May 31, 2013
Conservation Concerns — Despite the popularity of muskie angling throughout the Midwest and eastern Canada, little is known about the sub-lethal and lethal effects of fish release. Researchers in eastern Ontario, with assistance from Muskies Canada volunteer anglers, conducted a field-based study and captured 77 muskellunge ranging in size from 22.5 to 52 inches.* Blood samples from all fish were collected for physiological analyses and a subsample of 30 fish were radio-tagged to assess behavioral disturbances and survival of fish handled with and without air exposure.
Blood sampling and short-term radio-tracking revealed little physiological and behavioral disturbances during capture and after release. Fish exposed to air during periods of warmer water temperatures experienced heightened stress compared to individuals handled without air exposure. All radio-tagged muskellunge (15 per treatment) survived the catch-and-release event, and seven recaptures were reported.
A 30 percent mortality estimate is the only other figure that exists in the scientific literature. It was derived in a lab study where additional stressors imposed on the fish likely over-inflated the true estimate. The present study's estimate of 0 mortality, though impossible to achieve in a recreational fishery, is probably closer to the true level of mortality. Certainly, mortalities occur due to handling, but rates likely are negligible. The lack of differences — physiological, behavioral, and survival — between handling treatments suggests that the handling techniques used by many specialized muskie anglers are appropriate for the conservation of muskie fisheries.
*Landsman, S. J., H. J. Wachelka, C. D. Suski, and S. J. Cooke. 2011. Evaluation of the physiology, behaviour, and survival of adult muskellunge (Esox masquinongy) captured and released by specialized anglers. Fisheries Research 110:377-386.