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the water column. Clearly to support hundreds of millions and bil- 

 lions of zebra mussels requires some energy. That energy is being 

 transferred to zebra mussels, and much of that energy may have 

 gone elsewhere, for example, to native species. Thus, the potential 

 to alter the ecosystem, the trophic web of the ecosystem, it is just 

 absolutely fundamental. We are learning about that potential right 

 now. 



In terms of other ecological impacts, we have already seen the 

 disappearance of some native mussels in parts of the Great Lakes. 

 There is a great fear now that a number of our endangered species 

 of native mussels may, in fact, become extinct. The zebra mussel 

 is really the final straw. 



I think that there is no question that education activities will be 

 extremely important at slowing the spread of the zebra mussel 

 from the East to the West, and from the North to other parts of 

 the South. Right now, actually yesterday, the fourth international 

 zebra mussel conference just concluded, and over 500 people met 

 in Madison, Wisconsin, to address these issues. 



Senator Akaka. Most introductions of game fish have sought to 

 improve sport fishing, an industry largely dependent on stocking 

 and introductions. Federal and State fish resource agencies often 

 manage resources with fishing in mind, not necessarily for fish or 

 fish habitat. Such releases have rarely had any positive biological 

 impact on receiving habitats and ecosystems. I say this as a sport 

 fisherman concerned about protecting fish communities. 



Can we meet the needs of the sport fishing industry at the same 

 time we protect native fish populations? 



Mr. Carlton. Senator, I am not a fisheries biologist, but I can 

 speak to some of the more general principles involved with that 

 land of a concept. 



The sport fishing industry all over the world really is a balance 

 between on the one hand the economic and the biological £uid the 

 aesthetic benefits of sport fishing and food fisheries and biological 

 control and on the other hand the impacts on the natural eco- 

 system. 



In many ways, the needs of the sport fishing industry have been 

 fairly well served over these past many decades. The movements 

 of large-mouth bass, brown trout, sunfish, rainbow trout, other 

 salmonid fishes, have been extensive across the face of North 

 America, and many of those movements continue. 



I think the real critical issue is to make sure that these kinds 

 of activities no longer impact existing populations of native fish, 

 but particularly the native fish that are now restricted and that 

 have been decimated by human activities in terms of decreasing 

 their range and decreasing their population size. 



Another critical balance will be that the activities of those who 

 would like to expand or enhance or maintain sport fishing indus- 

 tries do not inadvertently impact some of the remnants of our na- 

 tive fish populations. 



Senator Akaka. In 1990, the EPA convened a workshop on intro- 

 duced aquatic nuisance species. One result of this workshop was a 

 recommendation that the United States aim for no new introduc- 

 tions of non-indigenous aquatic nuisances. 



