The green algal blooms that have been spreading through Lake Erie do produce toxins, but that probably shouldn’t keep you from munching a perch sandwich for lunch.

Great Lakes scientists, writing for a paper published Dec. 8 in the journal “Marine Drugs,” found yellow perch quickly get microcystin toxins out of their bodies when they’ve ingested food with the toxins.

Microcystins are the toxins commonly produced by the algal blooms that appeared earlier this year in Lake Erie.

“Based on our data on the toxin concentration in yellow perch tissue, it looks like the fish are able to eliminate it very efficiently,” said Julianne Dyble, an aquatic biologist for the NOAA Great Lakes Environmental Research Laboratory in Ann Arbor, Mich.

“However, our study does not conclude that eating perch carries no risk for microcystin exposure of illness,” said Dyble, the lead author of the report. “There are still unanswered questions.”

Study co-author Donna Kashian, assistant professor of biological sciences at Wayne State University in Detroit, offered a similar caution.

The study suggests fish can get rid of the toxin if the poison is at relatively low levels, but it doesn’t mean it’s safe to eat the fish when the toxin levels are very high, as in the Maumee River area last summer, Kashian said.

“We actually have not done any studies at that high a concentration,” she said.

The scientists appear confident the toxin doesn’t accumulate in the fish.

The scientists fed food pellets to fish swimming around in a laboratory, then killed them and checked to see how much toxin was left in their bodies. The fish were sampled at intervals of zero, five, 10, 15, 20 hours after they ingested the tablets, Kashian said.

The experiments showed the fish got rid of most of the microcystin toxins in their bodies within 24 hours.
Scientists apparently remain more concerned about mercury and PCBs in fish, which isn’t something the new study looked at.

Michigan’s Division of Environmental Health said that because of concerns about PCBs and mercury, women who may be pregnant and children should eat yellow perch only once a week.
 

Read more about the study here.