Deep in the arctic winter off Norway, a boat searches the icy ocean for sperm whales

The world's largest toothed predator is well studied in the tropics, but close encounters in the high latitudes remain rare. On stormy northern seas, these hardy researchers not only want to find them – they want to dive with them.

The fluke of a diving male sperm whale. Photo identification of flukes – which bear similar individualistic traits to human fingerprints – helps establish knowledge of the local whale populations.

Photograph by Sophie Bolesworth
Published 11 May 2021, 17:24 BST, Updated 26 May 2021, 09:34 BST

I'M STANDING on the stern of the 37ft expedition yacht Barba. Ahead, the serrated cliffs of Andøya, a Norwegian island 300km north of the Arctic Circle, mask the partial winter sun. Moderate offshore winds whip off the surface of Andfjorden and bring the temperature to 20 below.

“Whale blow, 200 meters to port,” calls helmsman Emil Gundersen. The yacht pitches hard. Photographers Tord Karlsen and Sophie Bolseworth steady themselves. Crewman Aksel E. Ørstavik and I hand fins and cameras to Norwegian captain and marine biologist, Andreas B. Heide, and French acoustic engineer and marine researcher, Fabrice Schnöller. Three male sperm whales pass 50 metres to port and the men dive in. It's the first documented moment that people have free-dived with sperm whales in this region of Arctic Norway during winter.

Sperm whales near Andøya

The Bleik Canyon begins 8 nautical miles offshore from Andenes on the northern tip of Andøya. The 50km submarine trench reaches like a tendril from land out towards the continental shelf, where water depths plummet from 200m to over 2000m. Here, upwelling forces nutrient rich water to the surface and brings with it a diverse array of marine life. Of particular importance are the deep-water cephalopods, which are believed to form an integral part of the sperm whale diet. Subsequently, the region boasts one of the largest known aggregations of sperm whales near land. However, only adult males have been documented in the high latitudes.

Andreas B. Heide, Emil Gundersen and Aksel E. Ørstavik and Hugh Francis Anderson (left-right) brave 40-knot gusts on the deck of Barba

Photograph by Sophie Bolesworth

Approaching Andøya at sunset. 

Photograph by Tord Karlsen

Fabrice Schnöller listens to sperm whale click communications via the hull-mounted hydrophone from the saloon of Barba.

Photograph by Tord Karlsen

Jonathan Gordon, who has spent the past 30 years studying sperm whales and is a Research Fellow at the University of St. Andrews’ Sea Mammal Research Unit, understands this is due to feeding opportunities. “Males leave as they mature and are found closer to the poles. The feeling is that the feeding must be better as they tend to grow a lot larger than females,” he says. “But if you ask for hard evidence that the feeding conditions are better, well – there really isn’t much.”

Tiu Similä, a Finnish scientist who pioneered long-term orca research in Norway, works closely with Gordon and has studied sperm whales in the Andenes region since 2016. “There is so much we do not know about the male sperm whales,” she says. “What is their diet? What is their habitat use pattern? How solitary or social are they? Do they compete, cooperate or maybe both?”

Left: Sailing into the frozen Trollfjorden, in Lofoten. Right: Heide searches for sperm whale blows from the deck. 

Photograph by Sophie Bolesworth (left) Tord Karlsen (right)

Since the late 1980s, tourist whale watching companies have operated in the area and often host scientists and researchers. But little time is spent at sea outside of the tourist season, which runs from May to September. During this period, the primary form of documentation is photo-ID. (Read: A guide to ethical whale tourism in the 21st century)

Based on data collected in this manner and collated over a 22-year period, it is estimated that the mean number of individuals in the area is 101. But this documentation accounts solely for the spring and summer months, and unlike the tropics, engaging with and recording these animals underwater is incredibly challenging; in winter, it has never been attempted.

Two adventurers align

Heide has spent the past decade guiding experts, free-diving and documenting whales in Arctic Norway aboard Barba, which he uses as a research and storytelling platform. In 2018, during his third season tracking orcas in the region, he first spotted sperm whales in the waters off Andøya. While his experience of documenting close encounters with orcas and humpbacks was extensive, he was yet to encounter sperm whales.

Heide and Schnöller enter the water to approach three young male sperm whales. Sperm whales do not spend a lot of time at the surface and can dive for extended periods, so being nimble is key. 

Photograph by Tord Karlsen

Spotting a dark sperm whale on a dark sea – and its blow vapour on a choppy one – is no easy task. Note the small dorsal fin of the species. 

Photograph by Tord Karlsen

Sperm whales take just 5-10 breaths at the surface before diving for up to 40 minutes. 

Photograph by Tord Karlsen

It was therefore fortuitous that he had been introduced to Schnöller earlier that season. “For me, they are one of the more mysterious whales due to their deep diving capabilities and because they spend a limited time on the surface, unlike orcas,” he tells me. “I wanted to go back with Schnöller to get a better idea of what I was seeing in the area.”

Schnöller’s experience began with a remarkable encounter with a pod of 20 sperm whales in the warm waters off the coast of his home on the Réunion Islands some 15 years ago. He then went on to found the Darewin Project in 2012. The project’s objective is to collate data and present it in an open-source format to encourage the wider scientific community to invest additional resources into whale communication research – studying the vocal ‘clicks’ by which the mammals engage with each other. And while he has over 200 underwater encounters in the tropics, he had never documented sperm whales in the arctic and was initially sceptical. “I thought it was almost impossible, that perhaps there was only one male, and that the conditions would be too hard,” he says. “But I wanted to try.” (Related: Ground-breaking effort launched to decode whale language.)

And so, a symbiosis rapidly formed between the two and a question was raised: Can we find, document – and interact – with sperm whales underwater during the Arctic winter?

The north calls

Within weeks, the team is assembled in Tromsø. We sit in the intimate saloon aboard Barba and gaze over the chart plotter. Heide’s route will take us past the island of Senja, across Andfjorden and around the tip of Andøya to Andenes and Bleik before a southward sail through Lofoten to Bodø. During the 10-day expedition, we will cover 300 nautical miles through some of Norway’s most marine-life-rich waters.

Research into whale communication is a vibrant field – but documentation of sperm whales in an environment such as this is challenging. Passive acoustic recordings help establish whale locations and aid with questions surrounding conspecific communication; photo-ID allows for the documentation of individuals; biopsy and faecal samples (whale poo is ejected in loosely aggregated plumes, which float until they break up) help understand genetics and diet; and tagging proffers information on orientations and movements. But in the Andenes region, these are limited, speculative and seasonal.

A whale dives. Deep water prey such as squid is thought to be a staple of this whale's diet; the sperm whale is the largest toothed predator on Earth but much is still mysterious about its deep-water behaviour. 

Photograph by Tord Karlsen

“For me, they are one of the more mysterious whales due to their deep diving capabilities and because they spend a limited time on the surface, unlike orcas.”

Andreas Heide

However, some observations have been made that will help guide our mission. Marine biologist and bioacoustics specialist Giulia Ercoletti has spent the past three years in Andenes observing sperm whales. She notes that while they remain far offshore and solitary during the whale watching season, they have been observed close to land and in groups during winter; it is widely believed that this is due to the aggregation of food.

(Related: this baby sperm whale was tangled in ocean rubbish for 3 years.)

“In winter you can see them in Andfjorden itself, and often in small groups,” she tells me. “They feed using echolocation, so it’s possible that when they’re close, their echolocation interacts with one another. But during winter, when they don’t have to dive so deep, perhaps the echolocation is less of a problem so they can hunt together.”

In evidence of Ercoletti’s observations, Heide’s original sighting places the whales at the opening of Andfjorden, so with the coordinates as our goal, we cast off. The conditions are treacherous, and we reach Andfjorden on our second day at sea under the onslaught of 40-knot gusts.

Left: Heide congratulates Schnöller after a successful dive with the whales. Right: Schnöller feels the pain of spending time in the arctic waters.

Photograph by Tord Karlsen (left); Sophie Bolesworth (right)

In the limited daylight, we’re proffered just 4-5 hours of searching per day, with darkness once again descending by 14:00. But it is as we approach Andfjorden that Heide spots the blow of a whale. We change course and tack in its direction. The whale dives, and from the fluke we confirm that it is a sperm whale. And then another surfaces, followed by two more close together. Karlsen and Bolesworth begin photo-identification as Heide consults the chart plotter. “We’re in the exact same area as when I saw them 2 years ago,” he comments. “This must be a hotspot.”

Gale-force gusts bellow from the mouth of Andfjorden and with the light quickly fading, we’re forced to sail onward to the safe harbour of Bleik. A palpable excitement spreads through the team; the whales are here and with right conditions, free-diving will be possible.

(Related: can today's whale species survive the age of humans?) 

Arctic fieldwork

It is the danger of executing fieldwork in these remote and volatile conditions that Heide notes as the most challenging factor. The line between safety and alarm is a fine one when both sailing and freediving offshore in the arctic, particularly during winter – and explains why in-water encounters here have never been recorded before. In addition, searching for, finding and documenting cetaceans has always been a balance between instinct and experience. Heide says that when searching for orcas, it is best to encounter them when they are feeding, or just after they have fed, in which they will likely be socialising. But with sperm whales, it is far harder to establish such parameters. “It’s very difficult to find an area where it’s both easy to access the water and where the whales are interested in you,” says Schnöller. “Perhaps these whales have never seen a human in the water before so this very first interest could lead to a big encounter.”

Clockwise from top left: the crew work and prepare until conditions improve; Fabrice Schnöller listens to acoustic recordings; Starch from potatoes helps keep water droplets off the underwater housing lens; A storm blows across Bleik harbour.

Photograph by Sophie Bolesworth

We cast off before first light with the intention of sailing 12 nautical miles to the location we spotted the whales the day before. However, as we round the headland, fierce winds slam against the bow and cast the yacht into a ceaseless pendulum. Spindrift from cresting waves fills the air and makes searching for whale blows impossible. We travel back to port. A storm arrives the next day and we are forced to remain in harbour. It is the unpredictability of the conditions that makes fieldwork in the arctic so slow. But it also offers necessary time to prepare.

Documentation and tech

The primary tool used to determine sperm whale location is the hydrophone. Either towed or mounted into the hull, it allows researchers to listen for a variety of vocalisations (clicks) most commonly associated with feeding and communication. This, in partnership with vision, is the best means by which to find sperm whales. Once found, photo-ID is the most common way to document individuals. Heide explains that a whale’s fluke is unique, much like our own fingerprints, so by photographing the fluke when a whale dives, researchers are able to determine the individuals in a given area. “We saw three travelling together, so it will be interesting to see if the same three travel together again,” he says. “When the weather clears, we will travel to the last spot we saw them.

But the technology used to document sperm whales is evolving. “Some new approaches, such as suction cup tags (DTAGS) with cameras attached, are a good way of understanding what they’re doing underwater,” notes Gordon. “They’ve also been used to record orientation and movement in conjunction with passive acoustics.” These methods help to understand what the whales are doing at depth. However, effective deep ocean technology is still in its infancy.

Fabrice Schnöller and Aksel Ørstavik are towed behind Barba while free-diving in frozen Trollfjorden. 

Photograph by Andreas B. Heide

Heide breaks the surface of the frozen Trollfjorden, Lofoten.

Photograph by Sophie Bolesworth

Using VR goggles, Fabrice Schnöller views 360-degree underwater footage.

Photograph by Sophie Bolesworth

For Schnöller, the importance comes from getting in the water itself to personally collect data to allow for a deeper understanding of these animals. Sperm whales possess the largest brain in the animal kingdom, and the neocortex, which controls higher-level brain functions such as cognition, perception and language, is not only larger, but far denser than our own. In addition, they also possess spindle cell neurones, which are directly linked with empathy.

This evidence suggests that sperm whales are capable of feeling, among other things, emotion and intuition, and goes some way to explain just how diverse their communications are. Utilising customised 360-degree camera systems, Schnöller hopes to capture a total underwater picture which, when paired with passive acoustic recordings and VR, will give scientists a broader picture and understanding of behaviour and communication. He has even developed a gun-like lens which he hopes will be able to rebound whale click communications to start the process of deciphering not just how they communicate, but what information they are communicating.

Frigid free-diving 

The weather doesn’t calm enough until our last day. We rise early and are once again at sea before first light. An onshore wind builds as we pass the headland, but as the dawn light splays across the turbid water, we spot our first whale blows.

Heide rests on the surface ice of Trollfjorden.

Photograph by Fabrice Schnöller

The team captured the only clear image of a male sperm whale underwater in this region of arctic Norway.

Photograph by Fabrice Schnöller

The team hopes their work studying the sperm whales at this latitude will give insight into the behaviour of this enigmatic species – and the way they communicate within their pods.

Photograph by Tord Karlsen

In quick succession we spot a number of individuals traveling away from shore. Heide spots three individuals travelling in unison and by comparing them to the images captured on our first day, he is able confirm that they are the same three. Schnöller notes that sperm whales tend to travel in the same direction when feeding. On the surface, they take 5-10 breathes before diving, which they signal by the bobbing of their heads before their flukes rise. “They normally dive for 20 – 40 minutes and travel in the same direction, so we have to get ahead,” he says. “They are curious animals, so we have to make ourselves attractive.”

(Learn about the new National Geographic documentary Secrets of the Whales.)

As we sail, Schnöller listens to and records the click communications through the hydrophone mounted into the hull of Barba and is later able to determine the size of the whales through their acoustic signature. He explains that while diving, the sperm whale emits a steady click in order to explore the environment and to communicate. Each click has a multi-pulse phase within the whales’ head, known as the Stable Inter Pulse Interval. This interval is determined by using a set of algorithms, and the specific length of these intervals can help establish the size of an individual. “The acoustics tell me that they are 10-metre-long sperm whales,” he confirms. “That’s small, even for young males.”

Watch a young sperm whale dive in the winter seas off Norway
Andreas B. Heide, a free-diver and captain of the research vessel Barba captured this remarkably intimate footage of a young male sperm whale diving off the coast of Norway. Read the accompanying article here. 

Heide and Schnöller change into their wetsuits and ready themselves in the dinghy towed behind Barba. As anticipated, the whales surface nearby and the men enter the water. With powerful kicks they close the gap and are alone at sea with the world’s largest toothed predator. It is a moment we had all hope for; a moment that lasts just a handful of seconds before the whales dive once again. But the men have captured the first videos and photographs of sperm whales underwater in this region; vital to the further understanding of these animals. Back onboard, the elation is profound. 

“The feeling of being underwater with these mysterious creatures is quite overwhelming,” says Heide. “We know so little about them but encounters like this help us to understand them better.” As the men go below deck, a snowstorm blows across the water and forms an opaque veneer over the already-fading light; our time with the sperm whales has come to an end and we begin our southward sail through the frozen fjords of Lofoten to Bodø. 

Later, in the warmth of the saloon, Heide and Schnöller discuss their observations. “I really thought it would be impossible to have an encounter here. But what I observe is exactly what I have observed in other places; it is quite possible to interact with them,” says Schnöller. “They were curious, but also uncertain. The best thing is to find an individual that is curious,” he continues. “I’m sure that if you come to this area day after day, they will get closer, and the curiosity will overcome the uncertainty.”

Fabrice Schnöller and Andreas Heide debrief over a warming drink in the galley of Barba. Heide says: “My primary objective is to bring people like Schnöller into the field, to provide a platform so that we can learn more.”

Photograph by Tord Karlsen

For Heide, an expedition like this allows him to get specialists into areas so remote and volatile that they would otherwise never be able to. “My primary objective is to bring people like Schnöller into the field, to provide a platform so that we can learn more. From what we’ve seen, there’s a lot to study here,” he says. “So little is known about [sperm whale] biology, their behaviour and what they’re eating. How big is the area they inhabit? Is it only around Andenes, or is it along a larger area of continental shelf?”

To the future 

One year on, Heide hopes to be able to answer some of these questions as part of the Arctic Sense expedition, which aims to explore and assess the polar Atlantic ecosystem. Throughout the 3,000 nautical-mile, 4-month journey, the team will conduct world-first oceanographic research into cetaceans, climate change and pollution.

Utilising a bespoke towed hydrophone array designed and built by Gordon in conjunction with Marine Ecological Research, Barba will once again sail to Andenes to gather further data to help expand knowledge of sperm whale distribution, behaviour and communication along the Norwegian continental shelf.

The team will then sail north to Svalbard, across the Greenland and Norwegian Seas to explore the remote island and waters of Jan Mayen, before a southward journey to London via the Faroe Islands, the Shetland Islands and Edinburgh.

“With Barba, we are able to bring experts into the field to gather critical data in a sustainable way, non-invasive way,” says Heide. “What I witnessed outside Andenes is a beacon of hope for marine conservation. It is our obligation to ensure we understand and protect our oceans and their inhabitants.”


Hugh Francis Anderson is a freelance adventure journalist based near Cambridge; follow him on Instagram. Sophie Bolesworth is a Cornwall-based researcher and photographer specialising in environmental projects. Tord Karlsen is a photographer from northern Norway. See more of his work here.

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