The status of Arctic charr Salvelinus alpinus in Britain and Ireland

Abstract

– The Arctic charr occurs in lakes across Britain and Ireland and was previously described here as 15 separate species. Most authorities now agree that all these stocks belong to a single polymorphic species complex Salvelinus alpinus (L.). This fish is given little protection in British and Irish law and there has been a steady loss of natural populations in recent years in all the countries concerned. A few new stocks have been created either intentionally or accidentally. In Scotland, only a small proportion of the 258 recorded natural populations has been studied and at least 12 of these are now extinct. There are at least four introduced populations originating from native Scottish stocks, but the fate of stocks introduced from Canada for aquaculture is uncertain. In England, there are eight extant populations in Cumbria and four others extinct. The status of introduced stocks in England is uncertain but there is probably one population surviving in Yorkshire. In Wales, eight lakes with resident Arctic charr populations have been recorded, three of these populations are natural, one is extinct and four have been introduced. In Ireland, of the 74 known populations, approximately 30% are extinct. There is no evidence to indicate that introduced stocks (some of them from Iceland) in a small number of lakes have survived there. A range of factors is involved in the extinction of populations and these include pollution, eutrophication, acidification, afforestation, engineering, exploitation, aquaculture, introductions and climate change. Much research remains to be done and unique stocks of this valuable species will continue to be lost unless positive action is taken through local conservation management backed by appropriate national legislation.

The Arctic charr (Salvelinus alpinus) populations of Windermere, UK: population trends associated with eutrophication, climate change and increased abundance of roach (Rutilus rutilus)

“…Within Britain and Ireland, a recent review of the status of Arctic charr by Maitland et al (2007) identified pollution, eutrophication, acidification, afforestation, engineering, exploitation, aquaculture, introduction of alien species and climate change as specific threats to this species. Understanding the impacts in Windermere of eutrophication, climate change and the recent roach expansion, following its introduction c. 100 years ago, thus has a generic importance beyond informing local conservation and fisheries management.…”

Population trends of Arctic charr (Salvelinus alpinus) in the UK: assessing the evidence for a widespread decline in response to climate change

“…However, in a recent review of the status of this species in Britain and Ireland, Maitland et al (2007) noted that in Scotland at least 12 of 258 such populations are now extinct, as are 4 of 12 native populations in England and 1 of 3 native populations in Wales. Northern Ireland possesses only one native population which is still extant as far as is known.…”

Hydroacoustic quantification and assessment of spawning grounds of a lake salmonid in a eutrophicated water body

“…Furthermore, the quality of such limited spawning areas is particularly sensitive to the local deposition of fine sediments and as a result the widespread environmental problem of eutrophication has frequently led to declines in recruitment and even to the local extinction of a number of lithophilic species (e.g. Maitland et al, 2007;Winfield et al, 2012;Winfield et al, 2013).…”