19 



Of course, such pests have also invaded the bays and lakes of Ha- 

 waii. 

 What implications does ballast water have for island ecosystems 



such as Hawaii? 



Mr. Carlton. We do not know very much so far about ballast 

 water release in island ecosystems. There have been cases of exotic 

 species introduced into ports and harbors, such as in Hawaii, and 

 we think that a good deal of the marine Ufe, for example, in Pearl 

 Harbor and Kaneohe Bay and Coconut Island area and the Ala Wai 

 Canal and so forth, really are composed of a great many exotic spe- 

 cies carried into, for example, the Hawaiian Islands by shipping 

 traffic over the past several decades. 



In fact, however, the attention on many islands has been almost 

 entirely on the terrestrial species, the land-dwelling animals and 

 plants, and so we have a really very poor data base on understand- 

 ing about some of these marine invasions and what they have done 

 on many islands. There is no question, though, that a lot of ballast 

 water is being released in ports and harbors. We have some data 

 on that for Hawaii already, and it is of concern in the same general 

 sense that we are concerned with other locations, and that is that 

 we really cannot predict very well when the next release will result 

 in a major invasion. 



Senator Akaka. Zebra mussels. Dr. Carlton, are an ever-expand- 

 ing threat to the Midwest. I understand they are beginning to mi- 

 grate into the Mid-Atlantic region. I am not sure that anyone has 

 seriously considered the impact of these pests in the West. If you 

 consider the number of Federal, municipal, and private dams, 

 aqueducts, and water projects located throughout the West, the 

 thought of a zebra mussel infestation is frightening. 



Would you speculate on the risks associated with zebra mussels 

 migrating to the Western lakes, rivers, and water projects? De- 

 scribe the economic and environmental consequences that such an 

 infestation could have on the region? 



Mr. Carlton. You are certainly right. Senator, in the potential 

 for zebra mussels to gain access to the Western United States. Last 

 November the California Department of Agriculture intercepted a 

 boat that had come out of Michigan, and in the intake of that boat, 

 the engine water intake, were zebra mussels coming across the 

 California border at Needles. In this case, those mussels were dead, 

 but it shows that such a transport event is very likely and is in 

 many ways inevitable. In a sense, then, we really cannot stop this 

 invasion. 



What we know about the zebra mussel comes from 150 years' ex- 

 perience in Europe and for the past half decade or more now in 

 North America. The impact on industrial and other water systems 

 in the West will be vast. It is daunting to consider what will hap- 

 pen when the zebra mussel gets to the California water systems, 

 for example. 



There is no question that we are looking at hundreds of millions 

 of dollars of retrofitting, of maintenance, of removal of zebra mus- 

 sels once they hit the West. That is an immediate, obvious impact 

 in terms of an economic industrial threat. Biologically and eco- 

 logically, the zebra mussel will also take a tremendous toll. Zebra 

 mussels extract a huge amount of food from the ecosystem, from 



