Competition between Kokanees and Utah Chub in Flaming Gorge Reservoir, Utah–Wyoming
作者:
David Teuscher,
Chris Luecke,
期刊:
Transactions of the American Fisheries Society
(Taylor Available online 1996)
卷期:
Volume 125,
issue 4
页码: 505-511
ISSN:0002-8487
年代: 1996
DOI:10.1577/1548-8659(1996)125<0505:CBKAUC>2.3.CO;2
出版商: Taylor & Francis Group
数据来源: Taylor
摘要:
KokaneesOncorhynchus nerka(lacustrine sockeye salmon) and Utah chubGila atrariafeed extensively on similar sizes and species of zooplankton in Flaming Gorge Reservoir. We measured the effects of Utah chub on the growth of kokanees in six 80-m3enclosures containing ambient zooplankton populations. Three kokanees and 0, 3, 6, 12, or 24 Utah chub were weighed and placed in each enclosure. After 21 d, fish were removed and kokanee growth was compared among treatments. Zooplankton biomass, chlorophyll-aconcentrations, and temperature profiles were monitored during each test. In May 1992, no competitive interactions were observed; in June 1992, however, zooplankton biomass and kokanee growth declined significantly as Utah chub densities increased. The best predictor of kokanee growth wasDaphnia pulexdensity, which explained 76% of the variance in kokanee growth. Differences in temperature and initial zooplankton biomass affected the strength of observed competition. Our results suggest that monitoring forage resources rather than nongame fish densities may provide a better framework for assessing competition among pelagic fish species.
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