Interrelationships among Production, Density, Growth, and Mortality of Northern Pike in Seven North-Central Minnesota Lakes

Abstract

Abstract Secondary production can be an important indicator of performance for a fish population. In this study we examined how density, growth, and mortality operated together to alter production of northern pike Esox lucius in seven north–central Minnesota lakes. Estimated densities of age-2 and older northern pike were 3–59 fish/ha and estimated production rates were 0.77–8.31 kg·ha−1·year−1 across the seven lakes. The relationship between density and production among the lakes was curvilinear, production being moderated by slow growth rates at high northern pike densities. The negative relationship between indices of individual fish growth and production was counterintuitive and demonstrated the overwhelming influence of density on northern pike population dynamics. Relationships between total mortality and either density or production were not apparent. Recreational fisheries in Minnesota appear to be harvesting much of the annual production of northern pike. Yet many northern pike populations are ma...