As they were removed from the swim tunnel, fish were sacrificed by cerebral dislocation. The heart ventricle, the liver and the remaining viscera were excised, emptied, wiped on absorbent paper and weighed to the nearest hundredth of a gram. Gill arches were also dissected and gill lamellae carefully collected and weighed. The heart ventricle was placed in an ice-cold dish until processed for myofibers oxygen consumption measurement (below).