X PREFACE. 



is not sufficient : they must be carried in perfectly clean water, 

 they must be perfectly prepared, the temperature of the transport- 

 tank must be kept within a few degrees of that of the stream into 

 which they are to be turned, and the stream itself must not only 

 be suitable for fry, but the part of the stream where they are 

 liberated must be skilfully selected. 



Next in point of deadliuess, the insane overcrowding of the 

 ova, and afterwards of the fry in the trays. This was supposed to 

 be the sovereign remedy for the admittedly meagre results. Do not 

 waste money over your hatching-house. Only lay down enough 

 eggs, and a few inches thick, if possible, and a very few pounds 

 will suffice to stock all the waters in the country ! The ova were 

 laid down in this manner at first by hundreds of thousands, after- 

 wards by millions. Tens of thousands of pounds sterling have been 

 spent wasted, if you like, and to-day we are still asking, Where 

 is the result ? Where ? 



But there is a yet more fatal cause of failure, a cause so hidden 

 that never was it suspected until the Howietoun experiments placed 

 it beyond a doubt. The maturity of the parents is of paramount 

 importance in determining the chance of the offspring in the 

 struggle for existence. Old spawners produce strong and healthy 

 fry ; young spawners, though comparatively more prolific, produce 

 weaker offspring, with a much smaller chance of holding their own 

 in the waste of waters. The problem is now solved. The culture 

 of the SalmonidcB is now an achieved success. And in the hope 

 that the methods followed may prove of use to those working on 

 the still larger question of our sea-fisheries, I will endeavour to 

 bring the experimental part of the work, in which I have been 



