The Arctic Char, Salvelinus alpinus, in Ireland

Taxonomy
The famous Swedish taxonomist Linnaeus classified the arctic char in 1758 as Salvelinus alpinus. Two hundred and fifty years later in 1908 Tate Regan classified the char of Ireland, Scotland, England and Wales. He recognised 15 species, six of which were from Ireland. He differentiated species based on morphology, meristics and proportional lengths typical of taxonomic studies during this time. The pitfall in using morphological and meristic characteristics in taxonomy is that many are plastic and subject to environmental modulation. Nevertheless, based on gill ray, gill raker and scale counts and on the ‘strength’ of the teeth as well as the ratio of the head length to body length, Regan identified six Irish ‘species’ of arctic char.

They are as follows;

Cole’s Char Salvelinus colii Lough Eske, Co. Donegal

Coomasaharan Char Salvelinus fimbriatus Lake Coomasaharan, Co. Kerry

Gray’s char Salvelinus grayi Lough Melvin, Co. Leitrim

Blunt snouted Irish char Salvelinus obtusus Killarney Lakes, Co. Kerry

Scharffe’s Char Salvelinus scharffi EXINCT Loughs Ennel and Owel, Co. Westmeath

Trevelyan’s Char Salvelinus trevelyani Lough Finn, Co. Donegal

Most char in Ireland are of the Cole’s char type. There is little to separate the various types and Regan admitted that there was very little separating, for instance, Cole’s char and Trevelyan’s char. He also acknowledged that all six ‘species’ were forms of Salvelinus alpinus. But for his own reasons he felt the trinomial nomenclature unnecessary. This led to some confusion in later years with some workers misinterpreting the classifications as species distinct from arctic char.

The arguments centered on the taxonomy were put to rest by the definitive work of Andy Ferguson in 1981. Electrophoresis of tissue samples from seven lakes containing four of Regan’s species (S. colii, S. grayi, S. fimbriatus, S. trevelyani) showed that the char were of a more homogenous nature than brown trout, Salmo trutta, from a similar geographical range. This indicates that despite the high degree of variation in morphology and meristics the specimens analysed are in fact conspecific, probably derived from a common ancestor during the last ice age.

While it is worth noting that the taxonomy of arctic char is still an issue in North America and Japan where many races are vying with each other for recognition as a separate species, e.g. Sunapee, blue back trout, red trout, white spotted char etc., a more salient point is that not being a separate species does not confer less value on a population of organisms. The char of one lake, or country, are no less deserving of our attention and conservation efforts than those in another.