How to obtain it. 165 



practical work. In water which stands at about 40 to 43 

 Fahrenheit ova will hatch in about ninety to ninety-six days, and 

 in about forty-two days or a little more the eye spots will begin to 

 appear. The time varies a little in the different species of 

 Salmonidce, and in the case of hybrids is often shorter than in that 

 of pure bred fish. The higher the temperature of the water the 

 sooner will the eggs hatch, and the colder it is the more they will 

 be retarded. Salmon ova have been hatched in thirty days, and they 

 have, in very cold water, been as long as one hundred and sixty days. 



In the year 1883, by using ice freely to lower the temperature 

 of the water, I kept some back for a hundred and thirty-two days, 

 and by so doing was enabled to have them hatching in my boxes- 

 at the Fisheries Exhibition at South Kensington on May i2th.. 

 They were the only British ova of Salmonidce in the exhibition. 

 They were sent from the Solway Fishery in water in bottles, and 

 travelled perfectly. In the warm London water they soon 

 hatched, and a few days later I was much amused when explaining 

 this to one of the spectators who came to see them. He gravely 

 said, " Haw, can't you wepeat the pwocess ?" Another seriously 

 asked " How long a salmon had to sit on its eggs before they 

 were hatched ?" Surely there is room for some instruction in fish 

 culture. 



In order to keep the ova in a healthy condition it is necessary 

 to run a good current of water over them. The quantity needful 

 varies according to the nature and quality of the water. I have 

 seen apparently good work done with a small flow ; indeed I have 

 myself, in early days, hatched salmon under a tap, from which a 

 mere trickle of water came. It is quite possible to hatch ova 

 without running water at all, by simply changing it twice daily ; 

 indeed, I may go even further, and say that they can almost be 

 hatched without water, for I have kept them for many weeks and 

 hatched them in damp moss. There are two points to observe in 

 carrying out such an experiment viz., that there is free access 

 for oxygen to the ova, and a means of exit for the carbonic acid 

 exhumed ; in other words, good ventilation. But to produce 

 really good fish a copious supply of good water must be at hand. 

 In the main hatchery at the Solway Fishery there is a supply of 

 over two hundred thousand gallons daily, and a similar supply in 



