HARPSWELL – Researchers are hoping to refine their knowledge about red tide, the algae blooms that can cause paralytic shellfish poisoning, and learn how outbreaks can be predicted.

Red tide testing now can detect early stages of an outbreak but there isn’t a way to predict occurrences, according to Darcie Couture, director of the Maine Department of Marine Resources biotoxin monitoring program.

“Whoever figures it out would have a pretty amazing tool on their hands,” she said.

Advances would be a boon for the shellfish industry.

The direct value of the softshell clam, mahogany clam, quahog, mussel and oyster industries in Maine was about $30 million in 2006, according to estimates by Kevin Athearn, a professor of natural resource economics at the University of Maine at Machias.

Athearn estimates that softshell clam harvesters lost about $2 million because of a severe occurrence of red tide in 2005, when the worst outbreak in decades hit New England from Cape Cod in Massachusetts to Schoodic Peninsula in Maine.

Red tide outbreaks create dangerous levels of toxins in bivalves, such as clams, mussels and oysters. The toxins do not harm the shellfish, which eventually flush out the substance, but the toxins can cause numbness, dizziness and nausea in humans, and even death.

This summer, four people in Washington County were hospitalized after eating contaminated mussels found on a barrel floating in the ocean. It was the first documented paralytic shellfish poisoning in Maine since at least 1980.

Researchers have gained some insight into why Alexandrium fundyense, the type of algae that has caused problems in the Gulf of Maine, is so troublesome for Harpswell Sound, finding that the water at the bottom is moving out while the water near the surface is moving in.

Because the algae have tail-like appendages called flagella, they hold their position near the top of the water and the current pushes them toward shore.

“It is a hot spot where red tide picks up in the spring,” Teegarden told the Maine Sunday Telegram. “This is routinely and regularly one of the first places to go.”