A migration game model is suggested to resolve adaptive migration in direction of increasing fitness over a complex global network of distant habitats. Many factors contribute to the migration process of highly migratory species and of primary importance are individual and collective dynamics regulating intra-specific competition and habitat selection processes. When applied to the Atlantic bluefin tuna the model predicts patterns of migration resembling those commonly observed for this species and predicts new migratory routes under future climate change scenarios.

Competition between jellyfish and forage fish for zooplankton prey is both a possible cause of jellyfish increases and a concern for the management of marine ecosystems and fisheries. Identifying principal factors affecting this competition is therefore important for marine management, but a lack of good quality data and a general theoretical framework have prevented general global analyses. We have developed a general mechanistic food web model that considers fundamental differences in feeding modes and predation pressure between fish and jellyfish.