Water Temperature Found to Drive Seasonal Shifts Between Dolphin Species in the Azores

A new study has revealed that water temperature is the key factor determining how common dolphins and Atlantic spotted dolphins share space in the Azores. Using 15 years of dolphin‑sightings data and species distribution models, researchers discovered a clear temperature threshold around 21°C that explains their seasonal patterns: common dolphins dominate cooler waters below this point, while Atlantic spotted dolphins become far more prevalent once temperatures rise above it. The study also found that month‑to‑month shifts in temperature strongly influence how much the two species overlap at sea. These findings highlight how sympatric species—those that live in the same area—use environmental cues to reduce competition, and they provide important insights into how future ocean warming could reshape dolphin distribution in the region.

Read full publication here: Silva, M. I. P., Tobeña, M., Machete, M., Silva, M. A., and Pérez Jorge, S. Water temperature drives the segregation between common and Atlantic spotted dolphins in Azorean waters. Global Ecology and Conservation 62 (2025). https://doi.org/10.1016/j.gecco.2025.e03769