Aspects of the conservation biology of Coregonus lavaretus in Britain

• Main Author: Etheridge, Elizabeth C.
• Published: University of Glasgow 2009
• Subjects: 591.7; QH301 Biology : QL Zoology : Q Science (General)
• Online Access: http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.512108

Conservation of phenotypically variable taxa such as the European whitefish (Coregonus lavaretus) can be particularly challenging. In this thesis it is argued that the recent designation of seven native C. lavaretus populations as three endemic species (C. clupeoides, C. stigmaticus and C. pennantii) by Kottelat & Freyhof (2007) are incorrect and cannot be substantiated with the results presented here. However, evidence for important infra-specific variation between populations has been found. Two native Scottish populations of C. lavaretus show considerable variation in morphology, trophic ecology and life history. The variation in these populations warrants protection, one conservation action becoming more commonly utilised in Britain is conservation translocation. It was found that there were significant differences between source and refuge populations in Scotland. The wisdom of using this conservation measure on a phenotypically plastic organism is discussed. Nevertheless the establishment of further refuge populations are considered to be a viable conservation action. Sub-structuring within the largest native Scottish population of C. lavaretus was not found. However, evidence of residence within certain basins of Loch Lomond was found through significant differences in muscle stable isotope signatures. Investigation was also made into the trophic ecology of other fish in Loch Lomond. It was found that brown trout (Salmo trutta) in Loch Lomond have a non-typical migration pattern and invasive ruffe (Gymnocephalus cernuus) now form an important part of the trophic ecology of this site. In Britain several whitefish populations have been invaded by ruffe, a species native to Britain, but not to these sites. An experiment is conducted into the protective ability against ruffe predation on C. lavaretus ova of substrates typical on spawning grounds. It was found that pebbles and gravel form the best spawning substrate. The impact this mortality may have on the life history of Loch Lomond C. lavaretus is discussed. Using information gathered in this study, recommendations for the management of Coregonus spp. are summerised. There is the potential for these recommendations to apply to other phenotypically plastic species that vary between sites such as Arctic charr (Salvelinus alpinus) and brown trout.