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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RESULTS

Length measurements taken from all three size classes
of fish subjected to each feeding regime at the beginning
(day 0) of the winter period and on days 70, 140, and 210
(end of winter period) showed that the Colorado squawfish
grew little at winter temperatures (Table 3). Increases in
total length over time were slight, and although some were
statistically significant, small differences between means
of large sample sizes are not necessarily significant from a
biological perspective (Toneys and Coble 1979). High
nitrite levels during the first 70 days of the experiment
(Appendix I) resulted in high mortality among medium fish.
Medium fish that died during the first 70 days were replaced
with slightly smaller fish. consequently, comparisons of
lengths, weights, condition factors, and lipid content for
medium fish were valid only among days 70, 140, and 210.
Declining condition factor during winter has been
reported for rainbow trout Oncorhynchus mykiss (Reimers
1963), brook trout Salvelinus fontinalis (Hunt 1969), and
brook and brown trout Salmo trutta (Cunjak and Power 1987).
I found that condition factor decreased significantly for
small and large fish between days 0 and 210. Although
condition also declined significantly for medium fish, these