URI Researchers Studying Oyster Aquaculture Health

By ecoRI News staff

KINGSTON, R.I. — Several scientists at the University of Rhode Island have been awarded grants to study oyster genetics, breeding, and diseases as part of a region-wide effort to support a growing oyster aquaculture industry and assist efforts to restore wild oyster populations.

“Wild and farmed oysters are facing major threats from water quality and disease,” said Marta Gomez-Chiarri, a URI professor of animal science who has studied oyster diseases in Narragansett Bay for more than 20 years. “Even though local water quality has improved in Rhode Island, oysters across the United States face localized threats from pollution and eutrophication while at the same time dealing with multiple factors of global ocean change, like ocean acidification, as well as changes in salinity and dissolved oxygen. We are only beginning to understand the effects of these multiple stressors.”

Gomez-Chiarri, along with URI assistant professor Jonathan Puritz and U.S. Department of Agriculture (USDA) scientist Dina Proestou, has teamed with shellfish geneticists and breeders from 10 other East Coast universities to form the Eastern Oyster Genome Consortium, so they can develop genetic tools to accelerate selective breeding efforts. The consortium, in a proposal led by Rutgers University, has been awarded a $4.4 million grant from the Atlantic States Marine Fisheries Commission to accelerate the pace of identifying the genes responsible for desirable traits such as disease resistance.

“We know that the oyster is very adaptable, so we’re trying to determine the genetic signatures of traits like disease resistance or tolerance for high temperatures or low salinity,” Gomez-Chiarri said. “But we also want to figure out what makes an oyster survive in Maine versus in the Gulf of Mexico where conditions are so different. We want to develop genetic strains that are adapted to each region. This grant will help us figure out the genetic tools to inform breeding so we can understand how to improve oysters from different regions and make them resilient to the threats in that region.”

“By leveraging new developments in genomics, we are in a good position to apply new and existing breeding technologies to additional locations more efficiently,” Proestou said. “This will help growers by providing them with selected oyster stocks that are well suited to specific growing environments.”

The URI researchers are also approaching the problem of oyster disease from another direction. They have received four grants to study how probiotics may be used to manage diseases in oyster aquaculture facilities.

One project, funded with two grants totaling $867,000 from the USDA to professors David Nelson, David Rowley, and Gomez-Chiarri, is examining the basic mechanisms of how probiotics work in oysters.

“It’s biological warfare between bacteria,” Nelson said. “Both the pathogen and probiotic have genes that encode mechanisms that allow each organism to successfully compete with and even kill its competitors when they interact. We’re trying to determine the arsenal of weapons that each bacterium has and how they use them against each other. This knowledge will allow us to better understand how we can use probiotic bacteria to protect oyster larvae from pathogenic bacteria.”

This investigation also examines the molecular mechanisms of virulence used by the pathogenic bacteria to attack the oysters.

A $300,000 grant from the National Oceanic and Atmospheric Administration will enable Nelson, Rowley and Gomez-Chiarri to work with companies to commercialize a probiotic they discovered through previous laboratory studies. They will work to scale up production of the probiotic and conduct hatchery trials to determine its effectiveness at combatting disease in a commercial setting.

Another $300,000 grant from the USDA will allow URI researchers to evaluate how a probiotic affects the microbial community throughout an oyster hatchery.

“We’ll be looking at all the microbes in the hatchery and how the probiotics interact with those in the water and in the larvae and on the surfaces of the tanks,” Gomez-Chiarri said. “Each tank is a world of microbes all its own.”