46o SALMON AND TROUT. 



cases to improve it), and if a number of ponds are constructed 

 on different levels, these will preserve the food, if the volume of 

 water passing through is sufficient, and yet at all times under 

 perfect control. The raising of trout appears to be entirely a 

 question of food, both in quality, size, and quantity; and unless 

 this can be provided naturally, the rearing of any great number 

 of fish is a most expensive undertaking, various kinds of meat or 

 offal having to be procured, and a staff of assistants constantly 

 employed in chopping or otherwise preparing the food. The 

 system of feeding at the Howietown Fishery is almost wholly 

 artificial, especially for the large fish, and this establishment 

 (by far the largest in the world) turns out great numbers of 

 yearling fish. There is but litde natural food to be found in 

 the water, but this has lately been introduced, and watercress 

 cultivated in all the ponds. A pisciculturist, however, relying 

 entirely on natural food must have larger ponds and more of 

 them, involving a considerable original outlay. Without proper 

 food, natural or artificial, the loss would be something difficult 

 to realise — perhaps equal to that arising in the natural state, 

 where it is thought to be probably not less than 999 per 1000 ! 



If a small proportion of the young fry — turned direct into 

 the ponds from the hatchery — die, they are devoured by fresh- 

 wv^ter shrimps and other carnivorous insects, valuable in them- 

 selves as fishes' food, arid also acting as Nature's scavengers 

 of the water ; but if proof is required that these do very htde 

 damage to healthy fry, the writer may mention that he has 

 frequently found 80 and 85 per cent, of yearlings, which were 

 placed in the ponds eleven months before as fry. Let anyone 

 observe, however, the rapidity with wliich a dozen shrimps will 

 demolish a dead ' fry.' They will cluster all round it, and in a 

 very few moments there will be nothing left but his little back- 

 bone — the fish get the best of it in the long run though ! 



Seth Green, a well known American pisciculturist, says 

 • Starvation ' is almost the only cause of mortality among fry 

 provided they have been properly treated in the earlier stages. 

 How many millions of fish have been deliberately (in some 



