The rain-drenched Aleutian Islands, which curve from Alaska's mainland to Asia, lie about 800 to 1,000 miles south of the Arctic Circle. So why do the U.S. government's Arctic plans include enhanced shipping safety in the Aleutians and the similarly subarctic Bering Sea?

There is a legal explanation. The 1,200-mile Aleutian chain, the Bering and other subarctic areas are considered part of the Arctic for the purposes of federal policy.

That legal definition comes from the Arctic Research and Policy Act of 1984. The Arctic, according to that act, encompasses "all United States and foreign territory north of the Arctic Circle and all United States territory north and west of the boundary formed by the Porcupine, Yukon, and Kuskokwim Rivers; all contiguous seas, including the Arctic Ocean and the Beaufort, Bering, and Chukchi Seas; and the Aleutian chain."

There is also a practical explanation: The Aleutian Islands and Bering are inextricably connected to the waters above the Arctic Circle, say scientists, government officials and indigenous leaders.

"Everything that happens further north in the Bering and everything that happens further north in the Beaufort and the Chukchi and even further north in the Arctic Ocean, a lot of that productivity is determined by what happens in the Aleutians," said Jim Gamble, executive director of the Aleut International Association, an organization granted status in 1998 as a permanent participant in the eight-nation Arctic Council.

That goes for the marine ecosystem of the Aleutians and Bering, which supports fish, birds and marine mammals that travel back and forth between the Arctic and lower latitudes, using waters that are covered by pack ice at varying times of the year.

And it goes for the ship traffic in and out of the U.S. Arctic. To get there and back, ships must go through the Aleutians and Bering, and if they need a full-service port, the closest spot to the Arctic is in the Aleutians, Gamble said.

"For ships and industry looking for service, really at this point in time, that's the only place to look," he said.

For the U.S. Coast Guard, protecting the Arctic means protecting the narrow marine passageway just south of the Arctic Circle. "As the only route between the Arctic and Pacific Oceans, the Bering Strait portends significant strategic importance in the future," says the Coast Guard's Arctic Strategy, released in 2013.

And many organizations have placed emphasis on protecting the busier waters south of the Bering Strait.

New International Maritime Organization standards, in effect as of Jan. 1, designate five "areas to be avoided" around the Aleutian Islands for vessels traveling what is one of the world's major shipping routes.

Close to 2,000 individual vessels pass through the Aleutians each year as they sail the Great Circle Route between North American and Asia. Accidents in the Aleutians, like the fatal grounding of the cargo ship Selendang Ayu in 2004, could have far-ranging repercussions if they harm areas where wildlife is concentrated.

The small tweak in shipping routes necessary to avoid those five island areas will result in big protections for seabirds, Steller sea lions and sea otters that congregate in the Aleutians, analysis shows.

The analysis is by the Aleutians and Bering Sea Islands Landscape Conservation Cooperative, one of several consortiums around the nation tasked with using science to address regional climate change and other environmental stressors.

Avoiding the five island buffers will lengthen ship voyages, but by less than 1 percent, said Doug Burn, a U.S. Fish and Wildlife Service biologist who is the coordinator of the conservation cooperative.

In return, ships' avoidance of those sensitive areas close to islands substantially reduces ecological risks from spills and other disturbances, according to the analysis. For seabirds, which gather in colonies on the islands, the risk is reduced by 17 percent; for Steller sea lions, which are listed as endangered in Western Alaska, the risk reduction is 21 percent; for sea otters, which are listed as threatened in the Aleutians, the risk reduction is 22 percent, Burn said.

The "areas to be avoided" designations are recommendations, not legal requirements, Burn said. "It's not like if you go in there the Coast Guard's going to write you a ticket for trespassing," he said. But insurance companies that would have to pay for damages from ship accidents are likely to take them seriously, he said.

The IMO has also addressed the Bering Sea in its Polar Code, a set of safety and environmental standards for ships operating in ice-prone waters that was adopted last May and will go into effect in 2017. The Polar Code using a broad definition of "Arctic," characterizing it as areas that extend down to Latitude 60 for North America, including much of the Bering, and even a bit farther south for Greenland.