Pacific walruses in Russia
1 May 2017
As climate change continues to adversely affect this important shared resource, ANATOLY KOCHNEV says effective research, monitoring and management of walrus populations will rely on the joint efforts of both countries.
BY THE EARLY 1960S, over-hunting saw the Pacific walrus drop to an estimated 50-90,000. Protective measures saw herds restored to the optimal population of 275-386,000 by the early 1980s. But even with significant harvest reduction, there are signs the Pacific walrus population is again decreasing. This trend was first observed in the mid-1980s when a survey by American researchers of the age and sex composition of the walruses in the Chukchi Sea showed alarmingly low population productivity and survival of young animals. This was confirmed by the Soviet-American aerial survey in 1990 when numbers were determined to be 201-296,000 indicating a 25 per cent decrease over 10 years. By the 2000s, numerous coastal haulouts on the Kamchatka Peninsula and the Koryak coast had stopped, and where the walruses did continue to haul out, numbers had fallen dramatically. Compared with the mid-1980s the number of walrus herds staying for the summer in the northern part of the Anadyr Gulf had almost halved. In 2006 joint US-Russia aerial surveys estimated the number of Pacific walruses had further dwindled to 129,000 – a return to the level of the early 1970s.
It is now clear that global climate fluctuations are the main cause of these decreasing numbers. Climate change has caused a significant decrease of summer and autumn sea ice cover making it difficult for walruses to rest on the ice floes or use them as platforms for feeding in the extensive shallows of the central Chukchi Sea. Walruses are forced to remain near shore for excessively long periods, creating dense haulouts in the tens of thousands. With such a concentration of walruses in the coastal waters, there is an acute shortage of food and many of the animals are in poor physical condition. There is also growing interference from predators and humans, leading to panic among the tightly-packed crush on shore and is likely the cause of annual mass deaths of walruses on coastal haulouts. This peaked in autumn 2007 when up to 10,000 animals died along the Arctic coast of Chukotka.
The decline of walruses from the southern part of the range is even more pronounced although it seems they have been able to adapt to ice losses, albeit in low numbers. In the absence of ice this adaptation is manifested as walruses concentrate on coastal haulout places located at a minimum distance from areas with the most productive sea floor communities, where bivalves and other organisms eaten by walruses predominate. Thus, the loss of energy in walruses during feeding and movement from land haulouts to feeding areas can be compensated by the high density of food. After a long break, walrus haulouts have again begun first on the Russian coast of the Chukchi Sea, and then on the northern coast of Alaska. These locations have seen regular use from August to November over the last two decades. I discovered one of these important haulout places in 2009 on the Russian coast of the Chukchi Sea near Cape Serdtse-Kamen’.
The monitoring conducted by myself and my colleagues from the Chukotka branch of the Pacific Research Fisheries Center in 2009-2016 showed that 75-115,000 walruses are concentrated at Cape Serdtse-Kamen’ and adjacent parts of the coast in October constituting the main part of the Pacific population. The mortality of walruses at Cape Serdtse- Kamen’ and other coastal haulouts remains high, but not as high as in the critical year of 2007. Observations at Cape Serdtse-Kamen’ indicate that in current years the population has stabilized although this is a temporary respite for walruses. If losses of ice habitat in the Chukchi Sea continue it is difficult to imagine how they will survive it.
The problem is further aggravated by the fact that the shrinking of the sea ice cover becomes a catalyst for increasing the anthropogenic pressure on the Arctic. Historically, high sea ice density created the conditions to make the Chukchi Sea a natural reserve for walruses and other marine mammals. Now the sea ice barrier has disappeared, and people are expanding their economic activities in the Arctic. In Russia, oil and gas exploration of the Bering, Chukchi and East Siberian seas and construction of a floating nuclear power plant in the East Siberian Sea is underway.
The intensity of navigation is increasing, with new civil and military complexes being built next to key Pacific walrus habitats. The reaction of walruses to an inevitably sharp increase in economic activity and possible pollution in most of their range is unpredictable.
Currently, efforts to protect the Pacific walrus in Russia involve limiting the traditional native harvest (any other harvest is prohibited, except for capturing calves for zoos and aquariums) and the creation of designated protected areas in Chukotka. In 1976 a federal reserve was established on the Wrangel and Herald islands which was extended in 1997 to the 12-mile coastal water area around these islands.
In 2012 a 24-nautical mile protective zone was created adjacent to the reserved water area. In 2013, the Beringia National Park was established in the Bering Strait area and the southern part of the Chukchi Sea. However, these measures are not enough for successful conservation and growth of the Pacific walrus population. Walruses like any other marine mammals actively move within the range, and they are difficult to protect by creating any limited protected land and water areas. Systematic, longterm monitoring of the Pacific walrus population is needed throughout all ranges, and effective control of anthropogenic activities, including flexible restrictions that respond quickly to changes in the distribution and behavior of walruses.
DR. ANATOLY KOCHNEV is Senior Scientist of the Mammals’ Ecology Lab of Institute of Biological Problems of the North, Russian Academy of Sciences