Harvest trends, growth and longevity, and population dynamics reveal traditional assumptions for redhorse ( Moxostoma spp.) management in Minnesota are not supported

Six species of redhorse sucker (family Catostomidae, genus Moxostoma ) occur in Minnesota, and all are harvested recreationally, particularly by bowfishing. Currently, this group is managed collectively as a single stock, yet contemporary data on life history, harvest levels, and population dynamics have not been analyzed. For years 2018–2021, we collected 31 silver redhorse Moxostoma anisurum , 16 shorthead redhorse M. macrolepidotum , 14 greater redhorse M. valenciennesi , and 1 golden redhorse M. erythrurum from Minnesota, and used otoliths (earstones) to estimate age. We found lifespans that exceed previously reported maximum ages for three of four species (17 years, M. erythrurum ; 27 years, M. valenciennesi ; 41 years M. anisurum ). We also observed four Minnesota bowfishing tournaments from 2019 to 2022 and analyzed number and composition of the harvest. We found that redhorse tournament bowfishing harvest is significantly increasing, with proportion of the total harvest represented by redhorse also increasing. We also analyzed pooled, statewide gill net catch survey data from 1993 to 2020 for redhorse to quantify effects of density dependence and several abiotic factors. We found that density dependence at the statewide level is ubiquitous across four redhorse species in Minnesota and evidence of species-specific carrying capacities, but the abiotic factors we tested do not explain significant variation in population growth rates. Collectively, our findings indicate that assumptions underlying the current collective, single stock management strategy for Minnesota redhorse are not supported by life history traits, harvest trends, and population dynamics.