Barkley Sound (BC075)
Description du site
Barkley Sound is located on the exposed southwestern coastline of Vancouver Island, British Columbia. The town of Ucluelet lies to the north side of the sound and the small village of Bamfield is in an inlet on the southern side. The sound is a prominent topographic feature that has low shores backed by rugged mountains, and is exposed to the open Pacific Ocean. A dominant feature of this site is the Broken Group Islands, a component of Pacific Rim National Park Reserve, which consists of approximately 100 islands and rocks in the central part of the sound. The outermost islands of the sound are fully exposed to the force of the ocean, while in the lee of the outer islands and in the inner part of the sound, there are protected channels and quiet bays. Forests are dominated by Sitka Spruce, Western Hemlock, and Western Red Cedar. Rocky headlands broken by sand or gravel beaches make up most of the shoreline. Northern Sea Lions often frequent the reefs around the islets.
Barkley Sound hosts six species of birds of global significance and two breeding species of national significance. In 1982, intensive surveys revealed 3,406 Marbled Murrelets in the sound, which is at least 1% of the North American population for this nationally threatened species. However, surveys in 1992-1993 revealed a population decrease of 41% compared to the previous decade. In summer, murrelets congregate in inshore and outer channel habitats, particularly within the islands of the Broken Group and Trevor Channel.
During spring migration, several different bird species congregate at this site. Globally significant numbers of Surf Scoters gather in the sound, with 52,000 recorded in 1989. Mew Gull concentrations reached 3% of their North American population, with 1,542 being recorded in spring migration. In the spring of 1979, a maximum number of Western Grebes (4,900 or 4% of the global population) were documented in the sound. Migrating Surfbirds are seen in very large numbers, reaching a maximum of 4,500 birds, or over 6% of the world population. Large flocks of Surf Scoters, gulls and grebes gather in the sound to feed on spawning herring. Birds are most abundant in areas such as the Macoah Passage where herring spawn is concentrated. In 1989, 74,148 waterbirds were recorded in the sound, further indicating the rich avifauna of the sound.
Most of the Canadian Brandt's Cormorants breed in Barkley Sound. In 1982 there were 51 pairs, a decline from a high of 150 pairs in 1970 that bred in six locations along the west coast of Vancouver Island. Brandt's Cormorants also stage in the sound in late summer, with peaks of 1,200 birds (mostly coming from outside Canada), which is more than 1% of the global population. Other breeding birds include 42 pairs of Black Oystercatchers (4% of the Canadian population) nesting on 13 islets, and 728 pairs Glaucous-winged Gull (almost 3% of the Canadian population).
Enjeux de conservation
Oil spills, and disturbance from boaters and other visitors are potential problems. A portion of the proposed site, protected as a component of Pacific Rim National Park is in relatively protected and accessible waters. Since it is close to Ucluelet and Bamfield and is a popular destination for tourists and vacationers, recreational boat traffic and kayakers could be a source of disturbance to flocks of seaducks and other avifauna. Some people approach too closely and/or land on the islands during the breeding season and thus disturbing seabirds. The decline in Marbled Murrelet numbers may be because of a loss of old-growth forest nesting habitat, but other possible factors are oil spills, gill-net fishing or oceanographic changes.
Menaces Potencielles ou Existantes
Status de Protection