84 



spectors of Fisheries have indeed made a laborious 

 analysis! of the figures obtained by the trawling experi- 

 ments of the Scottish Fishery Board, but this consists only 

 of a statistical re- arrangement of the data; the actual 

 conditions which might have influenced the catches were 

 not studied, and it appears to us that one of the methods 

 employed — that of reducing the total catches to numbers 

 of fish caught per mile trawled over — is fallacious, and, 

 when the small values dealt with are considered, likely to 

 lead to error. 



We have examined the results of the trawling observa- 

 tions made by our Fisheries steamer and by the bailiffs 

 with the object of determining how far the catch is 

 influenced by (1) the precise locality, (2) the tides, (3) the 

 form and dimensions of the trawl net, and the method of 

 using it. It is very generally believed by fishermen that 

 all these conditions affect the catch, but in trawling 

 observations it has been usual to consider large areas as 

 being uniformly stocked with fish, and to regard the 

 results of drags with traAvl nets of the same length of 

 beam, and of the same mesh, and employed for the same 

 length of time, as comparable, and there seems little 

 doubt that this assumption is unwaiiauted. 



(1) The Precise Locality. 



The fact that the distribution of fishes varies within 



close limits is brought out by many obsei-vations. On the 



21st October of this year a series of hauls were made in 



Luce Bay* by the " John Fell." The object of these hauls 



was to obtain living mature plaice for the Piel Hatchery, 



and a series of short hauls, rather than one or two long 



ones were made. Each haul lasted for about an hour and 



a quarter, and about 2| miles were fished over. The net 



t 16th Annual Report of the Inspectors of Fisheries for England and 

 Wales, 1902. 



=•- By permission of the Fishery Board for Scotland. 



