Effects of water velocity and substrate composition on foraging efficiency of an endangered benthic cyprinid, Nooksack dace (Rhinichthys cataractae subsp. cataractae)
- 138 Downloads
To identify the mechanisms whereby substrate embeddedness and water velocity influence Nooksack dace (Rhinichthys cataractae subsp. cataractae) prey capture efficiency, we stocked dace in foraging arenas with varying substrate types over a range of velocities (0, 25, 35 cm s−1) and measured their efficiency of prey capture. We stocked a known number of mayfly (Ephemeroptera), black fly (Simuliidae), and chironomid (Chironomidae) larvae in each foraging arena and measured the number of invertebrates remaining after 12 h. Foraging efficiency for mayflies was significantly reduced over unembedded substrate, and capture efficiency for all taxa decreased at higher velocities in all substrate treatments. Decreased foraging efficiency indicates that higher velocities may degrade the accuracy of prey strikes, that dace may alter their foraging behavior to reduce energy expenditures at higher velocities, that there is less available foraging habitat within their velocity tolerances, or that invertebrates become more interstitial at higher velocities. Although it is difficult to unambiguously discriminate among these mechanisms with our experimental design, our results suggest that dace are adapted to foraging in low-velocity micro-habitats within the boundary layer, and that their foraging efficiency may be sensitive to both the refuging ability of their prey and velocity and turbulence at their focal point.
KeywordsBenthic fish Embeddedness Boundary layer Capture success Foraging habitat
This work was funded by the British Columbia Ministry of Environment, Fisheries and Oceans Canada, and a Natural Sciences and Engineering Research Council of Canada discovery grant. We would also like to thank the reviewers for their careful review and comments on this manuscript.
- Anderson, P. G., B. R. Taylor & G. C. Balch, 1996. Quantifying the effects of sediment release on fish and their habitats. Canadian Manuscript Reports of Fisheries and Aquatic Sciences 2346: 110 p + Append.Google Scholar
- Avery-Gomm, S., 2013. Determining the impacts of hydrological drought on endangered Nooksack dace (Rhinichthys cataractae) at the population and individual level: Implications for minimum environmental flow requirements. M.Sc. Thesis, Department of Zoology, The University of British Columbia.Google Scholar
- Champion, J. M., 2016. Determining the effects of sediment deposition on the growth, survival, and foraging efficiency of the endangered Nooksack dace (Rhinichthys cataractae sp. cataractae), and on the abundance, distribution, and community structure of their invertebrate prey. M.Sc. Thesis. Department of Zoology, The University of British Columbia.Google Scholar
- COSEWIC, 2007. COSEWIC assessment and update status report on the Nooksack Dace Rhinichthys cataractae ssp. In Canada, Committee on the Status of Endangered Wildlife in Canada. Ottawa. Vii + 27 pp. (www.sararegistry.gc.ca/status/status_e.cfm).
- Davis, J. A., 1986. In Limnology in Australia. De Deckker, P. & W. D. Williams (eds). Academic Publishers, Hingham: 263–276.Google Scholar
- Gordon, N. D., T. A. McMahon & B. A. Finlayson, 1992. Stream Hydrology: and Introduction for Ecologists. Wiley, New York: 526.Google Scholar
- Hill, J. & G. D. Grossman, 1987. Home range estimates for three North American stream fishes. Copeia 2:376–380.Google Scholar
- Inglis, S. D., S. M. Pollard & M. L. Rosenau, 1997. Distribution and habitat of Nooksack dace (Rhinichthys sp.) in Canada. Fish and Wildlife Management, B.C. Ministry of Environment, Lands and Parks, Surrey, B.C. Reg. Fish. Report 237.Google Scholar
- McPhail, J. D., 1996. Status of the Nooksack Dace, Rhinichthys sp., in Canada. Report to the Committee on the Status of Endangered Wildlife in Canada (COSEWIC). Canadian Wildlife Service, Ottawa.Google Scholar
- Owens, P. N., R. J. Batalla, A. J. Collins, B. Gomez, D. M. Hicks, A. J. Horowitz, G. M. Kondolf, M. Marden, M. J. Page, D. H. Peacock, E. L. Petticrew, W. Salomons & D. H. Trustrum, 2005. Fine-grained sediment in river systems: environmental significance and management issues. River Resource Applications 21: 693–717.CrossRefGoogle Scholar
- Pearson, M. P., 1999. The biology and management of the Salish sucker and Nooksack dace. In Proceedings of a Conference on the Biology and Management of Species and Habitats at Risk, Kamloops, B.C. 15–19 February 1999.Google Scholar
- Pearson, M. P., 2004. The ecology, status and recovery prospects of Nooksack dace (Rhinichthys cataractae ssp.) and salish sucker (Catostomus Sp.) in Canada. PhD. Thesis, Institute for Resources, Environment, and Sustainability, The University of British Columbia.Google Scholar
- Pearson, M. P., T. Hatfield, J. D. McPhail, J. S. Richardson, J. S. Rosenfeld, H. Schreier, D. Schluter, D. J. Sneep, M. Stejpovic, E. B. Taylor & P. M. Wood, 2008. Recovery Strategy for the Nooksack Dace (Rhinichthys cataractae) in Canada. Species at Risk Act Recovery Strategy Series, Fisheries and Oceans Canada, Vancouver vi + 29 pp.Google Scholar
- R Development Core Team, 2015. R: a language and environment for statistical computing. R Foundation for Statistical Computing, Vienna.Google Scholar
- Smith, G. H. S. & A. P. Nichols, 2005. Effect on flow structure of sand deposition on a gravel bed: results from a two-dimensional flume experiment. Water Resources Research 41: 1–12.Google Scholar