VI PEEFACE. 



food ; to review the various fresh- water fish found 

 in Great Britain, and point out those which are 

 most valuable to us, and how they may best 

 be distributed, cultivated, and increased ; and, 

 further, to consider the merits of such fish as 

 it may be advisable to acclimatize, but which 

 are not at present included in our Fauna. Com- 

 prehensively considered, my plan is to indicate 

 how water may be made most productive, and 

 what should be done with those vast aqueous 

 deserts of lake and stream which are now com- 

 paratively valueless, but which would be mines 

 of wealth to us were it not for the ignorance 

 which generally pertains to everything vitally 

 connected with this subject. 



I believe water — neglected, ill-used water — 

 if properly tilled, to be much more valuable 

 than land, through its greater productive powers? 



1 Wbsi, edible animal is there that exists on land which possesses 

 the capability of reproducing 9,000 of its' own size in a period 

 little exceeding eighteen months ? This can, however, be per- 

 formed by a grilse of eight or nine pounds' weight. A grilse of this 

 size will deposit, say, 9,000 ova; in about fifteen or sixteen months 

 the fry from this ova go down to the sea, and in two or three 

 months more they have been known to come back to the river as 

 grilse of from five to ten pounds' weight. 



