During the study, the waters of the Mediterranean Sea, North Atlantic, and the northeastern Pacific Ocean were analyzed. The researchers examined over 700,000 data points on biomass changes, collected from nearly 34,000 fish populations between 1993 and 2021.
Additionally, the study revealed a paradoxical effect of heatwaves: in cold waters, they can temporarily increase fish biomass by 176%, while in warm areas, this leads to a sharp decline of up to 43.4%. The authors of the study note that such short-term growth can create a false impression of population status: if fishing quotas are increased based on temporary population surges, the populations may be at risk when temperatures return to normal or under prolonged warming conditions.
The scientists urge a reevaluation of traditional methods for managing fish resources. They highlight three main changes that need to be made: the introduction of emergency protective measures in the face of sharp temperature changes, consideration of long-term biomass reductions when planning quotas, and the necessity for international coordination, as fish populations move across borders in search of more comfortable temperatures. The authors believe that static national management models are outdated in the context of a changing climate.
