Sixgill Sharks And Zombie Worms: Unseen Azores Marine Life

Situated to the west of continental Portugal, the Azores archipelago is one of the most popular whale and dolphin watching destinations in the world. The cetacean rich waters of the Atlantic Ocean are home to numerous species of both, with dedicated whale anddolphin watching cruises providing the potential for some thrilling close encounters.

But the much-loved cetaceans are not the only marine creatures that make their home in the ocean surrounding the archipelago. Warmed by the waters of the Gulf Stream, this part of the world attracts some of the most fascinating creatures on Earth. While not all of them can be seen on whale and dolphin watching cruises, thanks to Sir David Attenborough's Blue Planet II documentary series, at least we know they're there…

Whalefall Feeding in the Deep

The Blue Planet II series provides unprecedented access to one of the last frontiers – our deepest oceans. Far below the surface of the Atlantic, in the Azores, the team captured the world's first vision of "whalefall" feeding from a specialised submarine, making a massive contribution to scientific research in the process.

Sixgill Sharks and Zombie Worms

Attenborough's team attached a transponder to a whale carcass before loading it with weights. As it sank to the seabed 750m below, the scientists and cameraman descended alongside in the Blue Planet II submarine. 

Even before the 30-tonne carcass hit the seabed, they captured dramatic footage of a group of six-metre deep-water sharks tearing it apart in a feeding frenzy. Unlike other species of sharks, as the name suggests the sixgill species of sharks (belonging to the Hexanchidae family) has six gills instead of the usual five - a more common characteristic of the prehistoric shark form. Due to its inaccessible habitat very little is known about this deep-water predator, so the Blue Planet II footage provides valuable scientific data to aid research.

At the other end of the scale, the Blue Planet II episode also features incredible vision of the bizarre looking zombie worms (Osedax roseus), which feed exclusively on the bones of the whale carcasses as they lie at the bottom of the ocean. These alien-like deep-water worms excrete an acid to help them burrow deep into the bones in order to feed on the fat within. Not only are the organisms sexually dimorphic, the microscopic males actually live inside the females, allowing them to produce vast numbers of eggs at will.  

Unravelling the Mysteries of the Deep

Just what happens to the carcasses of dead whales when they sink into the abyss of the deepest oceans had never before been witnessed, and the footage captured in the Azores is as unnerving as it is compelling. The sight of such a majestic creature being reduced to shark and worm fodder could be construed as sad, but in following its final journey scientists have been afforded a valuable insight into some little-known aspects of marine ecology. 

For nature lovers planning to visit the spectacular Azores archipelago, dedicated whale and dolphin watching cruisesare the ideal way to ensure the best sightings close to the surface of the water. But through Blue Planet II, Sir David Attenborough makes us all witnesses to the astounding mysteries that exist in the deepest reaches of the Atlantic Ocean.

Author Plate 

Marissa Ellis-Snow is a freelance nature writer with a special interest in whale and dolphin watching. As a passionate lover of marine wildlife, Marissa chooses the expert-led dolphin watching cruises organised by Naturetrek, which have brought her unforgettable sightings of a wide range of wildlife in some of the most spectacular regions on Earth.