7785

• UCREFRP Catalog Number: 7785
• Author: Thompson, J. M.
• Title: The Role of Size, Condition, and Lipid Content in the Overwinter Survival of Age-0 Colorado Squawfish.
• USFW Year: 1989.
• USFW - Doc Type: Colorado State University,
• Copyright Material: NO

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ABSTRACT OF THESIS
THE ROLE OF SIZE, CONDITION, AND LIPID
CONTENT IN THE OVERWINTER SURVIVAL
OF AGE-O COLORADO SQUAWFISH

Three size classes (small = 30 mm, medium = 36 mm, and
large = 44 mm) of hatchery-reared age-O Colorado squawfish
were held at simulated winter temperatures (3-40 C) in
aquaria for 210 days to assess the role of size, condition
factor, and lipid content on overwinter survival. Fish of
each size class were divided among six aquaria and furnished
one of three feeding regimes: dry-pellet-fed, starved, and
brine-shrimp-fed. - Fish in all size classes fed at winter
temperatures, and feeding activity was inversely related to
fish size. On each of days 70 and 140 of the simulated
winter period, one-fourth of the surviving fish in each
aquarium were removed and measured to determine length and
condition factor. The fish grew little, and condition
declined as length of exposure to winter conditions
increased. Condition declined more rapidly in starved than
in fed fish in all size classes. Lipid content of fish
was inversely related to winter duration for all size
classes and feeding regimes. Percent survival was
significantly lower in starved small and medium-sized fish

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