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introduction from the 1890s. And the opaque white seasquirt is the latest ad- 

 dition — the European Ascidiella aspersa, which seems to have newly appeared 

 in the mid- to late-19808. The Asian species arrived on our Atlantic seaboard 



f)re8umably on boat bottoms — but the new European seasquirt may be a bal- 

 ast water introduction. Scientists are not immune to moving species around, 

 and the orange California seasquirt appears to represent such an example in 

 our marine waters. It is probable that sampling this community a few years 

 from now — or tomorrow — would reveal another new invasion. These massive 

 populations of seaweeds and sea squirts coating marine installations can have 

 an extensive economic impact — and can alter dramatically the abundance of 

 native species. 



No coastal State or possession in the United States is now free from invasions — 

 nor is any region immune to future invasions. The long legacy of maritime com- 

 merce and other activities has left us with often extensive accumulations of exotic 

 species from around the world. The pace of these invasions appears to have in- 

 creased dramatically at the end of the 20th century. The lessons of past invasions 

 dictate that as long as a transport corridor for non-indigenous species is in place, 

 the potential for future invasions is high — invasions that include predators, competi- 

 tors, diseases, and pathogens. 



In many cases, these exotic species do not come to the attention of public or politi- 

 cal arenas. Such species are the interests and concerns of scientists — but since many 

 of these species appear to have no immediate, direct, and profound human impact, 

 they remain of relatively little concern outside the world of scientists. In turn, this 

 means that the mechanisms that brought these species to our shores continue 

 unabated, and with every new spin of the exotic species roulette wheel a non-indige- 

 nous animal and plant with vast potential for altering human society could be re- 

 leased. The wheel spins every hour, 24 hours a day, for our aquatic communities. 



Research in my laboratory on ballast water and sediments indicates that, without 

 controls, there will be new invasions into United States waters — waters that sup- 

 port important fisheries, navigation, and recreation — of exotic aquatic animals and 

 plants from Europe, Asian, and other countries, equal to or exceeding the impact 

 of the zebra mussel. 



Under current U.S. law, ballast water must be exchanged before entering the 

 Great Lakes. That is, ballast water from a foreign port must be deballasted and the 

 ship reballasted on the high seas. Thus, water released into the Great Lakes would 

 have a vastly reduced probability of leading to invasions by freshwater organisms. 

 Additional law soon extends this provision to the Hudson River. When a vessel is 

 bound for freshwater ports of the U.S., this exchange process has the added advan- 

 tage of the ocean salt water killing any freshwater organisms that may remain in 

 the ballast tanks after the exchange process. 



At the present time U.S. law does not require vessels from foreign ports to ex- 

 change their water if bound for ports other than in the Great Lakes (or Hudson 

 River). The current absence of Federal law has led and is now leading a number 

 of States to determine what actions can be taken at a regional level. However, even 

 if such laws were in place — and it is critical that we look in that direction — we also 

 now know that ballast exchange is only the first preliminary step in the prevention 

 of exotic aquatic invasions of harmful species. 



Ballast exchange is almost always only partially achieved — it is most often inipos- 

 sible to release all water from a ship before needing to reballast. Thus, vessels from 

 foreign saltwater ports bound for U.S. saltwater ports which have in fact atternpted 

 ballast exchange will thus almost certainly continue to release some of their original 

 water (and animals and plants therein) anyway — and in these cases the process of 

 reballasting with high seas saltwater will of course not kill the remaining saltwater 

 organisms. We believe this is a serious hole in ballast water control — because of the 

 potential shortfalls in saltwater-to-saltwater port transport, all of our coastal ports 

 are clearly at great risk from invasions, even if ballast exchange were in place for 

 our coasts. 



In addition, many vessels cannot and would not exchange their water during 

 storm conditions — conditions that can prevail on the open ocean for perhaps half the 

 year or more. 



These and other considerations mean that while ballast water exchange is a good 

 first step, "real" control efforts will mean studying other ballast water management 

 scenarios, demonstrating and implementing ballast water management technologies 

 in order to insure "environmentally sound" ships of the future. The recently com- 

 pleted "Shipping Study", mandated under Public Law 101-646, through the U.S. 

 Coast Guard, has outlined many of these options, which now need to be critically 

 examined for potential implementation. 



