The Arctic Char Salvelinus alpinus (L.) Species Complex in Ireland: A Secretive and Threatened Ice Age Relict
2004
Igoe, Fran | Hammar, Johan
Members of the Arctic char Salvelinus alpinus (L.) species complex were most likely the first freshwater fish to colonise Ireland after the last Ice Age. Once widespread and anadromous, they now form isolated populations, confined to inland freshwater lakes with suitable habitat (welloxygenated clean water, gravel shores and adequate depth when in the presence of other fish species). Adapted to Arctic conditions, they are extremely sensitive to environmental changes within their range further south, in which Ireland lies. The greatest threats to their present survival in Ireland are interspecific interactions from introduced fish species, eutrophication, acidification and climate change. The rate of extinction of entire populations has increased over the last few decades, and immediate steps must be put in place to preserve our remaining discrete populations. As marginal populations at the southern edge of the species range in Atlantic Europe, Arctic char in Ireland potentially hold some of the oldest genetic material in western Europe for the species complex. Such populations may be an important source of genetic material for the long-term survival of the species. Isolated in their respective lakes/lake catchments since the last Ice Age, they are of both genetic and evolutionary interest to scientists. This paper draws attention to the limited ecological data available on Arctic char in Ireland and attempts to place Irish Arctic char populations in context with the rest of the species’ range. Where possible, recent information is given on the various aspects of the biology, distribution and current status of the species.
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