Maine Lobster Die-Off Puzzles Scientists

The cause of a die-off of thousands of lobsters that made headlines a few months ago remains a mystery.

Even more puzzling, scientists can’t agree if there ever was, or still is, a serious health problem affecting Maine’s trademark seafood.

A Department of Marine Resources researcher suggested that reports of dead lobsters were overblown, but the head of the Lobster Institute at the University of Maine insisted that something is amiss.

Diane Cowan, the department’s senior lobster scientist, said she has received no recent reports of dead or weakened lobsters in traps.

“As far as I know, it could be explained by natural mortality,” Cowan said from her office in Boothbay Harbor. “We don’t have any evidence of anything of epidemic proportions.”

Many Theories, Little Hard Evidence

But Robert Bayer, executive director of the Lobster Institute, said there continues to be a problem at tidal lobster pounds. He believes people in the industry are reluctant to talk about it.

“Because of all the publicity, we probably don’t have all the information because people are getting gunshy,” he said.

After a record $136-million harvest last year, Maine lobster fishermen were alarmed when some began finding as many as a dozen dead lobsters a day in their traps in the late summer and fall.

The illness does not affect humans, researchers say.

The problem first came to the attention of researchers last winter when lobsters started dying in lobster pounds, where they are kept alive in cramped quarters. The death rate declined in the spring, but resumed in the late summer when lobster pounds were being restocked.

“Any time we lose lobsters, it’s a serious concern whether it’s one or a thousand. What’s frustrating to everyone is we don’t know what caused this,” said Pat White, executive director of the Maine Lobstermen’s Assn.

While there continue to be serious problems at tidal lobster pounds, Bayer said, problems with lobster in the ocean have lessened since the lobsters have migrated farther offshore.

Research indicates there is something wrong with lobsters closer to shore, where they migrate in the spring and summer. Data also indicate it’s worse in some places than others, but Bayer won’t say where.

About half of the state’s 65 tidal lobster pounds are seeing higher-than-normal lobster mortality rates, said Peter Daley, president of the Maine Lobster Pound Assn.

Some have seen mortality rates upward of 30%, while the typical rate is 5% to 10%, he said.

“There’s a problem in the industry with lobster that are not surviving, and it needs attention. Does someone have to go through bankruptcy before we realize it’s a serious problem?” he said.

Theories abound.

Scientists say they have identified higher concentrations of naturally occurring bacteria in the dead lobsters.

Pete McAleney from the New Meadows lobster pound in Portland said lobsters in shore could have been affected by the heavier-than-normal freshwater runoff during this year’s rainy June.

McAleney and others also believe that there are so many small lobsters crawling on the ocean floor that they’re becoming weakened from lack of food, leaving them susceptible to the bacteria.

Bayer doesn’t subscribe to the latter theory.

“The reason I don’t think that’s correct is because lobster are pretty versatile as to what they can eat. They will shift their diet depending on what’s available,” Bayer said.

The problems came to the public’s attention a year after Maine lobster landings hit an all-time high of 46.3 million pounds.

But lobstermen are worried about the lucrative fishery at a time when the government says lobster is overfished and juvenile lobsters are being caught in traps from the moment they’re big enough to be “legal.”

After problems were reported in lobster pounds, nervous lobstermen may have become too vigilant in watching for problems, leading to overstated claims about problems this year, Cowan said.

Daley can’t help but wonder if nature is out of whack because of the decimation of groundfish while lobster continue to thrive in the absence of natural predators like cod and haddock. “Maybe this is Mother Nature’s way of saying, ‘I’m going to put things back into balance for you,’ ” he said.