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What is Happening?The coast of British Columbia yields an abundance of clams, mussels, scallops and oysters for human consumption, yet large areas of the coast are closed for the harvest of these bivalve shellfish. These closures are due to sewage contamination or dangerous levels of toxins and pathogens, both natural and human-produced. Shellfish and the waters they inhabit are good indicators of the bacteriological health of the marine environment. Fecal coliform (FC) bacteria in the water indicate the presence of human or animal fecal wastes and the possible presence of disease-causing organisms. Shellfish growing waters are closed to direct harvesting when the median fecal coliform count exceeds 14 FC/100 mL and/or more than 10% of the samples exceed 43 FC/100 mL based on a minimum of 15 data points. By comparison the standard for drinking water is 0 FC/100 mL while the swimming water standard has a median of 200 FC/100 mL. The stringent standard for shellfish growing water is necessary due to the ability of bivalve shellfish to concentrate bacteria, viruses and toxins given their unique filter feeding mechanism. Sanitary closures (from sewage contamination) have
increased steadily since the 1970’s.
As of December 31, 2004, there were 123,832 hectares (ha) closed
to harvesting of shellfish in BC (including
conditional closures). This is now double the area covered
by closures before 1976. Of the closed areas, 71,818 hectares
are in the Georgia Basin. The largest closures include Burrard Inlet,
the Fraser River estuary and Boundary Bay (see
map) waters with numerous point and non-point sources of contamination.
As well in 2001, large (about 46,000 ha) temporary seasonal (September 15 - November 15) closures were invoked in Clayoquot and Barkley Sounds as a result of sporadic elevated fecal coliform counts believed to be caused by wildlife sources.
Further intensive testing led to a significant reduction in these closures the following year as illustrated by the significant drop in the area under closure observed in 2002 (see graph below). While the increase in the area under closure since 1976 is significant,
part of this increase is the result of expanding monitoring activities to areas which had not previously been tested (unclassified areas). Over the past decade, water quality monitoring surveys have been expanded to include water sampling in more remote locations such as on the North and Central coasts including the Queen Charlotte Islands - Haida Gwaii. Expanded testing has resulted in new sanitary closures but overall, this has led to a much larger increase in growing areas meeting the sanitary standard for direct shellfish harvesting. For a detailed outline of each sanitary shellfish closure please follow the hyperlinks on Fisheries and Oceans Canada's (DFO) shellfish contamination website. Source: Shellfish Section, Environmental Protection Branch, Environment Canada, Pacific and Yukon Region, 2005.
British Columbia has approximately 26,000 km of coastline. Environment Canada surveys the sanitary quality of approximately 2,600 hectares utilized for shellfish aquaculture as well as approximately 750,000 hectares utilized for wild shellfish harvesting. Sanitary survey and bacteriological data results are presented to the Pacific Regional Classification Committee, which is composed of federal agencies and BC provincial ministries, for determination of the appropriate classification. Shellfish growing areas are assigned one of three growing area classifications namely Approved, Conditionally Approved and Closed. Within the closed area classification the “Prohibited” status exists to prevent harvesting of shellfish for any purpose. Similar classifications are employed by the Washington State Department of Health for Puget Sound where pollution has made shellfish harvesting unsafe along the Sound’s heavily populated east shore from Everett to Tacoma. Since 1980, nearly one quarter of the area available for direct commercial shellfish harvesting has been downgraded in classification because of bacterial contamination in the Sound. It is important to note that shellfish must only be harvested from areas meeting the Approved classification and the Paralytic Shellfish Poisoning (PSP) or "red-tide" criteria. Monitoring for PSP toxins is conducted by the Canadian Food Inspection Agency (CFIA) and DFO is responsible for shellfish harvest management and bans. For further information on that program please consult DFO - shellfish biotoxins and CFIA - food safety websites. Why is it Happening?Shellfish filter large volumes of water from the aquatic environment to extract suspended food particles thus any harmful bacteria, viruses and toxic substances present in the water can be concentrated in the organism. Pollution of shellfish growing waters can occur from a variety of sources and under many different conditions. Sanitary shellfish closures are invoked where pollution such as runoff from urban and agricultural areas, sewage discharges, faulty septic fields or drainage from hinterland or wildlife areas adversely affect water quality. Multiple pollution sources account for the largest closures followed generally by agricultural/urban runoff, hinterland drainage, outfall sewage discharges and marine vessel discharges. Non point sources can be considered the largest contributor to closures.
The predominate method of human waste treatment and disposal utilized in single family homes located outside sewered areas is that of the septic tank and tile field absorption system. A number of properties located along the marine foreshores which rely on this method of sewage treatment are impacting marine water quality. Consequently sanitary closures in several areas are either directly or partially attributable to faulty on-site waste systems. Why is it Significant?Shellfish habitat which has become contaminated by sewage may have bacteria and viruses which can cause disease in humans. These pathogenic agents can result in illness ranging from mild gastroenteritis (stomach ache) to typhoid fever and infectious hepatitis. Adequate cooking will generally destroy the pathogenic organisms but shellfish are often eaten raw or undercooked, exposing the consumer to potential diseases. During the winter of 1924-25, an outbreak of typhoid fever from the consumption of contaminated oysters in the United States resulted in 1500 reported cases of illness and 150 deaths. This led to the development of the Canadian Shellfish Sanitation Program which is conducted according to protocols jointly agreed to by the Canadian and United States governments. As can be seen in the graph below, both the production and economic value of bivalve shellfish from aquaculture in BC has been steadily increasing since 1986. In 2003, over 73% of all bivalve production from BC came from aquaculture (BC Ministry of Fisheries, 2004) and British Columbia produced about 55% of Canada's oyster production. The economic potential for the farmed clam and oyster industry has been set at $100 million annually with over 4500 hectares in production (Coopers and Lybrand Report, 1997).
Source: The 1986 to 1990 data are from the Department of Fisheries and Oceans (http://www.dfo-mpo.gc.ca/communic/statistics/aqua/index_e.htm) and the data 1991 onwards are from an ongoing Statistics Canada, Agriculture Division database. In 2003, the shellfish industry in British Columbia which includes both wild and farmed (aquaculture) sources yielded an estimated landed value of $135.2 million or 21% of the total value of all BC fisheries (BC Ministry of Agriculture, Food & Fisheries 2004). The bivalve species of shellfish (clams, geoducks, oysters and scallops) comprised 40% of that value (BC Ministry of Agriculture, Food & Fisheries 2004). To the south, the State of Washington bivalve shellfish industry had a wholesale value of $77 (US) million in 2000 (Puget Sound Online). Closures can result in serious hardship to many people who depend on a healthy fishery for their livelihood or for their own consumption. As of 2002, BC's shellfish Aquaculture industry was providing local economic opportunities to 302 companies employing 800 people (BC Ministry of Agriculture, Food & Fisheries). What is Being Done?
A focus area under both initiatives has been on public education of the danger polluted waters pose to the shellfish industry, for example the effects of sewage discharged by recreational boaters. Recognizing the concerns voiced by boaters to the lack of sewage pump-out facilities, a total of seven marine pump-out facilities were constructed within the Georgia Basin prior to 2003 and an eighth is planned by March 2005. Through the collaborative partnership of local businesses, community and government, facilities were installed in Comox Harbour, Deep Bay, Madeira Park, Gibson’s Harbour, Ganges Harbour and Cowichan Bay. A facility is currently under construction in Lund Harbour with completion anticipated for March 2005. An alternative to fixed facilities is the mobile pump-out service provided by the Saanich Inlet Protection Society to recreational boaters in Saanich Inlet. This facility is solely operated by a non-profit organization and supported by volunteers and local businesses. As part of the pump-out service, volunteers have helped distribute copies of “Protecting BC ’s Aquatic Environment – A Boater’s Guide” as part of a boater education and awareness program. The guide provides green boater tips aimed at increasing the environmental awareness of boaters toward environmentally friendly boating practices and recognizing the effects of sewage discharge on shellfish growing areas. Copies of the guide are available through the Georgia Strait Alliance. Most recently, the GBAP has partnered with several coastal First Nations to raise public awareness of shellfish harvesting concerns. The Nanaimo River Estuary Project saw the Snuneymuxw First Nation (SFN) working with government agencies as well as various non-government partners to develop an estuary management plan. Under this plan, marine and freshwater monitoring was conducted and potential sources of pollution identified. Following the seven year long project, the opportunity for a seasonally controlled purification fishery on approximately 40 hectares of shellfish beach became available to the band along the eastern intertidal foreshore of Nanaimo Harbour. Shellfish harvesting in the spring/summer of 2003 has taken place in the Harbour on four occasions yielding over 10,400 kg of clams with resulting economic benefits to the SFN.
For more information contact: ShellfishPacific@ec.gc.ca Check the following sites for additional information on this indicator:
The following Web sites are not under the control of Environment Canada (EC) and they are provided solely for the convenience of users. Environment Canada is not responsible for the accuracy, currency or the reliability of the content. Environment Canada does not offer any guarantee in that regard and is not responsible for the information found through these links, nor does it endorse the sites and their content. Users should be aware that information offered by non Government of Canada sites that are not subject to the Official Languages Act, and to which Environment Canada links, may be available only in the language(s) used by the sites in question. For references used in this indicator click here. |
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Environment Canada (EC) has been monitoring the sanitary quality of shellfish growing waters on BC's southern coast since the early 1970's. It has an ongoing commitment to do so under the Canadian Shellfish Sanitation Program (CSSP) jointly administered by EC, Fisheries and Oceans Canada and the Canadian Food Inspection Agency. The primary mandate of the Program is to protect public health by preventing exposure to contaminated shellfish through controlling recreational and commercial harvesting of bivalve shellfish. In accordance with the 1948 Bilateral Agreement between Canada and the US, the CSSP is audited by the US Food and Drug Administration and Canadian auditors. The Agreement is intended to control and improve sanitary practices found in the bivalve shellfish industries of both countries and enable transboundary marketing. 
