Closures of sections of Narragansett Bay to shellfishing are commonplace after heavy rain, when higher levels of contaminants have been flushed into the bay. The shellfish are given some time to naturally cleanse themselves of bacteria as they filter cleaner water. Usually after a week, everything is back to normal.

But the bay shellfishing closure Friday, which continues today, is nothing like those preceding it.

The Department of Environmental Management took the action after identifying a harmful algae bloom caused by the presence of toxic phytoplankton Pseudo-nitzschia spp. While blooms have been experienced in Maine and Massachusetts, forcing shellfishing closures there, this is new to Rhode Island and rightfully raises questions to what can be done and what might be the long-term effects on an industry integral to the state.

DEM and the Department of Health’s quick action was unquestionably the right move. The phytoplankton can produce domoic acid, a toxin, which can cause amnesiac shellfish poisoning (ASP) in humans. Symptoms of ASP include short- and long-term memory loss along with other serious health effects.

So far, testing of shellfish meats haven’t conclusively ruled out the presence of the toxin and, erring on the side of caution, bay shellfishing remains closed. That’s a prudent step and promises to ensure the reputation of quality and safe Rhode Island shellfish products.

The big question is whether this is an anomaly, a once in decades phenomena, or has there been some change in the bay that is promoting the growth of this toxic phytoplankton? State biologists don’t have an answer yet.

Might this be a condition that can be addressed as Save The Bay has so successfully advocated in reducing and treating sources of bay pollution?

We’re anxious for answers and as equally anxious to see Rhode Island shellfishermen back at work and to enjoy without concern the fruits of their work.

Meantime, the state is playing it safe. That is reassuring.