May i8, 1888.] 



SCIENTIFIC NEWS. 



467 



Natural Wi^toiSt* 



FISH CULTURE. 

 The first difficulty which occurs to the observer with 

 respect to the multiplication of fish is to explain how it 

 is that many species should be, comparatively speaking, 

 so rare, though the ova which they annually produce may 

 be counted by thousands. But on closer examination 

 we find so many enemies besetting the baby-fish, from 

 its leaving the egg to its reaching a size fit for human 

 food, that we may almost wonder how any survive. We 



either flee or defend themselves they are beset by water- 

 beetles, water-scorpions, the larvae of dragon-flies, not 

 to speak of greedy fishes, both of other species, and 

 even of their own. The want of suitable food often 

 causes multitudes to perish. 



To obviate all these difficulties and to secure an ample 

 supply of fish suitable for human food systems of arti- 

 ficial propagation have been adopted, and that with a 

 very decided success. The fecundated spawn is placed 

 in breeding-boxes or tanks, constantly supplied with 

 fresh, pure water, at the temperature best suited for the 

 development of the fry. All enemies are carefully 





Hatching House, with Breeding Boxes, of the Solway Fishery, Dumfries, N.B. 



leave here, of course, on one side all the havoc occasioned 

 by polluted waters, by the influx of acids, alkalies, 

 metallic salts, and other poisons into our streams, 

 or by the presence of putrescent matters which 

 render the fish liable to fungoid diseases. These are 

 evils which it is hoped that legislation on the con- 

 tamination of rivers will ultimately overcome or 

 reduce to a minimum. But let us take a stream or a 

 lake of fairly wholesome water, well aerated, and receiving 

 neither house sewage nor industrial waste waters. Even 

 here fish-fife in its earlier stages runs fearful risks. The 

 spawn before it is vivified is liable to be devoured by 

 water-fowl, by crustaceans (cray-fish), by mature fishes, 

 and, we believe, by certain carnivorous insects. When the 

 young fry are first hatched out, and before they can 



excluded, and the young fishes are supplied with food, 

 consisting generally of boiled liver very finely minced. 

 Our illustration gives a general view of a fish hatching- 

 house, with its breeding boxes as established at the 

 Solway Fishery, Dumfries, by Mr. J. J. Armystead. 



After the fish have reached a sufficient size they are 

 allowed to pass from the breeding-boxes into the river, 

 and in future to shift for themselves. Much has 

 been effected in this manner in the United States and 

 in several parts of the Continent, though Britain, from a 

 variety of causes, has so far remained in the back- 

 ground. 



But fish-culture has not yet reached perfection, and 

 there is therefore room for the improvements devised by 

 Messrs. Paul and Reisenberger, and about to be carried 



