Contact Selectivity for Four Species Sampled with North American Standard Gill Nets

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The American Fisheries Society (AFS) has recommended standard gears and methods for collecting North American freshwater fish data, but selectivity of these gears, including gill nets, is poorly described for most species. We calculated contact selectivity for species commonly collected with AFS standard gill nets in lakes and reservoirs of North America, including Black Bullhead Ameiurus melas, Channel Catfish Ictalurus punctatus, Walleye Sander vitreus, and Yellow Perch Perca flavescens. The normal selectivity curve provided the best fit to empirical catch data for all species. Inclusion of a tangle factor improved model fit for Black Bullhead, Channel Catfish, and Walleye, indicating that tangling is an important means of capture for these species. Channel Catfish were more susceptible to tangling than the closely related Black Bullhead, likely because larger Channel Catfish are more vulnerable to tangling by spines in the smallest meshes, whereas Black Bullhead in the same meshes were wedged. Failure to include a tangle factor for Channel Catfish and Walleye would have underestimated peak length of captured fish by 80 and 40 mm, respectively. Tangling was not an important factor in Yellow Perch capture. Total selectivity curves for each species captured with the AFS standard gill net were calculated, and relative selectivity values are provided as correction factors for size-selectivity bias. Our correction factors and modeled selectivity curves for Channel Catfish, Walleye, and Yellow Perch corroborate previous studies that modeled selectivity of the AFS standard gill net for Channel Catfish, Walleye, and Yellow Perch, but our study provided novel information on Black Bullhead. Improved selectivity information for the AFS standard gill net may help to promote further voluntary adoption of AFS standard gears and methods.

Publication Title

North American Journal of Fisheries Management





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Taylor & Francis