468 SALMON AND TROUT. 
nuisance will continue so long as large ponds at the head or by 
the side of the river contain them. There is no keeping them 
back by fences, and frequently no attempt to do so ; the effect 
being, very often, that the best part of the river is occupied by 
pike, instead of containing a good stock of trout. Netting the 
ditches by the side of the river at spawning time is a good way 
of helping to exterminate these depredators. 
ON STOCKING, 
A pisciculturist is frequently asked which is the best kind 
of trout to stock a certain piece of water. The question can- 
not be decided without actual experiment, but a tolerably good 
inference may be drawn by comparison of the particular water 
with other in the same neighbourhood. 
Yearling fish should be introduced when the stock in the 
water has become low ; it is generally a waste of valuable fish- 
life to turn ‘fry’ into a stream or lake which already contains 
some trout ; if there are small tributary streams on the same 
property leading into the main water, the stock may be re- 
plenished year by year with ‘fry,’ or even ova; but as there 
would always be considerable loss, very large numbers must be 
introduced, and the tributaries must be well fenced (which is 
always a difficulty), so as to prevent the little fish from getting 
out, and any larger fish from getting in ; otherwise good results 
will seldom follow. The largest fish obtainable should be pro- 
cured ; the first expense being perhaps greater, but proving in 
the end less, and a greater security from cannibalism. Well- 
fed yearlings should run from four to seven inches in length, 
some may be even more, and these are to a greater extent capable 
of ‘holding their own’ against larger fish than the small-sized 
yearlings bred in some waters, and are therefore worth much 
more money. 
Salmo Fario (English brook trout) must take the precedence 
of all the other varieties, as it is the indigenous fish to most 
