When Chesapeake Bay oyster hatcheries began to see the unexplainable deaths of billions of larvae during summer 2011, the competing companies banded together to find someone to fix the problem.
Kuhn and other university researchers are conducting a first-ever test of water quality in Virginia’s oyster aquaculture hatcheries. The hatcheries provide millions of young oysters for the bay and pour millions of dollars into the state’s economy.
The research could expand the aquaculture industry, as well as assist with the complex restoration efforts of the Chesapeake Bay. Hatcheries sell the oysters to private farms and to state agencies, which use the oysters to help restore the bay.
Kuhn’s work is one of the aquaculture projects Virginia Tech researchers are involved in around the commonwealth. Aquaculture provides a source of protein to an ever-hungry world and drives economic growth. Other environmentally sustainable programs involve growing shrimp and tilapia and finding ways to maximize the quality of the fish.
“Our efforts in aquaculture around the state are helping make Virginia a competitor in the growing global market,” Kuhn said. “The research at oyster hatcheries is an opportunity for Virginia Tech to help both the state’s industry and the environment.”
The one-year, joint-research project received funding from the Virginia Marine Resources Commission. The Virginia secretary of natural resources and the Virginia Coastal Zone Management Program secured the money.
Researchers are testing water pumped from the bay to the hatcheries for pollutants. The plan is to identify the problem that led to the die-offs, then install a filter or treat the water. Hatchery employees conduct continuous, on-site monitoring.
“There has never been a water-quality program where the hatcheries are located,” Kuhn said. “This is important data for anyone concerned about the bay.”
Daniel Taylor, a senior research specialist with the Southwest Virginia Aquaculture Research Center, said a number of factors are causing the damage to the oyster hatcheries. “In the end, we could present some kind of a solution where one mitigation effort will assist with another one, and we could come up with a program that addresses one or two issues simultaneously,” he said.
The aquaculture industry not only pumps money into the state, but also sucks pollution from the bay. Adult oysters can filter as much as 60 gallons of water a day, pulling out pollutants in the process.
“By providing a healthy bay, you are not only boosting the economy, but you are also improving the ecological health of the watershed,” Taylor said. “That alone has tremendous ecological value.”
Researchers also are working on ways to create a self-sustaining, miniature ecosystem in aquaculture farms.
Fish and shrimp create waste, including nitrate. Studies show that high levels of nitrate compromise shrimp health and growth. Kuhn looked at using a biological filter to remove the nitrate present in tilapia wastewater while generating healthy bacteria.
“We can use that good bacteria to feed the shrimp,” he said. The goal is to find ways to reduce those levels by using biological filtration or simply replacing the old water, he said.
Scientists also are focused on practices for handling, processing, and storing freshwater shrimp. They want to maintain the quality and food safety of the large shrimp. The quality includes the taste, odor, texture, and appearance of the shrimp. The researchers want to see how much bacteria is in the shrimp’s food.
Virginia Tech is working with employees from Blue Ridge Aquaculture in Martinsville, Va., where Kuhn is developing new strategies to raise marine shrimp in recirculating water systems to provide domestically produced shrimp.
Kuhn and Taylor also are helping Virginia Cobia Farms in Saltville, Va., to streamline production of two marine fish, cobia and pompano, in recirculating aquaculture systems.
Other programs include an effort to add algae to tilapia feed to increase the omega-3 fatty acids, which would increase the fish’s market value.
“From the corners of Southwest Virginia to the Chesapeake Bay, Virginia Tech is involved in a variety of projects to help aquaculture drive the economy and help save the environment,” said Joe Marcy, head of the Department of Food Science and Technology.
Assistant Professor David Kuhn's research will help the oyster industry and the environment.
Virginia Tech researchers investigating the high mortality rate at oyster hatcheries in the Chesapeake Bay suspect that the culprit is polluted water pumped in from the bay.
Their work focuses on three areas: water chemistry, ocean acidification, and pathogenic bacteria, which causes diseases in shellfish. Ocean acidification is the ongoing increase of acidity of the earth's oceans due to climate change.
“We’re trying to look at a wide range of variables that could be contributing to the high mortality rates,” said Daniel Taylor, senior research specialist in the Department of Food Science and Technology.
Once the reason for the larval die-off is identified, Virginia Tech can take several measures to remedy the problem. David Kuhn, assistant professor in the Department of Food Science and Technology, said the team could combat ocean acidification by adding calcium and bicarbonate to the water to make it more conductive to larval oysters’ health and growth.
Filters also can be used to remove pollutants from the water and inactivate, disease-causing bacteria.
Research at the Southwest Virginia Aquaculture Research Center involves the Virginia Tech working with other universities, institutes, and private industries to help businesses address production issues. The public-private partnerships include research projects at Blue Ridge Aquaculture in Martinsville, Va., and at Virginia Cobia Farms in Saltville, Va.
At Blue Ridge Aquaculture, engineering, production, and marketing may lead to successful sale of shrimp in New York City and North Carolina. Whole shrimp sells in the Big Apple at $10 a pound. This premium price provides a business model that predicts economic viability.
At Virginia Cobia Farms, research is focused on ways to streamline production of two marine fish, cobia and pompano, in recirculating aquaculture systems. Virginia Tech also provides training for safe processing of fresh cobia and pompano. This public-private partnership has resulted in a multimillion dollar investment to expand production in Saltville.
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