Ceded Territory Sc enc Lac Vieux Desert Lake­ — On the road to recovery Into the Aquatic Vegetation—Technical Report Age-1 walleye opportunistically consume both invertebrates and fish, with fish being more nutritionally valuable.When present, young perch appear to be the preferred species followed by other soft-rayed fishes (e.g., shiners). Centrarchids (like bluegills) are typically consumed when soft-rayed fishes are unavailable, a common occurrence at the southern edge of walleye distribution. Mayfly nymphs and amphipods are an important part of the diet if the abundance of prey fish is limited. In mid-June, Great Lakes Indian Fish and Wildlife Com- mission(GLIFWC),MoleLake, and Wisconsin Department of Natural Resources (WDNR) biologists collected young walleye around the perimeter of Lac Vieux Desert Lake. Dur- ing that survey, a subsample of age-1 fish (most likely stocked extended growth walleye, 53 in total) were measured, weighed, and sampled for their gut con- tents. We provide a summary of relative abundance, condition, and commonly consumed prey items below. Age-1walleyewerecaught at a rate of 23.7 per mile during the survey, which is greater than the average spring survey catch rate of 11.2 per mile observed in other Wisconsin waters stocked with extended growth wall- eye (Kampa and Hatzenbeler 2009). Survival based on the Serns (1983) fall survey index indicates that 40% of the extended growth walleye (~20,000 fish) stocked last fall survived the winter. The survey results suggest that enough walleye from the Summary Young walleye eat both invertebrates and fish. In Lac Vieux Desert (LVD) Lake, 85% of the young walleye sampled in June 2017 had fish in theirdiet(thevaluablefooditem),nearly100%hadinvertebratesand/orfish in their stomachs, and 80% of these fish were in normal or above normal condition (i.e., a healthy weight). Moreover, we captured 23.7 young walleye per mile in June (by comparison the average across other lakes is 11.2 walleye/mile for spring surveys) and 12.8 walleye per mile in September (compared 9.9 walleye/ mile for fall surveys in naturally reproducing waters). Collectively, this indicates young walleye came out of winter in good condition, fed on invertebrates and fish over the summer, and an above aver- age number of fish survived to their second fall. This is a huge step towards recovering walleye stocks in LVD Lake, but there are several hurdles (e.g., establishing natural reproduction) to overcome in the future. Lac Vieux Desert walleye rehabilitation partnership LacVieuxDesertLakeisa4,300acreflowageinthe1842cededterritory that is located within the Wisconsin River basin on the border of Michigan (Gogebic Co.) and Wisconsin (Vilas Co.). The walleye population of Lac Vieux Desert Lake has experienced a well-documented decline in abundance and recruitment over the past decade. To remedy this issue, a cooperative walleye rehabilitation work group was formed that included Lac Vieux Desert Tribe (LVD), Sokaogan Mole Lake Tribe (MLK), Great Lakes Indian Fish and Wildlife Commission (GLIFWC), Lac Vieux Desert Lake Association,Wisconsin Department of NaturalResources(WDNR),andMichiganDepartmentofNaturalResources (MiDNR). Together, this group aims to increase the abundance of adult wall- eye to at least three fish/acre over the next several years. fall 2016 stocking (51,754 large fingerlings by WDNR) survived over the winter to potentially produce a good year-class in the future. However, these fish must survive another 2-3 years before they start contributing to the mature spawning population. GLIFWC and WDNR will continue to conduct fall surveys to help estimate survival of young fish over the summer. Approximately 85% of age-1 walleye consumed fish, with the most com- mon identifiable species being bluegill (n=10) followed by yellow perch (n=1) (unidentifiable fish = 31). Age-1 walleye were consuming invertebrates and fish, with almost 100% of the sampled fish having prey items in their stomachs (Table 1; Figure 1). Over 80% of age-1 fish had a relative weight (Wr) greater than 100, which means their body condition was above normal relative to walleye in other lakes inWisconsin (Figure 2). Overall, this indicates that most of the age-1 walleye came out of winter in good condition and started to feed on fish and invertebrates. Although there are many more hurdles to overcome in the next few years, we are one-step closer to recovering walleye stocks in LVD Lake. Please contact aaronshultz@glifwc.org for more information.­ —Mark Luehring, Adam Ray, Joe Dan Rose, Ben Michaels and Aaron Shultz, GLIFWC Inland Fisheries Staff Figure 2. Relative weight (Wr–weight of each sampled fish compared to a length-specific reference weight) of age-1 walleye (n=53) in Lac Vieux Desert Lake in June 2017. The equation used to calculate Wr for walleye was derived from 228 populations and over 48‚000 walleye in Wisconsin (Sass et al. 2004). A Wr greater than 100 indicates that the fish are in good condition or plump relative to other walleye in this region. Figure 1. Photo of prey items consumed by an age-1 walleye in Lac Vieux Desert Lake in June 2017. Table 1. Condition of age-1 fish captured in Lac Vieux Desert Lake in June 2017. Relative weight (Wr) compares the weight of each sampled fish to a length-specific reference weight. The equation used to calculate Wr for walleye was derived from 228 populations and over 48‚000 walleye in Wisconsin (Sass et al. 2004). A Wr greater than 100 indicates that the fish are in good condition or plump relative to other walleye in this region. Age Sample Total Length (mm) mean ± SE; Weight (g) mean ± SE; Wr mean ± SE; % stomachs Size range range range with prey 1 53 210.0 ± 2.3; 172.7-241.3 81.5 ± 2.9; 108.8 ± 1.3; 98 37-131 89.9 - 122.9 MAZINA’IGAN PAGE 12 • SCIENCE •