REPORT OF COMMISSIONER OF FISH AND FISHERIES. IxXXl 



the gamesomeuess aud excellence of flesh of the salmou, and I think it 

 would be perfectly safe to make the experiment. Under any circum- 

 stances, the Danube salmon is a less voracious fish than the pickerel, 

 and might probably require much less weight of food to acquire a given 

 amount of growth. 



Some of the other species referred to above will probably be taken up 

 for consideration at an early day. 



The restoration of food -fishes to localities originally tenanted by them, 

 or their transfer to new waters, is, however, a question of time; aud 

 in the immense extent of our river and lake systems, many years 

 must necessarily elapse before the work can be accomplished. It is also 

 inexpedient to attempt to cover too much ground at once, as in the 

 necessary limitations furnished by the amount of the appropriations, and 

 the difficulty of finding skilled assistants, it is considered the better 

 policy to render fish very abundant in a few centers by concentrating 

 effort upon them, and then from these centers to carry on the work else- 

 where. It is not a percentage so much as au absolute number of young- 

 fry that must be sacrificed to the rapacity of the pre-existing inhabit- 

 ants of the stream into which they are introduced; and it is evident 

 that, supposing that the average probability of destruction amounts to 

 10,000 fish in a given period, if we introduce only that number there 

 will be no surplus; whereas with 50,000 the excess will be enough to 

 allow the maturing of adults sufficient to stock the waters. 



It must, however, be borne in mind that it is not sufficient to take 

 measures for introducing the fish, whether young or adult, into new 

 waters, but that much then remains in the way of protecting them 

 when once established, and in securing their passage to and from the 

 sea. State legislation will be required to bring about the removal of 

 obstructions ; introduction of suitable fish-ways ; prevention of the pollu- 

 tion of the waters, and the capture of the fish at improper times', by im. 

 proper modes, &c. 



When we consider that the prime cause of the decrease in our salmon 

 aud shad fisheries is believed to be in the erection of impassable dams, 

 thus preventing their access to the spawning-grounds, it will be readily 

 understood that, unless some provision be made for surmounting these 

 obstructions, the fisheries cannot be self-sustaining. Fortunately, how- 

 ever, in the fish-ways, of which a great variety has lately been devised, 

 we have in most cases a practical remedy; experience having shown that 

 where these are inserted in dams, with the lower end perfectly accessi- 

 ble to the fish aud a sufficient volume of water issuing from it, fish will 

 ascend with great facility. This is especially the case with the salmon 

 and alewife, but it is also probably true of the shad. The general theory 

 of fish-ways, and the various forms suggested, or in use, will be found 

 given in detail in an admirable essay on the subject in the present report 

 as prepared by Mr. Atkins. 



Care must also be taken, in planting the fish, to introduce them as far 

 S. Mis. 71 Yi 



