The disease is often called "epi-zootic" shell disease. It's a bacterial infection that makes lobsters impossible to sell as food. It eats away at their shells and sometimes kills them.
The Maine Department of Marine Resources said researchers found the disease in about 1 percent of lobsters last year. But the overall presence of the disease remains low, especially compared to southern New England waters, where it's in the 20 percent to 30 percent range.
Scientists are still trying to figure out exactly what causes shell disease.
Some experts claim one possibility is that warm water temperature stresses lobsters and taxes their immune systems, making them more susceptible. That would help explain the shell disease found in the warmer waters off Massachusetts, and Long Island Sound, where the lobster fishing business has collapsed.