University of Exeter funding: NERC FRESH Biosciences PhD

Using physiology to generate novel control measures and management strategies for ectoparasite outbreaks in freshwater trout fisheries. PhD in Biosciences (NERC FRESH) Ref: 3759

About the award


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

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

Real Life challenges this project will address
Outbreaks of ectoparasite infestations of the fish louse (Argulus species) can cause mass mortalities and serious fish welfare problems, which can be devastating for inland freshwater fisheries that make a substantial contribution to the economy of rural Britain (supporting ~6,000 jobs and 430,000 trout anglers who spend £300M on game fishing and £6M on EA rod licence fees).

What you should know about this project
This project is focused upon solving the real-world problem of outbreaks of ectoparasitic infestations in freshwater trout fisheries in the UK, by using fundamental studies of physiology and behaviour of the crustacean parasites (Argulus species) and the fish host, and how they are influenced by environmental chemistry. Lab-based studies will assess the responses and tolerance of these organisms to changes in physico-chemical variables. We envisage a particular focus on CO2, with a view to providing fisheries managers and environmental organisations (e.g. Cefas, Environment Agency, British Trout Association) with a novel chemotherapeutic tool to treat outbreaks and limit the geographic spread within the UK. Engineering expertise is also incorporated into the project, in particular to assist in understanding the hydrodynamics of fishing lakes and in designing the most effective and safe methods for the large scale application (and post-treatment removal) of such chemical control measures. The supervisory team is ideal to support this multi-disciplinary project which combines novel fundamental science, with a clear real-world application. Rod Wilson (Exeter) provides support for fish and crustacean physiology, and freshwater chemistry (especially CO2). Jo Cable (Cardiff) provides aquatic parasitology expertise, and specifically for working with Argulus species and applying studies of their natural behaviour towards intervention solutions. Catherine Wilson (Cardiff) provides engineering expertise which will be invaluable in optimising (by modelling) and field testing the hydronamics of manipulating water chemistry on a large scale in trout lakes. Nick Taylor (Cefas) provides 25 years’ experience of working with fish pathogens, and Argulus in particular, including practical advice on field monitoring of the parasite and laboratory cultures, and epidemiological modelling. He also provides access to expertise of the Fish Health Inspectorate.

What expertise you will develop
The student will develop expertise in Physiology, Parasitology, Freshwater Chemistry, Fisheries Management and Engineering, specifically relating to freshwater fish and crustaceans, and the problem of treating ectoparasite outbreaks in trout fisheries.

Why this project is novel
There are currently no suitable control measures for outbreaks of ectoparasite infestation caused by fish lice (Argulus species) in freshwater fisheries. There is therefore an urgent need for novel solutions, such as chemotherapies that are suitable both environmentally and for human health, to avoid the devastating effects on this freshwater fishery.

Project specific enquiries should be directed to the lead supervisor, Professor Rod Wilson

Entry requirements

Applicants must demonstrate an outstanding academic record: at least a 2:1 undergraduate degree or equivalent, or relevant masters degree.

In addition to your academic record, selection will be based on the following criteria:

  • Why you are keen to pursue a freshwater bioscience PhD
  • What experience you have of freshwater research and interdisciplinary work
  • Whether you have the necessary personal and academic skills to complete a PhD project
  • Whether this scheme is suited to you and likely to best contribute to your career.

English requirements
If English is not your first language you will need to have achieved at least 6.5 in IELTS (and no less than 6.5 in any section) by the start of the programme.

How to apply

You will need to complete an application to the GW4 FRESH CDT for an “offer of funding”.

Please complete the application form at also sending a copy of your CV and a covering letter to the CDT by 9:00 on 16th December 2019.

After the closing deadline all applications and CVs will be forwarded to the lead Supervisor of the project(s) you have selected. They will interview you at a mutually convenient date in January 2020 (tbc) and submit their preferred candidate to FRESH CDT.

Shortlisted candidates will be invited to a panel interview in Cardiff in the week commencing 17th February 2020.  Further details will be included in the shortlisting letter

For further details regarding the application process please see the following web page

You do NOT need to apply to the University of Exeter at this stage - only those applicants who are successful in obtaining an offer of funding from the DTP will be required to submit an application to study at Exeter.

Data Protection
During the application process, the University may need to make certain disclosures of your personal data to third parties to be able to administer your application, carry out interviews and select candidates.  These are not limited to, but may include disclosures to:

  • the selection panel and/or management board or equivalent of the relevant programme, which is likely to include staff from one or more other HEIs;
  • administrative staff at one or more other HEIs participating in the relevant programme.

Such disclosures will always be kept to the minimum amount of personal data required for the specific purpose. Your sensitive personal data (relating to disability and race/ethnicity) will not be disclosed without your explicit consent.


Application deadline:16th December 2019
Value:3.5 year studentship consisting of full UK/EU tuition fees, as well as a Doctoral Stipend matching UK Research Council National Minimum (£15,009 for 2019/20)
Duration of award:per year
Contact: PGR Enquiries