314 W. M. SHEARER 



(c) The seals now seem to be destroying the sahnon from outside the net. It 

 seems that when a seal detects a salmon in the net, it swims round the outside 

 until the salmon becomes cornered in the angle between the inscale and the 

 side of the net. The seal is then able to kill and even eat the salmon without 

 damaging the net. During the period the net was fishing at Boddin nearly all 

 the fish caught were either eaten or left in an unmarketable state. Very 

 similar results were obtained during the period the net was fished at Burn- 

 mouth. 



(J) The net was more difficult to fish than a normal bag-net principally 

 because the nylon became soft when wet so that it was very difficult to shake 

 fish from the corner of the fish court and through the additional curtain of 

 netting at the door especially in rough weather. 



When this work on net protection was started a number of suggestions 

 were made to the commercial netsmen. Some of them were adopted and 

 some commercial netsmen tested other modifications which they had devised 

 themselves. For example, at Goswick and Cheswick netting stations the 

 following modifications were made, either singly or in combination, to a 

 large proportion of the fly-nets, jumper-nets and bag-nets during I959- 

 {a) The fish courts were made of nylon twine. 



(b) Screens were stretched across the angles of the fish court so as to eliminate 

 the acute angle between the scales and the side walls of the net. 



(c) A curtain of big mesh netting was fixed, either all round the outside of 

 the fish court, or only along each side opposite the small scales. 



When fly and jumper nets were modified in the three ways just mentioned 

 the results were encouraging, in that damage to the net and damage to the 

 fish caught in it was much reduced or eliminated. If it proved necessary to 

 replace a modified net by a normal cotton net damage once more became 

 severe. With bag-nets similarly modified, however, the nets were undamaged 

 but the catch was damaged, remains of salmon being left in the net. This 

 would seem to show fairly conclusively that the seals are eating the salmon 

 through the net from outside. 



It therefore seems clear that seals can attack salmon in modified bag-nets 

 but not in modified fly- or jumper-nets. It is suggested that this difference 

 arises because, although a bag-net is taut at certain states of the tide, it is 

 slack at other times, whereas a jumper- or fly-net, because it is moored in a 

 different way is taut irrespective of the state of the tide. It is further suggested 

 that it is during the period the bag-nets are slack that seals damage salmon 

 within nets which have been modified to prevent the actual breaking of the 

 netting. Perhaps the seal can, by swimming round the outside of the net, 

 comer salmon in the fish court and then grasp the fish by taking both fish 

 and slack netting in its mouth. Because of the tidal effect on bag-nets it is 



