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INLAND FISHERIES Cause for concern Ceded territory walleye decline Odanah Wis.Trends in some ceded territory walleye populations are becoming a growing concern to biologists spearers and anglers. GLIFWC and state agency monitoring programs have identified declines in adult walleye abun- dance on some of the more popular walleye lakes. In Minnesota on Mille Lacs Lake population estimates of spawning walleye have declined from 736000 in 2008 to 249000 in 2014. Similarly declines have been observed on Lac Vieux Desert Vilas County Lake Chetac Sawyer Co. Sissabagama Lake Sawyer Co. Nelson Lake Sawyer Co. Teal Lake Sawyer Co. the expansive Chippewa Flowage Sawyer Co. the chain of lakes in Minoc- qua Oneida Co. the Eau Claire Chain of Lakes Bayfield Co. the Pike Lake Chain Bayfield Co. Franklin Lake Forest Co. and others. A critical component of the walleye life cycle is the juvenile life-stage and this stage is where many of these populations are struggling. In some instances juvenile walleye are either not hatching or not surviving to their first fall. In others they are not surviving from the first fall to adulthood. Even though poor recruitment of young walleye is the main factor influencing many of these declines the causes of these year-class failures are often unclear. Juvenile walleye production and survival are influenced by the number of adults producing eggs and milt habitat food availability competition and predation. Onecommontheoryforwalleyepopulationdeclinesisthatoverharvestofadult walleyes has reduced their abundance and caused recruitment failure. However in mostofthecededterritorycasesofdeclinerecruitmentfailurebeganwhiletheadult population was large enough to produce good year-classes.Additionally estimates of adult harvest have been typically low enough to be considered sustainable. Habitat changes can have major impacts on juvenile walleye production. Shoreline development is a concern on many waters since walleye spawning and hatching occurs in near-shore rock or gravel areas. While it is unlikely for a single small development project to cause recruitment failure cumulative impacts of shoreline habitat changes could limit reproduction or hatching success. Secondary impacts like sedimentation threaten the rocky and gravel substrates that are often necessary for successful spawning. Fish community changes can also impact walleye abundance. In many instanceswherewalleyehavedeclinedotherpredatoryfishspecieshaveincreased in abundance. These fish species can compete with walleye for available food or even prey upon small walleye. Largemouth bass abundance has increased in many areas in northwest Wisconsin. In other lakes smallmouth bass or northern pike populations have increased.The impacts of these predators on walleye populations are largely unknown and can vary widely among lakes. Ingeneralwalleyeyellowperchnorthernpikeandormuskellungecomprise well-balanced coolwater fish communities. In warmer water centrarchid com- munities that consist of bluegill black crappie largemouth bass and smallmouth bass appear to be becoming more prevalent. Invasive species are adding additional stress to fish communities in many lakes. Zebra mussels filter out nutrients clear the water and may reduce plank- ton densities. Zooplankton provide a critical food source for hatchling walleye. Another problematic invasive that has begun to appear in many lakes is the spiny water flea. These large zooplankton can outcompete the native species that many juvenile and prey fish prefer to eat affecting the food chain. Fortunately to date zebra mussels and spiny water fleas are present in only a fewcededterritorywalleyewaters.Eurasianwatermilfoilandotherinvasiveplants can affect the lake habitat by forming thick weedy areas and tying up nutrients and energy that might otherwise be available in the food chain. In general bluegills largemouth bass and crappies inhabit areas with weed growth while walleye and yellow perch prefer sandy and rocky areas. In a few lakes invasive rainbow smelt are known to wipe out entire year-classes of walleye fry by aggressively feeding on them shortly after they hatch. Sincecausesofwalleyedeclinesareusuallycomplexandnotconsistentacross the landscape reversing negative trends will require an individual lake approach. Biologists have limited tools at their disposal to restore walleye populations. In someinstancesreducingharvesttopreservecurrentwalleyestocksiscritical.Steps have been taken to reduce tribal and state harvest on Mille Lacs Lake in Minnesota and the Minocqua Chain of lakes. Habitat protection and enhancement can play a big role in lakes where the strain of lakeshore development has significantly altered critical near-shore areas. Cooperative efforts to prevent the transportation of invasive species will continue to be important since removal efforts after invasives are established are rarely fully successful. Finally in lakes where walleye have had many consecutive years of failed recruitment walleye stocking strategies may be necessary to re-establish healthy adult populations capable of natural reproduction. By Mark Luehring GLIFWC Fisheries Biologist Walleye. photo by Eric Engbretson U.S. Fish and Wildlife Service Problems in Mille Lacs Lake continuedContinued from page 1 FondduLacChairwomanKarenDiveralsopoints out that Ojibwe people are place-based deeply rooted in their communities and culture. If the resources are depleted there are few other options for our people to continue our lifeways whether that be harvesting or continuing our cultural and spiritual practices. Tribal harvest For 2015 the tribes walleye allocation in Mille Lacswasonly11400pounds.ThesixWisconsinbands transferredtheirrespectivesharesofthewalleyequota to the Mille Lacs Band last spring. To date Mille Lacs and the Fond du Lac Bands harvested about 10000 pounds of walleye taken by both net and spear. There is also a pool of walleye reserved specifically for the incidental harvest of walleye caught when fishing. State closure On August 2 Minnesota Department of Natural Resources MDNR Commissioner Tom Landwehr announced the closure of the state walleye season in Mille Lacs Lake. Effective as of August 3 at 1000 p.m. no walleye fishing will be allowed until the December 1 ice fishing opener. The July 31 creel survey results indicated the state had exceeded their quota and prompted the closure. FollowingGovernorDaytonsrecommendations a Legislative Working Group on Mille Lacs Lake was formed with six senators six representatives several state commissioners along with Mille Lacs Chief Executive Melanie Benjamin and Karen McQuoid Mille Lacs Area Tourism Council. During an August 4 meeting of the Workgroup State Rep. Tom Hackbarth R-Cedar and Sen. David Tomassoni DFL-ChisholmWorkgroup co-chairs recommended re-opening the sport fishery to ease the financialstressontheareasbusinesses.Commissioner Landwehr responded that this would not be honoring the agreement between the tribes and the state who jointly manage the fishery and would likely be detri- mental to the fishery. Governor Dayton also opposed re-opening the fishery in an August 6 statement. Background Itwasmid-Julythatstatefisheriesmanagersfound themselves faced with an unexpected situationthe walleye bite in Mille Lacs Lake in early July had been exceptional along with increased fishing pressure. Additionally warmer water temperatures increased mortalityofanglerreleasedfish.Thesefactorsresulted in an unanticipated increase in total kill and pushed the state dangerously close to its 2015 quota of 28600 pounds of walleye. AsofJuly16thestatewalleyeharvesthadalready reached 25777 pounds and stakeholders were put on noticeshould the July 31 creel report indicate the state quota had been reached the state walleye fishery on the lake would be closed. In response to the news Governor Dayton called a July 20 meeting with officials from the MDNR the MilleLacsBandtheFondduLacBandandGLIFWC. Attending the meeting on behalf of GLIFWC Execu- tiveAdministratorJamesZornsaidheappreciatedthe quick notice regarding the potential overage and the willingness to abide by the law and close the fishery if the states quota is reached. Its a predetermined plan thatputsthenaturalresourcesfirstZorncommented. He also believes we must look at all the stressors that impact our resources whether it be wild rice moose or walleye. All these resources are impacted by the changing climates invasive species and a number of other contributing factors. We need to look at the bigger picture he says. Fisherymanagersspeculatedontheconditionsthat caused the hot bite in the first two weeks of July that pushedthepoundskilledquicklyupward.Accordingto the MDNR records this is only the second time in 30 years that walleye catch rates in July exceeded catch rates in the second half of June. In July the water tem- perature in Mille Lacs was the third highest on record. AtthatpointMDNRmanagersestimatedthathooking mortality was about 25 percent of released fish. Catch and release mortality numbers are added to the state quota. The tribal net and spear fishery in Mille Lacs are strictly monitored with harvest numbers available daily and individual tribes close their fishery as soon as their quota is met. Both state and tribal fishery managers have been workingdiligentlytounderstandthewell-documented decline in the Mille Lacs walleye population over the lastseveralyears.Whilethehatchesarehealthyyoung walleye are not surviving to become adult walleye. A varietyoffactorsmaybecontributingtohabitatchanges that negatively impact young walleye such as clearer water and a large number of predators. Fall assessments will provide fishery managers the data needed to take another look at the big lakes walleyepopulation.Asafeharvestfigureisdetermined jointly by state and tribal fishery personnel in January. On a brighter note the large 2013 walleye year class appears strong with 10 to 12-inch two-year olds beingrecorded.Itisthestrongestyearclasssince2008. MAZINAIGAN PAGE 4 FALL 2015