Between trips:

1. Don't dump "live" trash. When you purchase shellfish from the store, throw the empty half-shells in the garbage, not onto the beach. Even if the shells look clean, they may be host to some non-native hitchhikers. Similarly, if you order live shellfish or other organisms for restaurants, classrooms, or anywhere else, throw the packing material in the garbage (even if it's live plants or seaweed). Don't risk starting an invasion.

2. Don't release your pets into the wild: goldfish (or any other fish), birds, cats, dogs, and other animals can become feral, with devastating impacts on native species. In Hawai'i, for example, introduced avian malaria and feral cats are together driving native birds extinct. For the same reason, if you purchase lobster or any other live shellfish, but at the last minute can't bring yourself to throw them in the pot, don't release them at the shore-give them to a neighbor instead.

3. Seek out native trees, shrubs and flowers when you visit a garden nursery. Avoid planting exotics-they may use your yard as a launch site for a new invasion.

4. Get involved in local restoration projects to eradicate invaders and re-establish native species. Many local, regional and national parks will be delighted to have your help.

Whether we're out on the water for an afternoon, a weekend, or a month, our motivation is the same: to see the land and seascape from a different perspective, to enjoy proximity to the natural world. But by doing so, we can inadvertently contribute to damaging this resource, our health, and our economy. Introduced species are an expensive and environmentally devastating challenge; kayakers are in a unique position to help reduce the risks.

Marjorie Wonham is a Ph.D. candidate at the University of Washington, where she studies the spread and impact of introduced species. She is a fellow of the Environmental Leadership Program. Marjorie learned to kayak in the waters around Vancouver Island and Puget Sound, and now dreams of paddling in some of the places these marine invaders come from.

http://www.nas.er.usgs.gov/
U.S. Geological Survey list of invaders, including photos and species descriptions of seaweeds, plants and animals across the country

http://www.anstaskforce.gov
Home page for the U.S. Aquatic Nuisance Species Task Force

http://www.aphis.usda.gov
Home page for the U.S. Animal and Plant Health Inspection Service, responsible for regulating imports of live organisms, including agricultural species

http://www.invasivespecies.gov
U.S. federal site for scientific, legislative, and community information on invasive species

http://www.marine.csiro.au/CRIMP/
Australia's Centre for Research on Introduced Marine Pests

Specific Invaders:

Caulerpa ("killer" algae)
http://www.unice.fr/LEML/PagesStatiques/CaulStart.htm
University of Nice, France, Caulerpa-on-line information site

Spartina
http://www.willapabay.org/~coastal/nospartina/
Coastal Resources Science Center (CRSC), Willapa Bay, Washington, USA

Nutria
http://lionfish.ims.usm.edu/~musweb/nis/Myocastor_coypus.html
Gulf Coast Research Laboratory (GCRL) of the University of Southern Mississippi

Zebra mussel
http://nas.er.usgs.gov/zebra.mussel/
U.S. Geological Survey zebra mussel information site

Great Lakes
http://www.seagrant.wisc.edu/greatlakes/glnetwork/exotics.html
Sea Grant Great Lakes Network