Abstract
Physical obstructions are becoming increasingly recognized as major factors influencing the migrations, population structures, spawning success and recruitment of freshwater organisms. This paper presents a simple but effective method, intended for use by environmental managers, government agencies and conservation bodies, of rapidly assessing and prioritizing barriers to the migrations of diadromous fishes and lampreys for passage improvements. A prioritization matrix was developed using information on fish stock status, the passage efficiency of fishes at individual structures, the distance from the tidal limit and the passability of downstream barriers, and the quantity and quality of habitat upstream of each structure. Importantly, the ‘Likelihood of access’ was incorporated into the matrix to account for passage efficiency at downstream barriers. Barriers ranked as the highest priority for passage improvements were those characterized by poor fish stocks upstream, low passage efficiency, easy passage from downstream, and a large quantity and high quality of habitat upstream. Prioritization of migration barriers should ensure that access improvements are targeted to achieve optimum benefits.
This is a preview of subscription content, log in via an institution to check access.
References
Baras, E., and M.C. Lucas. 2001. Impacts of man’s modifications of river hydrology on the migration of freshwater fishes: A mechanistic perspective. Ecohydrology and Hydrobiology 1: 291–304.
Copp, G.H., L. Vilizzi, J. Mumford, G.V. Fenwick, M.J. Godard, and R.E. Gozlan. 2009. Calibration of FISK, an invasiveness screening tool for nonnative freshwater fishes. Risk Analysis 29: 457–467.
Cowx, I.G. 1998. Review of fish passage facilities in the UK: Issues and options for future development. In Fish migration and fish bypasses, ed. M. Jungwith, S. Schmutz, and S. Weiss, 220–235. Oxford: Fishing News Books, Blackwell Science.
Cowx, I.G., J.P. Harvey, R.A. Noble, and A.D. Nunn. 2009. Establishing survey and monitoring protocols for the assessment of conservation status of fish populations in river special areas of conservation in the UK. Aquatic Conservation: Marine and Freshwater Ecosystems 19: 96–103.
FAO (Food & Agriculture Organisation of the United Nations). 2002. Fish passes—Design, dimensions and monitoring. Rome: FAO.
Kemp, P.S., and J.R. O’Hanley. 2010. Procedures for evaluating and prioritising the removal of fish passage barriers: A synthesis. Fisheries Management and Ecology 17: 297–322.
Larinier, M. 1998. Upstream and downstream fish passage experience in France. In Fish migration and fish bypasses, ed. M. Jungwith, S. Schmutz, and S. Weiss, 127–145. Oxford: Fishing News Books, Blackwell Science.
Larinier, M. 2008. Fish passage experience at small-scale hydro-electric power plants in France. Hydrobiologia 609: 97–108.
Limburg, K.E., and J.R. Waldman. 2009. Dramatic declines in North Atlantic diadromous fishes. BioScience 59: 955–965.
Lucas, M.C., D.H. Bubb, M.H. Jang, K. Ha, and J.E.G. Masters. 2009. Availability of and access to critical habitats in regulated rivers: Effects of low-head barriers on threatened lampreys. Freshwater Biology 54: 621–634.
Moser, M.L., J.M. Butzerin, and D.B. Dey. 2007. Capture and collection of lampreys: The state of the science. Reviews in Fish Biology and Fisheries 17: 45–56.
Nunn, A.D., J.P. Harvey, R.A.A. Noble, and I.G. Cowx. 2008. Condition assessment of lamprey populations in the Yorkshire Ouse catchment, north-east England, and the potential influence of physical migration barriers. Aquatic Conservation: Marine and Freshwater Ecosystems 18: 175–189.
Nunn, A.D., G.H. Copp, L. Vilizzi, and M.G. Carter. 2010. Seasonal and diel patterns in the migrations of fishes between a river and a floodplain tributary. Ecology of Freshwater Fish 19: 153–162.
Raven, P.J., N.T.H. Holmes, F.H. Dawson, and M. Everard. 1998. Quality assessment using River Habitat Survey data. Aquatic Conservation: Marine and Freshwater Ecosystems 8: 477–499.
Renaud, C.B. 1997. Conservation status of Northern Hemisphere lampreys (Petromyzontidae). Journal of Applied Ichthyology 13: 143–148.
Tricarico, E., L. Vilizzi, F. Gherardi, and G.H. Copp. 2010. Calibration of FI-ISK, an invasiveness screening tool for nonnative freshwater invertebrates. Risk Analysis 30: 285–292.
White, E.M., and B. Knights. 1997. Dynamics of upstream migration of the European eel, Anguilla anguilla (L.), in the Rivers Severn and Avon, England, with special reference to the effects of man-made barriers. Fisheries Management and Ecology 4: 311–324.
Acknowledgments
The authors would like to thank the Environment Agency for partly funding both case studies, and Steve Axford, Barry Byatt, Paul Frear, Tim Jacklin, Mike Lee, Alex Lumsdon, Joel Rawlinson, Darren Rollins, Dan Smallwood and Neil Trudgill for conducting independent prioritizations. The prioritization matrix was developed, with permission, from an early draft of the (unpublished) Environment Agency’s National Fish Pass Prioritization Project. The views expressed in the paper are those of the authors and not necessarily those of the Environment Agency. The paper benefited greatly from the constructive criticism of two anonymous referees.
Author information
Authors and Affiliations
Corresponding author
Rights and permissions
About this article
Cite this article
Nunn, A.D., Cowx, I.G. Restoring River Connectivity: Prioritizing Passage Improvements for Diadromous Fishes and Lampreys. AMBIO 41, 402–409 (2012). https://doi.org/10.1007/s13280-012-0281-6
Received:
Revised:
Accepted:
Published:
Issue Date:
DOI: https://doi.org/10.1007/s13280-012-0281-6