Metabolic and functional impacts of hypoxia vary with size in Atlantic salmon.

Metabolic and functional impacts of hypoxia vary with size in Atlantic salmon. Comp Biochem Physiol A Mol Integr Physiol. 2019 Jan 25;: Authors: Oldham T, Nowak B, Hvas M, Oppedal F Abstract The most capricious environmental variable in aquatic habitats, dissolved O2, is fundamental to the fitness and survival of fish. Using swim tunnel respirometry we test how acute exposure to reduced O2 levels, similar to those commonly encountered by fish in crowded streams and on commercial aquaculture farms, affect metabolic rate and swimming performance in Atlantic salmon of three size classes: 0.2, 1.0 and 3.5 kg. Exposure to 45-55% dissolved O2 saturation substantially reduced the aerobic capacity and swimming performance of salmon of all sizes. While hypoxia did not affect standard metabolic rate, it caused a significant decrease in maximum metabolic rate, resulting in reduced absolute and factorial aerobic scope. The most pronounced changes were observed in the smallest fish, where critical swimming speed was reduced from 91 to 70 cm s-1 and absolute aerobic scope dropped by 62% relative to the same measurement in normoxia. In normoxia, absolute critical swimming speed (Ucrit) increased with size, while relative Ucrit, measured in body lengths s-1, was highest in the small fish (3.5) and decreased with larger size (medium = 2.2). Mass specific metabolic rate and cost of transport were inversely related to size, with calculated me...
Source: Comparative Biochemistry and Physiology. Part A, Molecular and integrative physiology. - Category: Physiology Authors: Tags: Comp Biochem Physiol A Mol Integr Physiol Source Type: research