336 THE DRY-FLY MAN'S HANDBOOK 



will adopt such tar products as will do the least 

 possible harm to the trout and other fish in the 

 streams. 



Mr. Corrie, who has had great experience in 

 investigating and reporting on cases of fish poisoning, 

 alleged to be caused by the light oils in the tar being 

 carried down into the rivers by rain or street wash- 

 ings, writes me as follows : — 



" I have no doubt that the great rush of flood water 

 which at or near Winchester drained into the Itchen 

 was responsible for the destruction of nearly all the 

 fish (trout, grayling, pike, eels and smaller fry) from 

 Winchester down to, and half a mile below, Twyford. 

 I do not say that the poisonous matter washed into 

 the river was only tar products, for I have a suspicion 

 that motor oils, etc., may help to form a very evil 

 slimy sediment and liquor when the waterproofing of 

 the surface of the road caused by tar allows nothing 

 objectionable to soak away. All pollution is swept 

 away to the lower levels almost as it might be off the 

 slated roof of a house." 



" In the Darenth (Sevenoaks district) some fifteen 

 miles of trout-water was completely poisoned when 

 flood- water off tarred roads swept into that stream. 

 Even the weeds were killed, and the trout, when dead, 

 had precisely the same appearance as our Itchen fish 

 below Winchester. Fishery owners and lessees might 

 approach the road authorities with advantage to per- 

 suade them to construct filtration beds at dangerous 

 points." 



