20 THE LIFE OF THE SALMON 



to make arrangements for a series of observations 

 by means of a boom-net used in fishing for sparlings 

 or smolts (osmerus). This net is worked from a 

 smack anchored in the channel ; the mouth when 

 extended by its booms and the pressure of the 

 current is 24' x 18'. Operations were commenced a 

 short distance below the mouth of the Earn, where 

 we had on the previous season lost trace of the 

 smolts, and were continued down the estuary at 

 intervals till a point was reached below the Tay 

 Bridge and opposite the city of Dundee, the essential 

 feature being the working of the net in the channel 

 or fairway. This fishing yielded most interesting 

 results. The net was set forty-six times, and salmon 

 smolts were now captured freely. Some 1085 young 

 salmon ids were taken, and the great majority of 

 these were salmon smolts, the others being sea 

 trout. 



Two points were specially noticeable : 



1. As the descent of the estuary was made, the 

 size of the salmon smolts did not increase. 



2. All salmon smolts captured were taken when 

 the net was set so as to fish the ebbing tide. When 

 the net was set so as to fish the flood tide or incoming 

 current sea trout were alone taken, and many of 

 these were nearly twice the size of the salmon smolts. 

 Sea trout were also taken during ebb tide. 



The natural inference from those observations 

 seems to be that, after congregating in great numbers 

 at the extreme upper limit of the brackish water, 

 the salmon smolts make a steady and comparatively 

 rapid descent to the open sea, without hanging about 



