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Living with the enemy in a warmer, polluted and changeable world: how do multiple stressors interact to influence host-parasite interactions in fish

Project supervisors: Dr Iain Barber - Department of Neuroscience, Psychology and Behaviour

Co-supervisor: Dr Will Norton, Department of Neuroscience, Psychology and Behaviour

University of registration: University of Leicester

Non-Academic partner: Dr Ioanna Katsiadaki (Cefas)

Project title: Living with the enemy in a warmer, polluted and changeable world: how do multiple stressors interact to influence host-parasite interactions in fish

Project outline:

Fish populations face a wide range of natural stressors, including parasite infections, whose effects are now augmented by anthropogenic environmental changes. Even in isolation, parasites have obvious potential to influence the health, reproduction and ultimately survival of host fish. However, the effects of infection can be exacerbated under changed environmental conditions. In a previous BBSRC-Cefas CASE studentship, we showed that elevated temperature and endocrine-disrupting pollutants can lead to more severe infection phenotypes among parasitised fish [1-4]. However, whilst the effects of anthropogenic stressors on host-parasite interactions are typically studied individually and in isolation, fish inhabiting degraded environments experience multiple anthropogenic stressors in concert, with additive, synergistic or antagonistic interactions potentially generating severe effects on populations. As yet, little is known about how multiple stressors affect host-parasite interactions in fish. Importantly, whilst the effects of individual stressors on host-parasite interactions may only be apparent at relatively high treatment levels, it is possible that stressors may combine to generate significant impacts at levels that are regularly encountered in degraded environments.

This project will utilise two experimental fish models - the 3-spined stickleback and the zebrafish - to test the hypothesis that environmental stressors have interactive effects on both the susceptibility of fish to parasite infections, and on the infection phenotypes that emerge among parasitised fish. We propose to carry out controlled dosing experiments in which lab-bred fish are held under a range of controlled environmental conditions, under normal or elevated temperatures, and with or without exposure to a one of range of chemical pollutants at environmentally relevant concentrations (including heavy metals, endocrine disrupting chemicals, and treated sewage effluent). In the first type of experiments, the effects of single and paired stressors on infection susceptibility (which will be measured using both immunological profiling and controlled exposure to infective stages of experimentally-amenable helminth parasites (Schistocephalus and Diplostomum). In the second type of study we will first expose fish to parasites and then study the effects of altered post-infection environmental conditions on the infection phenotypes that emerge.

Our results will represent the first rigorous experimental test of the hypothesis that multiple anthropogenic stressors can interact to significantly influence host-parasite interactions in fish. Since we will expose fish to combinations of environmental stressors that are encountered together in degraded environments, our study will be provide the first data on how stressors combine to influence the ecological impacts of parasitism in changing environments.

Closing date for applications: 8th January 2017

Check eligibilty and apply here

Please note:

iCASE students must fulfil the MIBTP entry requirements and will join the MIBTP cohort for the taught modules and masterclasses during the first term. iCASE students can then start their PhD project in Jan 2018 but must complete a 3-month miniproject (at a non-home institution) before the end of their first year. They will remain as an integral part of the MIBTP cohort and take part in the core networking activities and transferable skills training. MIBTP iCase.