During conversations with fishermen it appeared often that 

 they were well aware of the advantages of larger meshes o Therefore, 

 we certainly believe that they will begin to use larger meshes when 

 the small fish loses its value© This tendency is clearly shown by 

 the "snurrevaad** fisheryo They make such good hauls that they hardly 

 bother with the small plaice and are only too glad to save the labor 

 of picking the nets by the use of increasingly larger cod ends • 



The end conclusion undoubtedly must be that enlarging of the 

 mesh size is an effective means of protection for young fisho 

 However, there is one difficulty and that is that this effect is 

 lessened by an increase of the towing speedo If, for instance, 

 the whole fleet were fishing a certain sea and a certain minimtan 

 mesh width was ordered, the faster ships would catch more undersized 

 fish than those ships which towed slowero Moreover, by using a very 

 large mesh, the latter would lose small marketable fish which did not 

 get a chance to escape in nets which were towed faster<, 



bbo Special Devices to Promote the Escape of Undersized fish 



Several tests have been made with trawl nets fitted vrith devices 

 to facilitate the escape of undersized fisho 



Insofar as these nets are used exclusively for the catching of 

 roundfish, the device is aimed to make the selection curve steeper© 

 To this end, stiffeners were attached to the nets to decrease the 

 tension on the meshes in a lateral directiono These improvements 

 were effective during tests made on board American trawlers 

 (Herrington, 1935) but we did not receive the impression that they 

 came into general usco Another improvement was tried with the so= 

 called Rowton-Streamline=trawl, which was constructed in such a way 

 that the flow of water would force open the meshes o Neither did 

 this trawl come into general use© 



Another savings trawl was designed to let the undersized flat=» 

 fish (which are far wider than roundfish of the same length) escape 

 without loss of the oversized roundfisho Special panels with 

 irregular meshes {usually elongated meshes) were made in the nets 

 (Ridderstad=trawl, Gelder- trawl) while sometimes devices were fasten- 

 ed onto the trawl to make the meshes stand open (Ridderstad, 1915 | 

 Gelder, 1929) o Several tests have been made with these trawls 

 (Buchanan-=Wollaston, 1929j Davis, 1930| BQckmamis 1931) o With this 

 method, greater numbers of undersined flatfish could escape generally© 

 They were, however, very much harder to handle and the chance of 

 damage was considerably greater© The existing forms of "savings 

 trawls* certainly cannot be said to give a solution to the problem© 



Protection methods increase the density of the fish stock with 

 a consequent decline in the rate of growth© A decline in the rate 

 of growth will result from protecting the undersized fish by enlarg- 

 ing the chances of escape through the use of larger meshes, Conse= 

 quently the fish remain undersized longer and the chance i;hat they will 



