Epidemiology of bitter crab disease (Hematodinium sp.) in snow crabs Chionoecetes opilio from Newfoundland, Canada

Diseases of Aquatic Organisms

Stephen G. Sutton Paul G. O’Keefe Danny W. Ings Amanda L. Pardy¹  David M. Taylor2¹  Jeffrey D. Shields¹ 

关键词: Ecology;    Prevalence;    Host factors;    Abiotic factors;    Transmission;    Dinoflagellate;   

DOI  :  10.3354/dao064253

学科分类：生物科学（综合）

来源: Inter-Research

【 摘 要 】

ABSTRACT:The parasitic dinoflagellate Hematodinium sp. causes a condition known as bitter crab disease (BCD) in snow crabs Chionoecetes opilio and Tanner crabs C. bairdi. As the name of the condition implies, crabs infected with BCDare unmarketable due to their bitter flavor.We surveyed the distribution of BCD in 3 regions within the snow crab fishery of Newfoundland from 1997 to 2003.Over time, the disease has become firmly established in Conception and Bonavista Bays andpersists at low levels on the Avalon fishing grounds. An epizootic occurred within Bonavista and Conception Bays in 1999 and persisted in Conception Bay in 2000, reaching prevalences of over 2% to 9% in trapped and trawled male crabs and from 19 to 26% intrawled and trapped female crabs, respectively. Infections were highest in females and small males, i.e. the unfished and pre-recruit portions of the fishery. In a mortality study, all of the naturally infected crabs died and 50% of the experimentallyinoculated crabs died. Patterns in the molting cycle and prevalence of infection indicate that transmission occurs during the post-molt condition, and that overt infections probably develop 2 to 4 mo later with mortalities occurring at least 3 to 4 mothereafter. The hydrography of this bay may have contributed to the epizootic as infections were centered within the deeper confines of the bay. Analysis of various abiotic factors uncovered a significant positive association between prevalence, depth andmud/sand substrates; the nature of this relationship was not apparent but may be related to diet or alternate hosts. Lastly, given the increase in BCD in snow crabs in Newfoundland, we recommend that fishery management programs for Chionoecetesfisheries employ non-selective gear to monitor for Hematodinium infections in female and juvenile crabs because these under-sampled members of the population may forewarn of impending recruitment declines that might otherwise remain unexplained.

【 授权许可】

Unknown