The fin whale encounter

In 2021, we witnessed incredible feeding behavior from one of the largest animals on Earth: the fin
whale. It was a calm day in August at the mouth of Isfjorden, just outside the Longyearbyen
settlement in Svalbard. We were surrounded by blows as far as the eye could see. Our best estimate
was about 50 individuals, in scattered, fast-moving groups of around 10 individuals on average. After
a while, we came across two fin whales that were somewhat more stationary. I asked
cinematographer and surf photographer Hugo Petit if he was ready to get in, and he was.

The video above shows a small extract of what we witnessed during a feeding session that lasted
well over an hour. The fins were feeding on capelin, a small pelagic fish. They were joined by a pod
of white-beaked dolphins, making it all the more exciting. The whales were undisturbed by our
presence and seemed somewhat curious. Our biggest concern was being engulfed by the whales. As
they sped through the water with open mouths, their throat grooves expanded to hold up to 70 tons
(a small swimming pool) in a single mouthful.

Fortunately, Hugo and I avoided ending up like Jonah. We got back onboard Barba with nothing but
smiles, good memories, and some exciting bits of film. For Hugo, it was his first whale dive. For me, it
was my first underwater fin whale encounter and one of my better whale encounters to date.

Andreas

BACKGROUND

The footage was captured as we sailed and embarked on the Jan Mayen chapter of the Arctic Sense
expedition. During our dive, the vessel was safeguarded by Jaap Van Rijckervorsel, Hugh Francis
Anderson, and Annik Falck. An extended version of the encounter can be seen in the documentary
“Tales of Jan Mayen”, which premiered at the Kendal Mountain Film Festival in the fall of 2022.

IN-DEPTH ANALYSIS

As for a more in-depth analysis of the encounter, we asked Tom Grove from Whale Wise to provide
some context:

This footage is remarkable enough – fin whales are enigmatic, difficult to approach, and relentlessly
quick. In the video, we see fin whales release huge, concentrated clouds of bubbles, moving
explosively toward the surface. These clouds appeared to be close to the capelin shoals, suggesting
that they were being used to capture prey. We already know that some whales use bubbles to
forage for many years, none more famous than the huge bubble nets created by Alaskan humpback
whales to trap herring. Fin whales are also known to use bubbles, but to our knowledge, this has
never been observed underwater. How do these bubble clouds help with foraging? Their function
remains an enigma, but footage like this could lead us one step closer to finding out.

As for fin whales, they are an underappreciated marine mammal. The second-largest animal on Earth
(only to blue whales), fins can grow to 26 m long and 80 tons. Built for hydrodynamic movement, fin
whales are known as the ‘greyhounds of the sea’ and can sustain speeds between 37 km/h (23 mph)
and 41 km/h (25 mph). Fin whales are filter feeders – after engulfing an entire shoal of krill or fish,
they force the water out through baleen plates to leave their prey behind. Using this technique, fin
whales can consume two tons of prey in a single day.

They are true leviathans. It’s hard to believe that we humans decimated fin whale populations
worldwide: in the mid-20th century, 900,000 animals were killed by commercial whaling operations,
arguably the greatest slaughter of wildlife in recorded history. By the time a moratorium on whaling

was imposed in 1986, fins and other whale species were near extinction. Fortunately, nature is more
resilient than we give it credit for. Since the moratorium, fin whales have made an incredible
comeback across the global ocean and now number more than 100,000 animals. In fact, they may
now be the most common wild mammal by biomass (~8 million tons). This is important because of
their ecosystem function. In common with other great whales (such as blue and humpback), fin
whales contribute to healthy ocean ecosystems and may even increase the biomass of plankton and
fish. Even more remarkably, by defecating at the surface, whales stimulate plankton blooms that
sequester carbon dioxide from the atmosphere. Owing to their total biomass, fin whales could be
the most important whale species in fighting climate change. In short, we should all appreciate fin
whales.