Whales in the Arctic don’t have it easy. First hunted to the brink of extinction, today the large marine mammals face climate change, pollution and heavy shipping traffic with noise and collisions threatening their existence. One species, the North Pacific right whale is on the list of rarest whale species along with its Atlantic relative. But US researchers from the National Oceanographic and Atmospheric Administration NOAA hit the jackpot during a survey in the Gulf of Alaska: four of the rare marine mammals were discovered and partially identified within a very short time.
The four North Pacific right whales were identified south of Kodiak Island in two separate sightings in August. Two animals each showed themselves to the researchers, who were aboard the research vessel Oscar Dyson on a four-week observation and research mission. In the process, the team was able to make important visual and audio recordings that also help identify the animals individually. The animals in the first sighting southeast of Kodiak were observed foraging “This is a highly productive area of the Gulf of Alaska, known for having high densities of krill and other baleen whale prey,” explained Jessica Crance, marine mammal expert at the Alaska Fisheries Science Center and leader of the expedition. During the second sighting in the south of the island important data of their communication were obtained. “This work is really important. Climate change is already altering the North Pacific right whale’s sub-Arctic habitat, making the need to learn more about this critically endangered whale even more imperative,” she continues.
The importance of the sightings can be seen when looking at the population size of this whale species: only an estimated 30 animals (!) are known to exist in the eastern part of the North Pacific, the remaining approximately 70+ animals are assumed to exist on the western side. This means that the animals are on the brink of extinction and it is even worse that little is known about them. We do not know their migration routes and their birthplaces, which would be important for the protection of the animals. Identification images were therefore particularly important in the two sightings. Particular attention was paid to the head, which with its calloused outgrowths looks like a fingerprint. The researchers were thus able to recognise two animals and add two others to the database, a great success for animal conservation.
Other information about their way of life is also sparse. Jessica Crance, for example, managed to show as recently as 2010 that North Pacific right whales are the only right whales that also sing. “A right whale song isn’t like the melodic calls of the more familiar humpback whale. It’s more like a series of repetitive, stereotyped calls,” Crance adds. Therefore, it was also a special stroke of luck that the team was also able to record calls at the second sighting. Because animals there did not stay long on the surface, but quickly dived again after a few breaths. But below the surface of the water, the team managed to make some important recordings of the animals’ calls. The team also collected data on the Arctic krill on which the whales feed. Coupled with the oceanographic data, the scientists thus obtain valuable data on the way of life of these shy giants. “The ability to link marine mammals to prey resources and oceanographic features will enable us to better understand how these animals interact with their environment and the drivers behind their movement and distribution,” Crance says.
North Pacific right whales belong to the baleen whales. Together with their close relatives in the south and in the Atlantic and the Greenland whales, they were the first to fall victim to industrial whaling. Their slow swimming, their large fat content and their overall size of up to 18 metres in length and almost 80 tons in weight ensured that the populations had been decimated to such an extent that the animals are now high on the red list of endangered species, with just as many as in the low 100 left. “Comprehensive surveys like this, together with passive acoustics, are needed to learn as much as we can about endangered North Pacific right whales, and other marine mammals in Alaskan waters,” said Robyn Angliss of the Alaska Fisheries Science Center. “Our hope is that this will be the first of a series of rotating surveys of cetaceans in Alaska to fill these critical information gaps.”
Dr Michael Wenger, PolarJournal
