Usually, winter and low temperatures are not a huge concern for Portuguese shellfish farmers. High mortality rates among shellfish are typically felt in late spring and summer as water temperatures rise. However, in 2022, in late autumn, mortality rates appear to be higher, reaching 80% in some areas of the Algarve Coastal Lagoon, one of Portugal's main production areas known as Ria Formosa. Other areas in the country such as Setubal and Aveiro, are experiencing higher mortality rates than usual but not as severe as the south coast. Until now, no specific reason was given by the Portuguese authorities or entities, but farmers believe that pollution in the surrounding areas of the lagoon, brought by the current heavy rains or a new pathogen, can be the root cause.