4o6 THE DRY-FLY MAN'S HANDBOOK 



should often renew his stock by the purchase of ova 

 from abroad." 



The pisciculturist's yearlings and two-year-olds, 

 when grown to large dimen- 

 Short gill-covers and sions in stews, are at times 

 other deformities. very disappointing. Fre- 



quently the mortality among 

 these trout in the stew is somewhat alarming, and of 

 the dead ones taken out quite a large proportion are 

 found to have short gill-covers and other deformities. 

 Short gill- covers are often deemed to be caused by 

 overcrowding of the young trout at an early stage, 

 and of course the fish- farmer who delivers such fish is 

 prima facie guilty of a dire offence. He should, under 

 no conditions, send out for stocking purposes trout 

 which are in any way deformed, because these are 

 never satisfactory, and a large proportion die in the 

 stew. Mr. Corrie is of opinion that a large propor- 

 tion of short gill-covers and other deformities are, 

 according to his experience of practical hatchery work, 

 due to partial suffocation of the embryo. 



Fungus, which is a parasitic vegetable growth, is 



found at times in the stew. 



Fungus on trout. and occasionally even in the 



river. It is allied to the 

 deadly salmon disease, and when once established is 

 not easily cured. Immersion in strong brine is pre- 

 scribed and is at times successful, but even under 

 the most careful management trout once badly 

 affected by fungus will generally succumb. The 



