Nicolas W.R. Lapointe,a*† Steven J. Cooke,a* Jack G. Imhof,b* Daniel Boisclair,c‡ John M. Casselman,d‡ R. Allen Curry,e‡ Otto E. Langer,f‡ Robert L. McLaughlin,g‡ Charles K. Minns,h‡ John R. Post,i‡ Michael Power,j‡ Joseph B. Rasmussen,k‡ John D. Reynolds,l‡ John S. Richardson,m‡ William M. Tonnn‡

aFish Ecology and Conservation Physiology Laboratory, Department of Biology and Institute of Environmental Science, Carleton University, 1125 Colonel By Dr., Ottawa, ON K1S 5B6, Canada.

bTrout Unlimited Canada, Room 270 Alexander Hall, University of Guelph, Guelph, ON N1G 2W1, Canada.

cDepartment of Biological Sciences, University of Montreal, Montreal, QC, Canada.

dDepartment of Biology, Queen’s University, Kingston, ON K7L 3N6, Canada.

eCanadian Rivers Institute, University of New Brunswick, Fredericton, NB E3B 5A3, Canada.

fBritish Columbia Marine Conservation Caucus, 6691 Dunsany Place, Richmond, BC V7C 4N8, Canada.

gDepartment of Integrative Biology, University of Guelph, Guelph, ON N1G 2W1, Canada.

hDepartment of Ecology and Evolutionary Biology, University of Toronto, 25 Willcocks St., Toronto, ON M5S 3B2, Canada.

iDepartment of Biological Sciences, University of Calgary, 2500 University Drive NW, Calgary, AB, T2N 1N4, Canada.

jDepartment of Biology, University of Waterloo, 200 University Ave. W., Waterloo, ON N2L 3G1, Canada.

kDepartment of Biological Sciences, University of Lethbridge, 4401 University Dr., Lethbridge, AB T1K 3M4, Canada.

lEarth to Ocean Research Group, Department of Biology, Simon Fraser University, Burnaby, BC V5A 1S6, Canada.

mDepartment of Forest and Conservation Sciences, University of British Columbia, Vancouver, BC V6T 1Z4, Canada.

nDepartment of Biological Sciences, University of Alberta, Edmonton, AB T6G 2E9, Canada.

Received June 3, 2013. Accepted October 23, 2013.

Environmental Reviews, 2014, 22(2): 110-134, https://doi.org/10.1139/er-2013-0038

Freshwater ecosystems and the fisheries they support are increasingly threatened by human activities. To aid in their management and protection, we outline nine key principles for supporting healthy and productive ecosystems based on the best available science, including laws of physics and chemistry apply to ecology; population dynamics are regulated by reproduction, mortality, and growth; habitat quantity and quality are prerequisites of fish productivity; connectivity among habitats is essential for movements of fishes and their resources; freshwater species and their habitats are tightly linked to surrounding watersheds; biodiversity can enhance ecosystem resiliency and productivity; global processes affect local populations; anthropogenic stressors have cumulative effects; and evolutionary processes can be important. Based on these principles, we provide general recommendations for managing and protecting freshwater ecosystems and the fisheries they support, with examples of successful implementation for each strategy. Key management strategies include engage and consult with stakeholders; ensure that agencies have sufficient capacity, legislation, and authority to implement policies and management plans; define metrics by which fisheries resources and management success or failure will be measured; identify and account for threats to ecosystem productivity; adopt the precautionary approach to management; embrace adaptive management; implement ecosystem-based management; account for all ecosystem services provided by aquatic ecosystems; protect and restore habitat as the foundation for fisheries; and protect biodiversity. Ecosystems are complex with many intertwined components and ignoring linkages and processes significantly reduces the probability of management success. These principles must be considered when identifying management options and developing policies aiming to protect productive freshwater ecosystems and sustainable fisheries.

Here we review the best available science to describe nine key ecological principles governing the functioning of freshwater ecosystems and the fisheries they support. To develop each of these principles, existing literature was broadly reviewed, and a mix of classic papers, more recent reviews, and empirical studies related to each principle was cited. These principles must be accounted for to protect sustainable and productive fisheries and healthy aquatic ecosystems. Adherence to these principles is essential to the success of national and regional fisheries management plans, aquatic biodiversity protection plans, and associated policies, laws, and governance structures, along with monitoring programs. These principles are founded on our understanding of fish ecology, fisheries science, aquatic ecology, limnology, landscape ecology, evolutionary biology, conservation science, and watershed hydrology. Additionally, we discuss key components of successful fisheries management plans based on the history (including successes and failures) of freshwater fisheries management in Canada and beyond. The principles outlined here are generalized, though they are particularly relevant to both north temperate regions and those that are vast and diverse in terms of peoples, physiography, and ecology.

In seeking to outline the requirements for healthy and productive freshwater ecosystems, we draw upon our collective experience in Canada and beyond. Recent changes to Canadian fisheries policies have motivated responses by the public and the scientific community ( Reynolds et al. 2012 ; Cooke and Imhof 2012 ; de Kerchove et al. 2013 , Hutchings and Post 2013 ), yet a broad contemporary scientific assessment of what is required to manage freshwater fisheries resources is lacking. A template of the core ecological concepts underlying sound fisheries policies, based on the best available science ( Sullivan et al. 2006 ), will support policy and management decisions and the design of monitoring programs to evaluate the success of these actions.

Freshwater fisheries are undervalued for their vital contributions to food security and biodiversity ( Welcomme et al. 2010 ; Beard et al. 2011 ; Welcomme 2011 ). Inland fisheries are part of an integrated community, dependent on biodiversity for their resiliency to natural variation and anthropogenic disturbance. The concept of ecosystem health is comprehensive, including biotic and abiotic components along with chemical and nutrient cycles, as well as the services provided to humans ( Rapport et al. 1998 , 1999 ). A healthy and productive aquatic ecosystem may, therefore, be defined as one that is resilient to disturbance and maintains attributes of ecosystem structure and function such as habitat, species composition, genetic diversity, and production at levels similar to those observed in the absence of modern human activities. Conversely, perturbed ecosystems have one or more of these attributes compromised. Productive fisheries depend on healthy ecosystems, and the protection of fisheries requires the ongoing maintenance of ecosystem health.

In this paper Top of page Introduction Key ecological principles « Integration, application, and future direction References

Key ecological principles