18.07.2019 – A sign of the times

While all seasons are ideal for whale-watching in Madeira, I think its safe to say that we are all children of the summer here at Lobosonda, The calm conditions and bright sunshine add an extra touch of delight to the variety of marine encounters we are able to enjoy during this exciting time of the year. 

Apart from the expected encounters with Atlantic spotted dolphins (Stenella frontalis), a charismatic and cheeky species of dolphin that is abundant during the warmer months, we also have sightings with larger animals including medium-sized Baleen whales (Balaenopteridae) and groups of Sperm whales (Physeter macrocephalus). As if these encounters aren’t magnificent enough, summertime often gives us a glimpse into the true diversity of the deep waters of the Atlantic. 

Madeira’s geographical position and underwater topography occasionally allow cold waters from the deep to reach the oligotrophic waters at the surface, replenishing them with nutrients. This allows a proliferation of zooplankton, which are not only indulged on by baleen whales or plantivorous fish at the surface. Deep sea fish and cnidarians also surface at night to feed on the abundant plankton, some even remaining in shallower areas of the water column during the day to feed and, in turn, becoming an easy meal for different species of cetaceans, sharks and sea turtles. Apart from the occasional basking Loggerhead turtle (Caretta caretta), our team aboard the Stenella spotted a Warming’s lantern fish (Ceratoscopelus warmingii) struggling at the surface, a mesopelagic fish that only migrates to shallower waters after dusk and clearly did not dive back into the dark ocean in time.

The diversity of the deep also invites other visitors who don’t mind searching for their prey in deeper waters and will not wait for nightfall to hunt for food. The shy Pygmy sperm whale (Kogias breviceps) is one of the few species that our spotter often enjoys better observations of than we do. The timid nature of these mysterious cetaceans remind us of that of the beaked whales where most of what is known about them comes from the examination of stranded carcasses. At this time last year, in fact, our team had reported a dead carcass of this species to scientists at the whale museum who then performed a necropsy to determine the cause of death . Often, such carcasses serve as a feast for sharks patrolling the islands waters, like the one spotted by our zodiac today. Analysis of the stomach content of Pygmy sperm whales has shown that they primarily feed on cephalopods and tend to be sighted in offshore, upwelling areas like the waters off Madeira island.  

Unfortunately the individual was only observed by our spotter today and hastily dove before the Ribeira Brava could reach it in time. Nevertheless, it is humbling to know that these mysterious and rare deep-sea creatures swim amongst our more frequent visitors in the beautiful blue waters surrounding the archipelago. 

By Paula Thake

Sightings of the day

Ribeira Brava

13:30 Atlantic spotted dolphins, Baleen whale

17:00 Atlantic spotted dolphins, Pygmy sperm whale, Short-beaked common dolphins

Stenella

09:00 Atlantic spotted dolphins

12:00 Atlantic spotted dolphins, Sperm whale

15:30 Bottlenose dolphins, Short-finned pilot whales