Using physiology to generate novel control measures and management strategies for ectoparasite outbreaks in freshwater trout fisheries. PhD in Biosciences (NERC FRESH)

Lead Supervisor:

Professor Rod Wilson, Department of Biosciences, College of Life and Environmental Sciences, University of Exeter

Additional supervisors:
Professor Jo Cable, Cardiff University
Dr Catherine Wilson, Cardiff University
Dr Nick Taylor, CEFAS (Centre for Environment, Fisheries & Aquaculture Sciences)



The NERC Centre for Doctoral Training in Freshwater Biosciences and Sustainability (GW4 FRESH CDT) provides a world-class doctoral research and training environment, for the next generation of interdisciplinary freshwater scientists equipped to tackle future global water challenges. GW4 FRESH harnesses freshwater scientists from four of the UK’s most research-intensive universities (Bath, Bristol, Cardiff and Exeter) plus world-class research organisations the Centre for Ecology and Hydrology (CEH) and British Geological Survey (BGS).

For an overview of the GW4 FRESH CDT please see website www.gw4fresh.co.uk

Note, the research projects listed are in competition with other studentship projects available across the GW4 FRESH CDT Partnership. Up to 14 studentships will be awarded to the best applicants.


Project Description
Outbreaks of ectoparasite infestations of the fish louse (Argulus species) can cause mass mortalities and severe welfare problems for freshwater fish. This can overwhelm inland freshwater fisheries that make a substantial contribution to the economy of rural Britain, threatening their economic viability. This is growing problem, with over 70 % of UK trout fisheries having experienced an outbreak in the last 10 years. There is therefore an urgent need for novel solutions to help with management strategies that can mitigate both the major fish health problems created, and the negative impacts on the freshwater ecosystems and economy related to these inland fisheries. There are three reported species of “fish lice” in UK freshwaters (Argulus foliaceus, A. coregoni, and A. japonicus). Infestation in stillwater trout fisheries can cause mass mortalities, but also loss of appetite and condition in badly-infected fish, which impact greatly on the success of a fishery. Unlike sea lice and copepods, Argulus species continue to moult and grow even after reaching adulthood. Given the physiological extremes and energetic costs associated with the moulting process in crustaceans generally, this may present a weakness that can be exploited to provide an environmentally-compatible solution to outbreaks. Various drugs/medicines, and chemicals have been used to treat argulid infections. However, currently there are no approved drug treatments for Argulus due to problems with development of resistance by Argulus, health impacts on the fish themselves, legality of use with food fish species, costs, availability etc. Our understanding of the physiology of crustaceans and fish, suggests that using CO2 may provide a novel chemotherapy. Bubble curtains of high CO2 (up to 50,000 µatm) have been used successfully as a deterrent for invasive fish species in the USA (1), without causing mortality or chronic problems as fish are tolerant of acute exposure to very high CO2. However, crustacean moulting and calcification is highly impaired by even small elevations in CO2, which presents a potentially selective chemotherapy to the target the parasite whilst causing minimal (or at least temporary and acceptable) stress to the fish. It would also be cost-effective, easy to apply to all settings, and be feasible to restore normal conditions promptly following treatment of a trout lake.

The student will experience a multi-disciplinary training within a project that aims to address the need for a novel solution by integrating the knowledge and expertise of the following areas:
• Physiology (of freshwater fish and crustaceans)
• Parasitology (specifically the fundamental biology, including behaviour, of the crustacean ectoparasite Argulus, to understand its environmental requirements and limitations, and how these influence the interaction with fish host species)
• Water Chemistry (specifically inorganic chemistry and the differential tolerance of the fish host and the crustacean ectoparasite to these variables)
• Fisheries Management (specifically understanding current practices, and finding sustainable ways of incorporating novel solutions based on water chemistry that are compatible with wider environmental quality and human health and safety concerns).
• Engineering (required for modelling and testing the hydrodynamics of efficiently applying, and subsequently removing, high CO2 in trout lakes)
1) Cupp et al. (2018). Management of Environmental Invasions, 9(3): 299-308

Project specific enquiries should be directed to the lead supervisor, Professor Rod Wilson: [Email Address Removed]