7809 - Laserfiche WebLink

Home Browse Search

RESPONSES OF TROUT POPULATIONS TO ALTERATIONS IN AQUATIC ENVIRONMENTS: A REVIEW Richard S. Wydoski' Utah Cooperative Fishery Research Unit' Utah State University, Logan, Utah 84322 ABSTRACT Man has intentionally or unintention- ally disrupted, modified, or destroyed aquatic and riparian ecosyst~s in the Uni- ted States through agricultural practices, channelization of streams, darns, dredging, grazing, industry, mining, and urbanization. The effect of these activities has disrupt- ed natural watersheds, altered streamflows and water temperature, and changed water quality by increasing pollution, particular- ly sedimentation. Ecosystems, environmental quality, and public values are often damag- ed or destroyed through such alterations of the aquatic environment that may be irre- versible. The American public has become more concerned about the deterioration of . the environment and will continue to be in- volved in public policy decisions in the future. Therefore, the resource manager can influence political action and socio- logical pressures in the proper direction to conserve natural resources through ef- fective public relations. Many current laws already exist that can be used to pro- tect fish, wildlife, and other natural re- sources. Since laws are mechanisms for getting things done for society, they can be more effectively implemented or improved by demand from society. Federal and state conservation agencies must have close co- ordination and cooperation so that effective research and management priorities and pro- cedures can be established. A vast amount of published literature and numerous guide- lines for protecting aquatic environments are available to the resource manager. De- cisions regarding natural resource conver- vation will become more effective with improved methods or guid.elines and a. broader knowledge of why and howaquatic organisms respond to various impacts. INTRODUCTION Before the North American continent was populated and developed, the aquatic environments inhabited by trout were pris- l/ tine--i.e., they contained good to excellent water quality, the watersheds were stable, and adequate cover was available. As the settlement of North America progressed, various alterations were made to natural aquatic environments. Timber was removed to clear the land for agriculture and for building materials, streams were dammed and diverted for various purposes, and water quality was changed. As the human popula- tion of this country increased, various laws were enacted that encouraged the further settlement and development of land and wa- ter resources. These early laws were not concerned with the protection of such natur- al resources as fish, wildlife, or wild rivers. In those days, fish and wildlife served as a means of food or plain survival to the people and little thought was given to the conservation of these natural resour- ces that were rather plentiful at that time. In the American Southwest, the dominant em- phasis of most Americans was "mastery-over- nature" in which it became a person's duty to "alter and control" the environment (Kluckhohn and Strodtbeck 1961). This ori- entation encouraged technological advance- ments and development of water resources and was the key to settlement of these arid lands (Crawford and Peterson 1973). Man has intentionally or unintention- ally modified natural aquatic environments as he settled the North American continent and developed water resources to accomodate this expansion. His self-induced overpopu- lation and unbridled technology will bring about even further modifications to aquatic ecosystems that are vital to aquatic organ- isms. This paper will concisely summarize the various types of alterations that have been made to aquatic environments in the United States and provide selected examples of how trout populations have responded to these changes. In addition, a bibliography is provided with selected references that documents the paper and provides a ready starting point to the vast amount of liter- ature that is available on this broad but Present address: U.S. Fish and Wildlife Service, Fisheries Academy, Leetown, Route 3, Box 41, Kearneysville, West Virginia 25430. ?/ The Utah Cooperative Fishery Research Unit is jointly sponsored by Utah State Univer- sity, the Utah Division of Wildlife Resources, and the U.S. Fish and Wildlife Service. 57