On Stocking. 55 



best fry-ground are those portions of the stream 

 or river where the bottom varies from coarse 

 sand to small stones, and where small shallow 

 pools and slight eddies are interspersed. 



When the survey is made in winter great local 

 knowledge is necessary to determine the amount 

 of fry-ground available in summer. April and 

 May are the best months to make the survey, as 

 it is in those months the fry leave the redds and 

 are in more need of the protection yielded by 

 good fry- ground than at any subsequent time. 



Having found a stretch of good fry-ground, the 

 next business is to choose a situation, for the 

 redd, a few hundred yards above. If a tiny 

 stream or clean ditch can be found, a little 

 coarse gravel is all that is required, but if the 

 water has to be brought from the main stream, 

 or from a brook or ditch subject to high floods, 

 the redd must be cut some distance back from 

 the water and well above the highest flood, so 

 that even the bottom of the redd is above high 

 flood level. The principles which govern the 

 'construction of a redd are the same as governs 

 the construction of a hatching- box, 'viz., that 

 the stream or current washes every egg and re- 

 moves the carbonic acid exuded in the process of 

 incubation. In a redd the eggs are more spread 

 and a much slighter current is sufficient than 

 that required in a hatching-box. The redd should 



