Shrimp in South Carolina’s estuaries are getting pushed around by climate change

White shrimp, which tend to be South Carolina’s most economically important species, spend their adolescence in the state’s estuaries. In the past 40 years, winter temperatures within the North Inlet Estuary, located in Georgetown County, have been higher than in the past. Alongside those changes, the number of white shrimp spending the winter there also has increased, Kimball said.

If this change has an impact on the broader ecosystem, Kimball’s team hasn’t seen it in the surveys they do repeatedly in the estuary. It’s possible the white shrimp are outcompeting other species for resources, or benefiting other species as a source of prey.

At the same time, the size of white shrimp in the estuary is decreasing. Michael Kendrick, who oversees DNR’s crustacean research, said the exact driver of this change also is unclear, but he suspects the warmer waters are altering the shrimp’s growth patterns and how they move throughout the estuary as they grow up.

“We need further research to be able to test that,” he said. “We don’t know for sure that that’s what’s occurring, but that’s one of the potential mechanisms for helping us to understand why in these open estuarine waters, the shrimp size appears to be declining over time.”

The size of adult shrimp in the open ocean, where shrimp trawlers catch them, so far has remained largely unchanged, Kendrick said.

Unlike their white cousins, the numbers of juvenile brown shrimp in the estuary have not increased, likely because they don’t spend the winter in those warming waters, Kimball said.

Shrimpers and sellers

As scientists track the changing shrimp populations, shrimpers are on the front lines.

“While we’re not scientists, we are experiencing noticeable changes in the dynamic of the shrimp population,” said Bryan Jones, vice president of the South Carolina Shrimpers Association.