ARKHANGELSK, October 11. /TASS/. Russian scientists for the first time identified distribution features of Franz Josef Land's Atlantic walruses and put them into a separate cluster. The archipelago is inhabited by a fairly genetically isolated group of walruses, and this is important for their further protection, as well as for walrus studies in the Arctic's other parts, Svetlana Artemyeva, a researcher at the Russian Academy of Sciences' Severtsov Institute of Ecology and Evolution, told TASS.
The Atlantic walrus is listed in the Russian Federation's Red Data Book. The population shrunk significantly due to the hunting in the 19th - early 20th centuries.
"Our studies have shown a certain isolation, a reproductive grouping, which exists on the archipelago islands. Of course, it contacts other Atlantic walruses, but in fact there is a certain genetic isolation," the expert said. "The archipelago walruses are a peculiar, separate cluster."
Scientists have conducted various genetic studies, including on MHC genes (major histocompatibility complex), dubbed adaptive. It was for the first time such studies on Atlantic walruses have been conducted. "Such adaptive genes are considered to be the ones that change the fastest, by them we can see what is happening: not an isolation that happened a long time ago, hundreds of years ago, but exactly what has been happening in recent decades and centuries. We can note certain signs, and they demonstrate that this grouping stands out," she explained.
The research was carried out on Franz Josef Land for three years. Experts studied also walruses on the Victoria Island and the Oranskiye Islands in the north of Novaya Zemlya. Biologists used satellite transmitters. On the archipelago and on the Victoria Island, researchers observed about 6,300 animals, and taking into account those at sea, the number may reach up to 12,500. The number is approximate, she continued, adding earlier estimations said about 4-6 thousand walruses on Franz Josef Land.
Scientists believe that walruses live on Franz Josef Land all year round, in winter they move along with the ice edge. But on the Oranskiye Islands, walruses live only in summer and autumn - to there come both those from Franz Josef Land and representatives of southern populations, for example, from the Pechora Sea. Walruses of the Victoria Island are part of the Franz Josef Land cluster. This is yet another reason to include the Victoria Island into the Russian Arctic National Park, she said.
Most "clean" walruses
Results of toxicological studies show walruses on Franz Josef Land practically have no pollutants. Only mercury was detected, but in minor amounts that do not threaten the animals' health.
The expert compared her results with data on pollutants in Pechora Sea walruses, where navigation is active, where emissions are bigger, where there are river flows from the mainland - that situation affects the marine life. "Everything is pretty clean on Franz Josef Land, while in the Pechora Sea the levels of persistent organic pollutants, pesticides and heavy metals are much higher," she said. This affects the health of walruses, which is noticeable in their appearance. This part of the Atlantic walrus population requires comprehensive studies, she stressed.
What walruses eat
Walruses usually feed on mollusks and other benthic invertebrates. Biologists have found a total of 35 such species. Video surveillance using remote-controlled underwater vehicles revealed 11 species that previously had not been found in bottom samples. And not far from the archipelago's northernmost island - the Rudolf Island - the researchers found a bank (a shoal, a shoal in the ocean, the depth of which is significantly less than the surrounding depths, on banks often are big amounts of aquatic biological resources), where a large number of walruses feed. "Satellite transmitters showed that walruses go there, <...> spend some time there. We supposed there might be an attractive feed bank," the researcher said. The location is outside the national park's water area, and if navigation develops there, the area is better taken under protection, she said.
Certain studies were conducted for the first time. Biologists conducted a metagenomic test of the intestinal flora. "This is another way to study the animals' evolution <...>, and it is very interesting that part of the microbiota is similar to the microbiota of the California sea lion," she noted, adding those species do not overlap nowadays. When analyzing excrement, scientists could get a lot of interesting data. For example, the level of hormones can point to the level of stress the animal had.
Tests of fatty acids from subcutaneous fat can determine what the walrus mainly eats. There are cases when walruses killed and ate seals. This phenomenon has been understudied and some versions say this behavior may be associated with stress in a cub when the mother dies.
The data obtained during the studies of Franz Josef Land walruses will be used in the studies of the Laptev Sea walruses. Russia separates them into a subspecies. This is important for practical recommendations to companies working in that part of the Arctic. The walrus is a bio-indicator species that may be used to monitor the ecosystem. For this, however, scientists need to study the population's current conditions.