Short‐beaked common dolphins in the Gulf of Corinth are critically endangered

1. Local populations ('subpopulations') of globally abundant species can be exposed to human impacts that threaten their viability. Given the value of cetacean subpopulations as Evolutionary Significant Units, keystone and umbrella species, it is important to assess their conservation status separately and propose area-specific conservation measures. 2. We used a threat assessment process and applied IUCN Red List criteria to a regional population of short-beaked common dolphins Delphinus delphis in the semi-enclosed Gulf of Corinth, Greece. Available population-specific information about abundance and trends were compiled. The geographic range of the population (Area of occupancy and Extent of occurrence) was estimated, and the probability of extinction calculated through stochastic population modelling. 3. The subpopulation qualified as Endangered according to criterion A (population size reduction over three generations) and B (geographic range), and as Critically Endangered under criterion C (population size and decline) and D (very small or restricted population). The probability of extinction was estimated to be ≥ 50% in three generations, qualifying the subpopulation as Critically Endangered under criterion E (quantitative analysis). We concluded that the subpopulation should be classified as Critically Endangered. 4. Considering the high extinction risk faced by this subpopulation we recommend that a) immediate action is taken to mitigate anthropogenic impacts known or suspected to have a negative impact on cetaceans in the area (particularly commercial fishing, underwater noise, pollution and maritime traffic) and b) a Marine Protected Area is established in the Gulf of Corinth as a management tool for enforcing conservation action and facilitating the recovery of common dolphins.