Epidemiological determinants in outbreaks of bitter crab disease (Hematodinium sp.) in snow crabs Chionoecetes opilio from Conception Bay, Newfoundland, Canada

Shields, Jeffrey D.; Taylor, David; O'Keefe, Paul G.; Colbourne, Eugene; Hynick, Elaine

doi:10.3354/dao01825

Cited by 52 publications

(44 citation statements)

References 35 publications

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“…in other host species has long been associated with moulting (Meyers et al 1987, 1990, Eaton et al 1991, Field et al 1992, Dawe 2002, 2007. The main moulting period for brown crabs in Irish fisheries occurs from September to December (Tully et al 2006), coinciding with high infection intensities observed in Q4 in the present study.…”

Section: This Is the First Report Ofsupporting

confidence: 64%

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

Chualain¹,

Hayes²,

Allen³

et al. 2009

Dis. Aquat. Org.

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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.

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Section: This Is the First Report Ofsupporting

confidence: 64%

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

Chualain¹,

Hayes²,

Allen³

et al. 2009

Dis. Aquat. Org.

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“…It is distinctly possible that infections are transmitted during the molting of the host. This is a relatively common occurrence in diseases such as this, albeit not well documented except for rhizocephalan infections in crabs and some protozoal infections in crabs and lobsters (Tindle et al 2004, Shields et al 2007). Because crayfish were collected in nature, however, we acknowledge the possibility that wild-caught individuals may also vary in infection or disease susceptibility.…”

Section: Discussionmentioning

confidence: 95%

Ulcerative disease outbreak in crayfish Orconectes propinquus linked to Saprolegnia australis in Big Muskellunge Lake, Wisconsin

Krugner‐Higby¹,

Haak²,

Johnson³

et al. 2010

Dis. Aquat. Org.

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Crayfish populations in the area of the North Temperate Lakes Long Term EcologicalResearch (LTER) project, Wisconsin, USA, have been monitored for > 25 yr. In 2005, native crayfish Orconectes propinquus from Big Muskellunge Lake were found with ulcerated lesions in the cuticle. In 2006, lesions occurred in 9.5% of sampled crayfish from the lake (n = 3146). Ulcers generally occurred on the appendages of affected individuals but varied in location and severity. The prevalence of ulcers varied widely among sites, sample depths, and sampling dates, ranging from < 2% to > 20%. The prevalence of ulcers in crayfish increased from a minimum in early June to a maximum in late July and August. In aquarium trials, healthy crayfish representing either O. propinquus or O. rusticus co-housed with ulcerated crayfish did not develop ulcers within 4 wk of exposure. Gross and histopathologic analyses of ulcerated crayfish revealed the presence of filamentous hyphae in the lesions while hemocytic infiltrates, melanotic reactions and silver-stained sections indicated that the ulcers had an oomycete etiology. Excised samples of ulcerated crayfish cuticle grown in culture developed an oomycete that was identified as Saprolegnia australis by PCR amplification and sequence analysis of 2 different DNA fragments. This is the first report of the occurrence of ulcers in wild crayfish associated with S. australis infection in the USA. The advent of the outbreak and its underlying ecological causes are still under investigation.KEY WORDS: Shell disease · Epidemiology · Mortality · Aphanomyces · Saprolegnia · Crayfish Resale or republication not permitted without written consent of the publisherDis Aquat Org 91: [57][58][59][60][61][62][63][64][65][66] 2010 spores form on the tips of hyphal stalks and produce primary zoospores. Motile primary zoospores swim for brief periods before encysting as a primary cyst. Encysted primary zoospores produce secondary zoospores that are also motile infective forms, and which find a host and germinate into new hyphae. The process of producing and releasing more than one type of zoospore or infective element is called polyplanetism. Transmission of Saprolegnia spp. is a complex process involving 2 types of motile zoospore but with no intermediate host (Torto-Alalibo et al. 2005).Oomycetes of the genus Saprolegnia, especially S. parasitica, are economically important pathogens of fish and fish eggs. Infection with these organisms has caused heavy losses in salmonid fish hatcheries and 'winter kill' in catfish in aquaculture settings (TortoAlalibo et al. 2005). Outbreaks of saprolegniasis have also been reported in wild salmonid fish (Carballo et al. 1995) and in the eggs and larvae of amphibians (Blaustein & Wake 1995, Kiesecker & Blaustein 1995, Kiesecker et al. 2001. Increased severity and prevalence of infection in fish are associated with poor water quality and damage to the integumental barrier of the epidermis (Carballo et al. 1995). In adult fish, the lesions present as large penetrating...

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“…These estimates represent average natural mortality over the lifetime of a female and are lower than ours, which represent natural mortality of a female after terminal molt only. Prominent causes of natural mortality for pre-adult and adult females include fish predators such as skates and cod (Robichaud et al 1991, Chabot et al 2008) and in some areas (but not the northern Gulf of St. Law rence) bitter crab disease (Shields et al 2007, Mullow ney et al 2011. However, natural mortality rates of adult females may be higher on average than those of preadult females because of density-dependent sexual conflicts arising during the female's first mating period, which is intimately associated with terminal molt ; see Adler & Bondiuransky 2011 for more general considerations on sex ratio, density and the rate of ageing).…”

Section: Discussionmentioning

confidence: 99%

Estimating natural mortality and egg production of snow crab Chionoecetes opilio adult females

Drouineau¹,

Sainte‐Marie²,

Duplisea³

2013

Aquat. Biol.

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The natural mortality rate is a key parameter in ecology and fisheries, but it may be difficult to estimate as it is highly variable and often confounded with other factors such as fishing mortality and migration. This is especially true for crustaceans in general, as age determination is problematic, and for snow crabs Chionoecetes opilio in particular because density-dependent processes may lead to highly variable mortality rates across life history stages. In this context, we developed an original method to estimate the natural mortality rate of adult (i.e. terminally molted) female snow crab, and its consequences on egg production. This new method relies on shell condition, carapace width and abundance of adult females and was applied to a time series (1991-2012) of annual trawl survey data for a snow crab population in the Gulf of St. Lawrence, eastern Canada. Two natural mortality estimates were provided by the method depending on 2 distinct assumptions about the survey. Both estimates (0.66 and 0.78 yr −1 ) were high compared to previous estimates for snow crab. These values imply that female life expectancy after terminal molt was short and that primiparous females (first-time spawners) contributed a large share (at least 81%) of the total number of eggs produced by the case-study population over the period 1992 to 2010.

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Epidemiological determinants in outbreaks of bitter crab disease (Hematodinium sp.) in snow crabs Chionoecetes opilio from Conception Bay, Newfoundland, Canada

Cited by 52 publications

References 35 publications

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

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

Ulcerative disease outbreak in crayfish Orconectes propinquus linked to Saprolegnia australis in Big Muskellunge Lake, Wisconsin

Estimating natural mortality and egg production of snow crab Chionoecetes opilio adult females

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