The fishing season needs to start 45 days later to protect economic species

Scientists from Istanbul University Faculty of Aquatic Sciences, Istanbul University Institute of Marine Sciences and Management, and Middle East Technical University Institute of Marine Sciences investigated the effects of rising surface water temperatures in the Sea of Marmara, driven by climate change, on economic fish species.

The study, which focused on anchovy, bonito, bluefish, and young bluefish (çinekop), examined the fishing seasons for these species on a monthly basis between 2000 and 2022.

The research indicated that these species perform a reproductive migration from the Mediterranean through the Sea of Marmara to the Black Sea, known as 'anavaşa' in the spring, and a reverse migration from the Black Sea to the Mediterranean for overwintering in the autumn, known as 'katavaşa', and that this entire migration calendar is related to water temperature and the associated availability of food.

While it was determined that the surface water temperatures of the Sea of Marmara increase by 0.05 degrees each year and that this effect is felt throughout the basin, it was found that the migration calendar of fish species has changed due to the warming surface water.

According to the results of the study, there have been changes in the start and end periods of the fishing seasons for these species over the years. The start of the fishing season for bluefish and bonito has shifted from mid-September to mid-October, while the start of the fishing season for anchovy has shifted from mid-November to mid-October. Looking at the end dates of the fishing season, the season for bluefish and bonito, which used to end in mid-January, has moved back to mid-December, while the season for anchovy has moved back from February to mid-January. No difference was observed in the fishing periods for young bluefish (çinekop).