An annual fisheries newsletter from Grand Rapids Fisheries: Spring 2018

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1 Fisheries Update Contact us Minnesota Dept. of Natural Resources Grand Rapids Area Fisheries Office 1201 East Hwy 2 Grand Rapids, MN Phone (218) Did you know.. Minnesota is first in the nation in fishing licenses per capita. Anglers spend over 2 billion dollars on fishing in Minnesota each year. An annual fisheries newsletter from Grand Rapids Fisheries: Spring 2018 Changes to Pike Regulations Statewide New regulations for keeping Northern Pike will be the most noticeable change anglers see when they open the 2018 Minnesota Fishing Regulations Booklet. New pike fishing regulations have three distinct zones to address the different characteristics of pike populations in Minnesota. In response to angler interest, the new regulations are meant to provide better harvest opportunities across the state for sizes that make good table fare, around 26 to 28 inches. New regulations also reflect anglers concerns about the high number of small pike in much of central to north-central Minnesota; low numbers of pike in southern Minnesota; and a desire to protect larger pike in northeastern Minnesota. In the north-central zone (NC zone; including Grand Rapids Area lakes), anglers will be able to keep 10, but not more than two longer than 26 inches, and all from 22 to 26 inches must be released. Pike taken by spearing follow the same rules except one may be between 22 and 26 inches and one may be longer than 26 inches. The other two zones in the state with alternate regulations include the northeast zone and southern zone. For more information on these regulations visit mndnr.gov/pike. Other changes to pike regulations in the Grand Rapids area include modifying experimental regulations once present on Sand, Round and Bowstring lakes (and connected waters). These three lakes had a regulation that allowed a possession limit of nine pike and required all from 22 to 36 inches be released. Only one over 36 inches was allowed in possession. The intent of this regulation was to encourage harvest of the high number of small pike and improve size structure. DNR rulemaking requires all experimental regulations be reviewed after 10 years. Reviews were completed, comments were received, and responses were supportive of the change to the NC zone. Biologically, the NC zone regulation is similar to the prior regulation and is expected to produce a similar fishery. Other lakes in the Grand Rapids Fisheries management area that continue to have special pike regulations include Balsam, Coon-Sandwick, Island (Northome), North Star and Spider. High numbers of smaller pike are a concern throughout north-central Minnesota.

2 2018 Assessment Plan Spring panfish - Battle, Pickerel, Deer (near Effie), Split Hand and Little Split Hand June Johnson (near Marcell), Little Split Hand, Little Deer, Highland, Pancake, Bear and Little Ball Club July Owen, Burrows, Little Sand, Battle, Pickerel, Day, Deer August Split Hand, Rice, Moose, Arrowhead, Jessie, Swan, Trout (near Coleraine), Moose, Burnt Shanty and Mississippi River Fall Lakes Kinney Mine Pit, Judson Mine Pit, Erskine and Winnibigoshish* (additional Winnie sampling occurs throughout summer) Fall Streams Dark, Sand, Pokegama, and Rosholt Fisheries Management Challenges with Changing Lakes To quote Bob Dylan, the times, they are a changing, and biologists and anglers alike are taking notice. News of environmental changes to lakes and streams, commonly attributed to an exotic species, is a common occurrence in headlines. Meanwhile, studies document these changes and monitor their effects on fisheries. A recent Minnesota study documented changing catch rates for a variety of species between 1970 and It found that crappie, bass, pike, and Bluegill numbers increased, while perch and White Sucker numbers decreased. Although Walleye numbers have increased over the past 40 years, they were lowest in the 1970s, highest in the 1990s, and occurred at more moderate levels in the 1980s and 2000s. Changes in Walleye populations have also been documented throughout the upper Midwest and in Ontario. A recent study in Wisconsin found that walleye production declined in both stocked and natural populations. This study did not determine the cause of production declines, but suggested climate change and changes in the food chain were likely responsible. Another recent study in Wisconsin found that bass populations have expanded, while walleye populations have declined. This study showed a strong relationship between population trends and temperatures throughout the growing season. Changing water clarity also effects fish populations. Walleye thrive in dark environments, but lose this advantage as the water clears, especially following a zebra mussel invasion. One Ontario study indicated the primary biological factor limiting Walleye abundance (what biologists call carrying capacity) was associated with increases in water clarity. These studies documented changes in fish populations and strongly suggest environmental causes are responsible, indicating fisheries biologists are limited by the tools they have available to reverse such trends. Changes in water clarity, vegetation amounts, and water temperature are all being observed in Minnesota lakes.

3 In Minnesota, the DNR recognizes the social and economic importance of walleye and remains committed to doing what it can to provide angling opportunities. However, recent research has shown that a decade long attempt to improve walleye numbers through increased fingerling stocking densities found an optimal stocking density above which more fingerlings frequently failed to produce more fish for anglers. In 1948, DNR fish researcher John Moyle wrote that We cannot replace Nature; we can only aid her. Modern fish-culture is essentially the business of helping the fish take care of themselves. The fundamental fact is that nature is changing, our lakes do not contain the same environment as they did in past decades, and some lakes are becoming less suited for walleye. This presents biologists and anglers alike with some big questions. A fish manager might ask, How can the DNR continue to provide opportunities for walleye fishing whose popularity grew under different and more favorable environmental conditions?, while an angler might ask, How can I continue to fish in a changing environment and how will my tactics and target species change?. We realize this information does not provide anglers with any assurances and may raise more questions than it answers, but it demonstrates that a multitude of factors contribute to management decisions and public concerns are heard and valued. Area panfishing opportunities and thoughts on conservation Walleye may be the state fish, but sunfish, crappie, and perch are the most common fish harvested by anglers. These fish are found throughout the Grand Rapids area and provide great year round action and harvest opportunities. The fish have traditionally been targeted in the spring and winter, but summer and fall fishing has recently increased in popularity. Panfish are often easy to catch and can be taken with a variety of tactics. Panfish angling can be a very simple activity, but for many anglers, improved technologies and access to fast moving information have changed their approach to angling. In the old days, it was common to learn of a hot bite only after fishing had slowed down. You should have been here last week, was often the response from the clerk at the bait store. Today, anglers often read of a hot bite on a social media site at the very moment it s occurring. Anglers also have better boats, gear, and electronics. Ice anglers often have more reliable transportation, better fish houses for extended trips, improved augers, improved electronics and better tackle options. The possibilities seem endless, but the fisheries resource is still subject to the same natural limitations. Today, the resource is under more pressure than ever, especially when fishing is good. Trap netting, measuring, and weighing a Bluegill during a spring assessment. The good news is that panfish are resilient and populations can support relatively high harvest. However, a population shift from producing moderate numbers of large fish to higher numbers of smaller fish often occurs with high harvest. In fact, participants in a

4 recent University of Minnesota survey agreed that the quality of panfish in Minnesota had declined. Overall, a lake can only support so many pounds of fish. This means a lake can support a lot of small fish, a few large fish, or some combination in between. Populations tend to produce as many pounds as biologically possible. This is what biologists call carrying capacity. Many anglers believe small fish should be released to grow up, while large fish should be harvested. Unfortunately, this is the wrong line of thinking in most situations. Fish grow slowly in Minnesota, so large fish are often removed faster than they can be replaced. Often, the void that is created by the removal of large fish is filled by increased survival of young fish. While this is a great way to ensure high fish numbers, size quality declines as these small fish compete for food and space. Often, these fish will spawn at an earlier age and smaller size in an effort to maximize their reproductive potential. Unfortunately, the energy needed for spawning is diverted from growth, resulting in the population having poorer size structure. Once a size structure shift has occurred, it can be difficult to improve it. A better approach is to reduce harvest on lakes that currently support quality panfish. On some lakes statewide, the DNR has implemented special regulations to reduce panfish harvest so size structure can be maintained or enhanced. In the Grand Rapids area, only 5 sunfish may be kept from Bass, Dixon, Grave, Split Hand, and Little Split Hand lakes. A reduced bag limit of 10 sunfish exists on Deer, Battle, and Pickerel lakes. Split Hand has a 5 crappie limit. These regulations went through public input processes prior to implementation and had angler support. In other proposed cases, the concept of a special regulation for panfish did not have the support of anglers and was not implemented. Anglers can help maintain quality panfish, even in lakes without a special regulation. Anglers should voluntarily limit their harvest of larger panfish. If keeping a lot of panfish is desired, harvest smaller ones as they are easier to replace. For example, a good rule of thumb for sunfish would be to keep no more than 5 fish over 8 inches. High grading the 5 largest fish is illegal. Anglers should also try to distribute their take over more lakes instead of making multiple trips to the same lake. Anglers are encouraged to only take what they need for a meal or two. Minnesota can still produce high quality sunfish opportunities, but only if anglers consider the impacts of their actions. Protection of shoreline habitat will benefit panfish fisheries for future generations. Panfish Facts Bluegill may live 10 years or more, but grow very slowly at a rate of less than 1 inch per year. A trophy whitetail buck can be grown in 3 to 4 years, but a trophy sunfish or crappie often takes 8 to 10 years to grow On average, it takes 5 years to grow a 9 inch crappie in the Grand Rapids Area. Crappie also reproduce sporadically in most lakes, resulting in boom and bust fishing cycles

5 Changes to Lake Trout Management Lake Trout angling continues to be popular within the Grand Rapids area, with many calls and comments received by the office annually. Recent surveys on Caribou and Bluewater Lake(s) have indicated an increasing proportion of the captured fish resulted from natural reproduction, despite yearlings being stocked every other year since The reason for this is unclear and has been complicated by various strains of Lake Trout being stocked over time. It is believed that Mountain Lake strain (the only strain that has been available for inland stocking since 2011) is not surviving and recruiting to the fishery. The relative abundance of Lake Trout remains similar to past surveys, however, and the lakes continue to provide a fishery through natural reproduction. Maintaining sufficient spawning stock biomass is important for providing a natural fishery and will be closely monitored moving forward. These two lakes were surveyed in 2017 to collect additional samples from which age, sex, maturity, genetic analysis, and the contribution of stocked fish was determined. No stocked fish were caught in The 2016 LMPs detailed the conditions in which stocking would be discontinued, that included; 1) if natural reproduction is capable of sustaining the population, and 2) if Mountain Lake strain fails to contribute to the fishery. Other considered aspects included the potential unintended negative consequences of introducing additional genetics into a successfully reproducing population and the monetary cost associated with stocking. Stocking can be an important tool for providing or supplementing a fishery, unfortunately this is not the case with yearling Lake Trout stocking on these lakes at this time. After considering all information, yearling Lake Trout stocking has been discontinued in Bluewater, Trout and Caribou Lakes. Lake Trout stocking may be reevaluated in the future, but will be dependent on the outcome of genetic testing and suitable strain availability. Photos of sampled Lake Trout Deer Lake Muskellunge Survey Deer Lake is a 4,097 acre lake that has a native Muskie population. The lake was also stocked 8 times with Shoepack strain fish and once with Wisconsin strain fish between 1965 and Though natural reproduction has maintained the population, after this time period, the effects of stocking non-local strains that do not get as large as local strains remain. Muskie are difficult to sample using summer netting methods because they exist at such low densities. As a result, surveys targeting Muskie in the spring, when fish are concentrated in the warming, shallow water to spawn, are necessary to attain a better sample. In the spring of 2017, 20 large trap nets were set on April 18 and were fished until May 5. All sampled Muskie were tagged (marked). A total of 169 Muskie (one Hybrid) were

6 sampled; 85 males that ranged from 27.8 to 43.5 inches and averaged 37.0 inches - 83 females ranged from 31.9 to 51.3 inches and averaged 43.4 inches. Once the netting survey concluded, electrofishing was immediately used to resample the population and obtain a ratio of marked to unmarked Muskie in order to calculate an adult (30+ inches) population estimate. The marked population consisted of 164 adult Muskie caught in the trap nets. A total of 38 fish were sampled by electrofishing, of which 20 had been previously sampled with trap nets and marked. The estimate for adult Muskie was 305 fish, with 95% confidence that the population was between 211 and 399 fish. The estimate translates into one adult Muskie for every 13.4 acres. Many of the popular Muskie lakes in Minnesota have estimates of one adult for every 5 to 15 acres. Deer Lake is deep, clear and has relatively low fertility so all fish species tend to occur at lower densities than similar sized lakes with higher productivity. However, Deer Lake remains popular with Walleye, Smallmouth Bass, and Muskie anglers. For more information on the status of other fish species in Deer Lake, please refer to the Lake Finder tool on the MN DNR website. Information collected from sampled Muskie included length, weight, sex, maturity, anal fin rays to determine age, scale samples to determine growth and genetic ancestry. PIT tags were inserted for individual fish identification.