38 THE FISHING INDUSTRY 



number of plaice gather in Red Wharf Bay, off the north 

 coast of Anglesey, probably because it is sheltered from 

 the prevailing south-east winds. In February they 

 commence their spawning migration round the coast 

 of Anglesey to Cardigan Bay. 



Certain species of fish, instead of migrating from one 

 part of the sea to another, migrate from the sea to rivers 

 (anadromous), or from rivers to the sea (katadromous). 



Thus, in the spring or autumn, according to species, 

 the anadromous salmon and shad ascend rivers to spawn. 

 The eggs are deposited on clean gravel in clean water, 

 where they are likely to remain undisturbed. The 

 salmon does not feed when in the river, and after 

 spawning, becomes very thin and in poor condition. 



The Alaskan salmon, from which the bulk of American 

 canned salmon comes, exists in five species. It has a 

 similar spawning habit to the British salmon, except that 

 the same species always tends to use the same rivers. 

 Once having spawned, the fish dies, so that the parents 

 never see their offspring. The young larvae hatch out 

 in the fresh water and make their way to the sea, where 

 they pass the whole of their lives until they are mature, 

 some years later, and then, in their turn, ascend the 

 rivers to spawn. 



Eels are normally fresh-water fish. After living for 

 six or seven years in rivers and ponds and streams, they 

 become mature ana migrate to the sea to spawn. This 

 spawning always takes place in deep water (over five 

 hundred fathoms), the particular region chosen depend- 

 ing upon the species. Eels from the British Isles and 

 North -West Europe spawn in deep Atlantic, some 

 hundreds of miles west of Ireland. In the autumn, the 

 mature eels move down the rivers to the sea. When 

 approaching maturity, the yellowish coat of the eel 

 changes to silver. These " silver " eels pass into the 



