Cape Cod Times

April 30, 1999

RED TIDE SHUTS DOWN NAUSET, TOWN COVE

By DOUG FRASER

STAFF WRITER

EASTHAM - State officials closed down all of the Nauset estuary and Town Cove to shellfishing yesterday because of the plankton condition known as red tide.

High levels of the plankton species associated with red tide showed up in mussels collected earlier this week from the Roberts Cove area of Town Cove by volunteers working for the Eastham Natural Resources department. The volunteers were part of a phytoplankton monitoring program working on a project to forecast toxic levels in shellfish through water sampling.

Shellfish are filter feeders which consume and digest the red tide plankton, accumulating toxins present in the plankton's cell walls. The toxins are not harmful to the shellfish, which purge themselves over time, but are deadly to warm-blooded animals.

Eastham Natural Resource Officer Henry Lind said the name, in part, is attributable to tropical species of red tide plankton that cause fish to hemorrhage, turning the water red.

Around this time of year, Cape waters are tested weekly. The state analyzes the samples sent by towns.

Red tide has not been linked to development and water pollution, but could possibly occur more frequently or intensify in waters impacted by human habitation.

No shellfish may be harvested from Nauset estuary or Town Cove for at least two weeks, until testing shows two consecutive tests below 40 micrograms per gram of tissue. Levels in Roberts Cove went from 0 to 72 and from 72 to 185 micrograms in just two days.

Lind said previous years have had levels as high as 800 to 900 micrograms. The closure level is 80 micrograms.

Pleasant Bay and Cape Cod Bay are not usually prone to red tide. They have been tested and remain open.

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