are provided legal protection by one or more agencies as a result of this legislation. Species of special concern are recognized by agencies as declining in number or distribution, yet too few data are available to determine if they require designation as threatened or endangered. Although special-concern species may not be protected by legislation, they may receive some security through agency recommendations and regulations concerning collecting procedures (Johnson, 1987).
Williams and others (1989) provided a list of North American fishes that were classified as endangered, threatened, or special-concern species. This list consisted of 103 species classified as endangered, 114 as threatened, and 147 as special concern. The highest concentrations of listed taxa in the United States occurred in the southwest (Arizona, California, Nevada, New Mexico, and Texas) followed by the southeast (Alabama, Florida, Georgia, Mississippi, North Carolina, South Carolina, Tennessee, and Virginia).
The collection of species listed as endangered, threatened, or special concern by the Federal government is regulated by the U.S. Fish and Wildlife Service. U.S. Fish and Wildlife Service biologists serving as regional coordinators with the NAWQA Program can assist study-unit biologists in obtaining the necessary Federal permits for endangered, threatened, or special-concern species and ensuring that all regulations regarding these species are observed. Individual States also list and protect endangered, threatened, or special-concern species. Though the process of obtaining additional permits for the collection of these species may vary from State to State, regulations regarding collection must be observed and the necessary permits obtained before collections can be made.
Efficient data collection requires coordination of sampling with other fish ecologists, including agency fisheries biologists, university fisheries scientists and ichthyologists, and fisheries professionals employed by private organizations. These fish ecologists may have ongoing or planned sampling activities within the study unit. Information on the location, timing, and objective(s) of their sampling activities is helpful. Repeated sampling of an area by a number of different fish ecologists may seriously bias fish community data. Repeated collections within a relatively short time period reduces species diversity, thereby providing an erroneous representation of the fish community. Also, coordination of sampling with other fish ecologists may result in collaborative efforts that could enhance the characterization of fish communities in the study unit.
Electrofishing is the use of electricity to capture fish. The electricity is generated by a system whereby a high voltage potential is applied between two or more electrodes that are placed in the water. The voltage potential is created using either of two basic types of electrical current--direct current and alternating current. Direct current leaves the cathode (negative electrode) and enters the anode (positive electrode), flowing in one direction only