27.06.2023 – Category 4

There are so many reasons for us to admire cetaceans and feel inspired to learn more about our oceans through them. They are the ocean’s intelligent natives, using their resourceful nature to survive in an ever-changing environment. One of the biggest impacts on marine life is currently taking place through climate change and, this year, the Atlantic Ocean is experiencing unprecedented series of heat waves listed as category 4 by NOAA (the National Oceanic and Atmospheric Administration). 

Scientists in the North Atlantic Ocean are sounding the alarm, with recent readings showing temperatures 5 degrees celsius higher than usual in some parts of the Atlantic. The deep water around Madeira and the sand carried by North easterly winds from the Sahara are thought to dilute these effects, but this year’s El Ninō is thought to bring more heat waves and drought to the Atlantic and its coastlines.

While heat waves may have catastrophic effects on coastal species, particularly molluscs, fish, coral and seagrasses, they could change the way cetaceans use their habitats. Long term research is needed to really conclude effects on these long-lived animals but heat waves will undoubtedly change ocean physics, which in turn affects prey availability. This may particularly impact our seasonal visitors, which include the Atlantic spotted dolphins (Stenella frontalis) and the Short-beaked common dolphins (Delphinus delphis). Both species are often seen pursuing plantivorous fish, whose occurrence largely depends on the nutrients transported by ocean currents. A changing climate would affect such currents and may impact the availability of prey for these marvellous predators.

Scorching heat at the surface can also affect cetaceans. Our team sees more and more melanistic common dolphins every year, which could be a mutation occurring in the face of climate change. Hot sea temperatures near the coastline may also prompt animals to seek deeper, colder waters further offshore, affecting our sightings. 

It’s not just the cetaceans that are affected by these scorching temperatures – the region meteorological centre issued a red warning for the southern coast today, warning locals and tourists about the high temperatures. Our team did its best to keep our clients comfortable during this incredibly hot day and encouraged everyone to stay hydrated and wear sun protection. 

By Paula Thake

Sightings of the day

Ribeira Brava

09:30 Atlantic spotted dolphins

Stenella

09:30 Atlantic spotted dolphins

13:30 Atlantic spotted dolphins, Short-beaked common dolphins

16:00 Atlantic spotted dolphins, Short-beaked common dolphins