NEW ORLEANS — Federal officials say they're expanding the area of the Gulf of Mexico where fishing is shut down because of the massive Deepwater Horizon oil spill.
They had already shut down fishing from the Mississippi River to the Florida Panhandle soon after the Deepwater Horizon rig exploded and sank last month. Nearly 10 percent of federal waters were affected initially.
The National Oceanic and Atmospheric Administration announced Tuesday that it's expanding the closed area to nearly 46,000 square miles, or about 19 percent of federal waters.
NOAA Administrator Jane Lubchenco said the move was made in response to oil shifting southeast. That oil could enter the Loop Current, which would then carry it to the Florida Keys and even possibly up the Atlantic Coast.
University of South Florida researchers said Tuesday the Loop Current could pull the southern arm of the massive spill into the Florida Keys on Sunday.
But Lubchenco said that while aerial surveys show some tendrils of light oil close to or already in the Loop Current, most oil is dozens of miles away from the current.
Lubchenco added that it would take about eight to 10 days after oil enters the current before it begins to reach Florida.
Twenty tar balls were found by the Coast Guard off Key West, Fla., on Monday. They are being tested to see if they came from the Louisiana spill or elsewhere. Tar balls can occur naturally or come from other sources such as ships.
Key West, the southernmost tip of the popular Straits of Florida island chain, is a famous beach, diving and fishing resort which counted writer Ernest Hemingway among its fans.
Although people living there are used to hurricanes hammering their shores, the oil slick was a different kind of threat.
"The county hasn't called for an evacuation of tourists as they often do during a hurricane, but if the oil spill affects our waters there won't be any visitors to evacuate. No one knows where the tar balls are from, but they predict doom and gloom," said resident Charlie Bauer.
Officials say the oil spill has so far had only a small pollution impact on the shoreline and wildlife along the Gulf Coast, but oil debris and tar balls have been reported in Louisiana, Alabama and Mississippi. Miles of protective booms are being used to try to defend the shore.
The Associated Press and Reuters contributed to this report.