The Nooksack dace is a small (<15 cm) stream-dwelling cyprinid (minnow). It is considered a subspecies of the widespread and common longnose dace Rhinichthys cataractae. Within Canada it is known from four lowland streams in British Columbia’s Fraser Valley. The global distribution includes approximately 20 additional streams in north-west Washington. The Nooksack dace is extirpated from some tributaries in Canadian watersheds where it was abundant in the 1960s. Its current status in Washington State is unknown. Nooksack dace are strongly associated with riffle habitats and the proportion of riffle in a reach is the strongest predictor of their presence. Young-of-the-year fish require shallow pool habitats in close proximity to the riffles inhabited by adults. Home range size is typically very small (<50 m of channel) although a few individuals venture for at least hundreds of metres. This suggests that clusters of riffles may contain semi-isolated subpopulations and that metapopulation dynamics may be important at the watershed scale. Nooksack dace populations appear to be most vulnerable to seasonal lack of water, habitat loss to drainage activities, sediment deposition, and riffle loss to beaver ponds. Introduced predators are widespread in the range but probably have minimal impacts on Nooksack dace because of lack of habitat overlap. Hypoxia and toxicity are significant threats in some sections of at least one watershed, but do not threaten the species throughout its range. Attributes of critical habitat for Nooksack dace have been defined but not mapped or designated in this recovery strategy. Recovery of Nooksack dace populations is both technically and biologically feasible. It will involve the establishment and/or maintenance of sufficient high quality riffle habitat in each creek to maintain a population. The goal of recovery is to ensure long-term viability of Nooksack dace populations throughout their natural distribution in Canada.
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. 2007. Recovery Strategy for the Nooksack Dace (Rhinichthys cataractae) in Canada. Ministry of Environment. BC Recovery Strategy (Species at Risk)
Topic: Recovery Planning
Keywords: SARA, species recovery, species at risk, bc, recovery planning
Scientific Name: Rhinichthys sp. 4
English Name: Nooksack Dace
Other Identifier: Fisheries and Oceans Canada
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