Researchers have begun to raise red flags about mercury levels in Goliath grouper, as state and federal fishery managers debate allowing the fish as table fare.
The South Atlantic and the Gulf of Mexico fishery management councils and the Florida Fish and Wildlife Conservation Commission (FWC) have formed a committee to discuss possibly allowing a limited recreational or scientific harvest of the grouper. The species has been limited to catch-and-release only fishing since 1990.
Researchers found high mercury concentrations in Goliath groupers to a point where the fish showed "lesions compatible with chronic mercury poisoning," according to a 2013 study for the FWC's Fish and Wildlife Research Institute.
The higher levels of mercury are the end result of environmental poisoning through processes such as coal-burning plants and mines and other industrial uses, which seep mercury pollution into the waterways, according to officials. Smaller fish are contaminated and then are eaten by the larger fish.
"These concentrations were within or above the range known to cause direct health effects in fish after long-term exposure," according to the study.
Scientists Douglas Adams and Christian Sonne reviewed Goliath groupers collected from 1991 through 2012 from tropical and subtropical waters of the southeastern United States with the majority of specimens collected from 2000 to 2012. The fish were collected from Gulf of Mexico and Atlantic Ocean waters off Florida. The fish were collected after they died during cold snaps, or were illegally caught and confiscated directly by FWC law enforcement officers.
The 2013 Florida Fish Advisory, published by the Florida Department of Health, advises that children and pregnant women should not eat blackfin tuna, cobia, barracuda, king mackerel and all species of shark. The agency advises that no one should eat king mackerel larger than 31 inches, or any coastal shark species bigger than 43 inches.
The study found that mercury levels in adult Goliath grouper are as high as, or higher, than those of these restricted species. Levels are so high that mercury-induced lesions were found in adult Goliath grouper's liver, kidney and gills, said Chris Koenig, a retired Florida State University professor and a leading researcher in the field of Goliath grouper.
The study's findings provide evidence that Goliath grouper is not a viable fishery species, at least not the adults, Koenig said.
"Adult Goliath grouper have little to no value as a fishery species because of high mercury content in the tissues, high vulnerability to fishing, and low production rates," Koenig said. "Goliath grouper is becoming more valuable as a diver attraction, and some dive shop businesses are benefiting from their recovery."
Lower Keys spear-fisherman Don DeMaria argued the Goliath grouper is listed as endangered everywhere throughout its range and has not recovered to acceptable levels.
"This fish is worth much more alive than dead to the recreational dive industry," said DeMaria, citing an argument that many Florida Keys diver operators have continually made. "Mercury levels in mature Goliath grouper are above levels set by the FDA (U.S. Food and Drug Administration) for safe consumption. Above all, no one has presented a valid or defensible argument as to why this species should be open to harvest at this point."