7772

• UCREFRP Catalog Number: 7772
• Author: Bestgen, K. R. and M. A. Williams.
• Title: Effects of Fluctuating and Constant Temperatures on Early Development and Survival of Colorado Squawfish.
• USFW Year: 1994.
• USFW - Doc Type: Fort Collins, Colorado.
• Copyright Material: NO

Results
Hatch
Mean hatch at 18, 22, and 26°C in constant and fluctuating regimes was 54-79%
(Table 1) and did not differ significantly among treatments for main effects or for the
interaction (Table 2). When data for constant and fluctuating regimes were combined,
hatch was higher at 18°C than at 22 or 26°C. Hatch at 30°C was 39%.
Survival
Mean survival of larvae to d 7 in the 18-26°C treatments was 52-88% (Table 1), and the
overall ANOVA F-test was significant for both main effects (temperature and regime), but
not for the interaction (Table 2). Survival was highest at 26°C and was significantly
different from the 18 and 22°C treatments; neither of the latter temperature treatments were
significantly different from each other. Survival was higher in each fluctuating temperature
treatment than in the corresponding -constant temperature. Most of the significance of the
overall F-test for regimes was due to higher survival in the 18°C fluctuating than in the
18°C constant treatment. Survival of larvae to d 7 in the 30°C treatment was 12.5%.
Abnormalities
Abnormalities in the 18-26°C treatments was 2-22% (Table 1), and the overall F-test was
significant due to temperature level but not to regime or interaction effects (Table 2).
Lowest incidence of abnormalities was in the 26°C (4%, regime combined) and 18°C
(12.5%) treatments, which were not significantly different. Mean percent abnormalities was
higher in the 22°C treatments (19%); this rate was significantly different only from that
observed in the 26°C treatments. All larvae hatched in 30°C were abnormal.
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