Laserfiche WebLink
Missouri River basin due to introductions. These smaller and more laterally compressed <br />centrarchids include a variety of fishes stocked as game fish, including the crappies, <br />which are predaceous species that prey on small fishes, and redear sunfish, which <br />mainly prey on crustaceans, and bluegill, which are mainly insectivores. Other species <br />that are incidentally stocked include green sunfish, which is an especially aggressive <br />species with a relatively large mouth. Green sunfish preys on or competes with many <br />other fishes (e.g., Lemly 1985), and can eliminate native plains fishes from preferred <br />habitats (Lohr and Fausch 1996). All sunfishes should be suspected of preying on eggs <br />and/or young of other species. <br />— ictalurid bullheads and catfishes. Ictalurids eat a wide variety of food items, but all <br />should be suspected of consuming eggs and young of other species. As bullheads and <br />channel catfishes attain large adult sizes they also become more piscivorus. Bullheads <br />and channel catfishes are known to consume endangered chubs in the Colorado River <br />(Marsh and Douglas 1997). Because of their aggressive nature and inclination to eat <br />anything (see Tyus and Nikirk 1990) stockings of channel catfish are thought to be an <br />agent in the decline of humpback chub in the Yampa River of Colorado (Tyus 1998). <br />— exotic carps. Now one of the most abundant fish in the Missouri River basin, common <br />carp were widely introduced into the United States beginning in1877 (Laycock 1966). <br />Prior to extensive habitat alteration, few introduced fishes established populations in the <br />mainstream Missouri River, but common carp, introduced in 1879 has been the most <br />successful (Pflieger 1997). This highly- competitive and hardy species was widely <br />extolled as the "wonder fish from Europe" in the 19th century, but in the early 2e century <br />the fish was considered a "scourge and without friends" (Laycock 1966). Common carp <br />has been accused of degrading native fish habitats in the U.S. for over 100 years. Carp <br />eat the eggs of other fishes, including those of sturgeons, and have been implicated in <br />the decline of the endangered razorback sucker (Fuller et al. 1999). <br />Grass carp and bighead carp populations also are established in the Missouri <br />River, and silver and black carps also have been reported. The effects of these latter <br />carps, referred to as "Chinese carps" on native fishes is unknown, but at least one or <br />more of these species may compete with paddlefish, bigmouth buffalo, and other <br />species (Pflieger 1997). <br />The Great Lakes Fishery Commission (19 June 2002 letter from U.S. Chairman <br />Henson to the U.S. Subcommittee on Energy and Water) and the U.S.— Canadian Joint <br />Committee (5 July 2002 letter to the U.S. Secretary of State and the Canadian Minister <br />of Foreign Affairs) have requested immediate action pursuant to the Boundary Waters <br />Treaty of 1909, to stop the spread of three species of Asian carp (bighead, black and <br />silver carp) into the Great lakes. These agencies fear greater adverse impact on the <br />Great Lakes than has occurred from invasions of the parasitic sea lamprey that <br />destroyed the Lake Trout fisheries, or from the zebra mussel that resulted in <br />catastrophic losses to the power industry and has substantially altered Lake Erie and <br />Lake St. Clair ecosystems. <br />KII <br />