88 BREEDERS. 



according to the rotation, in which they remain until they are 

 nine years old, after which they are of little value for breeding, 

 the size of the egg having reached its maximum, and the number 

 having dwindled down to 500 to the pound. Of course I am 

 merely speaking generally, as some fish continue to improve for 

 several seasons after the bulk of their contemporaries have become 

 barren from old age. When trout are in their fourth year they 

 receive one meal of mussels and two of horse-flesh daily. In the 

 fifth year they are fed with more mussels and less horse-flesh. 

 The ova of fish on this diet is a beautiful orange yellow, and 

 very transparent. The next year clams (pecten) are substituted 

 for mussels, and the ova acquires a slight pink tinge ; after this 

 they are fed entirely on clams, and each succeeding year the ova 

 becomes of a darker pink colour. Fish fed on horse-flesh give the 

 largest number of eggs and of the palest colour. Trout fed on 

 clams yield the smallest number proportionally of eggs, but of the 

 largest size and darkest colour. If the conditions of food be equal, 

 the oldest fish give the largest and darkest eggs, and the fewest 

 proportionally. There are, however, many exceptions to the general 

 rule, for which I am as yet unable to account. 



SEGREGATION OF SEXES. 



Males of six years old and upwards are very subject to fungus 

 (Saprolegnia ferax), and if there is much infection in the pond it 

 is apt to spread to the females. It is therefore advantageous to 

 remove the males after they have been spawned the first time. 

 Females, when alone in a pond, feed more freely, and are almost 

 entirely free from disease. A great saving is also effected in cost 

 of the food. The expense of feeding a pond entirely on clams is 

 not grudged when the inhabitants yield a plenteous and rich egg- 

 harvest ; but it does seem wasteful to gorge on costly food a lot 

 of old males, not one-fourth of whom are required for breeding 

 purposes. Moreover, I think I have noticed better behaviour in 

 these gentlemen when living in bachelor quarters. They do not 

 seem to fight so much, and the wounds, which form the usual seat 



