Federally permitted commercial fishermen are limited to 3500 pounds per trip with a 24-inch fork length minimum size. This is North Carolina's first fish consumption advisory for ocean waters. The state began issuing mercury advisories for inland waters in the early 1990s. Mercury in large, long-lived fish is an international problem. Many states have issued advisories in the past decade.
Research continues into the cause of the problem.
Because high levels have been found in fish from relatively remote areas, researchers suspect that the mercury, which comes from industrial sources like coal-burning industries, chlorine manufacturing and waste incinerators as well as natural sources, is often spread through the air and deposited in water. Mercury can also come from some mining operations. As bigger fish eat smaller fish, the bigger fish get higher levels of mercury. The longer the big fish's life span, the more likely that it will accumulate mercury.