GRAND ISLE, La. — An oyster specialist has retired after more than a quarter-century with Louisiana Sea Grant and says he will continue research with a private company he co-owns in Alabama.
John Supan says in a Sea Grant news release that his business, Navy Cove Oyster Co. LLC of Fort Walton, Alabama, works on research with both LSU and Auburn University.
Supan started with Sea Grant in 1984 as an area fisheries agent, and has been executive secretary-treasurer of the Louisiana Oyster Dealers and Growers Association since 1985. He retired at the end of 2017 as director of the Louisiana Sea Grant Oyster Research Lab on Grand Isle.
He’s been working in recent years on oysters with extra sets of chromosomes that make them sterile so they stay fat in the summer rather than losing up to half their body mass to producing eggs or sperm.
Oysters with four sets of chromosomes, called tetraploids, are created in the lab. They’re mated with normal oysters to create oysters with three sets of chromosomes, which can be raised in cages well above the sea floor — and out of reach of many predators.
“My long-term goal for the program was always commercialization, and now we have commercial triploid farms all across the Gulf,” Supan said.
However, 15 to 40 percent of those being raised in the Gulf of Mexico sometimes die during the summer. Supan believes that’s caused by heat stress. He says he and doctoral student Brian Callam have been working on a new line of tetraploids that will include more southern genetic stock, and hopefully produce more heat-tolerant triploids for the Gulf.
He said he’s proud to have taught hundreds of people about hatchery operations, site and gear selection and oyster farm management.
“And I won’t be leaving the oyster world at all, I just won’t be in Grand Isle as much,” he said.