Shrimp from three Central American farms test positive for EMS, researcher says

Shrimp from three farms in two Central American countries have tested positive for early mortality syndrome (EMS), according to the lab run by the shrimp disease expert credited with discovering the cause of the disease that has ravaged shrimp populations in Asia and Mexico.

Samples from the three farms that were sent to the lab of Don Lightner, a University of Arizona professor and expert in diseases affecting farmed aquatic species, came back positive for EMS, Jee Eun Han, research associate at the lab, told Undercurrent News.

The samples were taken in 2013, 2014 and this year, said Han, who did testing on the samples.

She declined to name the countries where the shrimp was from, saying the lab’s research is not public yet and citing confidentiality agreements with the farms.

One source with direct knowledge of shrimp farming operations in Central America told Undercurrent he believes the countries are Honduras and Nicaragua.

As Undercurrent has previously reported, some producers in Central America have been seeing an increased amount of losses because of bacterial infections, but those haven’t been officially linked to EMS.

Lightner — whose team, according to a 2013 Global Aquaculture Alliance (GAA) statement, discovered that the disease is caused by a bacterial agent that produces a toxin in the shellfish’s gut — told Undercurrent he suspects EMS was transported to Central America in shrimp from Mexico, rather than from Asia.

“Probably it came through Mexico,” he said. “I think it came in with smuggled-in brood stock.”

The Mexican states of Sinaloa, Nayarit and Sonora lost about 70% of their annual shrimp production to EMS in 2013, with Sonoran shrimp farmers alone losing more than $77 million. An expert in the Mexican shrimp sector told Undercurrent at an industry gathering in Honduras last year there was concern that EMS had spread to the southern Mexican state of Chiapas.

However, farmers in Mexico have gotten more robust strains of shrimp that are more resistant to EMS, and stocks there are doing better, Lightner said.

Undercurrent has previously reported chances appeared good that EMS would spread to Honduras but that shrimp farms in the Central American nation may be able to weather the disease better than counterparts in Mexico because of genetic hardiness and better information than Mexico had when the disease first blindsided that nation in 2013.

Also known as acute hepatopancreatic necrosis disease, EMS is linked to a type of vibrio bacteria and was first reported in China in 2009 before spreading to Vietnam, Thailand, Malaysia and Mexico.

The GAA has said annual losses from the disease top $1 billion. The World Bank estimates the disease will have resulted in the loss of three million metric tons of shrimp by 2016.

However, the appearance of EMS in Central America probably will not greatly affect the global shrimp markets, the source with knowledge of the Central American shrimp industry said.

“Central America produces a very small percentage of the world’s shrimp supply and hence will not have any appreciable impact on market supply or prices,” he said.