EEPOKT OF COMMISSIONER OF FISH AND FISHERIES. LXI 



.spawning grounds, reucleriug the waters barren in a few years; in others 

 the reduction in the spawning areas has entailed a corresponding dimi- 

 nution in the ])roductiye capacity of the river, and caused important 

 and remunerative fisheries to become comparatively valueless. 



In the case of the salt-water predaceous species, the effect of obstruc- 

 tions in the rivers, whilst indirect, has been not the less potent in effect- 

 ing a reduction of their numbers by diminishing their food supjily. 



In my annual reports to Congress I have had frequent occasion tore- 

 vert to the disastrous effects of dams in our rivers in determining a re- 

 duction in the supply of our more important food fishes, and to urge the 

 erection of fish-ways as a most important and indispensable adjunct to 

 the restoration of our fisheries by artificial propagation, a work so 

 wisely inaugurated and so beneficently sustained by liberal appropria- 

 tions. 



Usually the work of construction of fish- ways may appropriately be 

 left to the States themselves, or to the coercion of State laws brought 

 to bear u]ion the owners of dams. In those cases, however, where the 

 General Government has created or maintains obstructions in our 

 streams it seems eminently projier and in essential harmony with the 

 work of artificial proiiagation, inaugurated and sustained by the Gov- 

 ernment, that suitable provision should be made to provide sufiQcient 

 l)assage-way for fish over the obstructions. 



My views in regard to the expediency and propriety of the General 

 Government undertaking the work at the Great Falls have already 

 been expressed in a letter to the Commissioners of the District, a copy 

 of which is inclosed for the information of your honorable committee. 



I can only add to the argument i)reseuted in that letter that the water 

 supply requisite for the fish-way will be necessarily under the control of 

 the District government, and must be subordinated to the necessities 

 of the water supply of the District. This renders it necessary that the 

 fish way, when built, should be operated subject to the entire control of 

 the autborities of the District government. 



I may state in conclusion that the opening of the upper waters of the 

 Potomac and its tributaries to the ascent of fish cannot have other than 

 a most beneficial effect upon the production of the river. That such a 

 result may be attained there is no reason to doubt. The difficulties that 

 may present themselves are mainly those of construction, and are en- 

 tirely within the resources of the engineer to overcome. 

 I have the honor to be, very respectfully, 



S. P. BATED, 



Commissioner. 



United States Commission of Fish and Fisheries, 



Washington, D. C, March 24, 1882. 



Dear Sir: I would respectfully suggest the propriety of including 

 in any proposition for the completion of the dam at the Great Falls the 

 construction of a suitable fish-way to admit the ascent of shad, salmon, 

 striped bass, herring, sturgeon, etc., to the upper waters of the Poto- 

 mac Ili%^er. Prior to the building of the original dam, it was possible 

 for many of these varieties offish to reach their spawning grounds ; but 

 of late years this has been rendered impossible, and, consequently, thv 

 supply has most materially decreased. Many of the fish of the Potomac 

 must have access to the upper waters of the river for the propagation 

 of their kind, suitable spawning grounds not occurring below the dam. 



Inasmuch as the injury above alluded to was brought about by an act 



