Lobster Shell Disease has been the buzzword up and down the East Coast these past five years, since its debut off Rhode Island and in Long Island Sound in 1999.

Before that time, Long Island Sound was the nation’s third largest lobster producer. The mysterious die-off of lobsters decimated New York’s $100 million industry.

The American Lobster is the most economically important single-species fishery in the Gulf of Maine, and a collapse of the lobster fishery here would be catastrophic. If we assume that Maine’s lobster (or “bug” as it’s often referred to by fishermen) is immune, are we only in denial? How far north could lobster shell disease spread?

Shell disease was first described in 1900 in crabs and reported in 1937 in American Lobsters that were held in pounds in Nova Scotia. There were reports again in the 1960s, 1980s and 1990s. Researchers found that the disease was relatively rare in the wild, infecting only five to eight percent of the natural population. It is less prevalent in cooler, deeper waters than in warmer inshore sites. According to Carl Wilson of the Maine Department of Marine Resources, “Shell erosion is seen in any population to some degree.”

While shell disease is not the only disease impacting lobster health, it’s an important one to understand. It is caused by bacteria that invade the outside of the lobster via pores in its shell. It ranges in severity from shallow pits that erode the shell and cause black spots to holes that fully penetrate the shell and fuse it to underlying membranes, thus preventing the lobster from molting, resulting in death.

It is still unclear whether the same bacteria was the primary cause of the lobster deaths in Long Island Sound. Some research points to stress factors that could likely have played a role. Warmer water temperatures, low oxygen levels, changes in salinity and toxins in the water leave lobsters in a state of environmental stress compromising their immune systems and making them vulnerable to bacterial attack. According to Bob Steneck of University of Maine, “The peak year of outbreaks in Rhode Island and Long Island Sound was in 1999, one year following what was deemed the warmest year on the planet.”

Lobsters are most abundant where temperature conditions are most suitable. The Gulf of Maine, New Brunswick and Nova Scotia account for approximately 90% of the total lobster harvest. Steneck states, “Maine lies very close to center of that range and it is not unreasonable to suspect that on the edges we might see higher rates of shell disease, but perhaps not in the center.”

Steve Train, a lobsterman from Long Island in Casco Bay, has seen an insignificant amount of shell diseased lobsters these last few years. “It may not be a real threat at this point,” he said. He suggests that water temperature in Maine may not be conducive for shell disease, but believes that more money should be spent in research. “It is still unclear what the causes are and running on a crisis management system is not the answer to this epidemic,” Train said.

Lobsters are “poikilotherms,” meaning they are unable to regulate their internal body temperature. The body of a lobster is basically the same temperature as its external environment. They are extremely sensitive to prevailing environmental conditions, such as water temperature and salinity having a huge influence on behavior, survival, growth, production of offspring, and susceptibility to diseases. Lobsters are capable of surviving in slightly higher and lower temperatures for short periods of time if properly acclimated.

In March 2005 a Shell Disease Workshop was held at the University of Massachusetts in Boston to bring scientists together to discuss lobster shell disease. The workshop ended with no conclusions due to the lack of sufficient information about shell disease, but participants did establish valuable collaborations.

“Research has been inconclusive all around,” said Patrice McCarron of the Maine Lobsterman’s Association. “It is scary that we still have no idea what causes it, we need to take a proactive approach so we are not left helpless if an outbreak occurs in Maine.”

The Maine Department of Marine Resources is recording data on the health of the lobster population through sea sampling, port sampling and inshore trawl surveys. “We need new stock assessment models, which include high quality data,” said Wilson. “In addition we also need more research dollars. The state should be funding fisheries research at a level of one to two percent of the value of that fishery. The Maine lobster fishery is worth 300 million dollars of which we are only receiving several thousand towards research.”

Rick Wahle from Bigelow Laboratory, who attended the March workshop with lobster settlement studies, said, “The clock is ticking in Maine. Massachusetts is doing a lot of testing and monitoring and monitoring shell disease in sea sampling programs and trawl surveys are crucial.”

Rhode Island and Long Island Sound may be Maine’s wake-up call, warning that the state’s lobster populations are not invincible. “Small communities depend on this resource to sustain a year-round communities. Because of this socioeconomic impact to our community we need spend more money on research,” said Steve Train.

Jennifer Litteral is Marine Programs Officer at the Island Institute.