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Disease and mortality in juvenile commercial shellfish - FC1208

Defra policy on shellfish aims to promote long-term sustainability for the UK shellfish industry. This currently contributes to a £250m per annum fishery industry for a range of species including crabs, lobsters, scallops, oysters, mussels, and cockles. Despite the value of the industry, there exists a basic lack of knowledge on the parameters which drive mortality in this animal group. In particular, whilst recent reviews have summarized the pathogens that may be present in adult stocks (e.g. of edible crabs, cockles), almost no information exists on which pathogens may adversely affect the most sensitive life stages (i.e. the juveniles). Improved information on the health status of early life stages provides an early warning for potential future issues for the fished stock. Furthermore, it may allow for management intervention to mitigate the negative effects of disease.

Recent investigations have shown that pathogens are increasingly being recognized as important components affecting general host life history, survival, population structure, and ecosystem functioning. Cefas has pioneered the concept of studying disease in early stages of a range of vertebrate and invertebrate host species. Notable recent examples include that of Longshaw et al. (2010), who demonstrated a significant role of parasitism in the growth and recruitment success of early life stages of cyprinid fish. Stentiford et al. (2010) demonstrated that the age of onset of specific fish diseases (including those caused by parasites) is an important feature discriminating flatfish populations sampled from different offshore locations and furthermore that diseases observed in certain life stages are often not observed in others. Recently, the work of Bateman et al. (2011) has provided the first definitive evidence that disease profiles differ in un-fished (juvenile) and fished (adult) populations of the edible crab (Cancer pagurus) in UK waters. In the latter case, previously unknown pathogens were shown to be highly prevalent in juvenile stock and were predicted to impose significant restrictions on the future potential of these life stages to become a component of the fished population. Very recently, Longshaw and Malham (2012) and Longshaw et al. al. (2012), working on cockles have suggested that key bottlenecks to stock success may exist in the pre-settlement and early benthic stages.
01. To determine the disease profiles of juvenile/larval/pre-recruit life stages of commercially important UK shellfish species including cockles, mussels, scallops and edible crabs. Sampling will be conducted over the three years. However, it is envisaged that more focussed surveys will be conducted in the final two years of the project.

02. To characterise pathogens of concern and any new or novel species recorded.

03. Liaise with stakeholders and fisheries managers to investigate the utility of including health data in shellfisheries population models

04. To provide data to stakeholders and fisheries managers of potential mitigation strategies to avert the negative effects of disease in these stocks
Time-Scale and Cost
From: 2012

To: 2015

Cost: £153,341
Contractor / Funded Organisations
Animal Health              
Fish Disease              
Shellfish Stocks