Epidemiology and Control - Epidemiology / Parasite Management

There is increasing awareness that knowledge of parasite biology and epidemiology is crucial for the effective long-term management of fish health. The parasitology group has carried out some important studies in this field, encompassing several parasite groups in different conditions. For example, our study of the population dynamics of salmon lice has demonstrated the value of fallowing and the effectiveness of single year-class stocking of farm sites. These findings have contributed substantially to management strategies for louse epizootics in salmon farms, to the benefit of both farmed and wild fish.

We have also studied the epidemiology of several parasites which are problematic in freshwater fisheries. As well as supporting monitoring programmes and contingency planning for notifiable diseases, the Parasitology Group has also used epidemiological studies to improve fish health. Chemotherapy is unsuited to these environments, so epidemiological studies and alternative control strategies are particularly important. For example, quantitative epidemiological studies of freshwater crustacean parasites Argulus foliaceus and Ergasilus sieboldi have enabled identification of the most significant risk factors for problematic outbreaks. These methods have then been used to produce practical management options for fishery owners, to minimise the risk of future epidemics.

The Parasitology group also works closely with government agencies to provide information and advice to support policy decision making. For example, we have been closely involved with the development of contingency plans for Gyrodactylus salaris, which will be used should this potentially harmful salmon parasite be introduced to the UK. Our research includes the development of risk evaluation models, to enable more accurate epidemiological predictions to be made and to improve monitoring strategies.

Selected References

  1. Holzer, A.S., Sommerville, C. & Wootten, R. (2006) Molecular studies on the seasonal occurrence and development of five myxozoans in farmed Salmo trutta L. Parasitology, 132, 193-205.
  2. Radford, A., Riddington, G., Paffrath, S., Bostock, J. & Shinn, A. (2006) An economic evaluation of the impact of the salmon parasite Gyrodactylus salaris (Gs) should it be introduced into Scotland: Summary Report. Prepared for the Scottish Executive Environment and Rural Affairs Department, Project Number SAQ/001/05. 132 pp.
  3. Taylor, N.G.H., Sommerville, C. & Wootten, R. (2006) The epidemiology of Argulus spp. (Crustacea: Branchiura) infections in stillwater trout fisheries. Journal of Fish Diseases, 29, 193-200.
  4. Turnbull, J., Bell A., Adams C., Bron, J.E. & Huntingford, (2004). Stocking density and welfare of cage farmed Atlantic salmon: application of a multivariate Integrated Welfare Index. Aquaculture 243, 121-132
  5. Dixon, B. A., Shinn, A.P. & Sommerville, C. (2004) Genetic characterisation of populations of the ectoparasitic caligid, Lepeophtheirus salmonis (Krøyer, 1837) using randomly amplified polymorphic DNA (RAPDs). Aquaculture Research, 35, 730-741.
  6. Ozer, A., Wootten, R. & Shinn, A.P. (2002) Infection prevalence (%) seasonality and host specificity of actinosporean types in Atlantic salmon fish farms in Northern Scotland. Folia Parasitologica, 49, 263-268.
  7. Ozer, A., Wootten, R. & Shinn, A.P. (2002) Survey of actinosprean types (Myxozoa) belonging to seven collective groups found in freshwater salmon farms in Northern Scotland. Folia Parasitologica, 49, 189-210
  8. Tucker, C.S., Norman, R., Shinn, A.P., Bron, J.E., Sommerville, C. & Wootten, R. (2002) A single cohort, time delay model of the life cycle of the salmon louse (Lepeophtheirus salmonis) on Atlantic salmon Salmo salar. Fish Pathology, 37, 107-118.
  9. Shinn, A.P., Bron, J.E., Gray, D.J. & Sommerville, C. (2000) Elemental analysis of Scottish populations of the ectoparasite copepod Lepeophtheirus salmonis (Krøyer, 1837). Contributions to Zoology, 69 (1/2), 79-87.
  10. McGeorge, J. & Sommerville, C. (1996). The potential for interaction between the parasites of wild salmonids, non-salmonids and farmed Atlantic salmon in Scottish sea lochs. Aquaculture and Sea Lochs, 59–71.
  11. McGeorge, J., Sommerville, C. & Wootten, R. (1996) The epizootiology of Sphaerospora truttae (Myxozoa: Myxosporea) infections of Atlantic salmon, Salmo salar L. at freshwater smolt producing hatcheries in Scotland. Diseases of Aquatic Organisms, 26, 33-41.
  12. Bron, J.E., Sommerville, C., Wootten, R. & Rae, G.H. (1993) Fallowing of marine Atlantic salmon, Salmo salar L., farms as a method for the control of sea lice Lepeophtheirus salmonis (Kroyer, 1837). Journal of Fish Diseases, 16, 487-493.
  13. Bron, J.E., Sommerville, C. & Rae, G.H. (1993). Influence of treatment with dichlorvos on the epidemiology of Lepeophtheirus salmonis (Kroyer, 1837) and Caligus elongatus Nordmann, 1832 on Scottish salmon farms. In: “Pathogens of Wild and Farmed Fish: Sea Lice”. Boxshall, G. & Defaye, D. (eds.) Ellis Horwood Ltd., 263-274.