FISHING AT HOME AND ABROAD 

 in lakes. Many of these lakes have disappeared; others have lost their 

 char population owing to a variety of causes, such as high temperature, 

 the intrusion of pike or, as in Ullswater, mineral pollution. In course of 

 time, char became restricted in Britain and Ireland to comparatively 

 few lacustrine colonies, totally isolated and debarred from intercourse 

 from each other. It would be strange, indeed, if one of these colonies, 

 occupying for tens of thousands of years a mountain lake in Wales, did 

 not develop some variation in colour, form and even structure from fish 

 of a common ancestry confined for a like period in a mountain lake of 

 the Scottish Highlands and from others dwelling under very different 

 climatic conditions in a lowland lake in Ireland. 



So far, there is no difference between Mr Tate Regan and myself. We 

 agree that a considerable variation exists between char of different 

 colonies, and that these variations are constant within such colonies, 

 thereby constituting a distinct race. But where I must part company 

 with Mr Regan is in his assumption that these variations would persist 

 if the char of different lakes were exposed to the same environment. 

 Unless they did so persist through several generations, it is clear that 

 prolonged isolation in colonies has not prevailed to establish separate 

 species. Moreover his reasoning about char might be more convincing 

 had he not pursued a converse line of argument in regard to trout; classing 

 all forms of British freshwater trout as " pertaining to one variable 

 species," and accounting for the presence of trout in all the waters of the 

 Hebrides, Orkney and Shetland Islands, where no other freshwater fishes 

 —roach, perch, etc. — are found, by the hypothesis that these trout "have 

 been derived from the sea-trout, which have lost their migratory instinct 

 in different places and at different times."* 



Owing to the deep-water habits of the char, it would be difficult, if 

 not impossible, to demonstrate by experiment whether a Welsh torgoch 

 reared in Windermere would transmit to its posterity permanent features 

 distinguishing them from the native char of that lake; but the burden of 

 proof surely lies upon those ichthyologists who proclaim the Welsh race 

 to be a species distinct from the Windermere race. Having seen repeatedly 

 how rapidly trout alter their appearance under the influence of condi- 

 tions of soil, water -area and food, and how soon those that are brought 



*Freskwaler Fishes of the British Isles, p. 55-57. I have expressed elsewhere (see p. 7 n. ante) my belief that both 

 salmon and trout are natives of freshwater which have acquired the sea-goin^ habit, just as British brook-trout, 

 when acclimatized in New Zealand, acquire it. Apart from other considerations, this seems far more probable than 

 that trout which had acquired the habit of visiting the abundant food supply in the sea should ever relinquish it. 



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