Lobster Shell Disease and Plastics: More Still

The mystery of why lobsters from southern New England suffer from shell rot is less of a mystery than why newspapers around here are missing UConn professor Hans Laufer's research into the link between shell rot and the chemicals that result when plastic bottles break down in the environment.

Yesterday's Providence Journal had a long story, by the usually-reliable Peter Lord, about a decision in many coastal Rhode Island towns to stop using a chemical called methoprene to kill mosquito larvae because of complaints from lobstermen who assert that methoprene is causing lobsters to grow more slowly, resulting in a lower lobster catch. Here's an excerpt:

The lobstermen vow to keep up their campaign until every town stops using the chemical.

Ingram, Pat Heaney and Lanny Dellinger, president of the Rhode Island Lobstermen’s Association, met near their boats at the State Pier here recently and explained why they think something is happening in Narragansett Bay and the public should be concerned.

“We figure there won’t be a lobster industry in a short time if this keeps up,” said Dellinger. “All the state wants to do is control us, but you can’t keep polluting the environment and still get fish.”

Local lobster catches topped off in 1999 with about 3,500 tons. Each of the following years got progressively worse. In 2005, the last year with complete figures, the take was less than 1,500 tons.

In response, the lobstermen have greatly reduced the number of traps they set and accepted one new size restriction after another designed to leave lobsters in the water longer so they can successfully reproduce.

Then Lord throws in a mention of shell rot:

Still, the catch remains low. And many lobsters, particularly those caught close to shore, are coming up with a disfiguring, and still unexplained, shell disease.

Now the lobstermen are finding oddities never seen before in their traps: female lobsters that have molted their shells while they are still covered with eggs.

And later:

An effort is under way to answer some of the lobstermen’s questions. Thanks to a $2.3-million grant sponsored in 2006 by Sen. Jack Reed and Sen. Olympia Snow, R-Maine, dozens of lobsters were pulled out of the Bay last week and shipped to 15 researchers around the country. They will appraise the lobsters’ health and look for answers to the shell disease and for indications of methoprene.

“I look at shell disease and it doesn’t make any sense,” says Kathleen Castro, a Rhode Island Sea Grant fisheries extension leader who is leading the lobster research project. “It’s a huge warning that we’re doing a number on our ecosystem.”

But there is an explanation for lobster shell disease: it's caused by alkylphenyls, chemicals that are released when bottles and other plastics degrade in the environment. As Professor Laufer said on the CBC, they are endocrine disruptors and they mimic crustacean hormones.

Now that might not be the only explanation, and the 15 researchers might find something else, but it is an explanation, by a real scientist.

Odd too that Kathleen Castro of Rhode Island Sea Grant didn't know of (or didn't tell Lord of) Laufer's work; her colleagues at Connecticut Sea Grant helped publicize Laufer's work.

And there's also this article in Connecticut Sea Grant's magazine, in which Laufer says he's observed one of the exact phenomena that Lord describes -- female lobsters that have molted their shells while they are still covered with eggs -- and which Laufer also links to alkylphenols.

I don't usually do this kind of thing but I sent Lord an email, pointing most of this out (in a nice way, I hoped). He said he'd look into it, which I hope he does.