More than 100 Olive Ridley turtles washed up dead on Mexican beaches this month, just weeks after the U.S. government banned imports of wild-harvest shrimp from Mexico on grounds that Mexican shrimp trawls endanger sea turtles, conservation groups and officials said.

Turtle protection groups in the Pacific coast state of Guerrero alerted wildlife officials in early April after large numbers of Olive Ridleys, an endangered sea turtle species, began turning up on their beaches. As of April 7, the death toll had reached 168 along a 100-km (60-mile) stretch of coastline, according to Costasalvaje, the Mexican branch of the U.S. green group Wildcoast.

Officials from the federal environmental protection agency (Profepa) later conducted their own survey and found 124 dead Olive Ridleys. Profepa officials reported many of the turtles had water in their lungs and large hematomas, prompting speculation they had been bludgeoned by fishermen after getting caught in shrimp nets.

Despite a seasonal moratorium on shrimping, local fishermen also reported seeing lights from shrimp boat at sea. However, authorities were still investigating the cause of the turtle deaths, says Joel González Moreno, Profepa’s director-general for inspections and monitoring of wildlife and coastal ecosystems.

U.S. bans Mexican shrimp

The reports follow the U.S. State Department announcement March 24 that it was revoking Mexico’s certification to export wild-harvest shrimp to the United States. The ruling said Mexico had failed to ensure the effective use of turtle excluder devices (TEDs), required under Mexican law since 1993 for all deep-water trawlers. The metal grids allow shrimp to collect in the nets while shunting turtles and other large marine animals aside.

Olive Ridleys (Lepidochelys olivacea) are the smallest of the seven sea turtle species that inhabit the waters off Mexico’s Pacific coast. They face a double threat from shrimping nets and poachers, who sell their meat, oil and eggs on the black market. In Mexico, the oil from turtle shells is widely believed to help cure respiratory ailments, while the eggs are prized as an aphrodisiac. Turtle soup, meanwhile, is considered a delicacy and is sold clandestinely in restaurants throughout the country.

“We’ve heard returning migrant workers are welcomed with turtle-meat dishes and, of course, turtle eggs,” says Costasalvaje’s Sergio Flores. Turtle soup also is served at weddings, baptisms and political events, Flores says.

Costasalvaje runs public-information campaigns to combat belief in such “mystical properties.” One involves posters featuring a bikini-clad model and the slogan: “My man doesn’t need to eat turtle eggs, because he knows they don’t make him more potent.”

The group launched the campaign in 2004 following the massacre of hundreds of Leatherback and Olive Ridley turtles on San Valentín beach, in Guerrero. “The main problem is the demand,” Flores says. “If there wasn’t this demand, there wouldn’t be a market.”

In recent years, Mexican soccer stars and music groups, such as Maná and Los Tigres del Norte, have joined in, urging their fans to abstain from consuming turtle products.

Although Olive Ridleys are the most numerous sea turtles in Mexico, they are also the most vulnerable. Their practice of congregating on a handful of Pacific beaches to lay their eggs—known as the arribada in Spanish—makes them easy prey for poachers, who can kill hundreds of turtles in a single day.

The relatively small Olive Ridley eggs—roughly the size of ping pong balls—also makes them easier to smuggle to other parts of Mexico and even into the United States.

Measure called unfair

Mexico’s government in recent years has taken measures to protect the turtles, including deploying the Navy to patrol beaches and fishing sites. Officials also have stepped up inspections of fishing boats to enforce the use of TEDs. From November through March, Profepa conducted 519 such inspections and fined 60 captains, the agency reported, responding to the U.S. ban on Mexican wild shrimp.

Rafael Elvira Quesada, Mexico’s environment secretary, criticizes the ban as “unfair,” arguing 95% of Mexican fishermen have outfitted their nets with Teds—a compliance rate he calls similar to that of U.S. fishermen. He adds U.S. officials did not take into account the raft of measures Mexico has put in place to protect the sea turtles in its waters.

Conservation groups point to the turtle deaths and other such cases in recent years as proof that Mexico’s measures—or their enforcement—fall short. In July 2008, the first year Costasalvaje began keeping mortality statistics, 71 dead Olive Ridleys were found washed up on Diamante beach in Acapulco. Another 86 documented turtle deaths occurred in the same region last year, according to Flores.

“It’s true authorities are becoming more sensitized to the problem and responding more rapidly,” Flores says. “But there’s a lot more to do. These deaths should not be happening.”