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By DOUG FRASER Red-tide toxins close Nauset to shellfishing
STAFF WRITER
Cape Cod TimesEASTHAM - This year's warmer weather has everything ahead of schedule: flowers bloomed earlier, osprey arrived ahead of time, and red tide closed Nauset estuary to all shellfishing two weeks earlier than last year.
"This is the earliest I've ever seen it closed," said Henry Lind, who has been Eastham's natural resource officer and shellfish constable for more than 20 years.
The red-tide algae prefer water temperatures between the high 40s and low 50s. Temperatures in the estuary are currently approaching the high 40s, said Mike Hickey, the state Division of Marine Fisheries chief shellfish biologist.
Algae lie dormant on the bottom during the winter months, protected in a hard case called a cyst. These cysts can remain dormant for as long as 30 years. Warmer water temperatures cause the algae to emerge from their casings and propel themselves upward toward sunlight.
The Division of Marine Fisheries suspends testing of shellfish areas during the winter when temperatures are too cold for the algae to bloom. They started testing shellfish areas last week. Yesterday, tests showed levels were approaching the acceptable limit of 80 micrograms of toxin per 100 grams of shellfish meat.
With rain expected to roil the waters and agitate more cysts, Hickey said levels would only go up.
Nauset estuary, which supports as many as 18 full-time shellfishermen in Orleans and Eastham at this time of year, will remain closed for at least two weeks. It will not reopen until the state records three straight tests of less than 80 micrograms that also show declining numbers over a two-week period.
Last year, the estuary was closed from mid-April to June. The longer the closure lasts, the more fishermen that are affected, as seasonal demand increases the numbers who want to harvest shellfish. Together, Orleans and Eastham sell nearly 400 commercial shellfish permits each year.
Red-tide toxins in shellfish meat cause paralytic shellfish poisoning. The symptoms vary, depending on the amount ingested and the allergic sensitivity of the person, but can be serious and even cause death.
Shellfish are not harmed by the algae and clean the toxins out of their systems within a few days of a drop in algae populations. The shellfish are then safe to eat and fishermen can make up some lost income. Last year, shellfishermen moved into Pleasant Bay and Cape Cod Bay while Nauset estuary was closed.
Nauset estuary is the only place along the Massachusetts coast where red tide is known to reside. It is believed that wind and waves pushed red-tide algae through a break in the barrier beach and into the estuary during a massive bloom offshore in 1972. The algae then took up residence, dropping cysts to the bottom in winter and blooming again when the water hit the right temperature in the spring and fall.
The only known way to get rid of the persistent algae is a stretch of long, cold winters, which would delay germination long enough for the algae to be buried under the sediments that fall into the water each year.