13.01.2020 – Mixed feelings

Despite the agreeable conditions, our Stenella had to cover a huge search area before finally stumbling upon small, dispersed pod of Short-beaked common dolphins (Delphinus delphis). These gorgeous dolphins aren’t just swift, elegant swimmers; they are also impeccable hunters and today it seemed Half-beaks (Belone belone) were on the menu. The dolphins occasionally leapt at the surface, exposing their decorative flanks to our guests. They use this strategy to intimidate and confuse the school of fish, who swim away terrified just beneath the surface.  

Dolphins weren’t the only ones indulging on the Halbeaks; our return to the marina was shortly interrupted by some Bigeye tuna (Thunnus obsesus) that leapt high into the air as they lunged at their prey. All tuna species have different hunting tactics, most of which are highly coordinated group efforts that at first glance may look very similar to the strategies used by dolphins. Bigeye tuna are amongst the most versatile of the tuna, being able to withstand the high pressures and cold whilst foraging in deeper waters and tolerate low oxygen levels. 

Although it is indeed amazing to see a species with a vulnerable conservation status to hunt in the wild, I couldn’t help but have mixed feelings about this sighting. It’s currently tuna season in Madeira and we already saw fishermen preparing the long-line buoys as we left the marina. Bigeye tuna belongs to one of the more vulnerable species of tuna, prompting the ICCAT (International commission for the conservation of Atlantic Tunas) to set stricter and lower catch limits for the species. Conservationists are also calling for stricter regulations on bycatch, particularly sharks; the Halfbeaks are a perfect example of how different species share the taste for the same prey.

There were some animals on the ocean today with little interest for Halfbeaks or Tuna. A couple of By-the-wind-sailors (Velella velella) drifted by our zodiac, their tiny blue tentacles reaching out into the water for zooplankton. We managed to fish one of these tiny siphonophores out of the water to display it to our guests before we made our way back to the marina.

 By Paula Thake

Sightings of the day

15:00 Short-beaked common dolphins