n6 f. day: periods of migration. 



Isles, than they do along the west coast, presumably because the Atlantic 

 is warmer than the German Ocean ; while among the latest rivers 

 they ascend are those of Devonshire and Cornwall, where the tempera- 

 ture of the sea is the highest. 



With the object of attaining the estuaries or mouths of rivers up 

 which they purpose ascending, salmon in small assemblages or schools 

 keep along the shore, only a short distance from land, swimming 

 rather high in the water, and betraying their presence by occasionally 

 leaping out of the sea as if they were endeavouring to reconnoitre 

 their way, or else they throw off a ripple in a calm as they move along 

 the surface ; while, as Mr. Sinclair remarks, their tracks are as well 

 known as those of cattle returning to the farmyard. Mr. D. Mackenzie 

 has also observed that along the coasts of Scotland salmon shoals 

 pass a short distance from the land, and 1 when a shoal meets with a 

 stake net some of the fish are caught in the traps or cruives, or what 

 are called its chambers, others start off; in short, the shoal is broken 

 and dispersed. The scattered fish, however, always guided by their 

 instincts, gather in again to the land, singly or in groups, and continue 

 their course with the tides, until they meet with another similar 

 engine, when the same capture and dispersion is repeated.' While 

 packs of Seals, Porpoises, Grampuses, and other enemies have been 

 observed to deter salmon from entering rivers, and also to break up 

 and scatter the shoals of fish. 



Salmon appear to possess a homeing instinct which induces them 

 to endeavour to return to the river where they were originally reared, 

 but instances are occasionally brought to notice when such could 

 not have been the case. Thus almost yearly we hear of a grilse or 

 of a salmon being captured off the mouth of the Thames or Medway, 

 sometimes even attempting to ascend, but from which localities all 

 these fish have long since been destroyed ; consequently they could 

 not be descended from eggs hatched in those rivers. 



Buckland recorded how a friend of his, who owned a well-known 

 island on the west coast of Scotland, netted a certain pool in his 

 fishery, and out of a number of fish which he captured he marked 

 twenty or thirty. He then put them on board his yacht, where they 

 were kept alive,' and he sailed with them almost round his island, 

 then up a creek to the mouth of a river, and turned them into a lake 

 about half a mile from the source of the stream from which they had 

 been originally captured, but with which it was in no way connected, 

 the two rising from different watersheds. It was as though the 

 salmon had been carried from one heel of an enormous horse-shoe 

 round to the other heel, and then taken right into the middle of the 

 horse-shoe, and there let loose. During the same season some of 



Naturalist, 



