A disease that rots lobsters' shells and can kill the crustaceans now affects 30 percent of lobsters along the New England coast, decimating the industry in many areas, scientists said Wednesday.
The disease's cause and how it spreads remain a mystery, though theories are emerging and the scientists said they will seek state and federal money for further studies.
The disease does not taint the lobsters' meat, but makes the shells too unsightly to serve whole. It can weaken lobsters so much that some die prematurely.
Researchers in the region first noticed shell disease in the 1980s, with shells marked by little black spots. But in recent years, the researchers said, shells have become fully enveloped by the disease, and in the worst cases have rotted entirely.
Scientists said trawl and trap studies show egg-carrying females are most susceptible to the disease. The studies also show lobsters living in warmer waters appear to contract the disease more readily.
Hans Laufer, a professor emeritus of molecular and cell biology at the University of Connecticut, said he believes lobsters may contract the disease from alkylphenols, chemicals that are byproducts from industrial sources. Laufer stressed that his studies were just preliminary.
Another scientist, Roxanna Smolowitz of the marine biological laboratory at Woods Hole, Mass., said bacteria attach themselves to the lobster's shell and begin to penetrate inward.
In 1999, the lobster industry in Rhode Island generated $30 million and employed 425 fisherman, according to Mark Gibson of the state Department of Environmental Management. Four years later, the industry produced $16.7 million and employed 279.
"Something's happening before they get to us, and that's what we need to know," said Mike Merchant, president of the Rhode Island Lobsterman's Association.
The symposium was hosted by the University of Rhode Island's Sea Grant program.