SEA-FISHERIES LABORATORY. 175 



ON MEASUREMENTS OF SOLES MADE IN 1920. 

 By James Johnstone, D.Sc. 



In June of 1920 a system of observations on board smacks 

 and steam-trawlers, working in the Irish Sea, was put in 

 operation by the Ministry of Agriculture and Fisheries. Two 

 " fish measurers," Commander A. E. Ruxton and Mr. W. C. 

 Smith, were stationed at the ports of Fleetwood and Whitehaven, 

 and, later on, a postgraduate student of the Zoology Depart- 

 ment at Liverpool University, Mr. G. F. Sleggs, B.Sc, was 

 engaged on similar work. The object of the observations was 

 to obtain data with regard to the sizes and general distribution 

 of the plaice caught by the first-class trawling vessels on the 

 offshore grounds of the Irish Sea. The measurers usually 

 worked on smacks sailing out from Fleetwood and Liverpool, 

 and, though their specific work was to observe the catches 

 of plaice made, they also measured all the soles caught. The 

 results are very interesting and are also quite novel, for there 

 were, previously, no measurements of the soles trawled on these 

 offshore grounds. Since these fish were the principal objects 

 of the fishing of the smacks the region where they occur was 

 pretty well worked and nearly 6,000 soles were measured. 

 Unfortunately it was impossible to arrange for the work to be 

 commenced earlier than the last day in May, so the spawning 

 period of the fish was not fully covered. 



The grounds trawled over are shown on the sketch chart 

 (Fig. 5). The irregularly-marked regions represent, rather 

 roughly, the parts of the sea worked on the various voyages 

 of the smacks with which the measurers went. The Roman 

 numeral gives the month and the suffix gives the number of 

 hours during which trawling went on. 



The principal sole-fishing ground is well shown : it extends 

 N.W. from Morecambe Bay Light Vessel up towards Maughold 



