11/7/17

by Tiffany Woods

The National Oceanic and Atmospheric Administration (NOAA) has awarded scientists at Oregon State University two aquaculture grants that aim to make oysters safer to eat and help hatcheries feed certain marine fish more efficiently.

Oysters filter water in a depuration tank, thus expelling potential contaminants from their tissues. (Photo by Lynn Ketchum)

The first project, funded at $150,000, aims to reduce bacteria known as Vibrio parahaemolyticus in oysters without altering their texture and consistency. Researchers plan to add naturally occurring marine probiotics, which are live or freeze-dried microbial supplements, to the seawater in depuration tanks. Depuration tanks are where oysters are sometimes held to flush out contaminants that may be in their tissues. Researchers have already isolated various marine probiotics that inhibit the growth of pathogens.

The researchers also aim to develop a dipstick containing antibodies to quickly screen adult oysters for V. parahaemolyticus. The idea is that people would not need special training or equipment to use this diagnostic tool.

Researchers aim to use marine probiotics to decrease bacteria in oysters. (Photo by Lynn Ketchum)

The leader of this two-year project is Shelby Walker, the director of Oregon Sea Grant, although the actual research will be conducted by the lab of Claudia Hase, a professor with OSU’s College of Veterinary Medicine. Partners include mAbDx, an immunodiagnostics company in Eugene, Ore.; and Reed Mariculture near San Francisco.

The other grant, worth $629,000, aims to improve the nutritional value of live prey fed to California halibut, California yellowtail and southern flounder. When they’re still in their larval stage, farmed saltwater fish are typically fed tiny rotifers and brine shrimp. However, these organisms are less nutritious than copepods, which are the natural prey of many marine fish in the wild. Given this, the researchers plan to feed rotifers and brine shrimp vitamin C and taurine, an amino acid. To make sure these nutrients don’t dissolve in the seawater, the researchers will encapsulate them in bubble-like liposomes, which can have impermeable membranes.

Oregon State University’s Chris Langdon received a grant to make prey that are fed to certain farmed fish more nutritious. (Photo by Stephen Ward)

The researchers plan to:

• determine the optimal concentrations that should be used for taurine and vitamin C,
• evaluate how these nutrients affect the growth, survival and stress resistance of the fish,
• develop methods to produce the liposomes on a larger scale instead of just at the laboratory level,
• study how long-term storage affects how the liposomes retain the nutrients, and
• determine how much it would cost to produce and store liposomes and how many liposomes would be needed to feed a certain amount of prey.

Walker will lead the three-year project, but the research will be conducted by the lab of Chris Langdon, a professor with OSU’s Department of Fisheries and Wildlife, and well as by staff at the subcontracted Hubbs-SeaWorld Research Institute in San Diego. Partners include the Texas Parks and Wildlife Department and Reed Mariculture. Bill Hanshumaker, a marine educator with Oregon Sea Grant Extension, will be involved with outreach activities.

Oregon Sea Grant will administer the funding for both projects. They are part of 32 grants totaling $9.3 million awarded by NOAA last week to further develop the nation’s marine aquaculture industry.

“This country, with its abundant coastline, should not have to import billions of pounds of seafood each year,” said Secretary of Commerce Wilbur Ross. “These grants will promote aquaculture projects that will help us reduce our trade deficit in this key industry.”

All projects include public-private partnerships and will be led by university-based Sea Grant programs.

“Industry is working alongside researchers on each of these projects, which will help expand businesses, create new jobs and provide economic benefits to coastal communities,” said Jonathan Pennock, the director of NOAA Sea Grant.

NOAA received 126 proposals requesting about $58 million in federal funds.