October 12, 2018 at 4:43 p.m.
Muskellunge study looks at age and growth rates
Muskellunge study looks at age and growth rates
The goal of this project is to validate age and growth of muskies without harvesting the fish. Currently, ear bones can be used to determine the age of different species of fish. However, this requires harvesting, or killing, the fish. The desire with muskies, as they are a species prized by many in the state as a top predator and who can take many years to reach maximum size, is to determine age and size in such a way as to keep the fish alive and release it back into the water.
Sass said Minnesota, Michigan and Ontario, Canada are also working on this project. The project is made possible due to the number of muskies that have been stocked and continue to be stocked, into Wisconsin waters.
Each stocked fish is tagged, allowing researchers, guides and other volunteer anglers to determine the age of the fish based on the information associated with that tag. The PIT (passive integrated transponder) tags allow researchers to determine if known-age fish are an accurate predictor of age of a musky.
The goal of the project is to use stocked fish to determine growth rates at various ages and to then be able to use the pectoral and anal fins of live, native fish to determine the age of those fish as well.
The study is being done in collaboration with Dr. Derek Crane and the Hugh C. Becker Foundation. Anal and pectoral fin rays are collected, which is a non-lethal and non-destructive procedure, and validated with stocked known-age muskellunge that have been PIT tagged.
The project is being done on the western part of the state in 16 lakes in the Hayward area. Recapture data has been collected from 2006-2018. Findings have included mean growth potential for fish within the study area, which may be indicative of many other areas in the state. The mean (average) female growth potential was found to be 45 inches, with the mean male growth potential to be somewhat smaller, at 39 inches. Continued stocking of age-0 PIT tagged fish will allow for more information regarding age and growth over time as well as survival estimates, Sass said.
The project is made possible due to the tens of thousands of age-0 hatchery-raised musky tagged and stocked as well as adult musky tagged during spring fyke netting, as well as spring and fall electrofishing.
Sass said one of the best contributing factors to the success of this project will be the number of guides and anglers who have volunteered to assist and who conscientiously record length and sex of all recaptured tagged muskies they catch, accounting for over 11 percent of all information gathered during the life of the project thus far.
The DNR does this as well, but the job is made much easier and much more information has been gathered due to the many on-the-water anglers and guides who gather this information from the fish they catch and report it back to the department.
Beckie Gaskill may be reached via email at [email protected].
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