VENICE, La. – A tide of sludgy oil has begun washing into Louisiana’s coastal marshes, officials said Tuesday, as BP remained days away from capping the oil gushing from a damaged well on the Gulf floor.

Loss of the marshes, where the Mississippi River enters the Gulf, could mean huge losses for the area’s seafood industry, and a reduction in Louisiana’s already skimpy shield against a hurricane storm surge.

“It’s our greatest fear,” said Billy Nungesser, the president of Plaquemines Parish, La., whose residents depend on a healthy fishery.

State officials said the oil’s arrival underscored the need for a radical solution: building a chain of small offshore islands to block the oil from the coast.

“This is the first time we’ve seen this much heavy oil this far into our wetlands,” Louisiana Gov. Bobby Jindal said at a news conference here in this last town before the coastal marshes begin. “We know there’s a lot more heavy oil behind it that hasn’t made it to shore yet.”

Interior Secretary Ken Salazar, meanwhile, told Senate committees Tuesday that the oil company would attempt a “dynamic kill” of the oil well on Saturday. That procedure involves pumping thick mud — not the “junk” that company officials had previously considered — into the drill pipe, in hopes of clogging it.

Also Tuesday, BP said it was slowly increasing the amount of oil it was siphoning away from the well to 2,000 barrels a day.