Why it matters
Even mild cases can downgrade market value. Severe cases can weaken or kill lobsters, and disease prevalence becomes more concerning as warming shifts Gulf of Maine conditions closer to Southern New England.
Epizootic Shell Disease (ESD)
A disease in which shell-associated bacteria degrade the lobster’s exoskeleton, creating lesions that can reduce marketability and survival.
Definition
Epizootic shell disease, commonly shortened to ESD, damages the lobster shell through microbial imbalance and progressive erosion.
Conservation impact
Bigelow Laboratory reported that nearly every lobster held in warmer experimental water developed signs of ESD over 140 days, and the disease progressed faster in Maine lobsters. That makes shell disease a key climate-vulnerability term, not just a pathology term.
Quick facts
- Cause
- Shell-surface bacterial dysbiosis
- Warming signal
- Warm-water lobsters showed widespread disease in experiments
- Management challenge
- No direct fishery-scale treatment once it spreads
Related reading
Understanding Epizootic Shell Disease in American Lobsters
Epizootic Shell Disease (ESD) has contributed to a 92% collapse in southern New England lobster landings since 1997. Driven by warming water temperatures and a bacterial consortium led by Aquimarina homaria, the disease erodes the chitin shell and compromises reproduction. Here is what the science says about its causes, impacts, and the path forward.
Climate Change and Lobster Migration: How Warming Oceans Are Reshaping Populations
As the Gulf of Maine warms at three times the global ocean average, American lobster populations are undergoing dramatic geographic shifts. GMRI's 2024 data shows the region recorded its 12th-warmest year, with scientists now predicting populations will decline to early 2000s levels within 30 years. Here is what the science says.