582 FISHING NETS, WITH SPECIAL REFERENCE TO THE OTTER-TRAWL. 



foot-roge would cause the otter-boards to approach one another, and 

 thus effectually spoil the fishing. Instead, they use a series of "bobbins" 

 or rollers in place of the ordinary bosom of the ground-rope. These 

 are of two sorts — a large, about 15 in. in length by 12 in. in diameter, 

 and a small, about 6 in. by 4 in. The small rollers alternate with 

 the large, and serve for the fixing of the settings of the bosom. Each 

 roller has an iron " bush," i.e. a hollow tube through the centre, and 

 through this is threaded the iron wire which forms the core of the 

 ground-rope. Since these bobbins are not always in use, it is necessary 

 to have some arrangement by which they can be readily shipped and 

 unshipped, and this is done in the following manner. The ground-rope 

 is made in three pieces, and the central part, about 20 ft. long, is 

 shackled on to the wings. When the bobbins are to be used, it is 

 a simple matter to unshackle the ordinary bosom of the ground-rope, 

 and shackle on the wire rope with the bobbins. 



These add very little, if anything, to the weight of the ground-rope, 

 and are better able to surmount obstacles and break up the hard 

 material on rough ground. 



Havino; thus described the structure of the otter-trawl in detail, 

 it may be of interest to compare it more particularly with other forms 

 of trawls, so as to display wherein its advantages and its limitations 

 lie. It has been shown that the otter-trawl and the beam-trawl are 

 alike in the structure of the bag, batings, pocket, and cod-end, and 

 in having a large square projecting in front. In these particulars they 

 differ from all other forms, and show a distinct improvement. The 

 advantage of the square is that the fish which are feeding on the 

 bottom fauna are well into the net before being disturbed by the 

 ground-rope. If the latter is in advance of the head-line or on a 

 level with it, as in the filets de hcenf and Petersen's trawl, for example, 

 very few of the swifter forms will be captured. Such has been our 

 experience during the past year. The first trawl employed on the 

 Association's steamer Oithona had a square only 8 ft. long, and whilst 

 it was an excellent instrument for catching plaice and soles, it was 

 useless, comparatively speaking, for whiting. They were caught, but 

 in no great quantity. Later, when a 24-foot square was used, the 

 whiting were well represented. As pointed out by Dr. Fulton,* the 

 presence of long wings, and, I may add, the absence of a square, is 

 one of the serious defects of Petersen's trawl. 



The advantage of the flapper and pockets, and of the mode of fixing 

 the net which makes them functional, is that once the fish are in 

 the bag of the trawl they cannot escape. In the Jilets de bceuf and 

 similar nets of the Mediterranean, the bag is exceedingly long, and 



• Aim. Report Scot. Fishery Board, xx. p. iii. p. 329. 



