The warmer days of spring have people thinking about all kinds of outdoor activities. Fishing is a top choice for many.
So again this spring there is need for a note of caution to enthusiasts in the form of an annual warning from the S.C. Department of Health and Environmental Control that has been with us since 1994: Limit the amount of fish being eaten from many bodies of water in South Carolina. The risk is mercury poisoning.
There is no one explanation for the elevated mercury levels in certain fish. Some mercury occurs naturally, but coal-burning industries, chlorine manufacturers and waste incinerators also contribute to high mercury levels in the air and water.
The fact that mercury has been found should be enough to prompt public compliance. Consumed in large enough amounts, methylmercury can cause nervous system damage, particularly in infants. The consumption advisories suggest safe amounts of fish meals, with a meal being a half-pound (or 8-ounce) serving.
The types of fish affected include primarily bowfin (mudfish) and largemouth bass, but species such as catfish, bluegill sunfish and redear sunfish have elevated mercury levels in some rivers.
In The T&D Region, the following advisories are in effect:
- Little Salkehatchie River — Do not eat any mudfish or largemouth bass. One meal a month of chain pickerel and warmouth. One meal a week of all other fish.
- Edisto River to Willtown Bluff — No eating mudfish, largemouth bass, chain pickerel, channel catfish or flathead catfish. One meal a month of blue catfish. One meal a week of black crappie, bluegill, redear sunfish and redbreast.
- South Fork Edisto River — No eating mudfish, chain pickerel, flathead catfish or largemouth bass. One meal weekly of redear sunfish and redbreast.
- North Fork Edisto River — Do not eat mudfish. One meal per month of chain pickerel, warmouth and largemouth bass. One meal per week of redbreast, redear sunfish and striped bass.
- Four Hole Swamp — No eating mudfish, largemouth bass or chain pickerel. One meal weekly of bluegill, redbreast, redear sunfish and warmouth.
- Congaree River from Columbia to the Santee River — One meal a week of mudfish and largemouth bass. No other restrictions.
- Lake Marion — One meal a week of mudfish and largemouth bass. No other restrictions.
The mercury issue is not unique to freshwater. Advisories for the Atlantic Coast off South Carolina include eating no King Mackerel over 39 inches or any shark.
DHEC warns that pregnant women, women planning to become pregnant, infants and children should not eat any fish containing mercury. The agency also advises that just because these fish may contain mercury, other fish from the same water are not affected. And using the water for recreational purposes is no hazard.
It is even arguable that many more fish affected by the advisories could be eaten without adverse health effects. The standards may amount to excessive caution.
Considering the potential health impact on the down side, however, individuals are wise to follow the advice. It's far better to be safe than sorry.