Next to the Blue Whale, the Icewhale (or: Bowhead Whale ‘Balaenamysticetus‘) is the largest animal in the world. These colossal animals can reach a weight of up to a hundred thousand kilo’s and live up to two hundred and fifty years old, the oldest mammal. With his massive stature, enormous curved mouth, white chin and the tail fin that can reach up to seven meters in width, the Icewhale is a very characteristic species that is easy to distinguish from other types of whales.
Hidden in the Arctic sea-ice
The Icewhale is the only large whale species that stays in the North Pole area year round, summer and winter. The animals have a strong connection to the sea ice. It is suspected that the ice protects the animals against winter storms or against attacks by orcas who cannot go that far into the ice due to their fragile high dorsal fins. But probably there are still other, undiscovered reasons why the animals settle in the ice. Perhaps it could be the richly present food under the ice. Or maybe they stay in the ice because it provides them with the right acoustics to make their whale songs heard
For a long time, it was assumed that Icewhales migrate along with the retreating and surging limits of the pack ice in summer and winter. By following animals with GPS transmitters, however, it has become known that in the polar winter, between Greenland and Spitsbergen, the Icewhales migrate far north in order to hibernate in densely packed drift ice. In order for them to be able to breathe, there must of course still be air holes in the ice.
Icewhales are fantastic singer-songwriters. Year-round recordings by an underwater microphone anchored to the bottom of the ocean show that, in the heart of the dark polar winter, Icewhales continuously produce extremely varied whale songs, the most complex songs of the animal kingdom
Nowhere else are the Icewhale songs as varied as amongst the Spitsbergen population. That is even more remarkable as only a few hundred animals still live between Spitsbergen and Greenland, much less than for example in the polar seas near Alaska and Canada.
Listen to the Icewhales of Spitsbergen:
Mating and reproduction area?
It has been suggested that the complex whale songs are part of the mating behavior of the animals. This would mean that the Icewhales gather deep in the ice during the dark polar winter months to reproduce there.
The reproduction areas of Icewhales have neither been discovered, nor described. Now that global warming is causing the sea ice to disappear quickly, it has become even more urgent to investigate to what extent Icewhales need the sea ice to survive.
Habitat, status and threats
Living areas around the North Pole
Icewhales live on the edge of the ice around the North Pole. Nowadays we distinguish four subpopulations. These subpopulations are separated from each other by more or less unbridgeable barriers. Examples include an impenetrable solid ice pack that extends up to the coast, such as in Siberia. Or a land mass such as the Kamchatka peninsula that separates the population of the Okhotsk Sea from that of the Bering Sea. It is not clear to what extent mixing of populations occurs due to the decrease in the ice surface of the North Pole. Just as ships are increasingly able to navigate between the Atlantic and Pacific Oceans through the northwestern passage, Icewhales could be doing the same. Populations that have developed separately for thousands of years can now mingle. Do these animals understand each other’s whale songs? And if mixing does occur, what does that mean for genetic diversity?
Status and actual threats
After the end of commercial whaling in the middle of the twentieth century, only few Icewhales were left. On the IUCN Red List, the species was indicated as “very rare”. After this all time low, two out of four subpopulations luckily managed to recover quite well. The population in the seas around Alaska and Eastern Siberia (Bering Sea, Chuckchi Sea and Beaufort Sea) has increased to around 16,000 animals. The Eastern Canada / West Greenland population now includes around 4000 animals. Its growth has since stagnated, probably as a result of climate change. Due to the receding ice, orcas are moving north in larger numbers, attacking young Icewhales.
Due to the increase in the number of animals after the end of whaling, the species as a whole has now been given the IUCN status of “least concern”. However, two of the four subpopulations are still characterized as “endangered.” The number of animals in the Spitsbergen population. The size of the Okhotsk population has fallen to only around 250 individuals.
Now the Arctic ice melts by global warming, not only will the habitat of the Icewhales decrease, but there will also be also a sharp increase in shipping and exploration activities. It is suspected that especially the vocal Icewhales are highly sensitive to disturbance caused by underwater noise from ship engines and sonars. It has been demonstrated that Icewhales already react to the air explosions of air guns used in seismic surveys performed at a distance of dozens of kilometers.
Willem Barentsz discovered Spitsbergen in 1596 on his search for the northern passage to Asia and gave Spitsbergen its name. Soon after, other explorers, such as Jonas Poole, Nicholas Woodcock and Willem Cornelisz. van Muyden came to Spitsbergen. They all spoke of the large amounts of Icewhales they found there. At the beginning of the 17th century it must have been swarming with Icewhales in the fjords and along the coasts around Spitsbergen.
The well-known Dutch polar explorer and archaeologist Louwrens Hacquebord, together with other scientists, has been able to estimate that before the start of the whale hunt around Spitsbergen and Greenland, around 50,000 Icewhales must have lived there. Taking the enormous weight of a single whale into account, this population corresponds to a biomass equal to 880,000 elephants or ten million cows. The food cycle in the Arctic must have been completely different than it is today.
Whale hunting started in the coastal areas. The wooden ships of that time could easily drop anchor in a fjord and wait for the Icewhales to come to them. The bulky heavy animals could be hunted much more easily than other, faster, whale species. Hunting for Icewhales had another advantage as after they had been harnassed, they floated due their thick layer of fat. Terefore, they could easily be dragged to the tear furnaces on the beach by just a few rowing boats strained in front of the dead animal. After most of the Icewhales had been caught along the coast, whaling moved more towards the edge of the pack ice in the open sea. The whales were now processed on board and the settlements with tear-off farms on shore were abandoned.
The Netherlands has dominated the whaling industry around Spitsbergen and Jan Mayen for decades. In some years over 200 Dutch whale ships traveled to the Arctic ice. This history still echoes in the countless Dutch geographical names in the Arctic. In addition to Jan Mayen and Spitsbergen you also have Amsterdam Island, the Hindelopenstraat, the Liefdeford and Uutkiek.
At the end of the commercial whale hunting in the mid-20th century, the population of Icewhales was on the brink of extinction. Recenty, Icewhales are starting to be observed more often around Spitsbergen. Especially notable are two observations of groups of 80 to 100 animals, done from the Dutch cruise ship Plancius in June 2015 and again in 2018 at almost the same location which was at the edge of the ice between Spitsbergen and Greenland. Of course, we do not know whether the increased number of sightings actually represents an increase in the number of animals, or whether the animals simply are more visible because of the shifting ice line and the increased number of cruise ships around.