72 THE SALMON. 



Itiill-trout is seen to be entirely independent of the sal- 

 mon and the grilse, being found in great multitude 

 M'here they are almost entirely absent, and vice versa. 

 ]^ow, if the grilse were a species as distinct from the 

 salmon, or Salmo solar, as is the bull-trout, should not 

 we find similar results, some rivers abounding with 

 grilse, yet almost without salmon ? But what is found 

 is not this, but the contrary : many or few grilse imply 

 many or few salmon. 



Mr. Mackenzie makes a sort of loose or partial denial 

 of this fact, by adducing the statement, that the Shin in 

 Sutherlandshire, a valuable salmon river, contains so few 

 grilses that they " are not calculated upon as part of the 

 commercial produce." But we have ascertained that 

 this statement, so inv as it is correct, is entirely explained 

 away l^y the fact that the Shin river is fished, not by 

 nets, but by a criiive, the hecks of which are of such 

 width as to permit most of the grilse to pass. This, of 

 course, accounts for the grilse forming a very small part 

 of the commercial value of the river ; but it does not 

 prove that few grilse frequent the river ; in point of fact, 

 they al)ound in much the usutd proportion to the salmon, 

 and as many as twenty have often 1)een killed by a 

 single rod in one day. Besides, the fact, which we do not 

 deny, that the proportion of grilse and salmon capturcd 

 varies greatly in a comparison between different rivers, 

 would not in the slio-htest invalidate our arsfument, 

 nor establish Mr. ]\Iackenzie's ; because the proportion 

 of captures of each kind is regulated not entirely l^y the 

 numbers of each frequenting the rivrr, Ijut by various 

 <^thor <'ivf'umstancos, l)oth artificial and natural. For 



