Small pelagic fishes (SPF) have extreme ecological and economical importance in marine ecosystems. Nonetheless, SPF are particularly vulnerable to environmental changes, being ectothermic, their performance is highly dependent on aerobic metabolism and on sea surface temperature. In this project, we will implement a multidisciplinary approach to determine the impact of temperature increment on SPF, using the European pilchard Sardina pilchardus as a model-system. We aim to understand the response of two different populations of sardines in terms of metabolic, physiological, reproductive and behavioural responses to climate change. The adaptation to changing environments and how organisms will respond to climate change are key discussion topics in contemporary biology and this project will contribute with novel and original findings to the study of the biological and ecological adaptation of marine fishes to ocean warming.