SEA-FISHERIES LABORATORY. 199 



the winter and spring months to emigrate out again into 

 one or other of the fishing grounds during the following 

 summer and autumn. But the larger plaice leave the 

 Irish Sea altogether, and migrate into Carnarvon and 

 Cardigan Bays, and even into St. George's Channel as far 

 South as the south-west coast of Ireland. Recaptures 

 indicating these migration paths are recorded in the 

 .Reports on the fish-marking experiments, and I have 

 published a chart* which shows to what an extent this 

 emigration of plaice from Liverpool Bay into Carnarvon 

 and Cardigan Bays has been demonstrated.! So far as 

 they go the results of the plaice measurements also confirm 

 this opinion. As a rule the plaice captured in the 

 southern grounds in Cardigan Bay — off Llanon and New 

 Quay Head, for instance, are large fish: thus the mean 

 length of one haul recorded in January, 1911, just as the 

 plaice-emigration from Bed Wharf Bay was taking place, 

 was 32 cms. The plaice measurements in Carnarvon and 

 Cardigan Bays are lamentably few, and although such work 

 was contemplated in the scheme of 1911, it has not been 

 carried out. But so far as the few observations made on 

 the " James Fletcher " by Captain Wignall go, they tend 

 to show that the large plaice population in Cardigan Bay 

 is not altogether a native one, but is recruited from the 

 larger fish moving to the South, out from Red Wharf Bay, 

 at the beginning of the year. It is also highly probable 

 that this is a real spawning migration on the part of the 

 larger plaice, and that, as a rule, the bulk of the eggs 

 which replenish the nurseries on the Lancashire, 

 Cheshire, and North Wales coasts have been drifted up 

 from St. George's Channel. 



* 'General Summary of the results of the Plaice-Marking Experiments 

 carried out during the years 1904-1909.' Ann. Reft. Lancashire Sea- Fish. 

 Laby. for 1910, pp. 153-190. Charts I-VI. 1911. 



f The contrary movement, that of Plaice from Carnarvon and Cardigan 

 Bays into Liverpool Bay, is represented by some very exceptional results. 



