Thousands of square miles off Alaska have been designated as critical habitat for North Pacific right whales, considered the most endangered whale in the world.
At least 11,000 of the slow-moving whales — prized by commercial whalers for their oil and baleen — once swam the waters of the North Pacific.
The whales were listed as endangered in 1973 and there are now believed to number fewer than 100 in waters near Alaska. A few hundred more may remain closer to Russia.
With so few whales remaining, scientists had a challenge coming up with the proper criteria for designating habitat, said Brad Smith, a biologist with the National Oceanic and Atmospheric Administration in Anchorage.
Scientists settled on recent sightings, sounds and the four types of plankton the whales eat to designate areas in the southeastern Bering Sea and south and east of Kodiak Island, Alaska.
"Sightings of right whales in the southeastern Bering Sea and Gulf of Alaska and locations of right whale calls were instrumental in identifying these important feeding areas," said Doug Mecum, acting administrator of the Alaska region of NOAA fisheries.
Even with the critical habitat designation, the recovery of the whales is tenuous, Smith said. The benefits of designating critical habitat likely will play out over a long period of time, he said.
"They are still considered an endangered species and that means there is some probability that these animals may go extinct in the foreseeable future," Smith said.
Commercial whalers decimated right whales in the 1800s and by the 1900s they were scarce. They came under international protection in 1935 but Japan and the Soviet Union did not sign the agreement and continued killing right whales.
Between 1963 and 1967, the Soviets killed 372 right whales in the Gulf of Alaska and the southeastern Bering Sea — an event that was thought to be the final blow.
"These takes devastated a population that, while undoubtedly small, may have been undergoing a slow recovery," NOAA said in its final rule.
Then, federal scientists got a surprise in the summer of 2004 when 25 right whales were spotted in the Bering Sea. That was twice as many as previously seen. A right whale was spotted last summer in the Gulf of Alaska.
Smith said both areas in the Gulf of Alaska and the Bering Sea are important areas for commercial fishing.
But the critical habitat designation is flexible, he said, allowing for activities that include fishing and oil and gas exploration, as long as those activities do not disrupt the production of the specific plankton the whales eat.
Brent Plater, a lawyer with the Center for Biological Diversity, which filed a lawsuit in 2000 to get critical habitat designated for the whales, said species that get critical habitat protection are twice as likely to recover.
Last year, a federal judge in San Francisco ordered the National Marine Fisheries Service to come up with its critical habitat proposal or explain why it could not.
The judge told the agency it could not study the issue any longer, but had to use the facts already at hand.
Plater said in the end the Fisheries Service did a good job.
"It is a good designation. It is based on solid sighting evidence," he said.
The next step is to make sure that other federal agencies that oversee activities in the designated areas cooperate with the rule to help the whales recover, Plater said.
If they don't, the future is clear, he said.
"Then we are going to end up back in court," Plater said.