Disclaimer: These postings were sent to us from a variety of media sources over the Internet. The content has not been reviewed for scientific accuracy or edited in any manner.
Two more tests showing safe levels are needed before bays, ponds can be reopened. Red tide keeps estuary closed
By DOUG FRASER
STAFF WRITER
Cape Cod TimesEASTHAM - When the Nauset Estuary was closed in March because of red tide, there were hardly any tourists and the demand for shellfish was weak.
Four months later, it's steamer season, and shellfishermen and aquaculturalists who depend on the 1,200-acres bays and tidal ponds for their living are still locked out by the longest and most intense episode of red tide anyone has seen in Nauset.
Soft-shelled clams, more commonly called steamers, are worth money only in the summer when tourists and locals alike wash them down with a beer or two. By September, the restaurants are often more empty than full, and the price paid to fishermen for steamers is cut in half.
"My shellfish farm is in that area," said Jim McGrath an aquaculturalist from Eastham. "I'm out of business and have been so all summer long, and I plan my harvest around this time of the season."
McGrath was one of two aquaculturalists affected and said he believed there were around a half-dozen wild shellfishermen who were heavily dependent on the estuary.
Eastham Natural Resource Officer Henry Lind said between 30 and 40 diggers routinely work those waters in summer. Orleans Shellfish Constable Dawson Farber said he anticipates 25 to 30 shellfishermen will work the estuary when it reopens. The total shellfish industry is worth up to $1 million annually in Orleans.
Red tide algae lie dormant on the sea bottom in the winter, protected by a hard-shelled cyst. When water temperatures warm up to the high 40s in spring, they emerge from the cyst and start to reproduce in surface water.
While they don't harm humans swimming in the water, once their toxins become concentrated in shellfish meat they can cause paralytic poisoning, a potentially life-threatening neurological reaction.
Shellfish can purge themselves of the algae and toxins within a couple of days once the concentration of algae in the water drops off, and are then safe to eat.
When the water warms in the spring, state shellfish biologists test for the presence of toxins by sampling shellfish from several areas of the estuary on a regular basis.
If shellfish from any area test above 80 micrograms of toxin per 100 grams of meat, the state closes the whole system to shellfishing. The state must record three straight tests over a two-week period that demonstrate both levels below 80 micrograms and that the levels are declining.
Numbers usually decline with the onset of hot weather, which raises water temperatures above the algae's comfort range of high 40s to low 50s.
Levels have spiked as high at 1,300 micrograms in Salt Pond in early June, the highest ever recorded in the estuary. Red tide algae first invaded Nauset estuary through a break in the barrier beach in 1972. It is the only place along the Massachusetts coastline where red tide has taken up residence.
The general trend is that the red tide shows up earlier and lasts longer every year. Levels as high as those in Salt Pond mean that more cysts are being produced and are seeding the bottom, possibly meaning a big bloom again this fall or next spring. Or, possibly much later, since the cysts can remain viable for up to 30 years.
The only remedy, said Lind, is for sedimentation to bury the cysts deep enough they never bloom. But mild winters lately have allowed the cysts to open before the spring rains and storms can wash sediment over them.
Other red tide drifts down from Canada in the late spring and fall. With more than three months of closures, this now marks the longest red tide episode in the estuary. Every area except Salt Pond has come out clean in recent tests, but the entire system remains closed. Lind said yesterday that efforts to get the state Department of Public Health and the federal Food and Drug Administration to agree to lift the ban in the other areas was not successful.
Lind said samples from this past Monday showed levels of 50 micrograms. Two more tests below 80 micrograms are needed, and samplings are scheduled for Monday and Wednesday.