Whether they're deep-fried, baked or served on the half-shell, most of the oysters eaten by Americans start their journey to the gullet in the Gulf of Mexico.

But with the Gulf now awash in oil, the supply is down, prices are up, restaurants are going oyster-less, and there appears to be no quick fix to the crisis. After all, suppliers on the Atlantic Coast and in the Pacific Northwest can't simply make more oysters.

"In general, it takes us two to four years to grow oyster crops, so it's hard to respond when there's a surge in demand from something like this," said Bill Dewey of the Seattle area's Taylor Shellfish Co. "The Gulf, and Louisiana in particular, is the leading oyster-producing area in the country, and so when they go down it creates a huge void."

Louisiana's oyster industry has been brought to a standstill since oil began gushing into the Gulf in April. Oyster beds have been closed — mostly as a precaution — and fishermen have been put on oil spill duty.

Red Lobster said Tuesday it is taking oysters off its menus when its supply runs out in a few weeks. "Passing along a higher cost to our customers is something we're not going to do," said Rich Jeffers, a spokesman for the nationwide chain of 666 restaurants.

Though oysters are grown from the Northeast's Long Island Sound to Humboldt Bay in California, industry officials estimate that 60 to 70 percent of the oysters eaten in the U.S. come from the Gulf. Those Gulf oysters grow in submerged beds from Texas to Florida, with Louisiana accounting for more than half of the supply.

Mike Voisin of Motivatit Seafoods in Houma, La., said only a small fraction of Louisiana's roughly 7,500 miles of shoreline has been touched by oil. But because of the closings and the diversion of fishermen, he estimated that only 30 to 40 percent of oyster farms are open.

"It has created confusion in the market, shortages in the market, higher prices," he said. "Pricing has gone up about 40 percent at the dock."

People who make their living off oysters say there is no full-blown nationwide shortage at this point, but dealers and growers on the Pacific and Atlantic coasts say they have been fielding calls from a new set of potential customers.

If Gulf oyster production continues to lag, it could be hard to make up the slack.

Imported oysters make up a very small segment of the U.S. market. Importers must participate in a strict federal program to make sure shellfish are safe from contamination.

But also, Gulf oysters have a certain cachet among seafood lovers because of their clean, refreshingly briny taste. The taste of an oyster is strongly influenced by the water it grows in, meaning a Japanese oyster cannot necessarily be substituted for a Gulf one, said Gavin Gibbons of the National Fisheries Institute, a trade group.

Pacific growers produce a different variety of oyster from the ones harvested on the Gulf and the Atlantic. In addition, Pacific growers — who largely farm their oysters, as opposed to the wild harvests of the Gulf — have struggled in recent years with production problems that some believe are related to acidic water.

On the East Coast, oyster production can drop in the summer. In Virginia, for example, oystermen switch to the lucrative crab market when the weather turns warm.

The industry is watching how the spill plays out. No one knows when the leak will stop, when the cleanup will be over or when business will be right again.

Unlike shrimp or fish, mature oysters cannot swim to clean water. A lot of oil washing ashore could be devastating.

Oysters in the Gulf are typically subtidal, meaning they stay underwater at low tide. A surface sheen or floating tar balls will not reach these oysters, unless a hurricane or another strong storm churns the water. Still, oysters pulled from water with crude on the surface could get oil on them, rendering them unfit for sale.

Ed Cake, an oyster biologist who has consulted for the oyster and the oil industries, said he is worried that the fresh water flushed into the Gulf to keep the oil away could kill saline-dependent oysters.

His larger fear is that underwater plumes of oil will reach the oyster beds. Mature oysters are filter feeders, sucking in some 50 gallons of water a day. Oil droplets can cause deadly lesions in the oysters, and heavier concentrations of oil could kill them directly.

"As long as the dispersed oil doesn't get to them, I think they'll be all right," Cake said.

One famous New Orleans oyster business, P&J Oyster Co., already is idle, and there are fears that more trouble could be headed their way.

"These guys are hanging on by a thread," said Ewell Smith, executive director of the Louisiana Seafood Promotion and Marketing Board. "What are these guys going to do if this thing keeps going south?"