48 Sir W. Jardine on the Common Salmon. 



and weight exactly agrees with that of the grilse upon their first 

 running elsewhere; and I think that very few attempt to enter the 

 rivers before attaining a weight of 3 lb. These marked grilse were 

 unfortunately killed ; but next year it is proposed to return them 

 again to the river, with an additional mark, and endeavour to 

 retake them a second season. Several other experiments are also 

 proposed, and as the nature and situations of the rivers present 

 every facility, I have little doubt of their success. 



Some rivers are what are called early, others late ; or, in other 

 words, the clean or high conditioned salmon commence to ascend 

 in spring, and the fish come into breeding condition, and begin 

 to spawn at an earlier period. The causes influencing this seems 

 yet undecided ; and where the time varies much in the neigh- 

 bouring rivers of the same district, they are of less easy solution. 

 The northern rivers, with little exception, are, however, the ear- 

 liest (a fact well known in the London markets) ; and going still 

 farther north, the range of the season and of spawning may be 

 influenced by the latitude. Artedi says, " In Sweden the sal- 

 mon spawn in the middle of summer." 



It has been suggested that this variation in the season de- 

 pended on the warmth of the waters, and that those highland 

 rivers, which arose from large lochs, were all early, owing to 

 the great mass and warmer temperature of their sources, that 

 the spawn there was sooner hatched. There are two rivers 

 in Sutherlandshire, which shew this late and early running 

 under peculiar circumstances. One the O'lkel, borders the 

 county, and springs from a small alpine lake, perhaps about 

 half a mile in breadth ; the other, the Shin, is a tributary to the 

 O'lkel, joins it about five miles from the mouth, but takes its rise 

 from Loch Shin, a large and deep extent of water, and connected 

 to a chain of other deep lochs. Early in the spring all the sal- 

 mon entering the common mouth, diverge at the junction, turn 

 up the Shin, and return as it were to their own, and warmer 

 stream, while very few keep the main course of the Oikel, un- 

 til a much later period. 



It is a mistaken opinion to suppose that the spawning season 

 is only between October and February. In many rivers it would 

 commence in the end of August, if the grounds and entrance to 

 the rivers were left open and unmolested ; and in some of the 

 Sutherland streams which have been left undisturbed for the last 



