In a move that has surprised some fisheries experts, the federal government has decided to consider listing North Pacific loggerhead sea turtles as a separate endangered species and setting aside areas along the California coast and off Hawai'i as their critical habitat.

The action came a day after two East Coast environmental groups petitioned the Interior Department and the National Oceanographic and Atmospheric Administration to take a similar step with another variety of loggerhead sea turtles along the Atlantic Coast.

No action has been announced on that petition.

Designation of the Pacific turtles as endangered would give them and their habitat increased protection under the Endangered Species Act.

It highlights a tactic by environmentalists to use the act to protect specific threatened groups within the same species.

Turtle advocates say tens of thousands of sea turtles are killed each year by commercial fishing and coastal development on both coasts.

Pacific fisheries managers, however, say great strides have been made in protecting Pacific loggerheads in recent years, both in the Pacific and on Japanese beaches where they nest.

Loggerhead turtles everywhere already are classified as "threatened" under the federal Endangered Species Act, but environmentalists say a higher level of protection is needed.

The Pacific turtles hatched in Japan migrate each year to coastal areas off California and Mexico and are also found in waters off the Hawaiian Islands.

The decision by the National Marine Fisheries Service to consider an upgraded definition for North Pacific loggerheads was published in the Federal Registry on Friday, calling for comments by Jan. 15.

It resulted from a July petition by the Center for Biological Diversity and Turtle Island Restoration Network, which seek to increase turtle protection worldwide.

The announcement starts a full review of the Pacific loggerheads.

"We find that the petition presents substantial scientific information indicating that the petitioned action may be warranted," the federal filing said.

Eric Kingma, an environmental coordinator for the Western Pacific Regional Fishery Management Council which oversees Pacific island fisheries from Honolulu, said he was "somewhat surprised" by the announcement since a five-year review of loggerheads was recently completed.

He also cited recent progress in protecting loggerheads, with only 17 turtles encountered by fishermen in the region over the past year.

And many of those were able to swim away, he said.

"We have significantly reduced sea turtle interactions in our fishery," Kingma said, adding that most of the destruction of sea turtles is off the coast of Mexico, where thousands of loggerheads have died.

Environmental groups have been working for years to grant special protection to the loggerheads.

"These ancient animals, which can live for a century or more, have swum the Earth's oceans since the days of the dinosaurs," says a release from the petitioners, who estimate loggerheads have declined by more than 80 percent, with fewer than 1,000 female loggerheads returning to nest each year.

The turtle advocates blame longline fishing, which is a method that uses hook-laden fish lines as long as 60 miles through areas where the turtles swim. The target is swordfish or tuna, but thousands of turtles, seabirds, marine animals and sharks are snagged by the lines.

"The survival of loggerheads will depend on preventing sea turtles from drowning in fishing gear," said Miyoko Sakashita, ocean program attorney for the Center for Biological Diversity in a news release hailing the federal decision.

"The decision to consider listing the loggerheads as endangered marks a first step toward heightened protections in the Pacific."

The group, however, criticizes the fisheries service for considering approval of a permit for an experimental longline fishery for swordfish off the California and Oregon coasts next year.

It says a similar fishery operated out of Hawai'i is responsible for the deaths of numerous whales in addition to sea turtles.

Turtles also are threatened by global warming, according to the environmental groups, with coastal erosion from rising seas threatening nesting beaches and skewing the ratio of females and males, with more females hatching when temperatures increase.