Calculating fish metabolic rates
Metabolic rate is the rate at which energy and matter are taken up, transformed and allocated to biomass (Brown et al. 2004). We calculated species metabolic rates using body masses and temperature specific to each site and sampling period. Temperature was measured below the water surface (using a thermometer) during fish sampling period. Per gram metabolic rate X was calculated using the following equation:
\(\ln X=ln\ i_{o}+a\times\ln M+\frac{E}{\text{kT}}\),
Where a = 18.8 is the allometric exponent, M is the body mass in g, E = -0.69 is the activation energy, k is the Boltzmann’s constant in eV.K-1, T is the temperature in Kelvin, and io is a normalization factor (Ehnes et al. 2011). Metabolic rates were calculated as joules hour–1 and then converted by joules year–1.