The mystery of white whales

The mystery of white whales

19 July 2018

Author: Darya Kuznetsova, a junior research associate at the Severtsov Institute of Ecology and Evolution and a participant in the White Whale Programme of the Russian Academy of Sciences’ Standing Expedition to Study Animals in the Red Data Book of the Russian Federation and Other Especially Important Animals of the Russian Fauna.


Beluga whales are one of the most recognisable toothed whales in the Arctic. Only 3.5 to 6 metres in length, adult belugas stand out among other whales with their characteristic bright white colour and large round foreheads. Only trained experts can tell apart two large baleen whales at sea (especially from a distance), but the appearance of white whales is so distinct that one can take them for a white-crested wave rather than for some other marine mammal. Like their closest relatives, the famous “unicorns of the sea” or narwhals, belugas live in the Arctic. It would seem that there are no mysteries in the lives of these numerous whales living in the Arctic seas and subarctic waters. However, there are many unsolved problems and unanswered questions in the ecology of beluga whales.


In 1776, while working in the Russian Empire, famous German naturalist Peter Simon Pallas first described a whale from the Gulf of Ob. Of course, those living on the Arctic shoreline discovered white whales much earlier: the indigenous peoples had been hunting the whales and gradually perfecting their skills long before our era. By the 16th century, special crews were hunting white whales on the shore of the White Sea; in the 18th century, there were seal-hunting ships in the Barents Sea, while in the Sea of Okhotsk, hunters killed whales with spears from their boats. In the beginning of the 20th century, these local hunts turned into large-scale whaling that reached its peak in the 1920-1930s. Beluga whales are lucky in a way: unlike many other whales, this numerous species was not hunted to extinction. However, fewer and fewer belugas were spotted in the regions where the most whales had been killed (in the Sakhalin Gulf, for instance, where people even built special processing plants). The Taui Bay in the Sea of Okhotsk suffered the same fate: after a couple of years of mass-scale hunting, the business had to close down as it was no longer profitable.


Whale hunting in the USSR gave rise to the study of this species: it was in the second third of the 20th century when the most scientific studies on beluga whales were published. A large number of caught whales were carefully examined, allowing researchers to learn about the anatomy and morphology of belugas in detail. In the middle of the 20th century, one of the most remarkable academic debates concerning this species arose: can belugas living in different waters of our country be considered a single species? Up to the 1970s, scientists kept classifying beluga whales into different species or subspecies and then back into a single taxonomic unit. Carefully and in detail, they studied every characteristic of these whales, from the height of their dorsal ridge and the length of their bodies (which ranges significantly in whales from populations living in different seas) to the bone structure of their fins, confirming or refuting the theories on the structure of this genus. Today, however, this case is closed: all beluga whales are classified as a single species of a monotypic genus.


While nobody is disputing the fact that white whales are a single species, isolation of the beluga whale populations still raises questions. Could whales migrating, for example, to the White Sea and the Kara Sea in summer meet and produce offspring? The gestation period of a beluga whale lasts for just over 14 months, with calves usually born in early summer, while mating occurs during the ice season. Where does it happen? Apparently, it happens wherever the whales migrate in winter. Therefore, the answer to the question about the population unity of the whales living in different water areas is literally hidden under ice.  Where do white whales spend winter? This is perhaps the biggest mystery of belugas in the Russian Arctic. 


Beluga calves are not white in colour. Newborns are milky grey but soon darken and become dark brown. Fishermen often call these calves “aubergines.” As they grow, the calves lose pigmentation and eventually turn white like adult whales. This change of skin colour allows scientists to determine the approximate age of the young belugas that they encounter. As the whales age, their skin becomes yellowish. (The life expectancy of belugas is up to 60 years.)


Identifying the belugas’ wintering areas is very important for understanding the structure within the species. In addition to scientific significance, the question of whether populations from different water areas mate has important practical implications. Currently the beluga is a species subject to hunting in the Russian seas. Every year, fishery agencies set a fishing quota for each water area, including for beluga hunting. Although Russia has not carried out industrial fishing of belugas for the purpose of carcass processing since the 1990s, some research articles suggest that white whale hunting should resume. In order to determine legal fishing quotas, it is fundamental that scientists understand if the whales migrating to different water areas in summer belong to the same population, and whether they mix during the mating season or there is a separate population in each water area. Do belugas in specific areas require protection? How big is the population that will be subject to hunting? Will it be able to reproduce sufficiently should the hunting resume? Is it necessary to set individual quotas for each bay in a sea, or is one quota enough for the entire sea? An in-depth understanding of the beluga whale population structure is required to answer all these questions.


There are two important factors to be noted: the lack of access to the Arctic waters for people and the specifics of the white whale environment. One of the belugas’ typical characteristics is philopatry: for calving, they return to the same place where they were born. Belugas usually are born in coastal waters, estuaries and shallow bays. This is where the whales are most frequently seen in summer. In these coastal areas where belugas appear every summer for reproduction or where they migrate for fish in spring or autumn, whales are relatively accessible for research, especially if there are people inhabiting the area. Several research stations are based along the White Sea shore near summer gatherings of beluga whales, and every summer is a busy time for scientists. The lifestyles of some populations are so thoroughly studied that scientists can even recognise many individual whales and know their life story, specifically, when they were born, to which female, how they grew up as well as their personal characteristics. The Laptev Sea shore is a different story. An encounter with a beluga whale is extremely rare and has an immense scientific value because it allows for expanding knowledge of this species distribution. 


Born to wander in the Arctic


Today, the distribution of Russian Arctic belugas in the summer is quite well studied, but the same cannot be said about the winter, when animals hide below the ice. It would be logical to suppose that when the ice season begins belugas go out into the sea, trying to avoid the coming ice and to remain in clear water for as long as possible. This means that belugas must stay in the areas where the ice is thin or broken during the entire winter and spring. However, the scientific data shows the opposite.


The beluga is fit for living among the ice. The whale can break through thin ice, up to eight centimetres thick, with its head when it comes up, hence creating air holes. Thicker layers of ice can be broken by its firm spine where other whales have dorsal fins. The genus Delphinapterus is translated as “wingless dolphin,” or a dolphin without a dorsal fin. The absence of a dorsal fin is how the whales adapted to life in the Arctic. All three Arctic species – the narwhal, bowhead whale and beluga – have no dorsal fin.


So what happens under thick ice fields? Thick pack ice with a 90% concentration does not frighten belugas and even serves as the main wintering place for some populations, a fact which has been proven by satellite tagging.


How can belugas survive in these conditions? It turns out they can breathe even under the ice fields if they can find an air hole. Echolocation helps them. A special frontal prominence characteristic to belugas hides an organ called the melon, which contains fatty tissue acting as a kind of lens. All toothed whales use the melon for echolocation to determine distance, the shape of objects and their location. This is how belugas swimming deep down in the water can find cracks, air holes and layers of air under the ice. A beluga can swim far between the patches of clear water because of its high speed (up to 20 km per hour) and its ability to stay underwater up to 10–15 minutes. This is how belugas can swim through thick pack ice using a network of cracks, canals and leads as well as breathing holes that ringed seals make.


But sometimes belugas get trapped by the ice. In this case, a whole group of animals can be caught in a small hole of open water, where they can be easily hunted by polar bears or humans. (There was a special kind of beluga hunt in ice holes in Greenland.) However, even if there is no such danger, belugas can spend more than a month without food waiting for the ice conditions to change and feeding on their fat layer alone.


All of this means that belugas can survive in very different ice environments. The most interesting fact is that belugas living in different waters choose different wintering places. Around the time when the ice period begins, they migrate, travelling thousands of kilometres, while in other areas they only go from the coast line towards deeper waters. Some belugas stay at the edges of the ice cover and others gather at ice with an 80% concentration. This means that scientists cannot simply circle areas on a map with certain conditions and suggest that they are inhabited by belugas. These conditions would differ for every population.


Scientists’ arsenal


The main methods modern scientists use to study the white whale’s geographical distribution are aerial surveys, ship observations and satellite tagging.


Aerial surveys are the best way to simultaneously inspect vast territories and count the animals spotted there. This is the most exact and accurate method of conducting beluga whale counts during summertime, when these white animals can be seen in clear waters rather well. During the ice season, beluga whales can be sighted from aircraft in open water areas, ice cracks and holes, or under thin semitransparent ice, but the share of such spots in the total surveyed area is not very great. Still, the most data on the white whale winter range in the 20th century came from aerial surveys of ice areas. Along with aerial surveys of the ice cover, researchers also collected data on encounters with the Arctic inhabitants.


Ship observations allow researchers to collect information on the animals spotted along the route. During winter and spring seasons, when the sea is covered with ice, ship observations are mostly conducted en route, along a vessel’s course to its destinations. During winter seasons, en route shipping monitoring of marine mammals’ number and distribution is not carried out in the Arctic seas.


The satellite tagging method provides data on animals’ movement over a lengthy period of time. Scientists attach a special satellite tag to a caught white whale, which is then released. During the next several months, the tag on the whale’s back transmits the animal’s coordinates several times per day. Some tags also transmit additional information such as the white whale’s diving depth, the amount of time it spent in the water and on its surface, and even parameters of the water surrounding the animal.


Using various methods and collecting the data received by those who work or travel to the Arctic, researchers are gradually lifting the veil of mystery from belugas. Each year, scientists learn more and more about the white whale’s life in the Arctic, as well as their interaction with ice and whales from other seas, and ecological and biological aspects of these fascinating polar animals. As regards some areas of the white whale habitat, we can certainly say where they migrate to hide during the winter season; as regards others, we can suggest a scientifically-based hypothesis. But up to now, any encounter with a white whale in the Arctic in winter has been a source of invaluable information for scientists.




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