Alternative Methods for Measuring Energy Content in Winter Flounder

Abstract

Indices of energy reserves may represent interesting parameters that can be used as bioindicators in environmental studies. The goal of this study was to identify a water–energy model that could predict energy reserves in winter flounder Pseudopleuronectes americanus. Winter flounder kept in captivity and fed different food types (either capelin Mallotus villosus or Atlantic herring Clupea harengus, amphipods Anonyx sarsi, and wet pellets) for 2, 5, and 14 months and wild fish captured in May, July, and October were used to show a large range in energy content. High levels of correlation were observed between water and energy contents in fish carcasses (r ² = 0.82) and muscle (r ² = 0.75). However, the biochemical composition of the liver remained relatively constant, despite changes in the hepatosomatic index. The condition factor (somatic weight/length³) was associated with energy reserves (i.e., water contents), but the coefficients of determination were smaller (0.18 < r ² < 0.34). We found that muscle water content, which can easily be determined, is an efficient way to accurately predict energy reserves in winter flounder.