Potential Effects of Climate Change on Growth, Prey Consumption, and Population Dynamics of Stream-Dwelling Smallmouth Bass in the Central U.S

We examined the population-level impacts of projected climate change on stream-dwelling smallmouth bass (Micropterus dolomieu, SMB) along a north-south gradient in the central U.S.  Using down-scaled regional climate projections from three global climate models, we generated scenarios for thermal habitat change for four populations ranging from the north  (e.g., Minnesota) to the south (e.g., Oklahoma).  We then used bioenergetics simulations to estimate growth and prey consumption under future climate projections.  Bioenergetics simulations showed that future growth potential is predicted to increase by 4 to 19% if not limited by food availability with moderate warming (2-3°C) by 2060.  Potential increases in stream temperatures and growth are greatest for southern populations.  With continued warming, growth potential would decrease where stream temperatures more frequently exceed 27°C.  Prey consumption is expected to increase in all populations with stream warming. Corresponding with changes in SMB growth, populations may experience shifts in spawning times and population growth rates.  Due to implications for species interactions, population performance and regulation of local fisheries, a better understanding of how SMB populations will respond to climate change is vital for management and conservation.