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One of the Biggest Arctic Migrations You’ve Never Heard of

Posted On May 12, 2014 by

Photo Credit: NOAA National Marine Mammal Laboratory

Ocean Conservancy will be publishing a blog series exploring the wonder of the Bering Strait and highlighting threats and solutions to this region.

The Bering Strait—located between Alaska’s Seward Peninsula and Russia’s Chukotka Peninsula—is the only marine gateway connecting the Arctic Ocean and Pacific Ocean. At its narrowest point, the strait is just 55 miles wide. Big Diomede Island (Russia) and Little Diomede Island (U.S.) are located near the middle of the Bering Strait, and are separated by a strip of water less than three miles wide. Despite its cold, remote location, the Bering Strait is a key biological hotspot, a region that contains a significant number of species – some of which are found nowhere else on Earth. This strait is both a bottleneck and a pathway for marine life.

In the middle of the Bering Strait, Big Diomede Island is located to the west and Little Diomede Island is to the east.

Each spring, millions of seabirds and hundreds of thousands of marine mammals traverse the narrow strait as they migrate to the Arctic Ocean. Sea ice—frozen seawater that floats on the ocean surface—plays a major role in this seasonal migration. In the spring, migratory birds and marine mammals gather in the Bering Sea and follow the retreating ice edge north through the Bering Strait and into the Chukchi Sea and the Arctic Ocean. The ice edge is highly productive, and the sea ice itself provides important habitat for microorganisms, birds and marine mammals. The Bering and Chukchi Seas are one of the most productive ocean ecosystems in the world.

Photo Credit: NASA, May 2000

Photo Credit: NASA, August 2000

Four species of ice-dependent seals—bearded, ribbon, ringed and spotted—use the sea ice for resting and as a platform from which to feed on prey like fish, shrimp and crabs. Polar bears and Pacific walruses hunt and feed on or from the sea ice. Open areas of the ice—called leads or polynyas—attract dozens of bird species, including the short-tailed albatross, spectacled eider and Steller’s eider. These and other bird species use the Bering Strait’s rich waters for foraging and as a pathway to the summer habitat in the Arctic.

Photo Credit: NOAA Fisheries

Under the chilly spring water, nearly 10,500 bowhead whales follow leads in the sea ice as they move north through the narrow passage of the Bering. These rotund black whales use their enormous heads to break through thick sea ice. Their common name originates from their bow-shaped skulls, which are over 16.5 feet long and about 35 percent of their total adult body length. In addition to bowhead whales, beluga and gray whales travel through the Being Strait on their way north to raise their young or feed.

With huge pulses of birds and marine mammals passing through this gateway from the Pacific to the Arctic each year, spring migration in the Bering Strait is truly one of nature’s wonders. There is no question that this narrow and biologically rich stretch of water is critically important, not only to Arctic species like walruses, bowheads and spectacled eiders, but also to wider-ranging species like gray whales and migratory seabirds.

The yearly migrations of marine mammals are essential to people living in Bering Strait communities and beyond. People living in the region’s communities rely on the continued productivity of the region’s marine ecosystem to support their subsistence way of life and cultural traditions as well as to meet other economic and community needs.

Of course, fish, birds, marine mammals, and subsistence hunters do not have a monopoly on the Bering Strait. As the retreat of summer sea ice in the Arctic Ocean has accelerated, the region is attracting more attention from industry. There is growing interest in shipping, oil and gas exploration, tourism and other commercial activities that contribute to increasing levels of vessel traffic through the Bering Strait. Increased traffic in this fragile ocean space could result in more pollution, ship strikes on marine mammals, as well as chronic and catastrophic oil spills among other potential impacts to the marine environment. The Bering Strait region is particularly vulnerable because it is home to such high concentrations of wildlife. We’ll explore these issues—and potential solutions—in future blog posts.