88 



THE SEA FISHERIES 



The sole differs from the plaice in its spawning habits. The 

 former spawns in somewhat deeper water than the latter, and the 

 spawning areas are more localised. In the Irish Sea there are three 

 well-defined areas in which spawning soles are found in great numbers 

 in the spawning season. Two of these areas have been heavily 

 fished by steam trawlers in the spawning season for the last few 

 years, and signs are not wanting that the third ground is also being 

 exploited. 



In the North Sea it appears to spawn in depths of about 22 

 fathoms (which corresponds closely with the Irish Sea sole), off 

 the Dutch and Belgian coast from the middle of April to the end 

 of June, May being the principal month. 



The body of the sole is much more flexible than that of the plaice, 

 and the sole escapes easily through the meshes of a net which will 

 retain a plaice of equal size and weight. This body flexibility 

 renders the marking of the sole a difficult operation, and does not 

 facilitate artificial hatching. In fact, the artificial hatching of 

 the sole on even a moderate scale has not hitherto been successful 

 in the British Isles. To this the depth of water at which the sole 

 naturally spawns, and the difficulty of obtaining milt from the 

 males are also contributory causes. The sole is nocturnal in its 

 habits, and is caught more frequently at night than by day ; and 

 in the daytime more frequently when the water is cloudy than 

 when clear. It seeks its food more by sense of smell and touch 

 than by sight, and in the Irish Sea, at any rate, prefers worms 

 (Nereids) to any other form of diet. 



An estimate of the quantity of soles landed in Northern Europe 

 for the years 1903-07 has been made by Redeke and Tesch, of the 

 Marine Biological Station at the Helder. In this table the quantities 

 are given in metric tons of 1000 kilograms. 



Average Catch of Soles, 1903-07 



England 



HoUand 



Belgium 



Germany 



Ireland 



Denmark 



Total 



Total 

 quantity. 



3762-6 



520-3 



3597 

 268-9 



I59-4 

 116-6 



Value, ;^s. 



Quantity from 

 North Sea. 



469,116 



63,969 

 40,153 

 29,838 

 12,515 



9,359 



2250-7 



520-3 



304-5 

 181-6 



26-6 



Percentage for 

 each country. 



69 

 16 



9 

 5 



From 1903-07 the greater portion of the catch went to Enghsh 

 fishermen : and the largest quantity came ^^^^ f^.^ort^^^^ 

 English fishermen still land the largest share of soles,, but the >Jorth 



