Ecological consequences of non-native parasites for native UK fishes.

• Main Author: Pegg, Josie
• Format: Thesis
• Language: English
• Published: 2015
• Subjects: Brama; Anguilla anguilla; European eel
• Online Access: http://eprints.bournemouth.ac.uk/24515/; https://eprints.bournemouth.ac.uk/24515/1/Pegg,%20Josephine_%20PhD_2015.pdf

Introductions of non-native species can result in the release of their parasites. Although the majority of parasites are lost during the introduction process, those that do get released can spill over to native species and potentially result in pathological, physiological and ecological impacts. Whilst it is increasingly recognised that native parasites can play important ecological roles, the ecological consequences of non-native parasites remain unclear. Consequently, through study of three host-parasite models, this research investigated the ecological consequences of non-native parasites in UK freshwater fish communities through assessment of their effects on hosts (individuals to populations), and on food web structure. The three non-native parasite: host systems were Ergasilus briani and roach Rutilus rutilus and common bream Abramis brama, Bothriocephalus acheilognathi and common carp Cyprinus carpio, and Anguillicoides crassus and the European eel Anguilla anguilla. These parasites were chosen as they reflect a range of life cycle complexity in parasites. The pathology of each parasite was identified using histology, with E. briani having substantial effects on host gill structure, B. acheilognathi impacted the intestinal structure of their hosts, and A. crassus substantially altered the structure and functioning of the host swimbladder. Whilst infections of E. briani and A. crassus had minimal effects on the body size, growth and condition of their hosts, chronic infections of B. acheilognathi did impact the growth and condition of C. carpio when measured over a 12 month period. Differences in the trophic ecology of the infected and uninfected components of the host populations were identified using stable isotope analysis and associated metrics, and revealed considerable differences in the trophic niche breadth of the infected and uninfected fish. In the component infected with E. briani, their trophic niche was constricted, indicating diet specialisation and a shift to feeding on less motile food ...