Introduction: Fishes in a warming and deoxygenating world

This account serves as the introduction to a Special Issue of journal Environmental Biology Fishes. It includes 18 contributions, 12 which deal predominantly with warming, four explicitly deoxygenation, one providing framework, and addressing how warming deoxygenation—which all contributions view, implicitly or explicitly, leading “oxythermic” stress—are used pretext cover up overfishing. The “Mean Temperature Catch” (MTC) concept Cheung et al. (2013, Nature 497:365–368) inspired five studies involving mainly temperature, including its first applications fresh water past, i.e., past 130, 7–8 thousand, 2 million years. Four jointly representing 4200 + populations 1100 species, effect temperature on maximum and/or asymptotic length fish behaving predicted by Gill-Oxygen Limitation Theory (GOLT). theory is also evoked in these explain cold denaturation causes grow smaller size when temperatures decline below 4 °C. These are here summarized whose conceptual affinities presented graphic form tree-like structure, provide basis for understanding changes community composition structure resulting from marine freshwater warming. Jointly, they some behavior position column deoxygenation their habitats.