Sex ratio patterns and shell microbial community of American lobsters in Atlantic Canada

Skewed sex ratios in American lobsters can impact mating behaviour and lower reproduction with potentially severe ecological and economic consequences. My research aimed to investigate lobster sex ratio patterns in two lobster fishing areas (LFAs) in southwestern Nova Scotia, Canada and to identify associated factors. I analyzed data from more than 270,000 lobsters sampled over ten years (2010-2019) by the Fishermen and Scientists Research Society. A mixed effect logistic regression revealed significant temporal patterns in sex ratios that differed by LFA, and that larger female lobsters were more prevalent in deeper areas and in areas with lower bottom temperature. These findings are also relevant with regards to the emerging epizootic shell disease (ESD), which is linked to shifts in the microbial shell community and rising temperatures, as it affects egg-bearing females more severely. My future work aims to identify and compare the shell microbiome of healthy and diseased lobsters using metagenomic sequencing combined with multivariate and network analyses. This will help identify associated microbes, regions at risk and the epidemiology of ESD. Monitoring population dynamics and disease threats to this iconic fishery species, especially in view of climate change, is crucial to ensure sustainable fisheries and healthy lobster stocks.