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<br />C) <br />c, <br />"" <br />(. ... <br /> <br />represented by individuals in the adult size class, These fish were collected from all three <br />major habitat types, however most were found in glide habitat. <br /> <br />G; <br />o <br /> <br />Non-native Fishes <br /> <br />Oncorhynchus clarki (cutthroat trout): Earliest reports of this species from fish surveys <br />within the study area occurred during the 1970s when small numbers of cutthroat trout <br />appeared in collections from the Animas and Piedra rivers, Since these early collections <br />this species has also been reported from Los Pinos River, and Florida River. Historically, <br />this species has been most common in collections from the upstream reaches of the <br />Animas River. It is likely that most cutthroat trout occurred in samples as a result of, <br />attempts to stock this species as a game fish. Cutthroat trout were represented by few <br />individuals during the habitat use study. Limited data suggests that this species frequents <br />pool habitat. <br /> <br />Oncorhynchus mykiss (rainbow trout): The rainbow trout is a non-native species which <br />occurs in the San Juan River drainage. Historically, this species was heavily stocked as a <br />game fish in most tributaries of the San Juan River. Rainbow trout were stocked in the <br />Animas River on a yearly basis for nearly 25 years (Smith 1976), and more than 4 million <br />rainbow trout were stocked into Navajo Reservoir between 1962 and 1968 (Graves and <br />Haines 1969). The earliest report of this species within the study area came from fish' <br />collections on the Animas River during 1954, By 1980 rainbow trout had also been <br />reported from the Florida, La Plata, and Mancos rivers, and every major tributary <br />upstream of Navajo Reservoir. Size and number of fish obtained in some studies <br />suggested that natural reproduction might have been occurring by the 1980s at higher <br />elevations in some tributaries upstream of Navajo Reservoir (Johnson 1987). Sampling <br />during the 1990s indicated that the rainbow trout is continuing to increase in occurrence <br />in most systems. At some of the upper site locations on the Animas River and tributaries <br />upstream of Navajo Reservoir this species has become one of the most abundant fish in <br />collections. The rainbow trout was represented by two size classes, juvenile and adult, in <br />the compiled 1994 habitat use data. Most of the few specimens collected in the juvenile <br />size class were found occupying glide habitat. Although adults were encountered in all <br />three major habitat types, most were collected from pool habitat. <br /> <br />Oncorhynchus nerka (kokanee salmon): This non-native species was only reported from <br />three sampling events during the historical fish sampling of tributaries to the San Juan <br />River. Each report ofkokanee salmon came from a tributary upstream of Navajo <br />Reservoir during the early 1990s. It is likely that reports of this species were the result of <br />spawning migrations from fish that had been stocked into Navajo Reservoir. Kokanee <br />salmon were not encountered during the MEC habitat use study, <br /> <br />Salvelinus fontinalis (brook trout): This non-native species has been stocked in the <br />Animas system and the La Plata River on several occasions since the early I 960s (Smith <br />1976). The brook trout was first reported from fish surveys within the study area during <br />1972. During this time the brook trout appeared in several collections from the Navajo <br /> <br />i,. <br /> <br />Draft Final Tributary Report <br />Miller Ecological Consultants, Inc. <br /> <br />January 31, 2000 <br />Page 22 <br /> <br />" <br />