147 



Of course much greater results would be effected by simply prohibiting the capture 

 of soles at all from the middle of February to the end of April ; but this could only be 

 done by prohibiting trawling during those months, for in my opinion soles once 

 captured in the trawl are usually too much injured to survive if again returned to the 

 sea. I have shown that they do not survive when placed in our aquarium tanks (see 

 p. 11 5). If trawling were prohibited who would compensate the fishermen and capitalists 

 engaged in the business ? That would be more expensive than maintaining a national 

 staff of pisciculturists to hatch soles' eggs. On the other hand, we must consider if it 

 is possible under any imaginary system that there should be a man on board every 

 trawler capable of artificially fertilising the eggs of soles during the spawning period. 

 It would scarcely be practicable to send out a trained pisciculturist in every trawler. 

 It is possible, however, in imagination at least, that the skipper of every trawler should 

 carry out the necessary operations, though it would probably be a long time before 

 trawling skippers would possess the necessary knowledge or care sufficiently for the 

 future. If such operations were expected of them they would have to be trained in 

 practical pisciculture, and pass an examination in that subject as they are now 

 required to pass in seamanship. 



I make no claim to originality in this idea. Years ago Professor Ewart, of the 

 University of Edinburgh, who has identified himself with the piscicultural work of the 

 Scottish Fishery Board, published the suggestion of a similar scheme to be applied to 

 herrings. I believe it has never been carried out, and I doubt at present if such 

 measures for maintaining the supply of herrings are required. It has occurred to me to 

 consider whether the same scheme might be applied to soles, and I think it quite pos- 

 sible that Professor Ewart's suggestion may hi the future lead to very important results. 



The only other possible methods of increasing the numbers of soles are to increase 

 the supply of food or to diminish the numbers of the natural enemies of the sole. No 

 practical means can be suggested by which the supply of food could be increased, but 

 it might well be worth while to rigorously destroy useless predatory fish which have no 

 value themselves and which live entirely on valuable food fishes. At present trawlers 

 constantly throw back anglers and dog-fishes into the sea alive after they have brought 

 them on deck. I think it would be advisable that these fishes should be systematically 

 killed before being returned to the sea, for if valuable fishes can be diminished in 

 numbers the abundance of their enemies could be reduced also. 



There is not much to be said about the domestication of soles. It is certain that 

 soles will live in captivity and grow to a large size. The Association is now making 

 arrangements to keep young soles in a large piece of enclosed sea-water at Sheerness. 

 But it is evident that the capture of young soles to be merely retained in captivity and 

 killed when mature will not prevent the diminution of the numbers in the sea. If the 

 adults were kept in captivity and their eggs taken and reared a new industry of sole- 

 raising might be started, but it is doubtful whether this would compensate for the 

 extermination of soles from the great trawling grounds. 



