Yellow Perch Population Assessment in Southwestern Lake Michigan July 1, 2014- June 30, 2015

To evaluate yellow perch population demographics and identify factors that continue to limit recruitment our objectives were to: 1) Monitor the age and size structure of adult yellow perch on a seasonal basis, 2) estimate the age and, if possible, sex composition of angler-harvested Dubet al.7yellow perch, 3)determine the relative abundance of demersal age-0 yellow perch and the availability of their macroinvertebrate and zooplankton prey, 4)monitor the abundance and diet of juvenile yellow perchon a seasonal basis, and 5) collect high resolution substrate data in the nearshore with focus on historical yellow perch spawning grounds.Results of this project will help strengthen management strategies for thisimportant sport fish species. These findings will be incorporated into yellow perch management decisionsthroughmulti-agency collaboration, which reflects a changing philosophy in the Great Lakes fisheries from jurisdictional to lake-wide management.Illinois Department of Natural Resources Division of Fisheries F-123-R-21unpublishednot peer reviewedOpe

Yellow Perch Population Assessment in Southwestern Lake Michigan July 1, 2013 – June 30, 2014

Reports on progress and results of the following study objectives: monitor the adult yellow perch population on a seasonal basis; determine the age composition of angler-caught yellow perch; sample demersal age-0 yellow perch and their food resources in nearshore waters; sample juvenile (age-0 through age-3) yellow perch in nearshore waters; survey nearshore substrate with a focus on historical yellow perch spawning grounds; data analysis and report preparation.Illinois Department of Natural Resources Division of Fisheries F-123-R-20unpublishednot peer reviewedOpe

Yellow Perch Population Assessment in Southwestern Lake Michigan July 1, 2011 – June 30, 2012

Reports on progress and results for the following project objectives: Improve annual assessments of the yellow perch spawning population, spring spawning assessment; Improve annual assessments of the yellow perch spawning population, fall assessment; Develop angler-caught age and sex distribution; Sample pelagic age-0 yellow perch and their food resources in offshore waters; Sample demersal age-0 yellow perch and their food resources in nearshore waters; Sample juvenile (age-0 through age-2) yellow perch in nearshore waters; Data analysis and report preparation.Illinois Department of Natural Resources, Division of Fisheries F-123-R-18unpublishednot peer reviewedOpe

Lake Michigan Offshore Reef Bathymetric Mapping July 1, 2017 – June 30, 2018

The return of self-sustaining lake trout populations in Lake Michigan is a long-standing rehabilitation goal of the Illinois Department of Natural Resources (IDNR) Division of Fisheries and the Great Lakes Fishery Commission. Annual stocking of juvenile lake trout at sites lakewide since 1965 has largely resulted in minimal success until recently. Patterson et al. (2016) evaluated Illinois’s fall spawning assessment data and found similar abundances of mature lake trout in recent years at unstocked Waukegan Reef compared to Julian’s Reef, the only site within southern management units stocked annually. This result, along with findings of high relative catches (~50%) of unmarked ‘wild’ lake trout adults at both reefs in recent years has prompted the need for fall spawning assessments at additional offshore reefs in Illinois waters of Lake Michigan. Identifying and monitoring previously unsampled lake trout spawning sites is critical for developing effective stocking and harvest regulations for this important, native sport fish. Attaining geo-referenced bathymetry data and developing accurate maps of potential spawning reefs is an essential next step facilitating the planning and implementation of lake trout spawning assessments at unsampled reefs in Illinois. Thus, the objectives of this project were to 1) document the location and extent, 2) collect bathymetry data, and 3) create contour and three-dimensional bathymetric maps of five offshore reefs in Illinois’ portion of Lake Michigan. Results of this project will aid IDNR in measuring the extent of lake trout rehabilitation success and identify important potential spawning habitats that may be targeted for future protection and/or enhancement.U.S. Fish and Wildlife Service F-65-R-32 and F-196-R-1Illinois Department of Natural Resources Division of Fisheriesunpublishednot peer reviewedOpe

Utilizing External Features and a Consensus Field-Based Approach to Determine Sex of Lake Michigan Yellow Perch

<p>Understanding fluctuations in population sex ratios is important for evaluating the effects of changes in population demographics and for making informed management decisions. The Yellow Perch <i>Perca flavescens</i>, an important sport fish in Lake Michigan, undergoes sexually dimorphic growth, likely resulting in differing vulnerabilities to angler harvest. However, sex ratio data from angler-harvested fish have not been collected because of the handling time and intrusiveness of the methods for distinguishing sexes. We utilized digital photographs of the urogenital papilla (UGP) from known-sex Yellow Perch to establish a method whereby UGP shape could be used to rapidly, accurately, and inexpensively determine the sex of Yellow Perch. Overall, 88.1% of Yellow Perch examined were assigned to the correct sex, and the sex ratio estimate of 48:87 (female : male) did not differ significantly from the known sex ratio of 46:89. Classification success was not affected by fish sex, TL, or month of collection. Our results demonstrate accurate, rapid, inexpensive, and nonlethal applicability of this method across a wide range of sizes and geographic and temporal scales. Applying this methodology will permit accurate sex ratio estimates for angler-harvested Yellow Perch, which can be used to better understand harvest composition and its implications for management.</p> <p>Received February 17, 2017; accepted June 9, 2017 Published online August 31, 2017</p