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by instinct turns quickly in the direction in which 

 it has last come where it was not frightened ; a 

 frightened ascending fish goes down, and a frightened 

 descending kelt goes up. In a small stream, how- 

 ever, escape by ascent is scarcely possible, and a 

 forced departure from the course prompted as natural 

 must only heighten and complete the alarm and 

 demoralisation of the creature. In the small streams 

 of the West Highlands the kelts which quickly and 

 naturally descend recover condition in the brackish 

 water at the mouths of the streams. If driven from 

 such a haven of refuge by fear or any other com- 

 pelling cause, recovery may be sought in fresh water 

 elsewhere. 



It does not always follow that fish caught in the 

 sea at a considerable distance from their breeding 

 river will not return thither. Yet in the search for 

 food and the following of herring shoals it is not 

 surprising that some fish may lose their bearings. 

 In the drift-net fishing for salmon which is conducted 

 off the coast of Ireland, nets appear to be shot at 

 times as far as eighteen miles from shore, and if fish 

 wander, say double or treble this distance, as salmon 

 marking shows us they sometimes do, they may 

 naturally resort to other rivers than were formerly 

 visited ; or, as has been suggested, some fish may 

 systematically wander to rivers commonly frequented 

 by larger fish, rather than return, after growth in 

 the sea, to the rivers of their youth. In the salmon 

 marking results we do not, however, find much evi- 

 dence of this. The numbers caught in bag -nets on 

 the open coast at a considerable distance from the 



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