So far only oil sheens have reached into some coastal waters in the southeastern US, and the oil's slow progress despite an uncapped seafloor gusher was allowing crews and volunteers to lay boom in front of shorelines.

That effort was stymied by choppy seas into the weekend but the calmer weather should help.

“You mentally want to push it back to the west, and then you feel guilty for doing so,” said Jan Grant, manager at the St. George Inn on St. George Island, Florida, about the path the spill might take.

BP PLC has been unable to shut off the undersea well spewing 200,000 gallons (757,000 liters) a day, but crews have reported progress with a new method for cutting the amount of oil that reaches the surface. They're using a remotely operated underwater vehicle to pump chemicals called dispersants into the oil as it pours from the well, to break it up before it rises. Results were encouraging but the approach is still being evaluated, BP and Coast Guard officials said.

Several river boat pilots said the edge of the oil slick Monday was 15 to 20 miles (25 to 32 kilometers) off the Southwest Pass, where ships headed to New Orleans enter the Mississippi River. The latest satellite image of the slick, taken Sunday night, indicates that it has actually shrunk since last week, but that only means some of the oil has gone underwater.

The new image found oil covering about 2,000 square miles (5,200 square kilometers), rather than the roughly 3,400 square miles (8,800 square kilometers) observed last Thursday, said Hans Graber of the University of Miami.

The consequences on those whose livelihoods rely on the richness of the sealife in the waters was obvious. Fishing has been shut down in federal waters from the Mississippi River to northwestern Florida, leaving boats idle Monday in the middle of the prime spring season. A special shrimping season will close Tuesday evening.

Inns and restaurants that count on tourists attracted to the beautiful blue-green waters and sandy white beaches already are getting calls about the spill, which has flirted with the coastlines before receding, mostly because of the weather.

Engineers from BP have failed to come up with a solution to halt the gusher that's been spewing into the sea since an offshore drilling platform blew up and sank April 20 and killed 11 workers. BP operated the rig that was owned by Transocean Ltd.

Crews haven't been able to activate a shutout valve underwater. And it could take another week before a 98-ton concrete-and-metal box is placed over one of the leaks to capture the oil.

Worse, it could take three months to drill sideways into the well and plug it with mud and concrete to stop the worst US oil spill since the tanker Exxon Valdez ran aground in Alaska, leaking nearly 11 million gallons of crude.

It's unlikely there would be a total shutdown of the shipping lanes at the Mississippi, the largest US river, which runs up the country's middle. However, there could be long delays if cargo vessels that move millions of tons of fruit, rubber, grain, steel and other commodities in and out of the country's interior are forced to wait to have their oil-coated hulls power-washed to avoid contaminating the Mississippi. Some cargo ships might choose to unload somewhere else in the US That could drive up costs.

“Let's say it gets real bad. It gets blocked off and they don't let anything in. They lose time, and they are very concerned about that,” said river pilot Michael Lorino.

“It's going to be very costly if they have to unload that cargo in another port and ship it back here because it was destined for here.”

BP said Monday it would compensate people for “legitimate and objectively verifiable” claims from the explosion and spill, but President Barack Obama and others pressed the company to explain exactly what that means.

By all accounts, the disaster is certain to cost BP billions. But analysts said the company could handle it; BP is the world's third-largest oil company and made more than $6 billion in the first three months of this year. The oil spill has drained $32 billion from BP's stock market value.

In the Chandeleur Sound on Monday, about 40 miles (65 kilometers) northeast of Venice, Louisiana, thick, heavy oil formed long clumps that looked like raw sewage. Dying jellyfish could be seen in the water. Sea turtles have been found dead on Mississippi beaches, but necropsies on five of the 30 did not find evidence they died from the effects of oil.

The news was better from Mississippi to northwestern Florida, where the sheen isn't expected to touch beaches before Thursday. Wind and sea currents have helped to keep the oil away from points farther west, said Coast Guard Capt. Steve Poulin.