DAO 83:59-66 (2009)  -  DOI: https://doi.org/10.3354/dao02013

Hematodinium sp. in Irish Cancer pagurus fisheries: infection intensity as a potential fisheries management tool

C. Ní Chualáin*, M. Hayes, B. Allen, M. Robinson

Applied Research Enhancement (ARE) Programme, Shelltec Applied Research Centre, Galway-Mayo Institute of Technology, Dublin Road, Galway, Ireland

ABSTRACT: Infection of Cancer pagurus by a parasitic dinoflagellate of the genus Hematodinium is described for the first time in Ireland. An industry-based monitoring programme was established to determine seasonality of infection intensity and prevalence in the country’s 3 largest brown crab fisheries in the southwest, north and southeast. The parasite was present in all areas for the majority of sampling periods, with highest prevalences recorded in pre-recruit animals of both sexes. Microscopic examination of haemolymph revealed trophont, plasmodial and dinospore stages of the parasite. Overall prevalence in males (16%) was higher than in females (9%). Prevalence of Hematodinium sp. infection ranged from 0 to 51%, but a distinct seasonal trend was not apparent. Infection intensity was seasonal with significantly higher peaks occurring in late autumn/early winter months than in other quarters, corresponding to industry reports of moribund and dead pink-shelled crabs in commercial catches. We postulate that seawater temperature or a temperature-linked process is a key factor in triggering the final stages of infection, as significant autumn peaks were followed by a reduction in infection intensity as temperature decreased in the late winter/early spring months with no increase in intensity again until the following autumn. We propose that infection intensity, rather than prevalence, provides a more appropriate indication of the period when there is greatest potential for biological and economic impacts; the parameter’s application as a fisheries management tool is discussed.


KEY WORDS: Cancer pagurus · Hematodinium sp. · Infection intensity · Fisheries management · Seasonal temperature


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Cite this article as: Ní Chualáin C, Hayes M, Allen B, Robinson M (2009) Hematodinium sp. in Irish Cancer pagurus fisheries: infection intensity as a potential fisheries management tool. Dis Aquat Org 83:59-66. https://doi.org/10.3354/dao02013

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