Muskellunge Management: Fifty Years of Cooperation Among Anglers, Scientists, and Fisheries Biologists
Integrating Voluntary Angler Catch Reports with Mark-Recapture Data to Model a Muskellunge Fishery in Clear Fork Reservoir, Ohio
Kevin S. Page and Edward Lewis
Abstract.—Voluntary angler catch reports can be a valuable tool for monitoring fisheries. In Ohio, angler reports have been integral for monitoring long-term trends in Muskellunge Esox masquinongy fisheries. The integration of angler catch data into mark–recapture methods has been increasingly advocated as a means of improving estimates of fish population metrics. A mark–recapture study was conducted to evaluate population demographics of Muskellunge during 1981–2006 at Clear Fork Reservoir, Ohio. Each spring, adult Muskellunge (N = 4,134; ≥609 mm) were collected and marked using trap nets. Anglers reported catches of marked Muskellunge (i.e., resightings) between marking events. A total of 4,134 Muskellunge were marked (609–1,245 mm), 1,227 (29.7%) were recaptured in trap nets, and anglers reported catching an additional 884 marked fish (21.4%). Recaptures and angler catch reports were analyzed using a joint mark–recapture, tag-resighting, and tag-recovery model (Barker model) within program MARK to estimate the probability of survival, angler catch, and emigration from the reservoir. Mean estimates of Muskellunge annual survival were 0.62 (SD = 0.22) for males and 0.71 (SD = 0.23) for females. The probability of Muskellunge being caught by anglers varied across years, and factors influencing angling vulnerability were unclear. The model tended to underestimate catch-and-release rates based on estimates derived from all angler catch reports, yet the trends toward greater release rates were generally consistent with expectations. The model suggested that emigration from the reservoir was constant over time, with any given Muskellunge having a 0.13 probability of emigrating annually. Angler catch reports provided the data necessary to make valuable inferences about the fishery that would not otherwise be available from survey netting only.