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of liquid rotenone to 259 km of streams. This project met all of <br />its objectives and has been considered a success (Lentsch et al. <br />in press). <br /> <br />Mechanical Control.-Mechanical-removal methods include <br />traps, seines, gill nets, barriers, electrofishing, and <br />harvesting (commercial and recreational). Species in the <br />families Cyprinidae, Catostomidae, Centrarchidae, and Percidae <br />are fishes most commonly targeted for control by mechanical <br />methods in the United States. Combinations of control methods <br />may be necessary to reduce different age classes of a species or <br />reduce target species when they are most vulnerable to particular <br />methods (Wiley and Wydoski 1993). <br />Mechanical-removal efforts are often attempts to thin <br />populations of undesirable fishes to improve the size structure <br />of gamefish populations. Rose and Moen (1953) reported an <br />increase in numbers of game fish in East Okoboji Lake, Iowa, <br />after intensive removal of nongame fishes. Pierce et al. (1963) <br />also reported a positive response in populations of gamefishes <br />after removal of golden shiner Notemigonus crysoleucas by netting <br />from a lake in Georgia. Crawford (1957) and Hulsey (1956) <br />documented an increase in numbers and weight of gamefish after <br />removal of 93,000 kg of undesirable fishes in Lake Nimrod, <br />Arkansas. <br />Mechanical removal of undesirable fishes, however, does not <br />necessarily improve populations of gamefishes (i.e., Hacker 1952; <br />26