9524

• UCREFRP Catalog Number: 9524
• Author: Kitcheyan, C. D. and e. al.
• Title: Evaluation of the Effects of Stage Fluctuations on Overwinter Survival and Movement of Young Colorado Pikeminnow in the Green River, Utah, 1999-2002.
• USFW Year: 2004.
• USFW - Doc Type: Denver.
• Copyright Material: NO

Movement Rates under Simulated Winter Conditions Component
Young-of-year Colorado pikeminnow ranging from 45 to 55 mm TL were acclimated to
laboratory conditions. Movement rates were quantified by video interpretation of movement of
individual Colorado pikeminnow in an observation arena at four water temperatures (1, 5, 10, and 15°C)
and at three levels of disturbance (0, 1, and 2 disturbance/min). Regression analysis was used to fit
observed data to models that describe rates of movement as functions of water temperature and
disturbance. The best approximating models were identified using Akaike's information criterion
(Burnham and Anderson 1998).
Bioenergetics Model Component
Construction and Evaluation ofBioenergetics Model
The bioenergetics model was constructed specifically for Colorado pikeminnow life stages and
temperature conditions that occur during winter in the Green River near Jensen, Utah. Energetic
characteristics of age-0 Colorado pikeminnow that were measured included: food consumption as a
function of fish size and water temperature; and metabolic rate as a function of fish size, water
temperature, and activity. Performance of the bioenergetics model was evaluated in two steps. First, the
model was used to estimate food consumption and respiration of Colorado pikeminnow in laboratory
studies described in this paper and the predicted outcomes were compared to observed responses. The
second evaluation step involved comparing modeled growth of Colorado pikeminnow to observed data
from an independent experiment (Thompson 1989).
To evaluate the effect of increased activity on overwinter survival, six simulations were
conducted using a variety of realistic fish sizes, temperature regimes, activity rates, and feeding
conditions. Each simulation started with fish sizes of 35, 45, or 60 mm TL feeding at 10% of maximum
ration for 118 d. At the end of each day, total length and fish condition (K) were updated. If fish growth
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