High on the deck of a bulk carrier at the Hudson Bay port of Churchill, Man., biologist Farrah Chan carefully lowers a fine-meshed plankton net down into the dark water of the ship’s ballast tank. Far below, a scuba diver assists her by collecting samples of marine life from the vessel’s hull. Chan is looking for alien species — aquatic invertebrates and plants that ride from port to port with the global shipping fleet, suspended in ballast water or clinging to hulls, rudders, and propellers. They can enter an ecosystem far beyond their natural range when a ship discharges its thousands of tonnes of ballast water, or when the organisms release larvae or are scraped off the hull.
“If non-indigenous species establish a breeding population in a new area,” says Chan, who is completing her doctorate at the University of Windsor’s Great Lakes Institute for Environmental Research, “they can severely damage their new environments, as well as economies and infrastructure — just as sea lampreys and zebra mussels have done in southern Canada.”
As summer ice diminishes and resource exploitation grows, more vessels visit the Arctic, each one a potential carrier of alien species. Warming temperatures could make it easier for organisms from more temperate areas to survive. “We need to know what species are hitchhiking into the Arctic,” says Chan. “We have information for most of the world — there are even some studies from Antarctica — but not the Canadian Arctic. My research is filling that gap.”
She chose the grain port of Churchill because it is one of the very few Canadian Arctic ports that receives vessels from global shipping points, ports such as Murmansk (Russia), Flushing (Netherlands), La Corunna and Gijon (Spain) and Annaba (Algeria). She’s been finding a wide variety of invertebrates — mussels, barnacles, copepods, and arthropods — and it’s a major challenge, she says, to determine which species are non-indigenous.
Chan’s work is helping determine where in the Canadian Arctic the risk is greatest, and this knowledge is essential for developing ways to keep invasive species out. “This research gives us a chance to protect the coast by directing proactive management efforts at high-risk sites,” she explains. “It’s much easier to prevent invasive species from being introduced than it is to control them later.”
This is the latest in a continuing blog series on polar issues and research presented by Canadian Geographic
in partnership with the Canadian Polar Commission. The polar blog will appear online every two weeks, and select blog posts will be featured in upcoming issues. For more information on the Canadian Polar Commission, visit polarcom.gc.ca