Two if by sea: invasive species are changing the ocean environment. (Currents).
For decades, the coastal United States has been under siege from an invasion of foreign animals and plants (see second feature this issue). New species arrive daily, and in a variety of ways. According to the Pew Oceans Commission, ship ballast water is the primary carrier of marine species throughout the world, although intentional introductions to control other species or mismanaged aquaculture aquaculture, the raising and harvesting of fresh- and saltwater plants and animals. The most economically important form of aquaculture is fish farming, an industry that accounts for an ever increasing share of world fisheries production. also often lead to the spread of new populations.
These invaders do harm by not only wiping out native species, but also change the habitat structure around them. Economic costs to shipping can be in the millions of dollars when non-natives foul nets or eat commercial market fish and crustaceans important for area industry.
According to Pew's James T. Carlton, new species are being introduced into U.S. coastal waters faster than ever, and the rate may be snowballing due to larger, more frequent shipping operations. Ballast water is pumped into vessels to maintain stability, and it is discharged in new ports. Linda Sheehan, director of the Pacific Regional Offices of the Ocean Conservancy, says ballast water is the second-most significant problem after habitat destruction nationwide.
Plants and animals Plants and Animals are a Canadian indie-rock band from Montreal, comprised of guitarist-vocalists Warren Spicer and Nic Basque, and drummer-vocalist Matthew Woodley. They are signed to Secret City Records. arrive as plankton plankton: see marine biology.
Marine and freshwater organisms that, because they are unable to move or are too small or too weak to swim against water currents, exist in a drifting, floating state. (drifters), nekton nekton: see marine biology. (free-swimming), fouling organisms (attached inside and on the hulls, propellers, and intake systems of vessels), and benthos benthos: see marine biology. (bottom dwellers). Plankton has proven to be the heartiest, and therefore most potent, form to arrive. Not all organisms that disperse to new areas can establish themselves however. Reproductive biology, and the presence of predators, competitors and parasites all play a role in a newcomer's survival chances.
Often reported as a maintenance problem, invading species take hold in dry dock areas such as marine oil-drilling/production sites or floating repair structures. Others make a home near land at nutrient run-off points from farms and power plants. Enriched or chemically altered waters in harbors are also key areas.
The invaders' arrival is not always accidental, however. In the past, Hawaiian resource managers introduced the red mangrove mangrove, large tropical evergreen tree, genus Rhizophora, that grows on muddy tidal flats and along protected ocean shorelines. Mangroves are most abundant in tropical Asia, Africa, and the islands of the SW Pacific. and Philippine seaweed. In 2001, Virginia officials released sterile Japanese oysters in Chesapeake Bay to boost the fishing industry, a move opposed by neighboring Maryland.
Another possible source of invasive species is aquaculture, which regularly imports exotic organisms. "Nearly one-third of the world's seafood supply is derived from aquaculture, and the government has reduced regulation to promote it," says Susan Williams, director of the University of California The University of California has a combined student body of more than 191,000 students, over 1,340,000 living alumni, and a combined systemwide and campus endowment of just over $7.3 billion (8th largest in the United States). at Davis' Bodega bo·de·ga
1. A small grocery store, sometimes combined with a wineshop, in certain Hispanic communities.
2. A warehouse for the storage of wine. Marine Laboratory. "The aquaculture industry can help itself by protecting cultured organisms through the control of invasive marine parasites," Williams says. In 1998, farmed Atlantic salmon Atlantic salmon
Oceanic trout species (Salmo salar), a highly prized game fish. It averages about 12 lbs (5.5 kg) and is marked with round or cross-shaped spots. Found on both sides of the Atlantic Ocean, it enters streams in the fall to spawn. escaped from a Pacific Northwest fishery and entered the wild population.
At the Monterey Bay Aquarium The Monterey Bay Aquarium, which is located in a former sardine cannery on Cannery Row in Monterey, California, is one of the largest and most respected aquariums in the world. It has an annual attendance of 1.8 million and holds 35,000 plants and animals representing 623 species. in California, senior marine biologist Steven Webster often deals with exotic species in their tropical exhibits. "We ensure that invasive species do not enter local waters by recycling water and by heavily filtering and applying ozone or ultraviolet light to our systems."
Scientists battle invasive species with everything from handpicking seastars/snails off the ocean floor to mowing down salt marsh grasses. One highly debated idea is the use of chemical control, as was tried in Darwin, Australia in 1999. There, Asian mussels were treated and effectively wiped out with aqueous chloride, sodium hypochloride and copper sulfate. However, much of the surrounding sea life was also killed off. In the summer of 2000, an unsuccessful attempt in Southern California with similar chemicals left high mortalities, but could not eradicate, the nuisance seaweed Caulerpa taxifolia.
"Scientists are wary of chemicals because of the lack of knowledge of all the effects they can have on the surrounding environment," says Carlton. "Chlorination chlorination Public health Addition of chlorinated compounds to drinking water as disinfectants. Cf Ozonation. is used when the impacts of it are thought to be less than the impact of the invading species. Most often, target species cannot be selected out and destroyed." Another possibility that needs further research is the use of benign anti-fouling agents on ships. Scientists recommend that companies develop new agents with lower chemical half-life that would have a lesser impact on other sea life. In the future, biocontrol--the use of one species to control another--may become a tool also.
On the federal level, former President Bill Clinton created the Invasive Species Management Plan, which went into effect in 2001. The plan charges the Coast Guard, National Oceanic and Atmospheric Administration Noun 1. National Oceanic and Atmospheric Administration - an agency in the Department of Commerce that maps the oceans and conserves their living resources; predicts changes to the earth's environment; provides weather reports and forecasts floods and hurricanes and , the Environmental Protection Agency Environmental Protection Agency (EPA), independent agency of the U.S. government, with headquarters in Washington, D.C. It was established in 1970 to reduce and control air and water pollution, noise pollution, and radiation and to ensure the safe handling and (EPA EPA eicosapentaenoic acid.
n.pr See acid, eicosapentaenoic.
n. ) and the Department of the Interior with researching new technologies, and it strengthens the National Invasive Species Act (NISA Nisa, rivers: see Neisse, rivers of Poland. ) of 1996. The problem with NISA, critics say, is that ballast exchange reporting for ships is voluntary, and some vessels are exempt from participation, as is the case with oil tankers in coastal trade and passenger vessels with "treatment" systems. Today, a National Ballast Water Clearinghouse reports data of transfers/invasions of species through a survey meant to oversee the rate of compliance of the voluntary regulations.
The EPA is now providing competitive research grants for environmentally sound control methods. The Clean Water Act encourages states to make individual policies of their own, and it prohibits the discharge of ballast if it contains oil enough to cause "... a film, sheen, discoloration dis·col·or·a·tion
a. The act of discoloring.
b. The condition of being discolored.
2. A discolored spot, smudge, or area; a stain.
Noun 1. , sludge or emulsion." The International Joint Commission's (IJC IJC International Joint Commission
IJC Internet Journal of Chemistry
IJC International Journal of Cancer
IJC International Court of Justice
IJC Independent Journalism Centre
IJC International Journal of Climatology
IJC International Journal of Control ) Water Quality board suggests short-term emergency ballast chemical treatment be used. But Sheehan believes that the EPA, Army Corp of Engineers and the Fish and Wildlife Service aren't doing nearly enough. "We sued the government for poor regulation of endangered species, and for non-response and weak oversight of the problems of ballast waters," says Sheehan.
The Pew Ocean Commission's recommendations include development of a national compulsory ballast reporting and fouling program, as well as a rapid response system involving alternatives to chemical treatment. Also needed, the commission says, is a National Marine Bio-invasion Research Program, and the creation of a nationwide education campaign, possibly under the National Sea Grant Program (a partnership between the nation's universities and National Oceanic and Atmospheric Administration) to increase public awareness of invasive species.
Money remains the principal stumbling block to an effective response to invasives. Carlton agrees with Sheehan that ballast regulation is extremely under-funded. "Our budget is affected by the classic up-and-down slopes of politics and funding," he says. CONTACT: EPA, (202)564-4700, www.epa.gov; Ocean Conservancy, (202) 429-5609, www.oceanconservancy.org; Pew Oceans Commission, (703)516-0605, www.pew oceans.org.