Hitchhikers and stowaways find success and spread.
Ron Martin and Bill Horns
From hitchhikers to stowaways, exotic species sometimes take the road less traveled and in many cases, it makes all the difference.
You might think that all exotics species are transported by natural phenomena such as wind or on animals. In fact, most new species reach Wisconsin waters through human activities. The rate of spread is far beyond any natural rate and often the environment is unable to cope with these invaders.
All of these new arrivals, regardless of the path that they take to get here, share one common characteristic. They have been introduced into an aquatic environment in which they did not evolve, and consequently have no natural enemies to limit their reproduction and spread. Given this competitive advantage, invasive species can cause serious problems for native organisms and disrupt natural communities.
Several species have been brought into the state and released intentionally for beneficial uses through aquaculture, the aquarium and pet trades, and horticultural practices, or to control other species. Some have harmed the aquatic environment while others have been beneficial. Still other exotic species have been introduced into this country unintentionally as a result of tourism, trade or commerce.
The round goby is an aggresive bottom-dwelling fish that came from Europe near the Caspian Sea. © Dave Jude
The major pathway for unintentional introduction of exotic species to the Great Lakes is through the ballast water of ships. Almost 800,000 tons of foreign ballast water is legally discharged into the Great Lakes each year. No state, federal or international agency has been able to effectively stop this.
Current regulations (in place since 1993) require that ships bound for the Great Lakes exchange their ballast water on the high seas (at a depth of 200 meters or 200 miles from shore). Also, technical solutions such as filtration, ozone, chemicals and ultraviolet treatment are being tested.
Recreational boaters, anglers, SCUBA divers, waterfowl hunters, bait industry, the aquaculture, nursery and aquarium trades, commercial barge traffic and canals are other potential pathways for exotic species.
About 161 species of exotic aquatic organisms have established a foothold in the Great Lakes.
As the Great Lakes has intensified as a transportation route, the rate of exotic species introductions has increased. More than one-third of the organisms have been introduced in the past 35 years, a surge that coincides with the opening of the St. Lawrence Seaway, which permitted more and larger vessels to pass between the Great Lakes and ports around the world.
The DNR's message to boaters, anglers, water-skiers, SCUBA divers, sailors and others who have the potential to spread exotic species is: Clean boats means clean waters. Cleaning boats can make a difference and the Department of Natural Resources and University of Wisconsin Sea Grant have strongly promoted this concept through public education and outreach efforts.
|A new policy on ballast water|
In March, the Great Lakes Panel on Aquatic Nuisance Species established a final policy on managing ballast water in the Great Lakes region. The policy document culminated about eight months of intensive effort and was developed by consensus of approximately 40 regional authorities well versed on ballast water issues. These authorities included representation from the states, the province of Ontario, Native American tribes, federal agencies, the maritime industry, environmental and other non-governmental groups.
The policy objective is to eliminate introductions of aquatic nuisance species in the Great Lakes-St. Lawrence system. The policy also is aims to reduce aquatic nuisance species dispersal between the lakes.
The policy recognizes that ballast water is a major pathway for introducing and spreading aquatic nuisance species, not only to the Great Lakes, but other coastal and fresh waters of North America. Ships take on ballast water to increase stability during ocean crossings and while moving between ports in the Great Lakes. Under the current regulatory system (in place since 1993), the U.S. Coast Guard requires all vessels bound for the Great Lakes to not only exchange their ballast water on the high seas, but to retain ballast onboard or use an environmentally sound alternative.
The policy statement developed a series of recommendations to address these concerns and advance a strong prevention and control effort. Key recommendations include:
- Establish criteria at the federal level for ballast water management practices/treatment technologies that are consistent throughout the Great Lakes region. To be effective the program must have the support of both the U.S. and Canadian governments.
- Address gaps and inconsistencies in ballast water management by adopting a binational, systemwide approach that coordinates regulations/guidelines among all jurisdictions.
- Apply regulations/guidelines at the federal, state and provincial levels to all vessels entering the Great Lakes-St. Lawrence system. Current U.S. Coast Guard regulations and Canadian guidelines apply only to vessels "in ballast" and excludes NOBOBs (vessels reporting no ballast on board), those vessels conducting coastal voyages and those vessels operating only on the Great Lakes.
- Ensure cooperation and coordination among all relevant U.S. and Canadian government agencies, the maritime industry and other stakeholders in developing and applying guidelines to manage ballast water.
- Evaluate alternatives to ballast water exchange on the high seas that are effective, environmentally acceptable, economically feasible, practical and enforceable.
- Secure, dedicated, long-term federal funding that provides sufficient support for research of alternative technologies.
The policy lays the foundation for a sound ballast water management program in the Great Lakes region notes Phil Moy, a fisheries and nonindigenious species specialist for the University of Wisconsin Sea Grant. Moy directed and coordinated this effort and further emphasizes that this policy document will be very important in addressing the changes that are needed in the National Invasive Species Act, which is up for reauthorization in 2002.
– Ron Martin
Ron Martin and Bill Horns work with aquatic exotic species issues for the Department of Natural Resournces.