Flounder Stocking Program Makes Headway

South Carolina biologists work to restore southern flounder from historically low numbers.

SCDNR Press Release | November 23, 2021

In May 2021, South Carolina lawmakers funded the development of a program to stock young flounder into state waterways. South Carolina Department of Natural Resources (SCDNR) biologists are now making headway on the project, with facility renovation plans, genetic sequencing, adult fish collection and visits to flounder-growing facilities underway.

Southern flounder are one of the state’s most iconic and sought-after saltwater fish. Biologists recently reported that the region’s flounder numbers were at historically low levels – including in South Carolina. Legislators responded this past spring with a suite of legislative changes designed to address the decline, including stocking – which is the practice of raising and releasing young fish into local waterways to help protect the wild population. Lawmakers also took the opportunity to increase some saltwater license fees, a portion of the funds from some of the increased fees will support the new flounder stocking program.

SCDNR’s stocking program is one of the oldest in the country. For three decades, staff have followed an ethically responsible, ‘do-no-harm’ approach to stocking saltwater fish in South Carolina’s coastal waters, conducting extensive genetic research to ensure that stocking has no harmful effects on the existing wild population. This genetic information, paired with SCDNR’s long-term monitoring surveys that target flounder, allow biologists to determine the ratio of hatchery-raised to wild fish in state waters – and thus how effective a stocking program has been. SCDNR biologists have pioneered and refined the agency’s flagship red drum stocking program over three decades, during which time they’ve have released over 30 million young red drum into state estuaries.

Flounder, however, are a trickier fish. Their short and unusually complicated lives make flounder more challenging to grow than species such as red drum and cobia. Because they’re bottom-dwelling fish, they also require more space than currently exists at SCDNR facilities. Plans are thus underway for significant renovations at the Waddell Center, SCDNR’s dedicated facility for stocking research in Bluffton. Staff are also beginning work to retrofit the hatchery facilities at the Marine Resources Research Institute in Charleston to meet the program’s needs.

Southern flounder are at historically low levels across the Southeast. Recent legislative changes aim to address that in South Carolina, including through the development of a flounder stocking program.

At the end of this month, SCDNR biologists are slated to visit colleagues at two different facilities in Texas to learn about the infrastructure used in their flounder stocking program. The Coastal Conservation Association – South Carolina has generously offered to cover the cost of two of the three SCDNR staff members that will be traveling to Texas.

“There have been multiple universities and facilities over the last 20 to 30 years that have worked off and on with southern flounder,” said associate marine scientist Dr. Aaron Watson, who will be part of the team traveling to Texas. “We’re excited to visit facilities that are in current production and learn from folks that have had to deal with and overcome many of the challenges we know we will face here in South Carolina.”

The team has also coordinated with collaborators from North Carolina to Florida to begin collecting genetic samples from flounder across the region, as well as developing genetic tools that will later allow biologists to monitor the effectiveness of the stocking program.

Lastly, biologists have begun the exciting work of catching and studying the adult flounder, or broodstock, that will eventually be used to spawn and produce young flounder for stocking.

The Waddell Mariculture Center, SCDNR’s dedicated facility for stocking research will undergo extensive renovations in preparation for the new stocking program.

Ethical stocking takes time—biologists estimate that they will complete baseline genetic, life history and spawning research within three to four years and begin the first small-scale, experimental releases of young flounder by year five.

“While producing southern flounder at a scale for stock enhancement represents a significant challenge, we’re excited about the opportunities this program presents to improve upon protocols and expand our stock enhancement footprint in the state,” Dr. Watson said.

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