UPDATED STATUS OF THE OLYMPIA OYSTER Ostrea lurida Carpenter, 1864 IN BRITISH COLUMBIA, CANADA, AND MANAGEMENT RESPONSE TO ENSURE CONSERVATION
The Olympia oyster, Ostrea lurida Carpenter, 1864, is the only oyster native to Canadas Pacific coast. An initial status report was prepared for the Committee for the Status of Endangered Wildlife in Canada (COSEWIC) in 2000, which led to the species being designated as Special Concern. Under the Canadian Species At Risk Act (SARA), species can be listed as Extinct, Extirpated, Endangered, Threatened, Species of Special Concern or Data Deficient. Olympia oysters were listed as a Species of Special Concern under SARA in 2003.
As a result, the Minister of Fisheries and Oceans Canada (DFO) was responsible for the development of a management plan that would ensure that Olympia oysters would not become either Threatened or Endangered. The plan was developed collaboratively with other government agencies and stakeholders and identified five objectives to ensure the recovery and sustainability of the species and was completed and posted to the SARA Public Registry in 2009. The overarching management objective was to ensure maintenance of the relative abundance of Olympia oysters at index sites over the next six years (2008-2013). Five categories of actions were identified to focus annual work planning. These were: 1) Protection (identification of map reserves); 2) Management (zero allowable harvest and mitigate threats from invasive species); 3) Research (focus on invasive species and diseases); 4) Monitoring and Assessment (identification of index sites and assessment methodologies); 5) Outreach and Communication (work with stakeholders to raise awareness of SARA and Olympia oysters). Since that time, DFO staff at the Pacific Biological Station in Nanaimo B.C. have been undertaking activities and research to meet the objective of the plan.
In 2009, funding provided by DFO and COSEWIC allowed for intensive field surveys for verification of historic records, abundance surveys of potential index sites and collection of voucher specimens to be held at the Royal British Columbia Museum.
Olympia oysters are widespread and abundant in the sounds and inlets of the west coast of Vancouver Island, where they form intertidal reefs in multiple locations. These natural reefs are no longer regularly seen in Puget Sound or on the US Pacific coast, and have generated considerable interest, particularly for restoration groups. Abundance is greatest in Barkley Sound and generally decreases with increasing latitude. Olympia oysters are abundant at sites in Sooke Basin and Gorge Waterway, both of which drain into the Strait of Juan de Fuca. In the Strait of Georgia, Olympia oysters are widespread at low densities and tend to be cryptic, attached to the undersurface of intertidal rocks, except in special circumstances where artificial habitat provides standing water (Nanaimo) or in areas modified for oyster culture (e.g., Ladysmith Harbour). Olympia oyster populations in Johnstone and Queen Charlotte Straits and the north coast mainland inlets are extremely rare and associated with lagoon habitats. The northernmost verified record is at Gale Passage, Dufferin Island, at approximately 52N. They are absent from the Queen Charlotte Islands (Haida Gwaii).
While most historic threats have been mitigated or are of limited scope (overfishing, pulp mill pollution, exotic drills and diseases), the recent establishment of European green crab, Carcinus maenas (Linnaeus, 1758), on the west coast of Vancouver Island presents a new and thus-far unquantified threat. Future work will focus on further verification of known sites supporting Olympia oyster populations, spatial analyses of habitat characteristics to predict potential suitable sites for verification, and surveys to monitor changes in abundance over time at specific index sites.
As a result, the Minister of Fisheries and Oceans Canada (DFO) was responsible for the development of a management plan that would ensure that Olympia oysters would not become either Threatened or Endangered. The plan was developed collaboratively with other government agencies and stakeholders and identified five objectives to ensure the recovery and sustainability of the species and was completed and posted to the SARA Public Registry in 2009. The overarching management objective was to ensure maintenance of the relative abundance of Olympia oysters at index sites over the next six years (2008-2013). Five categories of actions were identified to focus annual work planning. These were: 1) Protection (identification of map reserves); 2) Management (zero allowable harvest and mitigate threats from invasive species); 3) Research (focus on invasive species and diseases); 4) Monitoring and Assessment (identification of index sites and assessment methodologies); 5) Outreach and Communication (work with stakeholders to raise awareness of SARA and Olympia oysters). Since that time, DFO staff at the Pacific Biological Station in Nanaimo B.C. have been undertaking activities and research to meet the objective of the plan.
In 2009, funding provided by DFO and COSEWIC allowed for intensive field surveys for verification of historic records, abundance surveys of potential index sites and collection of voucher specimens to be held at the Royal British Columbia Museum.
Olympia oysters are widespread and abundant in the sounds and inlets of the west coast of Vancouver Island, where they form intertidal reefs in multiple locations. These natural reefs are no longer regularly seen in Puget Sound or on the US Pacific coast, and have generated considerable interest, particularly for restoration groups. Abundance is greatest in Barkley Sound and generally decreases with increasing latitude. Olympia oysters are abundant at sites in Sooke Basin and Gorge Waterway, both of which drain into the Strait of Juan de Fuca. In the Strait of Georgia, Olympia oysters are widespread at low densities and tend to be cryptic, attached to the undersurface of intertidal rocks, except in special circumstances where artificial habitat provides standing water (Nanaimo) or in areas modified for oyster culture (e.g., Ladysmith Harbour). Olympia oyster populations in Johnstone and Queen Charlotte Straits and the north coast mainland inlets are extremely rare and associated with lagoon habitats. The northernmost verified record is at Gale Passage, Dufferin Island, at approximately 52N. They are absent from the Queen Charlotte Islands (Haida Gwaii).
While most historic threats have been mitigated or are of limited scope (overfishing, pulp mill pollution, exotic drills and diseases), the recent establishment of European green crab, Carcinus maenas (Linnaeus, 1758), on the west coast of Vancouver Island presents a new and thus-far unquantified threat. Future work will focus on further verification of known sites supporting Olympia oyster populations, spatial analyses of habitat characteristics to predict potential suitable sites for verification, and surveys to monitor changes in abundance over time at specific index sites.