Crews went on the offensive against the worst U.S. oil spill, but communities down the coast were on the defensive as meandering slicks neared one of the world's most populous bird-breeding grounds.

"We are beginning a new phase," Department of Environmental Conservation Commissioner Dennis Kelso said Wednesday as fishermen were redeployed from protecting fish hatcheries to begin the long, tedious work of collecting oil from coves and inlets.Crews were on the beaches of Naked Island in the heart of Prince William Sound, scooping up pools of congealed oil and scraping it from rocks. The shoreline was covered in oil following the March 24 grounding of the tanker Exxon Valdez, which sent 10 million gallons of oil into the sound.

"At first it was feeling kind of futile, but I'm starting to feel like we're doing something now," said Bill Scheer, an unemployed Valdez cannery worker who has worked on the clean up for two weeks.

But farther west along the Kenai Peninsula, protective barriers were still going up as straggling patches of oil menaced the coastline and the islands north of Kodiak Island.

Coast Guard spokesman Roy Compton said Thursday the leading edge of the spill, sighted west of Gore Point on the Kenai Peninsula, continues to break up. But streaks of light oil sheen and heavy "mousse" continue to wash ashore in some areas, he said.

Winds were generally out of the northeast Thursday, meaning they could help push oil away from land, but the forecast called for a wind shift to the southeast, increasing to 35 knots with a gale warning, the Coast Guard said. Seas were forecast to increase to 9 feet in the Gulf of Alaska by Thursday night.

The herring fishery season set for this weekend in the Kodiak area will go on as scheduled, officials said, but samples will be taken of all fish caught and tested for contamination.

"The tips of the peninsula have been slimmed for the past couple of days, but the worst that could have happened hasn't happened yet," said Jon Erickson, a spokesman at Kenai Fjords National Park.

Erickson said a thin, oily sheen could be seen in Resurrection Bay on the park's eastern border, and thick streams of oil "mousse" and tar balls reached the shoreline.