ROCKPORT — A marine researcher is working on a tool he says will allow the state to forecast the level of economic loss suffered by its shellfish industry due to a harmful algae bloom called red tide, which discolors water and makes mussels and clams unsafe for people to eat.

Woods Hole Oceanographic Institution senior research specialist Porter Hoagland said the tool will help the state put a dollar amount on economic activity lost due to clam and mussel harvesting closures forced by red tide.

Red tide in the Gulf of Maine is caused by a certain type of algae that “produces a highly potent toxin responsible for paralytic shellfish poisoning in people and wildlife eating contaminated shellfish,” the National Oceanic & Atmospheric Administration says on its website. It happens along the Gulf of Maine coast most years, causing varying degrees of disruption to the state’s lucrative shellfish harvesting industry.

Hoagland said he will use historical data about the production and value of shellfish at the local level to estimate the value of shellfish production with and without closures.

The value of shellfish also depends on the time of year, he said. For example, he estimated, a two-month summer shutdown of half of Maine’s shellfish industry due to red tide likely would cost the state $7 million in economic activity.

Red tide closures limit the ability of fishermen to harvest softshell clams and blue mussels, popular food items that had a total value of more than $21 million last year, according to state data.

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“The tourists show up, they’re buying clams, and the price is high,” Hoagland said. “If it’s closed in January, there’s almost no impact.”

The tool is in development and could be available for use by the state this summer, Hoagland said.

The state contracted Woods Hole to do the work at a cost of $50,000 in 2012, state Department of Marine Resources spokesman Jeff Nichols said. The state is paying for the work with federal disaster relief funds, he said.

The ability to estimate economic losses due to red tide would help the state in applying to the federal government for disaster mitigation funds, Nichols said. The state’s coast has “periodically experienced widespread, severe red tide blooms,” with particularly bad years in 2005 and 2008, he said.

Some clam flats from South Berwick to Harpswell were shut down to softshell clam harvesting in June because of a red tide bloom.

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