent weeks. I was also encouraged by the reduced proportion of largemouth bass in the 10-13 inch range. Formerly the most dominant size group, anglers at Lost Land Lake may finally have harvested enough of these 10-13 inch largemouth bass to reduce their numbers to levels conducive to overall fish community balance. The proportion of larger bass seems to have increased somewhat, possibly due to the thinning effect of angler harvest (more food for survivors). But there is now a big cohort of largemouth bass in the 7-9 inch range (probably born naturally in 2015) that anglers will need to harvest heavily in the next year or two in order to facilitate increased survival of stocked walleyes.

Even smaller largemouth bass are opportunistic predators capable of eating and competing with walleyes. The photos above were taken in late September 2009 on Nelson Lake, where 13 of 28 bass captured within 0.1 mile of extended-growth walleye stocking sites 32 hours post-stocking were found to contain walleye remains in their stomachs.

Smallmouth bass were as rare as juvenile walleyes (1.1 per mile of shoreline), but the adult fish we captured were very robust. The biggest smallmouth (19.1 inches long) was shaped like a football! I believe a decline in largemouth bass will facilitate an increase in smallmouth bass, provided anglers continue to release even legal-size smallmouths (14 inches and longer) voluntarily. And because smallmouth bass are not known to eat or compete significantly with walleyes, we can have a great bass fishery. We just need to be selective about which bass we keep (largemouths) and which ones we release (smallmouths). See our new Bass ID poster in an earlier post for more info.

Fall electrofishing is not an effective method for assessing muskellunge population abundance or size distribution, but a few muskies are always captured incidentally to the primary target species. Two of the fish we captured were small enough (19.6 and 23.2 inches) to be natural recruits, which bolsters confidence in spawning habitat quality and the genetic integrity of our musky population. Two of the fish (34.0 and 37.8 inches) had PIT (Passive Integrated Transponder) tags embedded in them, indicating they had been stocked as 13-inch fingerlings in fall of 2012 – the last time muskies were stocked in Lost Land Lake. These fish had grown faster than the average northern Wisconsin musky during their first 6 growing seasons. A 42.3-inch female had been tagged as an adult in 2008 when it was 35.1 inches long. Max reported this is the third time this fish has been recaptured! It was caught in 2012 at 40.4 inches, in 2013 at 40.8 inches, and now in 2017 at 42.3 inches. Slow growth of larger fish points out the continuing importance of voluntary catch-and-release of legal-size fish 40 inches and longer if we are to maintain a trophy aspect to the musky fishery.

WDNR Fisheries Technician Evan Sniadajewski prepares to release a tagged 37.8-inch musky that WDNR had stocked in fall 2012 when just 13 inches long.

Northern pike were captured at a low rate (1.5 fish per mile of travel along the entire shoreline). Fish ranged from 5.1 inches (hatched this year) to 31.1 inches long. As with muskellunge, fall electrofishing is not the best way to assess population abundance or size distribution of pike, but the low capture rate of various sizes of fish indicates we do not have an over-population of small “hammer-handle” pike that plague many other lakes. Still, a good approach for Lost Land Lake anglers would be to continue harvesting mid-size pike (21-28 inches) so they do not become numerous enough to have a negative impact on survival of juvenile muskellunge or walleyes. Larger pike (28 inches and longer, which are relatively high in mercury content) can be released voluntarily in order to thrill another angler, another day.

The author’s wife, Sandy Neuswanger, with her biggest pike ever — a 32-incher caught in August of 2017.
The big pike was gently lowered into the water…
And with one impressive thrust of its long, strong body, it bolted to freedom!

Thanks to Max and crew for letting a lake association representative tag along so we could understand and support what WDNR is doing to make fishing better in our lakes. Max plans to conduct a more thorough baseline monitoring survey for fish on Lost Land and Teal lakes in spring of 2018. Results from those surveys will be used to fine-tune angler harvest guidance going forward.

BASELINE MONITORING

Wisconsin DNR fishery management biologists have scheduled baseline monitoring surveys to assess fish populations every four years in Lost Land and Teal lakes. The next surveys are scheduled for spring of 2018. Click on the PDF link below to see Fisheries Biologist Max Wolter’s most recent summary of surveys conducted in 2014.

2014 WDNR Fish Survey Summaries for Teal and Lost Land Lakes (PDF)

When Dave Neuswanger was still actively employed as WDNR Fisheries Supervisor for a six-county area in NW Wisconsin, he and Fisheries Biologist Joe Krahn teamed up to develop a new, user-friendly format for reporting the results of WDNR fish surveys. Click on the links below to see some of the first reports of this type, based on survey data collected in 2010 at Teal and Lost Land lakes.

2010 WDNR Netting Survey Summary for Teal and Lost Land (PDF)

2010 WDNR Electrofishing Survey Summary for Teal and Lost Land (PDF)

FISHERY RESEARCH

The oldest fish survey report we have on file from Wisconsin DNR presents the results of an adult muskellunge fyke netting operation conducted in 2008 under the direction of Fisheries Research Scientist Dr. Martin Jennings, who was stationed in Spooner at the time (now with Minnesota DNR). The purpose of Dr. Jennings’ project was to determine the feasibility and advisability of using Lost Land and Teal lakes as a triennial source of muskellunge broodstock for purposes of procuring fertilized eggs for culture at the Thompson Hatchery in Spooner. Information gathered for this report served as the basis for WDNR’s decision to use our lakes as a source of muskellunge eggs for the foreseeable future, allowing WDNR to stock fish from a healthy genetic stock with demonstrated capacity to grow large and reproduce naturally. Click on the following link to read this historic report.

2008 Muskellunge Fyke Netting Survey in Teal and Lost Land Lakes (PDF)

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