Order a rockfish at a restaurant in Maryland, and you'll likely get a striped bass. Place the same order in California, and you could end up with a vermilion rockfish, a Pacific Ocean perch or one of dozens of other fish species on your plate.

This jumble of names is perfectly legal. But it's confusing to diners — and it can hamper efforts to combat illegal fishing and seafood fraud, says the ocean conservation group Oceana.

Under current Food and Drug Administration rules, a single fish species can go by multiple names from the time it's caught to the time it ends up on your plate. Conversely, lots of different fish legally can be sold under a single name.

For example, that "grouper" on a menu could be one of 64 different species. It could be a fish known by the common name sand perch (scientific name: Diplectrum formosum), which is plentiful. Or it could be a goliath grouper, a critically endangered species. The FDA says all can be sold under the acceptable market name "grouper."

Oceana wants the entire supply chain — from boat to plate — to ditch the FDA's list of "acceptable market names" for seafood. Instead, it wants the FDA to require that a species' Latin scientific name or common name be used in all cases.

Oceana says more precise labeling of seafood — the kind it calls for in its One Name, One Fish report — will go a long way toward protecting vulnerable or endangered species and deterring illegal fishing. And it says it will help to put a stop to seafood fraud — an issue the nonprofit group has been working on since 2011.

"It's another tool to help with enforcement," says Oceana senior campaign director Beth Lowell. "People have a right to know about the food they eat. It shouldn't be that hard to find out what fish I'm eating without having to do a DNA test or ask the server, who has to ask the manager, who has to ask the distributor."

Jeremy Sewall is the chef and owner of the Boston-area seafood restaurants Row 34 and Island Creek Oyster Bar. He orders all his fish whole so that he knows exactly what species he's getting. He says he's all for accurate labeling and transparency in the seafood world.

"We work hard to find out where our fish is from and are extremely happy to share it with our consumers," he says. But the idea of using only a fish's common name or scientific name on menus "only adds confusion to an incredibly confusing industry," he says.

For instance, Sewall notes that he often serves local hake. But there are several local hake species. Does he change the scientific name listed on the menu each night, depending on what the catch of the day is? Requiring that kind of constant updating would be ridiculous, he says, not to mention a nightmare to manage.

But if guests do ask for specifics on their seafood supper, he says, his staff are always eager and able to answer.

For example, "if we're serving snapper for ceviche or crudo, we buy genuine American red snapper from the Gulf of Mexico and adjacent Atlantic waters. We try to trace it back to where it comes from, and we label it as American red snapper," he says.

Snapper is one of the species on Oceana's hot list. It calls out the FDA for allowing 56 species — everything from mullet snapper to Colorado snapper to golden snapper — to be sold simply as "snapper." It's not only that so many different fish species can be called "snapper"; according to Oceana's sampling of retail outlets, many fish sold as "snapper" are something else entirely. Oceana's sampling in 2013 found that, in all, one-third of the seafood sold at the retail level did not match its label.

"People should be able to know what they're buying. If they're buying a snapper, they should get a snapper," says Oceana's Lowell.

The FDA's own testing at the wholesale level has found fish fraud to be less prevalent but still problematic: A report released by the FDA in 2014 found that 15 percent of seafood products at the wholesale level were mislabeled.

Some in the fishing industry are backing Oceana's call for "one name, one fish." That includes Tri-Marine, a Washington-state based global tuna supplier, and the Southern Shrimp Alliance, an industry group. Both groups submitted comments in favor of specific labeling to President Obama's task force on illegal fishing and seafood. The shrimp group notes that farmed shrimp — which could have come from countries where antibiotics are widely used — are often mislabeled as Gulf shrimp.

But Gavin Gibbons, a spokesman for the National Fisheries Institute, the seafood industry trade group, says creating a "one name, one fish" rule "will have zero effect." He says most fish fraud occurs not because of name confusion, but because of intentional deceit. He says what's really needed is better enforcement through DNA testing, which the FDA is now ramping up.

Even if the seafood industry were in agreement behind the "one name, one fish" policy, it's not clear most consumers would care. Although many chefs like Sewall are willing to go the extra mile to make sure guests know the snapper is the real deal, the fact is, the effort often goes unnoticed by customers.

"The reality is, they're not interested," says Sewall. "They're hungry."

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