Development and evaluation of a bioenergetics model for bull trout

We conducted laboratory experiments to parameterize a bioenergetics model for wild Bull Trout Salvelinus confluentus, estimating the effects of body mass (12–1,117 g) and temperature (3–20°C) on maximum consumption (C _max) and standard metabolic rates. The temperature associated with the highest C _max was 16°C, and C _max showed the characteristic dome-shaped temperature-dependent response. Mass-dependent values of C _max (N = 28) at 16°C ranged from 0.03 to 0.13 g·g⁻¹·d⁻¹. The standard metabolic rates of fish (N = 110) ranged from 0.0005 to 0.003 g·O₂·g⁻¹·d⁻¹ and increased with increasing temperature but declined with increasing body mass. In two separate evaluation experiments, which were conducted at only one ration level (40% of estimated C _max), the model predicted final weights that were, on average, within 1.2 ± 2.5% (mean ± SD) of observed values for fish ranging from 119 to 573 g and within 3.5 ± 4.9% of values for 31–65 g fish. Model-predicted consumption was within 5.5 ± 10.9% of observed values for larger fish and within 12.4 ± 16.0% for smaller fish. Our model should be useful to those dealing with issues currently faced by Bull Trout, such as climate change or alterations in prey availability.