380 THE SALMON RIVERS OF SCOTLAND 



in years only recently passed some deadly netting used to be 

 practised. A fish-pass exists, and the in-coming tide flushes the 

 face of the dyke, but fish are naturally checked if the river is not 

 in running order. However, the Marquis of Ailsa has now entirely 

 discontinued the netting of the tidal water. 



The mouth of the Boon offers a rather peculiar question for 

 consideration. The action of the sea in throwing up gravel and 

 sand so acts upon the rather slanting entrance of the river that the 

 fresh water is gradually forced more and more northwards in its 

 direction. Floods, of course, assert themselves, but as the action of 

 the sea is incessant, and the correcting action of the river only very 

 intermittent, the general result is the slow turning northwards of 

 the river channel at its mouth. In defining the limits of estuaries 

 to such rivers as run directly into the sea on open beaches, as is the 

 case here, the Administrative Commissioners under the Salmon 

 Fisheries (Scotland) Act, 1862, commonly directed that a part of a 

 circle be drawn, with a specified radius, from a centre placed in 

 the centre of the channel at low- water mark. In this way a definite 

 estuary, inside the limits of which fixed nets could not be set, was 

 secured to a river with a shifting mouth. This was the first plan 

 adopted in the case of the Doon, but unfortunately it was not acted 

 upon, and in 1864 an estuary was laid down from fixed points on the 

 shore, viz. : " A Segment of a Circle of 400 Yards Eadius, drawn from 

 a Centre placed Half-way between the nearest End of the Two Eocks 

 on the opposite Sides of the Eiver Mouth. . . ." 



It is clear, therefore, that if fixed nets are fished close to the 

 northern limit of this estuary, and the river-mouth slowly shifts in 

 that direction, the real purpose of the estuary is slowly being 

 defeated. The mountain is coming to Mahomet. 



I have already indicated that spring fish are netted in the Upper 

 Doon. These fish enter the river at a quite early date some years, 

 the water-flow, plus the temperature, no doubt determining this to a 

 great extent. In 1907 a run of fish was noticed to enter as early as 

 8th January. In 1901 and 1902 the first spring fish were taken at 

 the opening of the fishing season on llth February. On other years 

 they are not present, apparently, till March, or even later. In 1908 

 the first fish was caught on 24th March. 



A great number of sea-trout also run the Doon and yield capital 

 sport in July. In some seasons, 1904 for instance, over 1000 sea- 

 trout may be taken by rod, and some of the fish are heavy weights. 



With regard to the total number of salmon taken in the season, I 



