Coastal Oysters

Eastern oysters thrive best at 5 to 15 parts per thousand of salinity.

When diners dip oysters into a spicy concoction or enjoy any of several dishes featuring the tasty bivalve mollusks, they can thank 20,000 people along the Gulf Coast – half in Louisiana.  

“The nation produces 750 million pounds of in-shell oysters annually in a $1 billion industry,” says Mike Voisin, CEO of Motivatit Seafood in Houma, La., chairman of the National Fisheries Institute and member of other seafood organizations. “The Gulf States produce 500 million pounds for a $500 million economic impact. Louisiana is the big gorilla in the oyster industry. Each year, Louisiana contributes up to 40 percent of the national oyster harvest, or more than 250 million pounds of oyster meat for a $275 million economic impact.”

Louisiana remains the “big gorilla” because the Mississippi River drains 41 percent of the contiguous United States and parts of two Canadian provinces. Freshwater and nutrients from its immense watershed mix with salty Gulf of Mexico water, creating an outstanding oyster habitat.

“Oysters need a mixing of fresh- and saltwater,” explains Patrick Banks, a Louisiana Department of Wildlife and Fisheries biologist in Baton Rouge. “They can tolerate a wide range of salinities, but too much of either can kill them.

Oysters thrive best at 5 to 15 parts per thousand of salinity. Seawater is about 35 parts per thousand.”

An eastern oyster, also known as an American oyster, reproduces by “broadcast spawning.” One female can spew up to 6 million eggs twice a year. After fertilization, a microscopic larva actually swims for a couple of weeks until it finds a hard, clean object on the bottom. Once it cements itself to that object, it never moves again. The young oyster, or “spat,” takes on the familiar form and begins to grow.

“It takes about 18 to 24 months for an oyster to grow from pinhead-sized to about 3 inches in diameter,” Banks says.

“An oyster can live up to 10 years, but few make it that long before something or someone eats it. They feed by drawing water in through siphons, filtering out microscopic particles and expelling the water. They breathe the same way, with gills inside their bodies.”

In many ways, harvesting oysters resembles cultivating any other crop. On private leases, oystermen spread shells, concrete or crushed limestone for larvae. They also transport spat from other areas to seed their leases. After two years, the oystermen can harvest that reef.

Depending upon state laws, oystermen can use either use long-handled tongs or “rakes,” metal devices that lift the creatures from the mud, depositing them into wire baskets. Oyster luggers, 40- to 60-foot boats crewed by two to four people, drag rakes along the bottom. Periodically, the crew winches in a rake and dumps the catch onto a culling table to pick through whatever they pulled aboard. Anything they don’t want or can’t sell goes back over the side.

“There’s nothing easy about harvesting or processing oysters,” Voisin says. “It’s hard, dirty, backbreaking work, but once it gets in your blood, it’s hard to get it out. Bycatch is minimal because it’s such a slow process. Fish and shrimp get out of the way. Oyster rakes do pick up cans and debris. I’ve even known people to pick up cannonballs. Once in a while, we catch some crabs, which the crew usually eats for dinner.”

Louisiana oystermen lease approximately 400,000 acres and may fish several million public acres. Because health laws prohibit oysters from sitting on deck without refrigeration for longer than 10 hours, most boats leave around sunrise and return that afternoon. In cooler weather, though, they might rake for two days and spend the night on the boat.

 At the dock, the crew unloads 1.5-bushel sacks, each holding about 100 pounds of oysters. Each sack sells for about $25. The captain, usually the boat owner, pays the expenses and shares the profits with the crew. Each deckhand generally pockets about $2 per sack. A 100-pound sack yields about 6 to 8 pounds of meat.

“Most oystermen own and operate their own boats,” says John Tesvich, 52, a fourth-generation oysterman who began captaining a boat at age 14. “In Louisiana, we can harvest oysters all year long on private leases, but an oysterman might only harvest one-third of the time. When not harvesting, he might do repairs on the boat, seed beds, mark lease boundaries or other things.”

At the docks, captains negotiate with brokers who buy the catch and haul it to the plants. At the processing plants, workers pressure-wash oysters to remove grit and debris from their shells. Then, they grade and separate the shellfish.

Big singles go to raw bars and restaurants with the rest destined for shucking.

Although Tesvich grew up working oyster boats running out of Empire, La., he now owns the Ameripure Oyster Co. processing plant in Franklin, La. He graduated from the University of New Orleans in 1979 with a mechanical engineering degree but returned to the family business two years later. He put his degree to good use designing boats and equipment.

“About 66 percent of the oysters caught in Louisiana go out of state for processing,” Tesvich explains. “When people started to worry about bacteria in the water, we developed the Ameripure Process that uses low-heat pasteurization to make oysters safer to eat. Another post-harvest process uses ultra-high pressure to kill bacteria. A third process is to freeze oysters to lower bacteria levels.” For more information on oyster processing, see
In Louisiana, oysters exist all along the coast, but the industry centers on Plaquemines, St. Bernard and Terrebonne parishes. In 2005, Hurricane Katrina smashed into that area, followed three weeks later by Hurricane Rita clobbering southwestern Louisiana and Texas. These storms destroyed about 70 percent of the oysters from Bayou Lafourche near Galliano, La., eastward to the Florida panhandle. The industry began to recover when hurricanes Gustav and Ike slammed Louisiana and Texas with another double whammy in 2008.

“Galveston Bay is the major oyster producing area in Texas, but since Hurricane Katrina, the industry moved down toward Corpus Christi and Matagorda Bay,” Voisin says.

Eastward, about 200 Mississippi luggers harvest about 386,000 sacks per season, says Scott Gordon of the Mississippi Department of Marine Resources in Biloxi. Most boats ply the waters of Mississippi Sound from Pass Christian to the Louisiana line. Oysters live in the Pascagoula River delta, Bay St. Louis and Biloxi Bay, but the state restricts the harvest in those areas.

“Before 2005, Mississippi produced more oysters than the entire East Coast of the United States, but Hurricane Katrina devastated our industry,” Gordon says. “We lost between 90 and 95 percent of our oyster resources, but we’re about back up to pre-Katrina levels now. We used federal disaster relief funds to rebuild reefs. The industry would not have been able to come back without it.”

In Florida and Alabama, harvesters can only use tongs when working public waters. Florida oystermen harvest shellfish in Apalachicola Bay all year long but must abide by seasons in other places. Sequestered by several barrier islands and fed by its namesake river, Apalachicola Bay and adjacent waters cover about 208 square miles.

“Florida typically produces about 2.5 million pounds of oyster meat per year,” says Mark Berrigan of the Florida Department of Agriculture in Tallahassee. “The bulk of that comes from Apalachicola Bay, but people harvest oysters all along the panhandle from Pensacola to Cedar Key. It’s about a $20 million economic impact to the state.”

Although Florida suffered from storms in 2004 and 2005, a chronic drought for the past several years did more damage to the Sunshine State industry. Reduced rainfall lowered water levels in the Apalachicola River while increasing demands on remaining stocks. With less freshwater entering the bay, salinity increased.

“We had a normal spring as far as rain goes in 2009, so many reefs are bouncing back,” Berrigan says. “Storms can disrupt reproductive behavior and substrate, but storms also have positive long-term ecological effects. They clear sediment off reefs and scour the substrate to make it better for the next generation of oysters.”

Hurricanes in 2004 and 2005 also devastated the Alabama oyster industry. The annual harvest dropped from about 800,000 pounds of meat before Katrina to 75,000 in 2008, says John Mareska, an Alabama Marine Resources Division biologist.

“The Alabama oyster industry has come to a standstill,” Mareska says. “We’ve lost just about all the public reefs. Katrina made a mile-wide cut in Dauphin Island that allowed more saltwater intrusion into Mississippi Sound. After Katrina, oysters were still plentiful, but the drought began in late 2005. Mobile Bay became more salty. Remaining reefs are not rehabilitating as fast as we would like.”

Although the coastal industry suffered setbacks, it will survive as long as the Mississippi River flows into the Gulf of Mexico. Highly resilient and prolific, Gulf oysters will continue to delight cuisine connoisseurs for many years to come.