So THE SEA FISHERIES 



hatching of 7,707,350 plaice larvae liberated ; no other fish are now 

 dealt with at these institutions. * At the Lancashire Committees 

 Sea Fish Hatchery at Piel about one million plaice and 10 million 

 flounder fry were liberated in 1914. 



Another claim put forward in favour of the hatcherv is that it 

 serves as a reserve of spawners. The number of spawners in the 

 various hatcheries is not always given. In the Scottish Report 

 for 1913 there is no statement as to the number of adult plaice 

 in the spawning ponds ; but in the ponds attached to the hatchery 

 at Port Erin there were 350 healthy plaice. The condition of these 

 fish which are confined under artificial conditions is probably less 

 favourable than it would be in a state of nature. In some of the 

 hatchery reports we learn that " very few fish had died," and in 

 others, " There is always a certain amount of natural mortality 

 among them, particularly during the summer." The mortality 

 rate among spawners is nowhere expressed as a percentage. The 

 claim that the hatchery provides a reserve of spawners or confers 

 immimity on a number of spawners will not bear detailed examina- 

 tion. Not only is there a mortality— the percentage of which is 

 unpublished — once the fish are put into the ponds, but there must 

 inevitably be a considerable mortaUty before the fish get to the 

 spawning pond. Special hauls are made by the scientific steamers 

 for the purpose of obtaining these fish, and the mortality that takes 

 place during the trawling, the time the spawners are kept on the 

 steamer, and during transference to the spawning pond should also 

 be taken into account. 



The theory that the spawning pond acts as a reserve of breeding 

 stock may, therefore, be dismissed, the probability is that the 

 percentage of mortality of these fish if left in the sea (from being 

 captured by commercial trawling and from their natural enemies) 

 is less than it is in the spawning pond, where the fish are detained 

 under artificial, i.e. unnatural conditions. In how many hatcheries 

 are the spawners kept from year to year ? Attempts have been 

 made from time to time to obtain spawn from fish caught in com- 

 mercial fishing (see p. 252). The writer has a vivid recollection 

 of the difficulties of collecting spawn from steam trawlers in the 

 Irish Sea in the spring of 1899. 



A further point urged by the advocates of sea fish hatching is 

 that there is an enormous mortality of eggs and larvae in the sea. 

 While on a priori grounds the statement that there must be an 

 immense destruction of eggs or larvae or post larval fish is indis- 

 putable, there is no clear evidence of the enormous destruction of 

 pelagic eggs of marketable fish in nature. It may safely be said that 

 * Except lobsters at Port Erin. 



