13. Southern Strait of Georgia/San Juan Islands

Site Overview

The waters surrounding the Canadian Gulf Islands and the US San Juan Islands are locally and traditionally referred to as the Salish Sea. Despite the demarcation of national territories, British Columbia’s southern Strait of Georgia and Washington State’s northern Puget Sound are an inseparable ecosystem, critical to a variety of marine life. This marine realm is shallow with a high-relief, rocky bottom around the islands. It also has tidal flats and a large river delta on the mainland coast at the mouth of the Fraser River, which is a major freshwater and nutrient source for the region. This inland sea features very strong currents and intense mixing, transporting nutrients and dispersing larvae.

Eelgrass (Zostera spp.) and kelp beds offer spawning and foraging habitats for fish, birds and mammals. Sponges and hydrocorals can be found at various locations on the seafloor. The rocky reef habitat in this area is inhabited by an array of rockfish species, including bocaccio (Sebastes paucispinis), yellowtail (S. flavidus), copper (S. caurinus) and Puget Sound rockfish (S. emphaeus). Bottom-dwelling lingcod (Ophiodon elongates), wolf eel (Anarrhichthys ocellatus), cabezon (Scorpaenichthys marmoratus) and kelp greenling (Hexagrammos decagrammus) also frequent this area. In recent years, there has been great concern over declining groundfish stocks in this area (Federal Register 1999, Musick et al. 2000). Salmon migrate through here and their presence supports a large number of salmon-eating mammals. The Fraser River/Georgia Basin region produces 10 million sockeye salmon (Oncorhyncus nerka) annually (DFO 1999b).

There are breeding colonies of several marine bird species in this area. Marbled (Brachyramphus marmoratus) and ancient (Synthliborampus antiquus) murrelets flock to feast on the forage fish this area provides, following winter breeding in Mexico and southern California. Cormorants (Phalacrocorax spp.), puffins (Fratercula spp.), many shorebirds and marine waterfowl nest and feed here as well. Black brant geese (Branta bernicla) in British Columbia are part of a larger Pacific population composed of several smaller stocks wintering along the Pacific coastline from Alaska to Mexico after breeding in the Arctic (Sedinger et al. 1994). During the last two to three decades, the Pacific Flyway population has generally fluctuated between 120,000–150,000 birds.

Resident killer whales are joined by sea otters (although rare), seals and sea lions as mammals that rely on this rich ecosystem. Gray whales come here to feed as well, following mating and calving in Baja California, Mexico. The population of harbor seal has grown since the 1970s in response to increased protection under the Marine Mammal Protection Act of 1972 and other conservation actions.

Though not a major fishing ground, this priority area experiences high anthropogenic impacts because of the dense human populations along the coast and the expanding marine tourism industry.