Office of Applied Science

Evaluating Vulnerability to Angling and Hooking Mortality in WI Lake Sturgeon Fisheries

The goal of this project is to quantify hooking mortality rates of lake sturgeon in order to better inform Fisheries Management biologists and the public on best angling practices and to ensure sustainability of Wisconsin’s hook-and-line lake sturgeon fisheries.

TIMELINE FUNDING Key Points Launch: July 2018 Federal Aid in Sportfish Completion: June 2021 Restoration »» The waters in the state of Wisconsin have some of the largest self-sustaining populations of lake sturgeon in the DNR PARTNER BUREAU Fisheries Management world, and these waters support valuable recreational and tribal lake sturgeon fisheries. Wisconsin has some of the largest self-sustaining populations of lake sturgeon in the world, and our waters support valuable »» The goal of this project is to quantify recreational and tribal lake sturgeon fisheries. Lake sturgeon hooking mortality rates of lake sturgeon to better inform Fisheries Management fisheries in the state are carefully regulated and monitored biologists and the public on best angling to prevent over-exploitation. However, little is known about practices and to ensure sustainability of hooking mortality rates for lake sturgeon. Wisconsin’s hook-and-line fisheries. A short-term mortality study will be conducted on lake sturgeon »» We plan to identify areas of lake in hook-and-line fishing waters in 2019. We plan to identify sturgeon concentration and quantify areas of lake sturgeon concentration and quantify the probability the probability of mortality for lake of mortality for lake sturgeon after an angling event. We will sturgeon after an angling event under different conditions (e.g., gear types and evaluate sturgeons’ post-angling stress response by measuring angling seasons). circulating levels of glucose and lactate in the blood and by quantifying reflex action mortality parameters. All sturgeon »» We will use a combination of reflex will be held and monitored over the short term (24-48 hours) action mortality parameters, blood until recovery or mortality is determined. A subset of fish will stress indicators and post-angling be monitored with externally mounted acoustic tags to track activity monitoring to quantify the physiological impact of angling stress physiological activity after an angling event. on sturgeon.

SPOKESPERSON Stephanie Shaw, PhD Inland Lakes Research Scientist [email protected] (715) 892-0375 Office of Applied Science

Muskellunge Age and Growth Study

Muskellunge age and growth are difficult to determine without harvesting fish, yet this information is important for managing muskellunge and evaluating stocking practices. In addition to other factors, this study examines non-destructive means for determining muskellunge age and growth.

TIMELINE DNR PARTNER BUREAU Launch: July 2009 Fisheries Management Key Points Completion: June 2019 »» We have collected samples from EXTERNAL STAKEHOLDERS muskellunge non-destructively FUNDING Anglers & fishing guides of WI Federal Aid in Sportfish throughout their native range to age Restoration first-time captures and to validate the age of known-age fish. »» We implanted thousands of fingerling Muskellunge are the State Fish of Wisconsin and support important muskellunge from the Governor Thompson Hatchery with Passive sport, trophy and tribal fisheries. Although many muskellunge Integrated Transponder (PIT) tags and populations in Wisconsin are self-sustaining, Wisconsin DNR hatcheries stocked them in northwestern WI lakes. also enhance many populations through stocking. We will evaluate stocking success and determine growth of known-age fish The majority of anglers in Wisconsin release muskellunge to enhance over time. trophy potential, making estimates of age and growth difficult to obtain. This study examines: non-destructive means for determining »» Staff, fishing guides and anglers have muskellunge age and growth; the contribution of stocked muskellunge teamed up to measure growth, check tags, and PIT tag additional adult to overall muskellunge fisheries; the effects of catch-and-release on muskellunge captured during surveys muskellunge mortality and size structure; and improved methodologies or angling events. for estimating muskellunge population size. »» Volunteer participation is critical. We welcome more fishing guides and anglers to join the study. We hope to expand our efforts beyond northwestern Wisconsin.

SPOKESPERSON Greg G. Sass, PhD Fisheries Research Team Leader [email protected] (715) 891-1875 Office of Applied Science

Understanding panfish trends and responses to angling and predator populations in Wisconsin lakes

This study assesses trends in Wisconsin’s panfish populations and their responses to angler exploitation and predator management to quantify their impacts on panfish abundance and size structure.

TIMELINE DNR PARTNER BUREAU Launch: July, 2019 Fisheries Management Completion: June, 2022 EXTERNAL STAKEHOLDERS Great Lakes Indian Fish and FUNDING Key Points Federal Aid in Sportfish Wildlife Commission »» Significant knowledge gaps exist in our Restoration USGS understanding of how panfish populations respond to regulation changes, panfish removals Panfish are some of Wisconsin’s most abundant and popular or promotion of predators. This project aims to fill in those gaps using population surveys, sport fish. Bluegill, pumpkinseed, black crappie and yellow perch angler creels, and experimental field studies. comprised 75% of the total fish harvested from Wisconsin lakes in »» We expect that population trends will vary the past decade. among panfish species (e.g., bluegill and black crappie populations will be stable, while yellow Currently, panfish management is complicated by unexplored perch populations decline). relationships between population characteristics (abundance, »» We hypothesize that panfish anglers will size structure), anglers, predators and environmental influences. maintain catch and harvest rates across large This project seeks to disentangle these issues by comprehensively gradients in panfish abundance (i.e., will be characterizing panfish populations, their responses to panfish and hyperstable), and that anglers will be selective for larger panfish when fishing lakes with gamefish management, and angler exploitation. smaller bag limits.

We will use a combination of standardized survey data and angler »» This project will also analyze environmental variables like water temperature, lake size, creel data to examine trends in population abundances, catch and water clarity on yellow perch recruitment, rates, and harvest rates, and test for relationships with angler offering predictions for their future behavior or predator abundance and management practices. Our sustainability. results will be used to offer suggestions to address management »» We predict that predator management (e.g., issues. Additionally, this study will expand upon an experimental walleye stocking, largemouth bass regulations) will be related to panfish size structure and regulations project currently underway to understand how abundance under some conditions and will exploitation affects panfish populations, helping managers to evaluate how predator management could be implement appropriate regulations to promote fishery quality and effectively used to promote robust and resilient panfish populations. sustainability into the future.

SPOKESPERSON Zachary Feiner Natural Resources Research Scientist [email protected] (608) 221-6331 Office of Applied Science Evaluating sustainable muskellunge exploitation in the Ceded Territory of Wisconsin

This study will develop a statistical catch-at-age model to estimate sustainable exploitation rates for muskellunge in the Ceded Territory of Wisconsin and reevaluate the safe harvest model that is currently used to determine tribal muskellunge spearfishing quotas.

TIMELINE DNR PARTNER BUREAU Launch: July, 2019 Fisheries Management Completion: June, 2022 EXTERNAL STAKEHOLDERS University of Wisconsin-Stevens Key Points FUNDING »» The goals of this project are to develop Federal Aid in Sportfish Point, Wisconsin Cooperative Key Points Restoration Fishery Research Unit, Great a muskellunge statistical catch-at- Lakes Fish and Indian Wildlife age model for the Ceded Territory of Commission Wisconsin to estimate a sustainable exploitation rate to maintain the fishery. Muskellunge are Wisconsin’s state fish, and an important »» The current muskellunge safe harvest species to recreational and tribal fisheries. Currently, model and associated limited reference the limit reference point for muskellunge exploitation in point (27%) likely overestimates the Ceded Territory of Wisconsin for angling and tribal tribal quotas on small lakes and spearfisheries is based on dated information and likely underestimates tribal quotas on large overestimates a sustainable limit reference point. lakes. Reevaluation of the current muskellunge safe harvest model may This research addresses a critical need for a statistical catch- allow for the appropriate distribution at-age model using the best available muskellunge data to of tribal muskellunge harvest to sustain evaluate the current limit reference point and inform an this fishery. adjustment if needed. »» This research is critically needed to ensure the sustainability and quality The statistical catch-at-age model will provide information of muskellunge in the joint Ceded on what management actions may be necessary to sustain Territory of Wisconsin fisheries. muskellunge populations in the joint tribal and angling fisheries in the Ceded Territory of Wisconsin. Muskellunge in northern Wisconsin are an economically and culturally important resource, therefore it is vital that we determine a sustainable exploitation rate and revisit the current safe harvest model.

SPOKESPERSON Stephanie Shaw Natural Resources Research Scientist [email protected] (715) 892-0375