Did you know that B.C. is under invasion? A crab with a voracious appetite, the European green crab, was introduced to San Francisco Bay almost 20 years ago and has now reached the Northwest coast of Vancouver Island. The consequences could be dire for B.C. fisheries.

Green crabs are insatiable consumers of our local clams, oysters, and mussels, and out-compete our native Dungeness crabs — all but green crabs are harvested here. Predictions of European green crab invasion estimate a loss of revenue from these fisheries anywhere from $9 to $26.8 million. This translates up to 826 jobs associated with harvesting and processing lost just due to this invading crab.

The shellfish threatened by this invasion provide more than just commercial revenue and recreational harvest. By filtering toxins and nutrients from Strait of Georgia, shellfish help to increase oxygen levels and reduce toxic poisoning in other organisms. In addition, this invasion will likely exacerbate the loss of biodiversity and alter important habitats, such as eelgrass beds, within our local marine waters. What’s worse, once they’re established, green crabs and other invasive species are virtually impossible to remove.

But these predictions are not foregone conclusions: we can still fight the invasion. While Green crabs are predicted to enter the Strait of Georgia in the near future, they have yet to arrive in our local waters. Maybe with coastal watch programs and tight controls on shipping we can turn back this and other invasions before our marine ecosystems are changed forever.

Costly
• The economic cost of European green crab in New England is estimated at an annual cost of $44 million.

• European green crab has spread outwards from San Francisco Bay invading the coastline from Baja California to the north-western coast of Vancouver Island.

• Green crab are predicted to continue their northward invasion until they reach southern Alaska.

– Kai Chan is an assistant professor and Canada Research Chair at the Institute for Resources, Environment, and Sustainability (IRES) at UBC; vancouverletters@metronews.ca.