SEA-FISHERIES LABORATORY. 267 



winter to the maturation of the reproductive organs. 

 There is undoubtedly a decrease in the metabolism of the 

 fish during the cold weather. It does not feed, or does so 

 to a very slight extent, during the months of December 

 and January, and the weight of a plaice of a certain 

 length is always less in the winter than the weight of a 

 fish of the same length in the summer. 



4. — T he migrations. 

 It should be noticed that many instances of quite 

 exceptional migrations are recorded in the tables. 'Thus 

 fishes liberated off the coast of Lancashire have been 

 recaptured off the East and South Coasts of Ireland, and 

 fishes liberated in the same area have also been recaught 

 at the mouth of the Bristol Channel. These lengthy 

 migrations would not surprise us if they were made by 

 actively growing fishes like the cod or hake, or pelagic 

 fishes like the mackerel, but one is accustomed to speak 

 of the plaice as a semi-sedentary fish. Leaving aside 

 these exceptional migrations, the results of this and last 

 year's experiments shew with some probability that plaice 

 in our waters do not move about in the winter to the same 

 extent that they do in the summer, and that the winter 

 migrations are mostly alongshore ones, with perhaps a 

 general trend to the North along the coasts of Cheshire 

 and Lancashire. In the summer, on the other hand, the 

 migration is an offshore one. There are evidences of a 

 tendency to the southward, and in the exceptionally 

 lengthy migrations already referred to, it is generally 

 this southerly migration that is made. While 

 plaice have been observed to travel from the coasts of 

 Lancashire and North Wales into Tremadoc and 

 Cardigan Bays, the opposite migration has only been 

 observed in two instances. 



