RICHMOND, Va. (AP) — A study of harmful algae in the James River has found high levels of a toxin in blue crabs but a state health official says there is no reason to believe there is a health risk to the public.
The three-year, $3 million study is being conducted by researchers from Virginia Commonwealth University, the Virginia Institute of Marine Science and elsewhere.
Researchers discovered high levels of a toxin called microcystin in blue crabs in the tidal freshwater James in August 2012. The toxin also has been found in crabs this summer but not at high levels, VCU river ecologist Paul Bukaveckas told the Richmond Times-Dispatch (http://bit.ly/14o0A9o ).
“We’ve been looking for the toxin in water and sediments as well as the things that live in the river, and we are basically finding it everywhere,” Bukaveckas said.
But toxin levels in fish such as menhaden and blue catfish were low.
“At this time, no human studies have demonstrated that people can become ill from ingesting shellfish tissue containing microcystin,” said Rebecca LePrell, the Virginia Department of Health’s director of environmental epidemiology.
She said that microcystin does not remain in edible fish and shellfish tissue for more than a few weeks.
“It is a noteworthy finding, and we would be interested in having more samples collected to further assess any potential risk,” LePrell said.
Thirty-six crabs were tested in 2012, all of which were caught near VCU’s Rice Center, a research site on the James in Charles City County about 20 miles southeast of Richmond. The toxin was found in the organs of all 36 crabs and in the meat of 26.
The toxin’s concentration in meat exceeded the World Health Organization’s guidelines in three crabs caught last August.
This summer, researchers are testing crabs in the brackish James near Jamestown to find out whether crabs are tainted in saltier water. The toxin has been in found in crabs in this area but not at high levels.
VCU fish ecologist Greg Garman said that there’s little or no commercial crab harvesting in the freshwater study area.
“It’s too soon at this time to make any definitive statement about the potential for microcystin to have a negative effect on the blue crab fishery,” Garman said.
Blue crabs are Virginia’s top commercial seafood catch.
“Consumers can be utterly confident that the product they are purchasing is of the highest quality,” said John Bull, a spokesman for the Virginia Marine Resources Commission, which manages fish in Virginia’s tidal waters.
Kimberly Reece, a Virginia Institute of Marine Science professor, said toxin-making algae don’t live and reproduce in the lower, salty James where crabbing is heavy, so the toxin should not be an issue there.
While toxins produced in the freshwater James can drift down to the salty area, dilution is expected to reduce their concentration, , Reece said.
Reese said the study’s findings are something to watch in the future but they don’t indicate a major problem now.
Information from: Richmond Times-Dispatch, http://www.timesdispatch.com