Skip to main content


Loading content

Jennifer Finlay

PhD student

 Geoffrey Pope 202


Geoffrey Pope Building, University of Exeter , Stocker Road, Exeter, EX4 4QD, UK


My research aims to improve the sustainability of salmonid aquaculture. During my undergraduate degree my research focused on the effects of plant-based diets on Atlantic salmon and rainbow trout, specifically how gene expression differed between salmonids that consumed a carnivorous diet and a plant-based diet.

Now, I am on a 4 year BBSRC SWBio DTP studentship in partnership with Ocean Matters Ltd., looking to optimize the production of lumpfish (Cyclopterus lumpus), a cleaner fish used to reduce sea lice prevalence in salmon farms. I am looking at how the water chemistry in which lumpfish are raised affects their physiology and behaviour, and how farmers could manipulate water chemistry to improve growth and welfare, and their effectiveness as a solution to the sea lice problem in salmon farms.


Biological Sciences (MSci)



  • University of Exeter Doctoral College Postgraduate Conference 3 Minute Thesis people’s choice and judge’s winner (May, 2019)
  • University of Exeter College of Life and Environmental Sciences best talk (November, 2019)


Research interests

Broad research specialisms:

  • Aquaculture
  • Physiology and behaviour of fish
  • Environmental Chemistry

Research projects

Project Title: Using physiology to improve the health and sustainability of cleaner fish (lumpfish) production

Supervisors: Professor Rod Wilson, Dr Rob Ellis, Dan Phillips

Funding Body: BBSRC (SWBio DTP)

Project Description:

Sea lice are one of the main barriers within salmon aquaculture, limiting the future sustainable growth of the industry. Sea lice graze on salmon skin and mucus, opening the fish up to infection and osmoregulatory distress. Sea lice prevention and treatment costs the industry and its consumers > £ 700 million globally every year. Current treatments include the use of chemicals which can harm the environment and are decreasing in efficacy over time, and mechanical delousing which can harm salmon welfare. One solution is to use cleaner fish, which naturally and effectively graze sea lice off salmon without affecting salmon welfare. Lumpfish (Cyclopterus lumpus) can reduce sea lice prevalence in salmon farms by 97 % when stocked at 10 – 15 % in salmon farms.

To reduce the impact on wild stocks of lumpfish, they are increasingly being intensively farmed to meet increasing demand from salmon farmers. Ocean Matters Ltd. is the largest producer of lumpfish in the UK and operate as a recirculating aquaculture system or RAS. RAS are viewed as an environmentally friendly and biosecure way to farm fish; they are land-based and continually filter water to remove unwanted particles and microbes. Water can be treated multiple times which keeps water use low and biosecurity high. However, recirculated water can result in the accumulation of unwanted metabolites, including ammonia and carbon dioxide which can reduce growth and negatively impact welfare. Ammonia is treated by biofilters which contain microbes which detoxify ammonia to less harmful forms of nitrogen. However, elevated CO2 within RAS is still an issue, as removal of the CO2 produced by respiration is much harder than replacement of the O2 it consumes. The effect of elevated CO2 depends on the species, life stage, and other aspects of the water chemistry the fish are inhabiting.

Not much is known about the basic biology of lumpfish, and so we don’t yet know how elevated CO2 impacts their physiology and behaviour. My PhD project aims to assess the water chemistry at intensive RAS lumpfish farms, and evaluate how the prevalent water chemistry conditions, in particular high CO2,  influences their growth and welfare, and ultimately their qualities as cleaner fish after transportation to the salmon farms.  


Supervision / Group

Back | Edit Profile