Research Document - 2015/077

Recovery Potential Assessment for the Salish Sucker In Canada

By Mike Pearson

Abstract

Little information is available on the natural history, abundance, population trends, and habitat use of the Salish Sucker. Consequently there are many uncertainties in this paper. The Salish Sucker is documented from 11 watersheds in Canada and six in Washington State. No populations are known to have been extirpated, but significant reductions in area occupied within many of the watersheds are documented. Insufficient information exists to estimate minimum viable population size, but the Salish Sucker’s life history traits are associated with rapid population growth, resilience to environmental disturbance, and the ability to rapidly (re)colonize habitat. Seasonal hypoxia is the leading threat, affecting up to two-thirds of the more than 180 km of proposed critical habitat in hot dry summers. Habitat destruction, seasonal dewatering, and toxicity are also considered significant threats. Sediment deposition, habitat fragmentation, and introduced predators may be significant but their impacts are poorly understood. Target population sizes vary from 1500 to 5000 adults in the 11 known populations. Estimates of current abundance exist for all or part of seven populations and are far below target populations in all cases. Achieving targets is feasible if the geographic extent of severe hypoxia in proposed critical habitat is reduced.

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