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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27

during the winter to partially offset the drain on lipid
reserves that typically occurs during winter. Shul'man
(1974) noted that fish take up and accumulate lipids during
periods of decreasing water temperatures. pierce et al.
(1980) found that age-O golden shiner Notemiqonus
crysoleucas deposit lipid in late summer to a point where
their energy reserves prior to winter exceed amounts
required for normal maintenance. Large age-O sand smelt
switch energy input from somatic growth to fat reserves
prior to winter (Henderson et ale 1988). As a result,
smaller sand smelt that channeled their energy input into
somatic growth were unable to accumulate adequate fat
reserves and, therefore, consumed their fat reserves and
died during the winter. Henderson et.al. concluded that the
rate of accumulation of fat reserves was size-dependent
because either small fish directed more energy into somatic
growth and maintenance or larger individuals had the
advantage of a wider 'size range of available food. Although
lipid content in wild age-O Colorado squawfish tends to
increase with size of fish (Appendix E), further studies are
needed to determine if lipid accumulation in late fall is
size-dependent.
Below 100 C, young-of-the-year smallmouth bass stop
feeding and become inactive (Oliveret ale 1979). My
observations revealed that at 40 C, captive age-O Colorado
squawfish fed readily and remained active. Because feeding