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Distribution and abundance of pelagic fish in Lake Powell, Utah, and Lake Mead, Arizona-Nevada

Western North American Naturalist

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Abstract

Pelagic fish communities (waters with depths >20 m) of Lakes Powell and Mead were examined quarterly from 1995 to 1998 using vertical gill nets and a scientific echosounder. Nets captured a total of 449 fish consisting of striped bass (57%/45% [Lake Powell/Lake Mead]), threadfin shad (24%/50%), common carp (15%/4%), walleye (3%), channel catfish (2%), and rainbow trout (<1%). Each reservoir contained concentrations of pelagic species separated by expanses of habitat with few fish (<10 kg·ha⁻¹). Reservoirs experienced dramatic seasonal and annual fluctuations in pelagic biomass. Lake Powell's biomass peaked at the Colorado River at 709.7 (± 46.5) kg · ha⁻¹ and Lake Mead's reached 291.9 (± 58.2) kg · ha⁻¹ at Las Vegas Wash. These locations supported estimated fish densities of 124,668 fish · ha⁻¹ and 15,131 fish · ha⁻¹, respectively. Maximum reservoir biomass peaked in August 1996, with Lake Powell supporting 10,852,738 ± 5,195,556 kg (27.6 × 10⁻ fish) and Lake Mead 1,926,697 ± 892.994 kg (10.8 × 10⁻ fish). Biomass ebbed in May (1996 and 1997), when Lake Mead supported 65% (296,736 kg vs. 453,097 kg) and 62% (101,016 kg vs. 162,262 kg) of biomass levels found in Lake Powell.

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Additional publication details

Publication type:
Article
Publication Subtype:
Journal Article
Title:
Distribution and abundance of pelagic fish in Lake Powell, Utah, and Lake Mead, Arizona-Nevada
Series title:
Western North American Naturalist
Volume:
64
Issue:
3
Year Published:
2004
Language:
English
Publisher:
Monte L. Bean Life Science Museum, Brigham Young University
Contributing office(s):
Fort Collins Science Center
Description:
6 p.
First page:
306
Last page:
311
Country:
United States
State:
Arizona, Nevada, Utah
Other Geospatial:
Lake Mead, Lake Powell