Population and Economic Activity

Trends in Shellfish Closures Due to Sewage Contamination

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Closures of shellfish harvesting areas in B.C. has been increasing.

Shellfish beds are closed to harvesting when samples show contamination with bacteria (fecal coliforms) from human or animal wastes. Possible sources of contamination include urban run-off, sewage discharge, and agricultural drainage.

Records for coastal B.C. show:

• Closures have continued to increase since the 1970s, mainly linked to the increasing number of people and associated sewage discharges.

• Outside of the Georgia Basin, closures tripled from 1989 to 2004. This was partly due to expanded monitoring for contamination, but it also reflects the increasing development of the shoreline.

• The increase in 2001 was due to a temporary closure in Clayoquot and Barkley sounds. The contamination likely came from wildlife sources on land and was flushed into the ocean by heavy rains.

• In 2004, more than half (58% ) of the area closed was in the Georgia Basin.

For detailed information, including graph data, see In-Depth report.

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