By Dr. John J. Hidore

The Rising Temperatures of the Arctic

February 22, 2014—World temperatures are warming at a record rate and the global climate is changing rapidly due to rising temperatures of our planet. Though the planet is warming, the rate at which it is warming is inconsistent from place to place. Temperature changes in the Arctic are taking place faster than anywhere else on the planet. The warming is affecting both the physical and biological character in this region. The most widely known affect is the melting of sea ice. The melting of the sea ice is significant, but the melting has many side effects.

Climate Change and the Walrus

The changing arctic climate has started to change much of the arctic wildlife. Among the species affected is the walrus. Walruses are large marine mammals that may weigh up to 2700 lbs or more. They spend nearly two-thirds of their lives in cold water. A walrus carries large tusks which are used to root out food living on the ocean floor. The tusks are also used to help move around on the slippery ocean floor. Off shore of the land masses surrounding the Arctic Ocean. the ocean floor drops slowly on what is generally referred to as the continental shelf. Beyond the edge of the continental shelf the depth to the ocean floor drops to several thousand feet in places. Walruses mainly feed on the continental shelf in water less than 300 feet deep. They will, however, feed as deep as 600 feet.

Declining Sea Ice

Sea ice plays a critical part in the lives of the walrus. Walruses cannot swim indefinitely like some seals, and must rest between forays searching for prey. They use sea ice as a platform for searching for food and as a place to rest during their annual migration. Females also use the sea ice during the summer as a place to give birth and nurse their infants. When the walruses are on the sea ice they tend to spread out over large areas. In late summer they migrate to warmer waters. In the past they tended to move onto land in late August during their migration. There are two species of walrus in the arctic. One is the Pacific walrus which inhabits the Bering, Chukchi, and Laptev seas. The other is the Atlantic walrus which is found along northeastern Canada and Greenland.

The Arctic region is now the warmest it has been in 40,000 years. The sea ice has melted to record lows. This has limited the area where walrus can haul out on the ice if it melts too far from land. When the sea ice retreats beyond the edge of the continental shelf and over deeper water, instead of hauling out onto the ice, the walruses head for land and congregate.

Walruses: Herding On Land

Huge gatherings of Pacific walrus have taken place in the last decade. In 2007, an estimated 6,000 walruses gathered along the Alaskan coast. In the fall of 2008, few walruses came on shore as some sea ice remained near shore. In September of 2009, some 3,500 Walruses were near Icy Cape on the Chuckchi Sea 140 miles southwest of Barrow. In 2011, some 30,000 congregated on a beach about a mile long. Large numbers of walruses have also been seen on shore at Cape Lisbourne. Large congregations have occurred in the years since. The same phenomenon is taking place on the Arctic coast of Russia near the Chukchi sea. Herds of tens of thousands were gathering on this coast. Near Point Schmidt, a herd of some 40,000 was sighted. The total population of Pacific walrus is not known, but estimates place it at about 200,000.

The large herds on land are a threat to the walruses. The threat comes from several sources. One is that they tend to stampede when some unusual event startles them. Individuals are often killed during the stampede. Russian biologists reported several thousand, mostly young, were crushed to death in one stampede. For example, noise from hunting weapons and polar bear attacks can cause a stampede. Pilots of small, low flying aircraft are being warned to stay away from the herds as the noise can cause them to stampede. Large gatherings in a limited space also are more favorable for the outbreak of disease. The concentration of such large numbers also has a severe effect on the clam population offshore from the herds. This extensive harvesting may result in an unsustainable population of their food supply.

The decline of sea ice and the changing environment are not only a threat to the walrus population but serve as further evidence of a warming planet. Biologists are asking for the walrus to be declared an endangered species since the outcome of declining sea ice on the species is not yet clear.