Decline of the Native Fish Fauna of the Sierra Nevada Foothills, Central California

TitleDecline of the Native Fish Fauna of the Sierra Nevada Foothills, Central California
Publication TypeJournal Article
Year of Publication1974
AuthorsMoyle, P. B., & Nichols R. D.
JournalAmerican Midland Naturalist
Date Published07/1974
AbstractA survey was made of the fishes occurring in streams of the Sierra Nevada foothills above the San Joaquin Valley, California. Twenty-four species were collected, 12 native, 12 introduced. The present distributions of these fishes were compared to their pre-1900 distributions, as inferred from old records. Overall, the ranges of introduced species and rainbow trout have expanded while the ranges of native species, especially California roach, hardhead, Sacramento squawfish and Sacramento sucker, have contracted. Healthy populations of native fishes were found only in a rather narrow middle elevation band of comparatively undisturbed sections of foothill streams. The native fish populations in different foothill stream systems are now isolated from each other and are, thus, in danger of local extinction as foothill development proceeds. The study indicates that populations of native stream fishes, even if they do not contain endangered species, should be protected, to make sure that severe natural conditions, when combined with human alterations of the streams, do not destroy unique assemblages of fishes.