Alien Invasive Species Impacts on Large Lake Ecosystems and Their Economic Value

Abstract

Gail Krantzberg

Globalization of trade and travel has made possible the spread of alien species across the planet. Invasive species are presently considered as one of the major threats to biodiversity in many locations throughout the world. Thousands of AIS have been transported globally by a number of anthropogenically-mediated vectors, including ship-mediated vectors (e.g., ballast water, hull-fouling), recreational boating, live bait, aquarium trade, live food fish, and unauthorized introductions. Ballast water is one of the leading vectors for transporting and introducing species, both in Canada and around the world, and is responsible for the transport of at least one third of all documented marine invasions. Since invasive species have no regard for political boundaries, efforts to prevent invasions need to be interjurisdictional. Given, also that invasive species often travel as contaminants of trade transfers, for example, in the ballast tanks of ships, reducing the spread of invasive species via this pathway would either require constraints on where ships travel, or the installation onto all ships of expensive ballast treatment technology, thereby increasing the cost of shipped goods. As such cost benefit analysis involves trade-offs with other activities, complicating decisions about how impacts can best be managed.

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