Research Document 2021/001

Pre-COSEWIC review of DFO information on Northern Abalone (Haliotis kamtschatkana) along the Pacifc Coast of Canada

By Obradovich, S.G., Hansen, S.C., Zhang, Z., MacNeill, S., Nichol, L.M., Rooper, C.N., St. Germain, C., Curtis, D.L., Waddell, B.J., and Barton, L.L.

Abstract

This review presents updated DFO data on Northern Abalone (Haliotis kamtschatkana) for use in a Committee on the Status of Endangered Wildlife in Canada (COSEWIC) status report. Northern Abalone were first designated as “Threatened” in 1999 by COSEWIC and re-designated as “Endangered” in 2009, and have been legally listed as “Endangered” under the Species At Risk Act since 2009. Northern Abalone occur from Salisbury Sound, Alaska to Bahía Tortugas, Baja California. Genetic studies show no evidence for more than one population of Northern Abalone in BC. Adults generally occupy exposed and semi-exposed coastal waters of less than 10 m depth, but have been observed from the low intertidal zone to 40 m depth. The extent of occurrence in BC waters was estimated at 6,985 km² based on a recently developed habitat suitability index model. The largest recorded shell length for a Northern Abalone in BC is 165 mm. Northern Abalone reach 50 mm in 2-5 years and 100 mm in 6-9 years. Fifty percent of individuals are sexually mature around 50 mm and 100% are mature at 70 mm. Estimated total mortality (0.20 – 0.50 y⁻¹), varied by region and with the presence/absence of Sea Otters (Enhydra lutris). All fisheries for Northern Abalone have been closed since 1990, including commercial, recreational, and First Nations’, but illegal harvest continues to be a major concern for this species. Density time series based on the DFO Northern Abalone Index Site Surveys show that estimated Northern Abalone densities have declined since the start of the time series (1978 in Northern BC), but have shown recent large increases in juvenile (shell length ≥ 20 mm to < 70 mm) densities and small increases in adult (≥ 70 mm) densities in Northern BC. However, the survey is marked by high variability in observed and estimated densities. Densities from a repeated transect survey near Kitkatla, BC, in 2000 and 2016, show similar trends to the densities estimated from the DFO Northern Abalone Index Site Surveys in Northern BC. Patterns are less clear in Southern BC where densities are much lower and have not shown large increases in any size category.

Research Document 2021/001 (PDF, 1,905 KB)

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