An earlier spring may sound nice, unless you’re a New England lobster.
New findings reveal that as coastal waters in the northeastern U.S. continue to warm—bottom temperatures in Long Island Sound have increased 0.7°F per decade over the last 40 years—resident lobsters are becoming increasingly susceptible to epizootic shell disease, a condition that has depleted the southern New England population and severely impacted the local lobster fishery.
The findings stem from a collaboration between William & Mary’s Virginia Institute of Marine Science and Dominion Energy’s Millstone Environmental Laboratory. The lab maintains a unique, long-term record of lobster abundance and health in waters near Dominion Energy’s Millstone Power Station in Waterford, Connecticut.
The research, funded by NOAA’s Saltonstall-Kennedy Program and led by then postdoctoral associate Maya Groner of VIMS, suggests that the increased prevalence of shell disease in area lobsters stems from two factors—an earlier onset of warmth-induced spring molting, and hotter summers.
Groner and her co-authors—professors Jeff Shields and John Hoenig of VIMS along with Don Landers and John Swenarton of the Millstone Lab—published the results of their work in the most recent issue of American Naturalist.
“We used the lab’s mark-recapture dataset, now going on 37 years, to investigate relationships between temperature, molting phenology, and ESD [epizootic shell disease],” says Groner, currently a research ecologist at the Prince William Sound Science Center in Alaska. Phenology refers to the study of how plant and animal life is affected by seasonal changes.
“Our work shows that temperature increases due to climate change have caused a phenological shift in the molting patterns of lobsters, making them more susceptible to the disease,” says Groner. The team’s results pertain mostly to male and juvenile lobsters, as females have a different molting pattern, typically molting every two years in the region.
As the name implies, epizootic shell disease occurs when the bacterial populations that normally inhabit the surface of a lobster’s carapace change and begin consuming the cuticle, causing it to erode.