of the Fishery Board for Scotland. 329 



rough, even if they are provided with hinges to fold up. Dr. Hjort 

 mentions also a pelagic otter-trawl as part of the equipment of the 

 Michael Sars, but states that it was little employed during the cruise. 

 The pelagic otter-trawl was introduced as an instrument of marine 

 research by the Prince of Monaco, and it is in this apparatus, I believe, 

 that we shall find what is desiderated. The ordinary otter-trawl, fitted 

 with fine-meshed netting, might itself be used for the purpose, but it 

 has the disadvantage that the lower part of the net lies far behind 

 the upper part, and fish disturbed and striking downwards (as they do) 

 may escape capture. It is well-known that a steam trawler by going 

 full speed aliead can lift the otter-trawl from the bottom, and I made use 

 of this fact for pelagic fishing, having the small-meshed (6 mm.) net 

 around the cod-end of the trawl and the head-line buoyed with a series 

 of " pallets " or large floats, the heavy ground-rope hanging down 

 keeping the mouth of the net open. It was towed for three-c^uarters 

 of an hour in GO fathoms off Aberdeen, with 85 fathoms of warp out, 

 but as the experiment was made in January, only three small fishes — a 

 sprat, a post-larval herring, and a post-larval flat-fish — were taken. 

 Judging from the efiiciency of the net in capturing small fishes on the 

 bottom, I think its use in this way in raid-water in summer and 

 autumn, when" pelagic forms are numerous, Avould be successful. 



There is another disadvantage in the ordinary otter-net employed as 

 I have described, both for bottom fishing and for pelagic fishing. While 

 the number of fishes taken by it in the former case has been proved 

 by practice to be large, and sufficient for the assortment of the diflerent 

 generations and the determination of the rate of growth, it is evident 

 that it does not furnish the real numerical proportion of the various 

 generations or series. The small-meshed net envelopes oidy a part of the 

 otter-trawl, and although it is the most important part, into which the 

 great majority of fishes, unless the smallest, are probably guided, there 

 can be no doubt that large numbers of small fish escape from the 

 otter-trawl before they reach the cod-end, i.e., through the still larger 

 meshes of the back and sides. Thus the smaller fishes — the earlier 

 generations — are not duly represented. For scientific purposes, such as I 

 have referred to, it would be desirable to employ a special otter-trawl of 

 somewhat smaller dimensions than the large ones used on steam trawlers, 

 made of hemp with smaller meshes, and entirely enveloped in a fine- 

 meshed net, a canvas chafer being used below it and the cod-end buoyed. 

 Experience has shown that the fine net is less liable to injury when 

 placed outside the hemp-net than when within it, in which case con- 

 stant friction takes place between them. With a net of this kind the 

 due representation of the smaller series would be much more complete. 



In this connection I may refer to a net which has been much used by 

 Dr. Petersen in Denmark and elsewhere on the Continent, and which is 

 fully described in one of the reports of the Danish Biological Station.* 

 It is an otter drag-seine, consisting of a seine used in eel-fishing with otters 

 attached to the wings to spread it. The net has given good results in Dr. 

 Petersen's hands, but it seems to me from the figures and description not 

 only to have no advantages over the otter-trawl net, but to have a con- 

 siderable disadvantage from the presence of the two long wings attached 

 to the mouth of the bag, which must disturb fish on the bottom before the 

 net is over them. The disadvantage in regard to flat-fish is not so great 

 as with respect to round fishes, because when disturbed they do not, as a 

 rule, rise high above the bottom, but I think that with this net a large 



*Eighth Report, Copenhagen, 1899. 



