DAO prepress abstract  -  DOI: https://doi.org/10.3354/dao03216

Green crab Carcinus maenas symbiont profiles along a North Atlantic invasion route

Jamie Bojko, Paul D. Stebbing, Alison M. Dunn, Kelly S. Bateman, Fraser Clark, Rose C. Kerr, Sarah Stewart-Clark, Ása Johannesen, Grant D. Stentiford*

*Email: grant.stentiford@cefas.co.uk

ABSTRACT: The green crab, Carcinus maenas, is an invader on the Atlantic coast of Canada and the USA. In these locations, crab populations have facilitated the development of a legal fishery in which C. maenas is caught and sold, mainly for use as bait to capture economically important crustaceans, such as American lobster (Homarus americanus). The paucity of knowledge on the symbionts of invasive C. maenas in Canada and their potential for transfer to lobsters poses a potential risk of unintended transmission. We carried out a histological survey for symbionts of C. maenas from their native range in Northern Europe (in the UK and Faroe Islands), and invasive range in Atlantic Canada. Nineteen separate symbiotic associations were identified from C. maenas collected from 27 sites. These included metazoan parasites (nematodes, Profilicollis botulus, Sacculina carcini, Microphallidae, ectoparasitic crustaceans), microbial eukaryotes (ciliates, Hematodinium sp., Haplosporidium littoralis, Ameson pulvis, Parahepatospora carcini, gregarines, amoebae), bacteria (Rickettsia-like organism, milky disease), and viral pathogens (parvo-like virus, herpes-like virus, iridovirus, Carcinus maenas bacilliform virus and a haemocyte-infecting rod-shaped virus). Hematodinium sp. were not observed in the Canadian population, however parasites like the Trematoda and Acanthocephala were present in all countries despite their complex, multi-species lifecycles. Some pathogens may pose a risk of transmission to other decapods and native fauna, via the use of this host in the bait industry, such as the discovery of a WSSV-like virus (“rod-shaped virus”) and amoebae, which have previously been found to cause disease in aquaculture (Salmo salar) and fisheries species (Homarus americanus).