Managing the Nation's Fish Habitat at Multiple Spatial Scales in a Rapidly Changing Climate
The goal of this project is to provide guidance to aquatic resource managers and decision makers for managing this habitat and their associated aquatic communities. Our proposed research will inform management and conservation efforts performed at multiple spatial scales, ranging from the regional prioritization of critical aquatic habitats to local population dynamics of ecologically and economically valuable fish species.
An important first step in managing the nation’s fish habitat is a comprehensive assessment of the current state of habitat at national, regional and local scales. Successful management of aquatic habitat will also require a capacity to forecast changes in habitat as result of future changes in climate, land-use, and other natural and anthropogenic factors. Successful conservation and management will need to determine what are the critical habitat and resource strategies to conserve in order to maintain freshwater biodiversity, freshwater fisheries and ecosystem function in the future.
Smallmouth bass (Micropterus dolomieu, SMB) is a broadly distributed, economically important species in the USA and Canada. Although previous research has suggested that projected climate warming may allow SMB to thrive beyond their current northern distribution, little research has been devoted to the population-level effects of climate change on warm-water fishes, including SMB.
We modelled the impacts of projected climate change on growth of stream-dwelling SMB along a north–south gradient in the central USA. Using downscaled regional projections from three global climate models, we generated scenarios for thermal habitat change for four populations (in Oklahoma, Missouri, Iowa and Minnesota) and used bioenergetics simulations to estimate prey consumption and growth under future projections. Bioenergetics simulations showed that prey consumption is expected to increase in all populations with moderate stream warming (2–3 °C). Growth potential is predicted to increase by 3–17% if not limited by food availability with stream warming by 2060 and was most pronounced for southern populations. For each 1 °C increase in stream temperature, SMB consumption would be expected to increase by about 27% and growth would increase by about 6%.
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 recommended for effective management and conservation.