The Scottish Naturalist. 227 



ON THE "YELLOW FINS" OF THE ALLAN-WATER. 



By W. C. M'INTOSH, M.D., F.R.S.E., F.L.S. 



CO little notice has been taken in the Tay of any species of 

 *^ fish but the salmon, that public attention has been some- 

 what removed from the question of the young of the salmon- 

 trout and other migratory forms. Especially has this been the 

 case in the Allan- water, where many anglers seem to have cap- 

 tured the " yellow fins " as legitimate fish, confounding them 

 with the common river- or "yellow" trout. So sure were 

 certain experienced anglers of the correctness of this opinion, 

 that they viewed the silvery coating assumed by the " yellow 

 fins " as only a temporary garb, which was afterwards thrown 

 off, the fish becoming very like the common trout, and being 

 present in the Allan-water at all seasons, — a conclusion, as we 

 shall afterwards see, not without some foundation. 



Before entering into the special case of the Allan-water, it 

 may be mentioned that the obscurity, in certain respects, which 

 still envelops the history of the salmonoids, is not confined only 

 t:o the public; for Widegren, after an examination of Scandina- 

 vian types, and Malmgren of those of Finland, have asserted 

 that the migratory, lacustrine, and fluviatile forms of Europe are 

 mere varieties of the same species, capable of inter-breeding and 

 producing fertile hybrids ; an opinion which has been recently 

 supported by Rasch. Dr. Albert Giinther, however, than whom 

 no living man has greater experience in the structure and 

 arrangement of fishes, inclines to an opposite view, and, in the 

 present state of science, his judgement is most to be relied on. 



In the Allan-water salmon are comparatively rare, whereas 

 salmon-trout are not uncommon ; and the Fishery Board of the 

 district, knowing that the "yellow fins" are really migrator) 

 fishes (the young of sea-trout), and, of course, wishing to carry 

 out the intention of the Act for the preservation of fishes of 

 the salmon-kind, found it necessary that the public should un- 

 derstand that the capture of the so-called " yellow fins" was 

 really an infringement thereof ; as, indeed, the Tweed Commis- 

 sioners had done before them. The legal aspects of this ques- 

 tion do not concern us, and we shall therefore proceed to glance 

 at the relations of the "yellow fins" (a term synonymous with 

 11 orange fins") to the salmon-trout and other migratory fishes. 



