2o6 DISCOVERY REPORTS 



organisms tend to be lifted most and consequently the silk net is placed in front and 

 the 7 mm. net nearest the cod-end. The precise positions for obtaining the best results 

 are easily found by experiment. It will be noticed that the nets must be specially shaped, 

 with the upper side longer than the lower, so that they may stream out properly when 

 the net is fishing. For the silk net an old tow-net may be used with the fore part cut 

 away obliquely at an angle of about 40°. This system of attaching fine nets to a trawl 

 was apparently first advocated by the late Dr E. W. L. Holt^ and deserves to be more 

 widely adopted. It can be employed equally well with beam trawls, but is of course 

 impossible with an Agassiz trawl, which is fitted with two foot-ropes and is designed 

 to fish either way up. Since Hjort has shown that a 40 ft. otter trawl can be worked 

 successfully even in mid-ocean, little can be said in favour of the Agassiz pattern, and 

 the impossibility of attaching fine nets is a very serious objection to its use. 



On board the ' William Scoresby ' the procedure in shooting the trawl is the same as 

 that used on commercial vessels and does not require description. In the ' Discovery ' the 

 trawl was shot first of all from the port side of the ship, where, by swinging one of the 

 life-boats on special davits, a length of clear rail had been provided between the main 

 and mizen rigging. This position was, however, inconvenient and it was found better 

 to shoot the net over the stern, with one board hanging on each quarter. If, when 

 using the warp on the port side, the starboard board was slipped a few seconds later 

 than the other, the trawl could always be shot clear. 



A 30 ft. beam trawl was carried in the 'Discovery' in addition to the otter trawl, 

 but the latter proved to work so well that it was not used. One of the 30 ft. nets was, 

 however, adapted for use with otter boards and was employed on a few occasions. 

 Small beam trawls, with beam 8 ft. in length and with i in. mesh (knot to knot) at the 

 cod-end, were carried on both vessels and were used mainly from boats in shallow 

 water, generally with a coarse silk net attached to the back. 



Rectangular Nets consist merely of a rectangular frame with a long bag of netting, 

 towed by four bridles : for all practical purposes they are identical with what is usually 

 called the D-net. Three sizes were taken : (i) with frame 8 ft. by 2I ft. with bag of | in. 

 mesh, (ii) with frame 4 ft. by i j ft. with bag of 7 mm. mesh, and (iii) with frame 3 ft. by 

 I ft. with bag of 4 mm. mesh. In the first of these the frame was made of flat steel, 2 in. 

 broad and ^ in. thick, with a series of holes along one edge for the attachment of the 

 net. In the other sizes the frame was of {^^ in. round galvanized steel, which proved rather 

 weak for the larger of the two. In these frames the ends were not welded, but were 

 connected by means of an eye on the one part and a screw thread and nut on the other. 

 The nets were attached to galvanized rings threaded on the frames. The two larger 

 sizes were used from the ' Discovery ' and coarse silk nets were sometimes attached 

 to them: the smallest was for work from boats. Nets of these types are efficient on 

 suitable ground, but were not used on many occasions. 



1 See Caiman, Fisheries, Ireland, Sci. Invest., 1904, i, p. 4 (1905). 



