SNAKEHEADS TO SWANS - EXOTIC EXTREMES

7/24/02
Contact Dr. Tom French, 508.792.7270 x 163 or Todd Richards x 138

A voracious Asian fish and an elegant European bird may not appear to have much in common but the Snakehead fish and Mute swan are both exotic species with the potential to damage the Massachusetts environment. Lessons learned from the introduction and spread of the Mute swan over the past century are important to remember when viewed in the context of the Snakehead, a new exotic species making inroads in the United States. Swans were introduced from Europe in the late 1800s to grace estates and
parks in New York. They became established as a feral population shortly thereafter and have spread up and down the Atlantic coast, numbering more than 13,000 today. Massachusetts alone is currently home to nearly 1,000 mute swans and the numbers continue to climb. Larger and more aggressive than native waterfowl, mute swans have displaced native species by dominating food sources, habitat and nesting sites. Their long necks enable them to reach and uproot aquatic vegetation inaccessible to other birds and their robust appetites result in about one pound of nutrient-rich droppings being produced per bird per day. In many ponds and wetlands, where once a diversity of aquatic plants and animals existed, mute swans have damaged the vegetation, degraded water quality and driven out native species. Adult swans are also aggressive toward people in defense of their nests and young. A particularly bold bird has been in the news of late because it repeatedly assaulted canoeists on the Eel River in Plymouth. Now, another exotic, the Snakehead fish, is making headlines having been discovered reproducing in a Maryland pond. A predatory fish, the Snakehead can impact native and established fish, amphibian and invertebrate populations, damaging the species diversity and natural processes at work in lakes in ponds. The Snakehead is a hearty fish, able to survive out of water for extended periods, enhancing it's potential to spread between water bodies. Unlike the swan, it is not aggressive toward people.

In Massachusetts, two specimens of Snakeheads have been documented in the past twelve years. In 1990 a Snakehead was caught by an angler in Pomps Pond, Andover and in 2001 MassWildlife fisheries biologists caught a Snakehead while sampling Newton Pond in Shrewsbury with electrofishing gear. Both fish are believed to have been illegally kept in aquariums and then liberated. They now reside as curious specimens at Harvard University's Museum of Comparative Zoology along with assorted pirahna and other exotics. Like the swan before it, the Snakehead and other invasive species, have the potential to harm the environment. In response, Secretary of the Interior Gale Norton has proposed a nationwide ban on the importation and interstate transport of live Snakehead fish. Massachusetts prohibits the possession and sale of Snakeheads and other candidate aquarium trade fish that can survive above 30 degrees north latitude or below 30 degrees south latitude. Similarly, fish may not be released into the waters of the Commonwealth without proper permits.

The Snakehead is not a current threat in Massachusetts waters, but like mute swans, European starlings, English sparrows, purple loosestrife, water chestnut, gypsy moths and dozens of other exotics before it, the possibilities of the fish becoming established are real. As history has shown, people create exotic wildlife problems by moving and releasing species in new environments, while the wildlife themselves seek only to survive and reproduce. History has taught the lesson, now it is up to us to heed it.

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Bill Davis, Wildlife Biologist
Media & Public Affairs Coordinator
MassWildlife, Field Headquarters
Westboro, MA 01581
TEL (508) 792-7270 x 153, FAX (508) 792-7275
EMAIL bill.davis@state.ma.us
http://www.MassWildlife.org

Stephen Vantassel is a Certified Wildlife Control Professional. He is a nationally known writer including having been an assistant editor for Wildlife Control Technology magazine, author of numerous ADC articles as well as The Wildlife Removal Handbook rev.ed and the Wildlife Damage Inspection Handbook rev. ed. Mr. Vantassel is also a vocal critic of the growing animal rights movement. He has exposed the fallacies and deceptions of the animal rights protest industry through debate, lecture and publication.

7/31/02

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