INFLUENCE OF TEMPERATURE 111 



assists and quickens the incubation of all sub-aqueous 

 eggs, and hastens the metamorphosis of all insect life. 



Mr. Livingstone Stone is decidedly against the estab- 

 lishment of breeding pounds in the natural bed of 

 streams, but his objections are due to the dangers 

 connected with such a locality. Trout, he admits, 

 will flourish most when placed in strong-running, 

 natural trout water, plentifully supplied with natural 

 food, and he also admits the difficulties of regulating 

 the temperature of water conveyed in aqueducts. I 

 consider that so long, then, as the owner of a hatchery 

 is secure against floods and natural dangers, the natural 

 food and temperature of productive trout streams 

 will secure the most favourable breeding of his trout. 



Under favourable circumstances the rapid growth 

 of a trout is extraordinary. Trout from the upper 

 waters of the Dart, where natural food is scarce, and 

 the fish in consequence are small, quickly grow to a 

 very large size when placed in the more productive 

 waters of ponds and reservoirs. Trout will feed better 

 in fairly temperate weather than when it is very cold, 

 and a rise in temperature after a cold spell is productive 

 of good sport, due to the improved appetites of the fish, 

 to the greater activity of insect life, and sometimes to 

 the recovery of trout after spawning. Trout lose their 

 desire for food as the spawning time approaches, and 

 though they commence feeding after it is over, they 

 do not regain their full feeding powers until the warm 

 spring weather is reached. My experience of trout 

 has convinced me that they acquire an increase of 



