Wisconsin Fishery Project
Evaluation of methods used to estimate population metrics for adult muskellunge in northern Wisconsin lakes
June 2014 - June 2018
- Wisconsin Department of Natural Resources
The goals of this research are to: 1) provide an improved method for predicting muskellunge abundance when recent population estimates are not available; 2) evaluate temporal variation in adult muskellunge abundance within Wisconsin lakes and 3) obtain estimates of survival and growth based on mark-recapture information collected on trend lakes. Specific objectives will be to determine if: 1) alternative methods can be used to explain greater variation in the abundance of adult muskellunge within northern Wisconsin lakes than the current linear model that relies solely on lake surface area as a predictor variable; 2) estimates of adult muskellunge abundance are relatively consistent over time, such that estimates that are 3 to 4 years old could still be used to represent abundance within an individual lake; 3) marking muskellunge with passive integrated transponders (PITs) can be used to estimate rates of growth, mortality, and recruitment of adult muskellunge as well as sex-specific estimates of gear selectivity and catchability in selected trend lakes and 4) rates of growth and mortality calculated from ages estimated using nonlethal structures such as scales and fin rays are similar to those obtained using mark-recapture of fish implanted with PITs. To complete these objectives, Fisheries Analysis Center (FAC) and the Wisconsin Cooperative Fishery Research Unit (WICFRU) will work with WDNR to obtain existing estimates of adult muskellunge abundance and other abiotic and biotic variables that will be used to develop models to predict adult muskellunge abundance. Additionally, FAC and WICFRU will assist with scheduled mark-recapture surveys on the 4 trend lakes. Muskellunge will be marked with PITs in addition to the fin clips already used to mark fish and scales and/or fin rays will be collected for age estimation. Staff from FAC and WICFRU will assist or fully conduct annual mark-recapture assessments for up to 3 years on at least two trend lakes; this additional sampling will allow us to assess temporal variation in adult abundance, obtain additional estimates of mortality and growth, and to compare gear selectivity and catchability between sexes.