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PhD Studentships: Assessing and predicting the impacts of non-native fish parasites: From Hosts to Ecosystems

Josie Pegg

Bournemouth University

Supervisor(s): Robert Britton and Demetra Andreou

The global introduction rate of freshwater fish has doubled in the last thirty years, primarily through fish movements in the aquaculture industry. When fish are moved from their natural range and introduced into a new range, they are likely to be host to a number of parasites. Whilst some of these parasites might be lost during the introduction process, often some will remain. If transmitted to native species, infection consequences can include pathological damage and, potentially, modifications to host behaviour, fitness and energetics. Given that native parasites have recently been shown to play important roles in food webs through, for example, increasing connectivity, nestedness and robustness, then further introductions of parasites into ‘infectious food webs’ have potential to modify these food web properties.

My research explores this using three non-native fish parasites introduced into UK freshwaters in order to identify their consequences for individual hosts, assess how these scale up into population and community effects, and determine their modifications to the structure of the invaded food web. Three non-native parasites will be studied which represent groups with varying complexity in their lifecycles so that they can demonstrate how, for example, the number of hosts in the life cycle affects food web structure.

Ergasilus briani has a simple life cycle, involving host-to-host transmission in their preferred host species of roach Rutilus rutilus and common bream Abramis brama. Bothriocephalus acheilognathi has a complex life cycle involving intermediate hosts before their definitive fish host becomes infected, where the final host here is common carp Cyprinus carpio. Anguillicoides crassus also has a complex life cycle but it involves several paratenic hosts (in which the parasite remains immature) before being transmitted to its preferred definitive host, in UK waters the European eel Anguilla anguilla. Transmission to eels is often through predation of a paratenic host.

Using both field case studies and experimental mesocosms the consequences of these parasites for food web structure will be assessed using two principal methods: food web topology and stable isotope analysis.

My report on my attendance at the Canadian Conference For Fisheries Research 2014 is here.


Faculty of Science and Technology
Bournemouth University
Talbot Campus
PooleBH12 5BB

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