true

ISRA FACTSHEETS

NORTH AMERICAN PACIFIC

ISRA FACTSHEETS

NORTH AMERICAN PACIFIC

Haida Gwaii ISRA

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Haida Gwaii ISRA

Haida Gwaii

Summary

Haida Gwaii is located in British Columbia, Canada. This area sits on the continental shelf of northern Pacific Canada between the mainland and the archipelago of Haida Gwaii. The benthos comprises carbonate sediments (coarse shell debris) and rocky and gravel substrates with patches of unique glass sponge reefs. The area is influenced by highly dynamic oceanographic conditions, including predominantly semi-diurnal tidal currents, wind-driven subtidal currents, and high freshwater inflow. Within this area there are: undefined aggregations (North Pacific Spiny Dogfish Squalus suckleyi).

Haida Gwaii

Haida Gwaii

DESCRIPTION OF HABITAT

Haida Gwaii is located in British Columbia, Canada. This area sits on the continental shelf of northern Pacific Canada between the mainland and the archipelago of Haida Gwaii. It covers part of Hecate Strait and Queen Charlotte Sound with Vancouver Island lying to the southeast. The benthos comprises carbonate sediments (coarse shell debris) and rocky and gravel substrates (Carey et al. 1995). The area overlaps with patches of unique glass sponge reefs (Hannah et al. 2019).

The area is influenced by highly dynamic oceanographic conditions, including predominantly semi-diurnal tidal currents, wind-driven subtidal currents, and high freshwater inflow (Dodimead 1980; Cummins et al. 2022). Seasonal wind patterns drive circulation and productivity, with boreal summer northwest winds deflecting surface waters offshore, which results in deep, nutrient-loaded, coastal water being forced into the shallow sounds, while in winter, prevailing southeast winds tend to restrain upwelling and drive downwelling (Dodimead 1980; Cummins et al. 2022).

This Important Shark and Ray Area is benthic and pelagic and is delineated from inshore and surface waters (0 m) to 285 m based on the depth range of Qualifying Species in the area.

CRITERION C

SUB-CRITERION C5 – UNDEFINED AGGREGATIONS

Haida Gwaii is an important area for undefined aggregations of one shark species.

Between 1998–2025, the International Pacific Halibut Commission (IPHC) conducted annual longline surveys during summer months (May–September) across nearshore and offshore waters from Southern California to Alaskan waters (Gulf of Alaska, Aleutian Islands, and Bering Sea; IPHC 2026a). Surveys were conducted at ~1,200 stations each year at depths of 15–503 m. Longlines consisted of 4–8 skates (longline units) with 96–104 hooks per skate with soak times between 5–24 hours (IPHC 2026b). Non-halibut species were counted either as subsample counts (20% observations, the majority for sharks) and whole-set counts (100% observations). The average (± standard deviation) number of hooks per set across the surveys was 643 ± 119, while the number of hooks observed per set (i.e., where bycatch was recorded) was 207 ± 120. Nominal catch-per-unit-effort (CPUE) was estimated as the number of individuals caught per 100 hooks per hour.

Across IPHC surveys, North Pacific Spiny Dogfish were recorded in 15,525 sets during longline surveys, 2,384 (15.4%) of which were recorded inside this area between the months of May–August at depths 10–285 m (IPHC 2026a). For this species, individuals were counted in subsamples (20% of the observations) in 12,132 sets (78.1% of the total). The third-highest mean CPUE of North Pacific Spiny Dogfish in the region (Southern California to Alaska) was reported from this area (mean = 0.76 individuals/100 hooks/hour; range = 0.01–6.9) compared to adjacent areas in the region (mean CPUE outside the area = 0.41 individuals/100 hooks/hour; range = 0.006–13.3). Multiple individuals (>10) were recorded in 1,632 sets (68.4% of the sets with the species captured inside this area) with 424 individuals being the maximum number recorded in a single set (mean = 44.2 individuals/set). High abundances of North Pacific Spiny Dogfish have been associated with aggregations and are mostly related to seasonal increases in abundance of prey species (Beamish 1992).

Additional information is required to understand the nature and function of these aggregations.

Haida Gwaii

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