Drivers of Growth, Migration, and Bioaccumulation in Target Fish Species: Implications for a Changing Regional Climate

A changing regional climate in the northeastern US has significant implications for the fundamental bioenergetics of fish species, with implications for their population resilience and their ability to provide critical ecosystem services, with particularly important implications for tribal communities. For example, warming soil and water temperatures may increase the accumulation of toxic methylmercury (MeHg) in aquatic food webs and in freshwater and migratory fishes. High levels of MeHg currently generate most of the fish consumption advisories across the northeast US, and climate-driven increases carry substantial economic and health risks. However, climate impacts Hg dynamics via multiple pathways ranging from impacts on ecosystem biogeochemistry up to individual fish physiology, growth, and behavior. Further, a changing climate will interact with other major trajectories of environmental change, in complex and often indeterminate ways. To address these important information gaps, and working with our cooperators at the USGS Conte Anadromous Fish Research Center, Dartmouth College Toxic Metals in the Environment Laboratory, and the US Forest Service Mercury-Sulfur Initiative, we are currently engaged in four major lines of research:

1) Synthesis: We are developing a searchable database of science products associated with climate change and bioaccumulation and drafting the synthesis paper that is particularly focused on management and adaptation options.

2) Experiments: We are conducting a set of laboratory experiments testing the additive and interactive effects of multiple stressors (high temperatures, food limitation, crowding), along with direct induction of stress response (via cortisol implants) on growth, growth efficiency and Hg bioaccumulation in native eastern Brook Trout (Salvelinus fontinalis).

3) Field studies: Field studies involve two components. First, we are sampling multiple ecosystem components (water, aquatic invertebrates, fish) in brook trout and Atlantic salmon streams spanning a north-south gradient and representing a wide range of physical and chemical conditions from northern Vermont to West Virginia. Second, in a set of intensively studies sites in Massachusetts, we will be looking at growth, habitat use, and bioaccumulation in cold and warm sites at the individual fish level.

4) Tribal engagement: We are assessing bioaccumulation and water quality impairment associated with a changing climate in the context of the unique role of migratory fishes in tribal nations and communities of the Northeast. We will work with both NECASC and NRS tribal liaisons to conduct workshops and assessments on this topic.