Metabolic depression in UV-B exposed larval coregonids

Abstract

Exposure to UV-B radiation has been found to have negative effects on fish, such as reduced survival and growth, but sublethal effects, such as metabolic costs of increasing UV-B irradiance, have received little attention. We studied the oxygen consumption rates of vendace and whitefish larvae under enhanced UV-B irradiance in the laboratory. In addition, we studied energy allocation for digestion and activity in whitefish larvae. UV-B exposure had no clear effect on the minimum or routine oxygen consumption rates of vendace larvae, but the metabolic scope of vendace larvae and the maximum oxygen consumption rates of both vendace and whitefish larvae decreased. In the allocation experiments, enhanced UV-B irradiance mainly decreased the oxygen consumption allocated for digestion in whitefish larvae. In the field, the direct impact of increased UV-B irradiance on coregonid digestion and growth will be negligible, but some indirect effects, such as increased risk of predation, are possible.