January 12, 2016 — Bob Rheault was having an open house at his young shellfish hatchery, so he arrived early in the morning with bottles of wine and plates of cheese. That’s when he noticed he had a problem.
“There was an odd substance floating on the surface of the tanks,” Rheault says. He looked through a microscope, “and there were no bodies to be seen … just empty shells with bacteria climbing all over them.”
In oyster and clam hatcheries, a bacterial infection can cause the population to drop from 10 million to 1,000 larvae overnight. That’s what happened to Rheault, who had no larvae to show his open house guests. Antibiotics aren’t approved for use in U.S. shellfish hatcheries (though they are worldwide)—and, by the time an infection sets in, all the larvae are dead anyway—so the only thing for a hatchery owner to do when confronted with an infection is dump everything out, clean the tanks, and start over.
Or that used to be the only approach. Now, researchers at two labs seem to have found a solution.
The problem of bacterial infections in hatcheries has been worsening over the past decade as the waters of the Northeast warm. Rheault, who is now the president of the East Coast Shellfish Growers Association, says that thanks to climate change, bacterial infections now kill off 10 to 20 percent of the Northeast’s shellfish larvae each year. And because the bacteria, Vibrio, gets into the tanks via seawater, it affects not only shellfish but also lobsters, by turning their shells black and making them impossible to sell. (Some lobstermen eat the animals themselves or send them to be cooked and processed, since the meat is still good.)
Researchers have now found a tool to fight the Vibrio bacteria: probiotics. Teams at both NOAA’s Milford Laboratory in Connecticut and the University of Rhode Island (URI) have harvested beneficial bacteria from healthy adult oysters that can help oyster larvae fight off bacterial infections. And the URI researchers are exploring the possibility that a similar concoction could help treat lobster shell disease as well.
Read the full story at Civil Eats