Thursday, December 5, 2013
A toxic bloom of red tide that has closed most of Maine's clam flats is so intense that it also has turned parts of the ocean reddish-brown and is believed to be responsible for killing fish and birds.
Levels of the toxin are the highest in more than 30 years and are reminiscent of New England's worst-ever red tide, in 1972. That bloom also turned coastal waters reddish-brown and poisoned wildlife -- effects so rare in Maine since, that current state officials and clam diggers say they have never experienced them.
''The levels are extremely high. Some areas that have never been toxic before are toxic now, and people need to be aware that the levels that are out there are dangerous and potentially lethal,'' said Don Anderson, a senior scientist at the Woods Hole Oceanographic Institution in Massachusetts.
Red tide is dangerous to people who eat clams, mussels or other shellfish that ingest the toxic algae. Smaller doses can cause tingling or numbness, while larger doses can cause deadly paralytic shellfish poisoning.
Clams sold by certified dealers have been harvested from areas unaffected by the outbreak. People who collect their own clams or mussels are believed to be at the greatest risk.
A woman from Swans Island was hospitalized earlier this month, for example, after eating clams that were harvested for personal use from a closed area, according to state officials. She experienced tingling around the mouth and jaw for several hours, but recovered.
Similar poisonings have been reported in recent summers, but the risk of a more severe poisoning case is especially high this summer.
''With this (red tide), even a small number of clams would get people very sick and might actually be fatal if harvested from certain locations,'' Anderson said.
Tomalley, the green substance in lobsters, also is considered unsafe to eat because of red tide. Lobster meat as well as meat from scallops and from fish are not affected by the toxin.
State officials typically close shellfish beds when the toxin approaches levels of 80 micrograms per 100 grams of meat. This summer, toxicity scores have exceeded 4,000 and 5,000 micrograms in mussels collected at both ends of the state.
State officials have been scrambling to test different areas along the coast by liquefying clam and mussel meat and injecting it into mice. The mice are dying so quickly in many cases that the areas are simply closed before the more detailed testing that determines how much toxin is present.
A red tide in 2005 led to toxicity scores as high as 3,000 micrograms. That algal bloom shut down the New England shellfish industry for so long, it qualified for $5 million in federal disaster assistance.
The higher levels this summer are expected to keep some Maine flats closed for weeks.
''This is when we actually make our money, from the end of June to September,'' said Adam Morse, a Freeport digger. ''We need the wind to shift. It's blowing the wrong way. Right now, it's blowing in.''
Red tide is caused by a natural algae that lives offshore and spreads into coastal waters, where conditions can be ideal for summer blooms. Recent wind patterns helped bring the algae to shore, but it's not known whether the heavy, prolonged rains this summer may have played a role in the severity of the bloom, Anderson said.
Red tide algae is so thick in parts of the ocean that researchers last week encountered reddish-brown water off Portsmouth, N.H., and Cape Ann, Mass.
Such visible blooms elsewhere in the world gave red tide its name but rarely happen in New England. The reddish water off Portsmouth contained ''millions of cells per liter, which is something very, very unusual up here,'' Anderson said.
Scientists also believe that they have witnessed another rare side effect: fish and bird kills.
A total of 14 Atlantic and shortnose sturgeon, an endangered species, have been found dead near the mouth of the Kennebec River since last Friday. The fish are known to eat clams and were likely poisoned by red tide, said Pat Keliher, director of sea-run fisheries and habitat for the Department of Marine Resources. ''We've never seen it before,'' Keliher said.
Three of the dead fish are now in a DMR freezer in Hallowell. Their stomach contents will be tested to either confirm or rule out red tide, he said.
Last week, about 20 dead eider ducks and other waterfowl washed ashore in Cape Elizabeth, according to Judy Camuso, a wildlife biologist with the Maine Department of Inland Fisheries and Wildlife. Officials immediately suspected red tide in that case, too.
''They are known for eating shellfish,'' Camuso said.
Five of those birds are in a U.S. Department of Agriculture freezer in Augusta. The agency might conduct tests, although the animals appear to be too decomposed to officially determine a cause of death, said Kirk Shively, a wildlife biologist for the department.
Maine officials also suspect red tide might have played a role in a report last week about sick cormorants at Reid State Park in Georgetown. They don't expect to determine an official cause in that case, however.
Anderson, who has been studying red tides for 30 years, said he's not surprised that animals are getting sick and dying this summer, given the toxin levels along the Maine coast.
''In the big '72 outbreak, they found it in the very beginning because of dead birds,'' he said.
Staff Writer John Richardson can be contacted at 791-6324 or at: