Influences of the Longnose Sucker on the Early Life Stages of Cutthroat Trout in Tributaries of Yellowstone Lake, Yellowstone National Park, Wyoming.

Abstract

The purpose of this study was to determine what, if any, influences the longnose sucker (Catostomus catostomus) have upon the cutthroat trout (Salmo clarki) population with special reference to early life stage interactions. The specific objective of this investigation was to determine if the introduced sucker was having a deleterious effect upon the growth and survival of indigenous trout fry. Cutthroat trout and longnose suckers use tributaries of Yellowstone Lake as spawning areas and the potential for intraspecific competition between fry of both species is considerable. The maintenance of an ecologically sound population of cutthroat trout in Yellowstone Park is a prerequisite to the National Park Service policy of maintaining native flora and fauna in national parks.