Our new study, which examines the changes in the 20-year catch data of anchovy, horse mackerel, sardine, bonito and bluefish species and the increase in the surface water temperature of the Marmara Sea, reveals that fish with shifts in their fishing calendars face dangerous levels of fishing pressure. According to the study we published with Assoc. Prof. Taner Yıldız and Assoc. Prof. Ekin Akoğlu, which shows that there are shifts in the well-known fishing calendar of fish due to climate change, the migration of fish such as bonito and bluefish is delayed as the water temperature cools: The fishing seasons that started in mid-September have now shifted to mid-October. In this situation, fishing is concentrated on species such as anchovy and horse mackerel. When bonito and bluefish arrive in the Marmara Sea with a delay, the amount of fish that make up their main food source is considerably reduced.