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' APPENDIX B aquaculture and fishery species along with their associated (free-living and parasitic) organisms, release of organisms associated with pet industries or pest management practices, recreational boating, bait handling, water transport, and ornamental and landscape practices. Nonindigenous aquatic species are causing significant economic and ecological problems throughout North America. Zebra mussels, Asiatic clams, Atlantic salt marsh cordgrass, purple loosestrife, and other invasive species threaten western waters. A 1996 report by The Nature Conservancy emphasizes that invasive, non-native species are one of the leading threats to the I ecological integrity of our nations forests, grasslands, and waterways. Examples of problems that are caused by nonindigenous species in fresh and marine waters include: • The Central Arizona Project estimates that an infestation by zebra mussels will increase its operation and maintenance costs $4 to $5 million annually. This does not ' reflect cost to farmers, other customers and water treatment plants nor the financial and environmental effects of the additional use of ground water that will occur to avoid impacts. Major Great Lakes water users spend $30 million annually to monitor and control zebra mussels. • The Japanese oyster drill has decreased aquaculture profits 55 percent, increased production costs 17 percent, and causes 25 percent mortality in out planted seed oysters. • The invasion of the Asian clam has altered the food web in San Francisco Bay by depleting phytoplankton stocks to the detriment of important salmon and striped bass fisheries. ' A newly introduced species, if it becomes established through reproduction, can disrupt the natural ecosystem balance by altering the composition, density and interactions of native species. This disruption can cause significant changes to the ecosystem, such as alterations to the ' foodwebs, nutrient dynamics and biodiversity. New introductions also can cause costly socio- economic impacts even if effective prevention and control mechanisms are established. Eventually, each newly introduced species will become integrated into an ecosystem that is in a I constant state of flux; or the introduced population will not survive and become extinct (New York State Department of Environmental Conservation, 1993). (Note: The remainder of this section can probably be completely deleted but we will need to add a similar section with Colorado River Basin examples.) ' Approximately 10 percent of the Great Lakes' nonindigenous aquatic species have resulted in significant negative ecological and economic impacts. The following examples portray the extensive ecological and economic impacts caused by aquatic nuisance species that have been introduced into the Great Lakes region. The invasion of the sea lamprey in the 1940s has resulted in substantial economic losses to recreational and commercial fisheries, and has required annual expenditures of millions of dollars to finance control programs. During the 1940s and 1950s, the sea lamprey, a top predator which DRAFT ANS Plan for CRFWC (April 23-24, 1998) Page 3