Industrial and ecological consequences of the introduction of new species in continental aquatic ecosystems: The zebra mussel and other invasive species.

Surface water is withdrawn from rivers for various industrial uses; among these, power production accounts for a large proportion. Many aquatic species settle in the raw water circuits of power plants, disrupting their operation and occasionally putting the whole plants out of use. In certain cases, the arrival of new species raises a serious problem for the industry. The introduction of two Dreissena species in the American Great Lakes, followed by their gradual spread southwards in recent years, has generated industrial damage estimated at five billion US $ per year by the turn of the century. The ecological impact of the zebra mussel in North America has been widely studied and is thought to be considerable during the phase of rapid spreading of the species. In Europe as well, the zebra mussel constitutes a threat for industrial circuits. For this reason, the species has been the object of numerous studies, particularly in France in the Seine, Rhone and Moselle rivers. Two new invasive species have recently appeared in European rivers : the Asian clam Corbicula fluminea and an amphipod : Corophium curvispinum, thus adding to the list of organisms (sponges, hydroids, bryozoans, molluscs) previously found in power plant circuits on French rivers. To ensure the availability of plant circuits, it is essential to be able to control the development of these species. This, in turn, implies in-depth knowledge of them in both biological and ecological terms. This paper presents a brief overview of present industrial methods, or methods now under study, for checking the spread of such organisms.