Red Tide Closes Harbor, Bay To Shellfishing

CHATHAM --- For the first time since 2005, shellfishing grounds have been closed because of toxic red tide.

After testing revealed high toxin counts in shellfish meats taken from the fish pier, all of Pleasant Bay and Chatham Harbor were closed to the taking of shellfish last Friday. Officials said they don’t know how long the closure will last.

Three years ago, red tide shut down most of the town’s shellfishing grounds for two months at the height of the summer season. The outbreak threw dozens of commercial shellfishermen out of work and cost the industry an estimated $1.7 million.

Twenty to 25 shellfishermen dig on the flats in the harbor and Pleasant Bay on a full-time basis, according to Shellfish Constable Stuart Moore. While the shellfishermen who dig soft-shelled clams can move to other areas that remain open, those who fish for blue mussels are out of luck. The harbor holds the only harvestable mussel resource in town, said Moore.

“The musselers are kind of out of business,” he said.

The closure includes Chatham Harbor, Pleasant Bay, Ryder’s Cove, Crow’s Pond and Bassing Harbor. Basically, all of the waters north of the 1987 inlet are closed, said Moore. South Beach, Monomoy, Stage Harbor and Nantucket Sound remain open to shellfishing. The closure only impacts shellfishing; the waters remain safe for swimming.

While much of the state’s shoreline north of the Cape Cod Canal is closed because of red tide, only Nauset Inlet on the Cape was closed until last week. Paralytic shellfish poison (PSP) toxin, the technical name for red tide, began showing up in low levels in samples taken from the fish pier about three weeks ago, said Dr. Robert Duncanson, director of the town’s department of health and environment. The numbers rose slowly but then began to fall before rising again last week.

“We’ve been kind of teetering on the edge of this for three or four weeks,” said Moore.

On Thursday, the state closed the bay and harbor to mussel fishing when levels rose to 73 micrograms per 100 grams of shellfish meat, just below the 80 microgram closure threshold. Results Friday from samples of soft-shelled clam meats taken Thursday showed levels in the 90s, prompting the closure to all shellfishing.

Shellfish from the closed area will continue to be tested on a regular basis, Duncanson said. However, he noted that reopening an area to shellfishing is complex and time-consuming process. Three consecutive samples below the 80 microgram level are necessary, and any sample with a higher number, even if it is still below the closure threshold, requires starting the whole process over again. It’s likely to take at least two weeks to reopen the bay and harbor, even if levels immediately begin to decline. Shellfish from flats on Monomoy and in Nantucket Sound will also be sampled, now that red tide has shown up in local area, he said.

If eaten, PSP-contaminated shellfish can cause severe illness or even death in humans. Lobster, crab, shrimp and fin fish are not affected by the toxin, and any shellfish already on the market are safe to eat, Duncanson stressed.

Red tide is caused by Alexandrium fundysense, a microscopic algae that blooms under certain conditions. It can lay dormant in the ocean’s bottom for years before germinating.

The origin of the current bloom is uncertain. Moore said the conjecture is that the bloom came from offshore, and that it may have been facilitated by the more efficient tidal exchange in the bay and harbor due to the new inlet in North Beach.

“But that’s just conjecture,” cautioned Duncanson. The bloom may also be a reoccurrence of the red tide that closed shellfishing in the same area in 2005.

The 2005 closure, the worst in 35 years, devastated the town’s commercial shellfishing industry, promoting a disaster declaration that eventually resulted in financial settlements for some shellfishermen. Many shellfishermen put down their clam rakes to find other work. “A bunch of them never came back,” Moore said.

That, combined with what Moore said was a cyclical decline in the soft-shelled clam resource, contributed to an overall drop in the number of commercial shellfish permits and the value of the town’s shellfish harvest. In 2004, 521 commercial permits were issued, and the total wholesale value of shellfish landed in town was $3.7 million.

Last year, 364 commercial permits were issued, and the wholesale value of the harvest was $2.8 million. The amount of soft-shelled clams landed declined by almost half, from 31,000 bushels in 2004 to 16,000 last year. Mussels and quahog harvests increased, however. In 2004, 16,000 bushels of mussels were harvested, while 24,000 bushels were landed last year. Quahog landings totaled 15,000 bushels in 2004 and 23,000 last year.

Because of the overall decline in the industry, Moore said the impact of this red tide closure won’t be as significant. “Situations have changed a bit,” he said. However, he is nervously watching the testing process, hoping that the toxin doesn’t find its way to Monomoy or Stage Harbor, still the town’s most important shellfishing areas.

6/26/08