Home » People » Dr Fran Hockley

Dr Fran Hockley


Fran CUSACI graduated in July 2009 with a degree in Ecology from Cardiff University which included a Professional Training Year (PTY) at the Centre for Environment, Fisheries and Aquaculture Science (Cefas). During this year I surveyed diseases in crayfish, including both the native white clawed crayfish Austropotamobius pallipes (Longshaw et al. 2012)and the introduced American Signal Pacifastacus leniusculus, Virile Orconectes virilis, and Turkish Astacus leptodactylus, crayfish (Longshaw et al., 2012). I also surveyed tropical crayfish which had been seized at UK borders, illegally imported for the aquarium trade. For my final year project I studied the host specificity and microhabitat of a monogenean parasite Onchocleidus dispar in the introduced pumpkinseed fish Lepomis gibbosus (Hockley et al., 2011). After graduating I worked for the Shellfish Hygiene Statutory team at Cefas. In this role I surveyed new shellfish farms in Scotland and produced reports with the aim of designating a sampling point for classification of the new site to ensure that the shellfish are safe for human consumption. I then started my PhD in October 2010, in collaboration with Cardiff School of Engineering, and funded by BBRSRC with CASE support from Cefas. My PhD is entitled “Modification of fish behaviour by parasites under variable flow conditions”.




Telephone: +44(0)29 208 76907

Extension: 76907

Location:  Cardiff School of Biosciences, The Sir Martin Evans Building, Museum Avenue, Cardiff, CF10 3AX Room: C7.07


Supervisors: Professor Jo Cable (Cardiff School of Biosciences), Dr Catherine Wilson (Cardiff School of Engineering), Dr Matt Longshaw (Fish Vet Group) and Dr Nick Taylor (Cefas)

Funding: BBSRC with CASE Partner Cefas

Flume lab

My research focuses on native and introduced parasites and their impact on swimming and social behaviour of fish hosts within a dynamic environment. The key aims are to better understand the direct and indirect effects of parasites on their host and improve our knowledge of swimming behaviour of fish in riverine environments with unidirectional flow. My work is divided between the aquarium facilities in the Organisms and Environment Division in the School of Biosciences and the Hydro-environmental Research Centre  in the School of Engineering.

Parasites affect the behaviour and fitness of riverine fish. This is well established from both laboratory and field studies, and yet most laboratory studies have been based on static flow conditions. In their natural environment, riverine fish are subject to heterogeneous flow velocities and turbulence, and may use this to their advantage by selecting regions which balance energy expenditure for station holding whilst maximising energy gain through feeding opportunities. The ability of fish to maintain position or swim against a current is an essential survival requirement in rivers to avoid being washed downstream or reach migration destinations. In my projects, I aim to bridge the gap between static flow tank conditions and field experiments by using artificial flumes in the Hydro-environmental Research Centre to demonstrate the importance of considering flow velocity and turbulence when investigating fish health.

001Many parasites have developed the ability to manipulate host behaviour in order to increase transmission rate, survival or longevity. For example, parasites which are transmitted in the food chain can alter the host behaviour by making them more susceptible to predation by definitive or intermediate hosts. On the other hand, the hosts may alter their behaviour in order to rid themselves of the parasites (for example by grooming), or to compensate for the metabolic drain induced by the infection. The degree to which host behaviour is changed may be dependent on the intensity of infection rather than simply the presence of a parasite. In addition, co-infections with more than one parasite species may have differing effects on host behaviour than the individual species acting alone

Fish commonly experience turbulent and changing flow rates in rivers throughout their lifetime, and adapt their swimming behaviour in order to maintain position or to migrate up- and downstream.  The three recognised modes of swimming; sustained, prolonged and burst swimming, is used interchangeably by fish, and are ecologically important in influencing migration, feeding, growth, predator evasion, inter- and intraspecific competition, and reproduction.  Open channel flumes can be used in the laboratory to study various aspects of swimming behaviour, and can be adjusted to vary depth, flow rate, substrate and generate hydrodynamic perturbations using stationary objects.

I will be using various host and parasite study systems to investigate the effects of parasites on host behaviour under turbulent flow conditions. These include commonly used model systems (guppies and sticklebacks) and a species of major conservation importance European eel Anguilla anguilla.

Current studies include:

  • Effect of parasites on the shoaling behaviour of guppies under static and flow conditions (Hockley et al. 2014a)
  • Turbulence and velocity utilisation of guppies Poecilia reticulata in relation to parasite load (Hockley et al. 2014b)
  • Effect of flow condition on the transmission of Gyrodactylus turnbulli infecting the Trinidadian guppy (in prep)
  • Burst swimming performance of sticklebacks Gasterosteus aculeatus in static and flow conditions in relation to natural parasite load (in prep)
  • Utilisation of turbulent bed boundary layer by sticklebacks to improve critical swimming performance (in prep)
  • Swimming behaviour of European eels Anguilla anguilla infected by an invasive swim bladder parasite Anguillicoloides crassus gill parasites Pseudodactylogyrus spp.  (submitted)

I am a member of the British Ecological Society (BES) and British Society for Parasitology (BSP), for which I have presented at their annual meetings since the start of my PhD. I have recently been elected onto the committee for the IAHR (International Association for Hydro-Environment Engineering and Research) Cardiff University Student Chapter. I am also interested in Marine conservation and biodiversity, and as a member of the Marine Conservation Society (MCS) I volunteer as a ‘Sea Champion’ to help support the MCS at a local level.


Hockley F.A., Wilson C.A.M.E., Graham N., Cable J. (2014a) Combined effects of flow condition and parasitism on shoaling behaviour of female guppies Poecilia reticulataBehavioural Ecology and Sociobiology 68:1513-1520.

Hockley F.A., Wilson C.A.M.E., Brew A., Cable J. (2014b). Fish responses to flow velocity and turbulence in relation to size, sex and parasite load. Journal of the Royal Society Interface 11: 20130814.

van Oosterhout C., Mohammed R.S., Xavier R., Stephenson J.F., Archard G.A., Hockley F.A., Perkins S.E., Cable J. (2013). Invasive freshwater snails provide resource for native hermit crabs. Aquatic Invasions 8: 185-191.

Longshaw M., Stebbing P.D., Bateman K.S., Hockley F.A. (2012) Histopathological Survey of pathogens and commensals of white-clawed Crayfish (Austropotamobius pallipes) in England and Wales. Journal of Invertebrate Pathology 110: 54-59.

Longshaw M., Bateman K.S., Stebbing P., Stentiford G.D., Hockley F.A. (2012) Disease risks associated with the importation and release of non-native crayfish species into mainland Britain. Aquatic Biology 16: 1-15.

Hockley F.A., Williams C.F., Reading AJ.., Taylor N.G.H., Cable J. (2011) Parasite fauna of introduced pumpkinseed fish Lepomis gibbosus: first British record of Onchocleidus dispar (Monogenea). Diseases of Aquatic Organisms 97: 65-73.

International Conference presentations

Hockley FA, Wilson C, Brew A, Graham N, Cable J (2012) Effect of flow, host size and parasitism on fish behaviour. British Ecological Society Annual Meeting, University of Birmingham, UK. Oral presentation 17th – 20th December 2012.

Hockley F.A., Wilson C., Graham N., Cable J. (2012) Effects of flow dynamics and parasitism on shoaling behaviour in guppies. Cefas Student Day, Weymouth, UK. Oral presentation 12th April 2012.

Hockley F.A., Brew A., Graham N., Wilson C., Cable J. (2012) Flow dynamics and parasitism affects swimming behaviour in the guppy Poecilia reticulata. British Society for Parasitology Spring Meeting, University of Strathclyde, Glasgow, UK. Poster presentation 2nd – 5th April 2012

Hockley F.A., Eakins L., Kemp P., Williams C.F., Reading A., Cable J. (2011) Influence of parasite burden on European eel swimming behaviour. British Society for Parasitology Spring Meeting, University of Nottingham, UK. Oral presentation 11th-14th April 2011