Angler Data Informs Fish Population Status

Anglers are inherently good at identifying patterns and determining when changes occur. The size and color of what lure lands the most fish, for example, can change from one day to the next. Even if it comes down to tipping a lure with a small piece of blue flake curly tail grub to catch the finicky fish, anglers are going to figure it out and adjust. Anglers are also good at noticing trends in the populations they fish such as changes in abundance or sizes.

Information from the angler side (or fishery-dependent data) can provide a unique perspective compared to data collected from annual population surveys (fishery-independent data). Using angler information for management purposes can be challenging, however, given that the information can be biased and not collected in a standardized fashion. Illinois Department of Natural Resources (IDNR) and other agencies are testing whether a smartphone app could be used to collect angler information in an organized, coordinated approach to make the information more readily available, reliable and useful.

The Illinois Walleye Challenge

Walleye, sauger and saugeye, also known by their scientific genus Sander, are a popular sportfish among many anglers in Illinois. The IDNR Division of Fisheries invests a great deal of time and resources into the culture, stocking, and management of Sander species. For instance, the Division of Fisheries Hatchery System cultured and stocked 149 million fry or fingerlings of Sander species (71 percent sauger, 24 percent walleye and 5 percent saugeye) in more than 90 Illinois lakes and rivers for anglers to pursue over the last decade (2014-2023).

Determining whether management strategies are working to maintain or enhance these fisheries requires monitoring. Typical monitoring approaches for these species often require additional targeted sampling using nets or electrofishing surveys at night, which can be labor intensive. Each year biologists are faced with a decision: “Do I survey fewer waterbodies and collect a lot of information from each or do I collect less information to cover more waterbodies?” The consequence is that waterbodies managed for Sander species are either not all sampled on an annual basis or lower quality information is collected across all waterbodies. IDNR, like other states’ natural resource agencies, are trying to envision additional sources of information to assess the status of Sander populations, angler satisfaction and return on investment.

Developing a Virtual Fishing Competition

Faced with a similar situation, Iowa Department of Natural Resources staff joined forces with anglers to assess Sander populations in Iowa. In 2022 and 2023 Iowa DNR piloted a statewide virtual fishing competition using the MyCatch mobile app developed by Angler’s Atlas. Anglers simply take a picture of their catch on a measuring device using the app. Once the fish is reviewed by the Angler’s Atlas team and is deemed to meet specific rules it appears on a live leaderboard where anglers can see who is in the lead. Information collected from the “Iowa Walleye Challenge” revealed that fisheries managers could gain valuable information about Sander populations and fisheries from angler-derived data, including size distributions, relative abundance and angler success.

In 2024, funding from the Association of Fish and Wildlife Agencies provided the opportunity for the Walleye Challenge to expand into a larger fisheries research project. This became known as the 2024 Midwest Walleye Challenge and involved collaboration between natural resource agencies and anglers across 12 states (Illinois, Indiana, Iowa, Kansas, Michigan, Minnesota, Missouri, Nebraska, North Dakota, Ohio, South Dakota and Wisconsin) and two Canadian provinces (Manitoba and Ontario). Separate competitions were run for each state or province because of differing regulations and seasons.

The 2024 Illinois Walleye Challenge was held from May 30 – June 30. To increase participation, anglers had the option of competing free for a certain set of non-cash prizes at the end of the competition. An optional $25 entry fee gave anglers the opportunity to win additional cash prizes throughout the competition in addition to the non-cash prizes. Unique prize categories totaling $20,000 were designed to address data requirements of fisheries biologists:

• “Tough Luck” prizes for those who don’t catch anything
• “Most Waterbodies Fished” prizes
• Longest fish prize
• Random-draw prizes so that anyone who caught a walleye, sauger or saugeye has a chance at winning a prize, regardless of its size.

The Illinois Walleye Challenge Results

Similar to Iowa’s pilot year, Illinois had lower participation than expected for the 2024 Illinois Walleye Challenge. Preliminary results indicated that 31 anglers participated. Anglers logged 864 hours of fishing across 43 waterbodies throughout Illinois and caught a total of 434 qualifying fish with about half of the trips resulting in zero fish caught (148 out of 297). As expected, the number of fish caught per hour of angling varied widely across waterbodies, ranging from 0 to 1.61 fish per hour (37 minutes per fish). On average it took anglers approximately 2 hours to catch a walleye, sauger or saugeye in Illinois waters. Although final results are pending, it is clear that fishing was slower than usual in Illinois this spring. Despite the slow spring, Illinois anglers can hold their heads high by having the highest catch rate across the 14 states and provinces.

Pistakee Lake, the largest lake within the Fox Chain O’Lakes (Lake and McHenry counties), ranked among the highest waterbodies in terms of total hours fished. Compared to 3.5 hours of electrofishing surveys in the fall of 2023, anglers keyed in on the most abundant sizes of Walleye (12 inches) during the 2024 Illinois Walleye Challenge. Walleye shorter than 10 inches and longer than 18 inches were not represented in the angler’s information, however. Based on Iowa’s pilot events we know that increasing participation is key to higher quality information. Generally, as angling effort increases the proportion of fish in each length group become more similar between angler-derived data and standardized survey data. Compiling information across all states and provinces may help determine the minimum amount of effort to provide high quality information.

Increasing Participation

So that begs the question, “how do we increase participation?” To increase angler participation, the Iowa Department of Natural Resources sent more than 1 million emails to Iowa anglers and used social media to attract attention. This massive effort increased participation from 2022 to 2023 by only 17 anglers. 2024 was the first year that free participation was offered so there is hope that this incentive resulted in higher turnout.

Fishing Locations are Kept Secret

Based on what we are hearing from anglers the primary factor dissuading participation in these virtual tournaments concerns disclosing the location of their secret fishing spot. Although the app captures the location of the angler’s catch, or the location the fish picture was taken, a nondisclosure agreement ensures that the exact location within a waterbody can only be seen by Angler’s Atlas. Live leaderboards only display the name of participating anglers and the size of their largest fish. Competitors cannot determine where any fish was caught during or after the competition.

Obtaining high quality angler-derived population data is of course only one of many steps in the fisheries management process and requires fisheries biologists to interpret the data, consider the potential biases and follow up with standardize population surveys. This information could be valuable for highlighting areas that need more immediate attention. However, less confidence would be put towards information from waterbodies that had low fishing effort. Regardless, encouraging anglers to get out and fish is already a win in our book.

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David Glover, Rivers and Streams Program Manager for the Division of Fisheries, Illinois Department of Natural Resources.