The recovery of American white pelican (Pelecanus erythrorhynchos) populations could influence the management of valuable sport fisheries across their range. At Strawberry Reservoir, Utah, predation by seasonal flocks of pelicans on Bonneville cutthroat trout (Oncorhynchus clarkii utah) raises concerns about trout spawning and survival. In this study, we will estimate the numeric impact of pelican predation on cutthroat trout and other fishes (e.g., rainbow trout O. mykiss, kokanee salmon O. nerka, and Utah chub Gila atraria) in Strawberry Reservoir. We will investigate if the presence and foraging behaviors of pelicans suppresses cutthroat trout spawning success and movement. To accomplish this, we will experimentally manipulate the distribution of pelicans via selective hazing techniques. We will then monitor the behavioral response of cutthroat trout to the presence or absence of pelicans through redd and fish counts, as well as tracking movement into and out of the spawning tributaries via PIT-tag detection arrays. We will use data from our field collections to develop a population model, to estimate the mortality experienced by cutthroat trout due to pelican predation , and determine if the level of predation is sufficient to reduce overall trout abundance, relative to other sources of mortality. Presented here is a synthesis of previous studies that investigated the role of pelican predation on fish populations, as well as preliminary pelican counts and evidence of pelican predation on stocked cutthroat trout in Strawberry Reservoir.
Available at: http://works.bepress.com/frank_howe/2/