140 MARKETABLE BRITISH MARINE FISHES CHAP. 



left to produce an adequate supply of young. This point 

 appears to have been reached according to the experiments and 

 observations of the Scottish Fishery Board, for in the Firth of 

 Forth and St. Andrew's Bay, notwithstanding the prohibition of 

 trawling in the territorial waters, and the absence of other fishing 

 destructive to young flat-fishes, the number of the latter has not 

 increased. To remedy this state of things artificial propagation 

 has been recommended, and in certain cases adopted. We may 

 here briefly discuss the question how far artificial propagation 

 appears capable of increasing the supply of fish, whether in 

 conjunction with or independently of the protection of .the 

 young. 



Firstly, it may be pointed out that up to the present time 

 artificial propagation of marine fishes is limited to the produc- 

 tion of fry at the stage when the yolk is nearly absorbed, which 

 are then liberated in the sea. From this stage onwards they are 

 no better off than fry which have been hatched under natural 

 conditions. At Arendal, on the south coast of Norway, and at 

 Dildo Island, in Newfoundland, there are two hatcheries almost 

 entirely devoted to the propagation of the cod. In both these 

 cases it is stated, and there is no reason to doubt the statement, 

 that a greatly increased number of fish have been seen and 

 captured in the neighbourhood of the hatcheries as a direct 

 result of the millions of fry liberated. Cod and other fish have 

 been hatched also in hatcheries on the coast of the United States, 

 but not very regularly, and in 1894 the hatchery of the Scottish 

 Fishery Board at Dunbar commenced operations, the latter 

 establishment dealing principally with the plaice. Now it may 

 be admitted that locally an increase in the supply of fish may 

 be produced by the annual liberation of some millions of fry. 

 But we have to consider firstly the proportion between the value 

 of this increased supply and the cost of the hatchery. At present 

 we have not the data necessary for making this comparison, but 

 it should be always remembered that the cost of the hatchery 

 has to be met, not out of the total value of the fish derived from 

 the hatchery-, but out of the value of the fish after the cost 

 of catching and marketing has been deducted. The fry having 

 been liberated in the sea, those of them which survive to reach 

 marketable size have to be caught. If we suppose one firm to 

 have the exclusive control of a sea fisher}-, and to establish a 



