New Monitoring System Shines Spotlight on Red Tide Hot Spots

by Laurie Schreiber

The development of inexpensive, handheld devices is expected to provide marine scientists with a way to identify emerging “red tide” hot spots and allow for targeted closures of shellfish harvests focusing only on impacted beds.

Earlier this month, scientists at the University of Maine were awarded $201,187 for the first year of an anticipated 3-year $574,028 project to investigate methods that would provide early warning detection of toxic Alexandrium blooms, also known as red tides, in the Gulf of Maine.

Some species of Alexandrium algae produce a toxin that can become concentrated in shellfish tissue. Eating shellfish tainted with this toxin can lead to paralytic shellfish poisoning (PSP), a potentially fatal human illness.

The project is expected to allow scientists to detect and measure levels of toxic Alexandrium cells in water samples, providing Maine officials with an early warning of increased potential of PSP contamination in shellfish.

According to Darcie Couture, director of the Department of Marine Resources’ Marine Biotoxin Monitoring Program, the early-earning system that is in development will eventually provide an important tool for water quality monitoring volunteers and DMR staffers in the field.

According to information from the DMR’s website, Maine has historically had high levels of paralytic shellfish poison during the warmer periods of the year.

“Shellfish samples are collected statewide between March and October and evaluated at the two PSP laboratories (Boothbay Harbor, in the western portion of the state and Lamoine, in the eastern portion),” the DMR said.

Couture and her staff process the data at the Boothbay facility for interpretation, and appropriate closures are made when necessary, the DMR said.

The occurrence of red tide over the past summer wasn’t too bad, Couture said.

“Not terrible,” she said. “We always have some problem with red tide in Maine, but compared with some of the more disastrous years, 2011 wasn’t quite as bad.”

In 2011, she said, red tide resulted in closures in areas where the toxin typically occurs, “which is certain chunks of southern Maine, certain areas of eastern Casco Bay, and further Down East.” Cobscook Bay was closed for a limited period of time, and other isolated areas had closures that were limited in geographic area and in length of time, she said.

There were major blooms in 2005, 2008, and 2009. Maine received disaster declarations for red tide impacts on the shellfish industries in both 2005 and 2008. In 2005, 46 coastal towns, 40 percent, suffered closures of the clam flats for 30 days or more.

In 2009, red tide closures began in late April. At the peak of the bloom, more than 97 percent of Maine’s inshore shellfish resource was closed to harvest due to red tide, and 100 percent of the offshore federal waters were closed for several months during the major harvesting season. Red tide closures remained in place in some parts of the state through late September.

“Everybody agreed it was horrific year,” Couture said of the 2009 bloom.

Still, she said, there were some “tiny” inland pockets – among them, Frenchman's Bay – that managed to stay clear of red tide for the entire season.

“These were tiny exceptions,” she said. “And there was not a lot product coming out of them.”

Couture said that the specific phytlankton species that causes red tide in Maine is active and blooming from April through September.

During that window of activity, she said, the DMR is assisted by about 40 volunteers along the entire Maine coast who collect water samples weekly. DMR staffers also regularly sample shellfish through the warm-weather period.

“The bulk of the program is collecting shellfish samples along the coast, from hundreds of spots every week,” she said. “We take the samples back to lab every day.”

If an area is closed to harvesting due to PCP, she said, the DMR continues to monitor shellfish from that area so that it can be opened again when the time is appropriate.

The systems in design at the University of Maine consist of handheld portable field kits that volunteers can use to screen toxin levels in the field, she said.

“It’s another tool that will help us assess quickly, in the field, what’s going on,” she said.

In addition to volunteers, the DMR employs about 15 staffers during the red tide season, she said. “We’re out every day and it’s very labor-intensive,” she said.

Couture said there is no clear relationship between large-scale climate or environmental changes and the occurrence of red tide.

“Locally, we have regular blooms offshore in the Gulf of Maine,” she said. “And we can have them inshore when there’s a long period of northeasterly winds, which push them inshore.”

Couture said that red tides are more correctly called “harmful algal blooms.”

Worldwide, the blooms are caused by dozens of different species of toxic phytoplankton, which have a variety of impacts. One type of harmful algal bloom that occurs in Florida, for example, causes fish kills and, when it hits the beach, it become aerosolized and can cause respiratory problems in humans.

The blooms are not always red in color, she said. The “red tide” that occurs in Maine almost never blooms to such density that it turns the water red, although the red hue did appear with the 2009 bloom, she said. Toxic Alexandrium blooms affect all filter-feeding shellfish; these include mussels, softshell and hardshell clams, and oysters.

The University of Maine project was funded through a national competition of the Monitoring and Event Response of Harmful Algal Blooms program run by NOAA’s National Centers for Coastal Ocean Science.

Research will be carried out at the University of Maine with research partners at the Department of Marine Resources Biotoxin Monitoring Program. The MERHAB program was first authorized by the Harmful Algal Bloom and Hypoxia Research and Control Act of 1998. HABHRCA was last reauthorized in 2004.

Earlier this month, Sen. Olympia Snowe introduced legislation to again reauthorize the act.

According to a press release from Snowe’s office, the “Harmful Algal Blooms and Hypoxia Research and Control Amendments Act of 2011 enhances the research programs established in the Harmful Algal Blooms and Hypoxia Research and Control Act of 1998 and reauthorized in 2004.” The provisions contained in the reauthorized act “will enhance our nation’s ability to predict, monitor, and ultimately control harmful algal blooms and hypoxia,” Snowe’s statement said. “Maine’s shellfish industry has experienced severe economic losses due to red tide over the years.”