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all tlie ripe eggs and milt -which ought to have developed into the next generation were 

 actually devoured by the people who ate the shad. The pisciculturists, under the 

 direction of the Fish Commissioner, therefore first invented methods and apparatus by 

 which the eggs of the shad could be artificially fertilised and hatched, and then they 

 organised a system under which every year a large number of the ripe fish captured 

 were stripped of their eggs and milt which were returned either to the same river or 

 others in the form of healthy fry. The consequence is that now the estuaries on the 

 Atlantic side of the United States yield annually a rich harvest of adult shad, and this 

 valuable fishery is absolutely dependent on the piscicultural operations of the National 

 Fish Commission. 



Let us now consider the case of the sole. Soles are captured without- intermission 

 the whole year round, and their habitat is practically only coextensive with the 

 trawling grounds. Soles do not, our knowledge enables us to infer with some 

 certainty, migrate or travel about to any great extent. There may be of course 

 distant areas where soles are abundant, but the existence of these is not sufficient to 

 maintain the sole population of the extensive areas where they are constantly captured. 

 Now I have shown that the artificial fertilisation and hatching of soles' eggs, though 

 presenting unusual difficulties, is by no means impossible. It is almost impossible to 

 interfere with trawling. Suppose that by further experiments it were shown that 

 millions of soles' eggs could be artificially fertilised, hatched, and returned to the sea. 

 It is evident that this would necessarily have the effect of increasing the supply of 

 soles. For all these eggs would be procured from soles captured for the market, and 

 would, if not artificially hatched, be devoured along with the soles themseh-es. Of 

 course the expense of providing properly equipped hatcheries and mamtammg a staff 

 of men who would collect the eggs and take care of them during development would 

 be very large. But if this expense were provided from the public funds, some return 

 for it would be received by the public in the form of more abundant and cheaper soles. 

 Whether the national account on this item would result in an annual profit or an 

 annual loss I am not yet prepared to say. 



On the other hand, it seems to me at least possible that the artificial fertilisation 

 of the eggs would alone be sufficient, and that the artificial hatching in expensive 

 hatcheries would be unnecessary. We have at present little reason to assume that, 

 given a certain number of fertilised eggs more fry would be produced from them by 

 hatching them in artificial apparatus than by placing them in the sea to develop under 

 natural conditions. It is conceivable that the ripe females and males captured by the 

 trawl during the spawning season should be stripped by a man on board a trawler, 

 and the fertilised eggs so obtained should be simply thrown overboard. This would 

 be a direct gain to the sole population of our seas, for every one of those eggs would, 

 if not artificially fertilised, be sent to market inside the female soles and cooked. In 

 fact ripe eggs are now cooked in the ovaries of soles in enormous numbers everj' 

 spawning season. 



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