Lobsters live in an environment where bacteria constantly snow down on them. Many bacteria like to eat chitin and calcium, the essential components of a lobster shell. When certain bacteria break through the protective layering of the shell, additional bacteria enter the wound increasing its size, and rendering the lobster more susceptible to predators and secondary infections. This increases mortality for lobsters in the wild. We study this disease in the laboratory to isolate the causative agents, and ideally develop ways to help individuals recover from this disease.

Modelling shell disease

We have been working on a laboratory model to understand shell disease. First published as the host susceptibility model, we later amended this model to include personalize health curves. This later model accounts for all observations and to date appears to predict all empirical evidence. 

Lobster Health Curve model 2012

Host Susceptibility model 2007

The Shell Disease Microbiome

Over time, we have partnered with microbiologists and pathologists to understand the bacterial causes of this disease. We have used many methods, from culture dependent techniques to more advanced high throughput sequencing (using a comparison of American and European lobsters), we have greatly expanded our knowledge of the microbiome associated with lobster shell disease. Our current work with Dr Bowen's lab of U Mass Boston is finding transition communities bacterial before there is any physical sign of disease. 

A backlit picture of a molt from a lobster with shell disease. The light areas are where bacteria have consumed the shell and only the underlying membrane remains.

etiology with culture dependent techniques 2012

European v American lobster shell disease 2014

An individual lobster photographed at 2 week intervals showing the progression of shell disease, and ultimately the molt to an asymptomatic shell.

Mitigating Shell Disease

One issue for American lobsters and other crustaceans is that many public aquariums hold them as exhibit animals. Shell diseases animals do not present well to the public. So we are using our laboratory model of shell disease to examine factors that can help mitigate and potentially stop shell disease.

2018 Treatment of a laboratory-based model of shell disease in hatchery raised American lobsters (Homarus americanus)