A new study analyzes the larval dispersal of nine fish species in the western Mediterranean and identifies three large areas in which there is barely fish exchange, so fish would remain in the same area all their life. The study, published in the journal Progress in Oceanography, is led by experts of the Faculty of Biology of the University of Barcelona and the Biodiversity Research Institute (IRBio) of the UB, the Blanes Center for Advanced Studies (CEAB-CSIC), the Balearic Islands Coastal Observing and Forecasting System (ICTS—SOCIB), and the Mediterranean Institute for Advanced Studies (IMEDEA, CSIC-UIB).