We used a number of different data sets and four criteria to evaluate evidence of competition and predation between walleye Sander vitreus and northern pike Esox lucius, muskellunge E. masquinongy, smallmouth bass Micropterus dolomieu, and largemouth bass M. salmoides in northern Wisconsin lakes. The four criteria were as follows: (1) indices of population abundance were inversely related, (2) two species had shared resources or one species preyed on the other, (3) competition or predation was strong enough to produce a measurable effect, and (4) experimental manipulations produced results consistent with the hypothesis of competition or predation. Using these criteria, we identified which species interact most strongly with walleyes, determined the most likely mechanism for interaction (predation, competition, or both), and characterized the effects of walleye stocking on these species. Largemouth bass was the only species that strongly interacted with walleyes: (1) indices of largemouth bass and walleye population abundance were inversely related in lakes with self-sustaining walleye populations; (2) the diet of largemouth bass included juvenile walleyes; (3) walleye growth was positively related to indices of largemouth bass abundance; and (4) survival of stocked walleyes was negatively related to indices of largemouth bass abundance, and indices of largemouth bass abundances increased as an index of walleye stocking intensity increased. A bioenergetics analysis of one lake that was stocked with 39,300 juvenile walleyes, but also has some natural reproduction of walleyes, suggested that the largemouth bass population could consume up to 82,500 juvenile walleyes per year. Our findings suggest that largemouth bass interact strongly with walleyes through predation, that they can limit the survival of stocked walleyes, and that walleye stocking can result in increased largemouth bass populations. Therefore, management goals seeking to simultaneously maximize largemouth bass and walleye populations may be unrealistic.
Catch and Release Muskie Fishing – Let Them Go – Let Them Grow