168 Sir F. A. Mackenzie on the Breeding 



about three-quarters of an inch in length, and they swam 

 about easily, all marked distinctly as Par. The baskets re- 

 commended by Professor Agassiz proved superior to the wire 

 bags of Mr. Shaw. In the latter only about 20 per cent, 

 came to maturity, whilst in the former not above 10 per cent, 

 proved barren, and in the baskets used 5th of December not 

 above 5 per cent, was unproductive. It is impossible to say 

 exactly the proportion of ova which came to life either of that 

 artificially impregnated and deposited in the open gravel, or 

 of what was spawned by the fish themselves naturally, but so 

 far as could be judged, they succeeded equally well with that 

 in the baskets. Perhaps the baskets may have a preference over 

 the other methods tried, as affording more certain protection 

 to the spawn during winter ; and it is proper to state, that 

 the last-described mode of depositing the ova and milt was 

 most successful. There can be no doubt, from the success 

 which has attended these experiments, that the breeding of 

 salmon or other fish in large quantities is, comparatively 

 speaking, easy, and that millions may be produced, protected 

 from every danger, and turned out into their natural element 

 at the proper age, which Mr. Shaw has proved by repeated 

 experiments on a small scale to be when they have attained 

 about two years of age. When the par marks disappear they 

 assume the silvery scales of their parents, and distinctly show 

 a strong inclination to escape from confinement and proceed 

 downwards to the sea. 



Professor Agassiz asserts, and I fully believe with truth, that 

 the ova of all fish, when properly impregnated, can be con- 

 veyed in water of a proper temperature even across the At- 

 lantic, as safely as if it were naturally deposited by the parent 

 fish; so that any quantity of salmon or other spawn can 

 (after impregnation on the banks of a river) be carried to other 

 streams, however distant, which may be favourable for hatch- 

 ing. It may be right to observe, that as the fry are to remain 

 two years in the artificial pools where hatched, fresh places 

 must be used every second year for the spawn, as even one- 

 year-old fry will destroy spawn, or their more infantile brethren, 

 if left together ; old spent salmon are also destructive both to 

 spawn and fry. 



It can only be ascertained by experience what kind or 

 quantity of food will be required for the fry. Carrion hung 

 at the top of the pool in which they are, would, in the opinion 

 of Professor Agassiz and Mr. Shaw, supply them with mag- 

 gots ; but in this there are difficulties, and when tried by 

 me this season, a few of the fry were found dead round the 

 carrion given to them. The droppings of cattle allowed to 



