Effects of Climate Change on North American Inland Fishes
Special Issue of Fisheries, July 2016
The full issue will be available for open-access download for one month starting on or around June 30.
Physiological Basis of Climate Change Impacts on North American Inland Fishes
J. E. Whitney, Robert Al-Chokhachy, David B. Bunnell, Colleen A. Caldwell, Steven J. Cooke, Erika J. Eliason, Mark Rogers, Abigail J. Lynch, and Craig P. Paukert. Fisheries 41(7):332-345.
Global climate change is altering freshwater ecosystems and affecting fish populations and communities. Underpinning changes in fish distribution and assemblage-level responses to climate change are individual-level physiological constraints. In this review, we synthesize the mechanistic effects of climate change on neuroendocrine, cardiorespiratory, immune, osmoregulatory, and reproductive systems of freshwater and diadromous fishes. Observed climate change effects on physiological systems are varied and numerous, including exceedance of critical thermal tolerances, decreased cardiorespiratory performance, compromised immune function, and altered patterns of individual reproductive investment. However, effects vary widely among and within species because of species, population, and even sex-specific differences in sensitivity and resilience and because of habitat-specific variation in the magnitude of climate-related environmental change. Research on the interactive effects of climate change with other environmental stressors across a broader range of fish diversity is needed to further our understanding of climate change effects on fish physiology.
- Neuroendocrine: Climate change can result in chronically elevated environmental stressors that challenge the neuroendocrine system of some fishes, elevating metabolic costs and decreasing growth and survival.
- Cardiorespiratory: Climate change can expose some fishes to thermal conditions outside of their species- or population-specific optimal thermal range for aerobic scope, but for other species or populations thermal conditions will become more suitable and aerobic scope will increase.
- Immune: Climate change may elicit hyperactive or suppressive responses from fish immune systems, both of which may result in compromised immune function; these immunocompromised fish have to cope with a climate-altered environment containing altered disease prevalence, pathogenicity, and novelty.
- Iono- and osmoregulatory: Rising salinities associated with climate change will disrupt the hydromineral balance of fishes with narrow salinity tolerances, decreasing their abundance in assemblages while leaving fishes with broader salinity tolerances less affected.
- Reproduction: Deviations from optimal temperatures, salinity, and dissolved oxygen will influence reproductive timing and investment of fishes, thus potentially reducing reproductive output and success.
Contact: James Whitney, Department of Biology, Pittsburg State University, [email protected]
Climate Change Effects on North American Inland Fish Populations and Assemblages
Abigail J. Lynch, Bonnie J. E. Myers, Cindy Chu, Lisa A. Eby, Jeffrey A. Falke, Ryan P. Kovach, Trevor J. Krabbenhoft, Thomas J. Kwak, John Lyons, Craig P. Paukert, and James E. Whitney. Fisheries 41(7):346-361.
Climate is a critical driver of many fish populations, assemblages, and aquatic communities. However, direct observational studies of climate change impacts on North American inland fishes are rare. In this synthesis, we (1) summarize climate trends that may influence North American inland fish populations and assemblages, (2) compile 31 peer-reviewed studies of documented climate change effects on North American inland fish populations and assemblages, and (3) highlight four case studies representing a variety of observed responses ranging from warmwater systems in the southwestern and southeastern United States to coldwater systems along the Pacific Coast and Canadian Shield. We conclude by identifying key data gaps and research needs to inform adaptive, ecosystem-based approaches to managing North American inland fishes and fisheries in a changing climate.
- Climate change is altering abundance, growth, and recruitment of some North American inland fishes, with particularly strong effects noted on coldwater species.
- Evidence of evolutionary responses to climate change is currently limited but includes earlier migration timing and hybridization in some coldwater species.
- Shifts in species’ ranges are changing the structure of some North American fish assemblages, resulting in novel species interactions, such as altered predator–prey dynamics.
- Complex interactions between climate change and other anthropogenic stressors make separating and understanding the relative magnitude of climate effects challenging.
- To sustainably manage North American inland fishes in the face of climate change, research should move beyond distributional studies, ground-truth projected impacts, increase geographic and taxonomic representation, document sources of resilience, implement monitoring frameworks to document changes in assemblage dynamics, and provide better decision-support tools.
Contact: Abigail J. Lynch, USGS, National Climate Change and Wildlife Science Center, [email protected]
Identifying Alternate Pathways for Climate Change to Impact Inland Recreational Fishers
Len M. Hunt, Eli P. Fenichel, David C. Fulton, Robert Mendelsohn, Jordan W. Smith, Tyler D. Tunney, Abigail J. Lynch, Craig P. Paukert, and James E. Whitney. Fisheries 41(7):362-373.
Fisheries and human dimensions literature suggests that climate change influences inland recreational fishers in North America through three major pathways. The most widely recognized pathway suggests that climate change impacts habitat and fish populations (e.g., water temperature impacting fish survival) and cascades to impact fishers. Climate change also impacts recreational fishers by influencing environmental conditions that directly affect fishers (e.g., increased temperatures in northern climates resulting in extended open water fishing seasons and increased fishing effort). The final pathway occurs from climate change mitigation and adaptation efforts (e.g., refined energy policies result in higher fuel costs, making distant trips more expensive). To address limitations of past research (e.g., assessing climate change impacts for only one pathway at a time and not accounting for climate variability, extreme weather events, or heterogeneity among fishers), we encourage researchers to refocus their efforts to understand and document climate change impacts to inland fishers.
- Climate change impacts on fishers arise from changes to fish, changes to other environmental conditions, and possibly from climate change mitigation and adaptation efforts.
- Changes to nonfish pathways can change fishers’ behaviors that disrupt existing equilibriums between fish stocks and fishing effort.
- In some U.S. States, fish species targeted by recreational fishers appear to have changed from coldwater to warmwater species since 1991.Managing these impacts requires an understanding of connections and feedbacks within and between ecological and social systems.
- Future research should focus on impacts from climate variability including extreme weather events and impacts to subpopulations of fishers (e.g., southern U.S. fishers).
Contact: Len Hunt, Ontario Ministry of Natural Resources and Forestry, Centre for Northern Forest Ecosystem Research, [email protected]
Adapting Inland Fisheries Management to a Changing Climate
Craig P. Paukert, Bob A. Glazer, Gretchen J. A. Hansen, Brian J. Irwin, Peter C. Jacobson, Jeffrey L. Kershner, Brian J. Shuter, James E. Whitney, and Abigail J. Lynch. Fisheries 41(7):374-384.
Natural resource decision makers are challenged to adapt management to a changing climate while balancing short-term management goals with long-term changes in aquatic systems. Adaptation will require developing resilient ecosystems and resilient management systems. Decision makers already have tools to develop or ensure resilient aquatic systems and fisheries such as managing harvest and riparian zones. Because fisheries management often interacts with multiple stakeholders, adaptation strategies involving fisheries managers and other partners focused on land use, policy, and human systems, coupled with long-term monitoring, are necessary for resilient systems. We show how agencies and organizations are adapting to a changing climate in Minnesota and Ontario lakes and Montana streams. We also present how the Florida Fish and Wildlife Commission created a management structure to develop adaptation strategies. These examples demonstrate how organizations and agencies can cope with climate change effects on fish and fisheries through creating resilient management and ecological systems.
- Adapting to climate change requires managing habitats, landscapes, and ecosystems to develop resilient fisheries.
- Resilient management is as important as resilient ecosystems.
- Managing for resilient systems requires collaboration between fisheries management and a wide range of partners focused on land use, policy, and human systems.
- Monitoring and managing for long-term change is needed.
Contact: Craig Paukert, USGS, Missouri Cooperative Fish and Wildlife Research Unit, Department of Fisheries and Wildlife Sciences, University of Missouri, [email protected]