BANGOR - Thanks to a decline in red tide levels, the entire Maine coast is now open to clam harvesting.

While the gathering of mussels, oysters and some other shellfish is still restricted in some areas, the state Department of Marine Resources hopes to begin lifting those prohibitions within the next week or two.

"Everything is moving in the right direction," said Darcie Couture, director of the department's biotoxin monitoring program.

Red tide is caused by blooms of naturally occurring algae which produce a toxin that is absorbed by shellfish as they feed. Clams, mussels and other shellfish with high levels of toxins can cause people who eat them to become sick or even die.

Red tide had reached record-high levels in some areas, resulting in extensive closures for more than two months that have hurt shellfish harvesters and dealers. Areas that had never before been closed, particularly in Hancock and Washington counties, were placed off-limits.

The contamination was so high that the state, for the first time, detected potentially toxic levels in the tomalley, or liver, of lobsters. That led state health officials and later the U.S. Food and Drug Administration to reiterate their long-standing warnings against eating lobster tomalley. Toxins do not accumulate in lobster tail or claw meat.