Dynamic rates of Freshwater Drum near the northern extent of their range: evidence of environment-recruitment relationships

Abstract

Estimation of population dynamic rates is one of the most established and widely recognized components of modern fisheries management, yet this information is rarely collected for non-threatened native species. Pejorative views of native, underrepresented fish have contributed to a dearth of research and management efforts for these species. We sought to reduce this knowledge gap for one of the most widely distributed freshwater fish in North America, Freshwater Drum Aplodinotus grunniens (Rafinesque, 1819). We calculated estimates of growth, mortality, and recruitment from lotic environments in the most northern drainage of their range (i.e., Hudson Bay). Our estimates of growth (K, Brody growth coefficient) are similar to studies as far south as Alabama, USA. Estimates of annual mortality (4–10%) and longevity (62 years) are consistent with latitudinal trends observed in the standing literature. We found evidence of recruitment variability (recruitment variability index = 0.53), with a positive association between growing season degree days and year-class strength. Hydrologic variables of discharge during the cold season and rise rate were found to have negative relationships to recruitment. This research gives insight into factors regulating Freshwater Drum populations and will provide useful information for the management and conservation of this widespread but underappreciated species.