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American white pelican predation on Cui-ui in Pyramid Lake, Nevada

North American Journal of Fisheries Management

By:
, , , and
DOI: 10.1080/02755947.2013.855278

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Abstract

Anthropogenic changes to the Pyramid Lake–Truckee River ecosystem in Nevada are suspected to have altered the predator–prey balance between American white pelican Pelecanus erythrorhynchos and Cui-ui Chasmistes cujus. We estimated the loss of the adult Cui-ui population to pelican predation over a 13-year period by netting and tagging Cui-uis as they aggregated at the mouth of the Truckee River prior to their spawning migration into the Truckee River. Cui-ui access to the Truckee River typically required traversing a shallow delta (a foraging advantage for these American white pelicans). Dams and greater frequency of low stream flows also contributed to American white pelican foraging success. We used tag recoveries from Pyramid Lake's nesting colony of American white pelicans along with an experiment to estimate the chance of tag recovery within the colony to calculate the number of tagged fish taken by American white pelicans. We also used numbered tags to test whether there was a size preference for Cui-uis taken. Our results showed that the primary source of adult Cui-ui mortality was from American white pelican predation in the Truckee River. Within a 13-year period American white pelicans had taken 90% of the tags deployed during the first 7 years of the interval. There was no preference for the size of Cui-uis taken. A better understanding of the effects of heavy cropping by American white pelicans on Cui-ui population dynamics is still needed.

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Additional Publication Details

Publication type:
Article
Publication Subtype:
Journal Article
Title:
American white pelican predation on Cui-ui in Pyramid Lake, Nevada
Series title:
North American Journal of Fisheries Management
DOI:
10.1080/02755947.2013.855278
Volume
1
Issue:
34
Year Published:
2014
Language:
English
Publisher:
Taylor & Francis Group
Contributing office(s):
Western Fisheries Research Center
Description:
11 p.
Larger Work Type:
Article
Larger Work Subtype:
Journal Article
Larger Work Title:
North American Journal of Fisheries Management
First page:
57
Last page:
67
Country:
United States
State:
Nevada
Other Geospatial:
Pyramid Lake