5001 - Laserfiche WebLink

Home Browse Search

{ t ~ (.y • ®~~7 ~a~l ~0~18a~ FISHERIES PROBLEMS ASSOCIATED WITH THE DEVELOPMENT OF THE LOWER COLORADO RIVE~~ ; _t, 4 , _ ~ : , , by Stephen J. Nicola? ABSTRACT The lower Colorado River has provided 'a generous source of water for the growing urban and agricultural centers of the American southwest. The process of obtaining, delivering, and using these waters has not been without its adverse effects on native and introduced fishes. The native freshwater fishes of the lower Colorado were uniquely adapted to life is the turbulent, turbid river. They underwent a decline at the time when Hoover Dam and other major water storage structures were built. on the lower river; however, the lack of early studies has made it difficult to identify the most probable cause of this phenomenon. The construction of water storage reservoirs created conditions that favored the development of fisheries for exotic game species. The productivity of these fisheries is impaired by dredging and other water management activities that damage or destroy back- water marshes and lakes favored as spawning and nursery areas. Efforts to sustain sport fishing. values in the Lower river have involved stocking of new species, and mitigation for damage or loss of habitat. Mitigation may involve restoration or improve- ment of existing habitat, or the acquisition of land to develop new habitat. However, these. measures do not fully compensate for lost fishery values. Since 1973 there has been a renewed interest in restoring native fishes to the lower Colorado River. State and federal wildlife management agencies are now actively pursuing this possibility. The dual problems of restoring native fishes and maintaining existing sport fisheries will continue to present a formidable challenge to resource managers of this disturbed and continually changing desert habitat. 1~Inland Fisheries Endangered Species Program Special Publication 79-4. This report was prepared as part of a federal Endangered Species Act grant-in-aid project, "California E-F-1, Endangered, Threatened, and Rare Fish", and is reprinted with minor revi- sions from proceedings of the conference on Alternative Strategies for Desert Development and Management, sponsored by the United Nations Institute for Training and Research and the California Department of Water Resources, 31 May-10 June, 1977. Senior Fishery Biologist, Endangered Species Program, Inland Fisheries Branch, 1416 Ninth Street, Sacramento, CA 95814. PO?;QE: T8IBI~TEHIAL MAY BE PRO?3C?!D 1