2G4 BULLETIN OF T1IK UNITED STATES FISH COMMISSION. 



73 THE INJURIOUS EFFECTS OF RAFTING ON THE 1-AKE ANO 



RIVER FISHERIES OF SWEDEN.* 



By Prof. A. J. MAOIGBE1V. 



Freshwater fisheries. — In those parts of onr country where 

 these fisheries have been carried on with proper care, they have on the 

 whole not undergone any great changes, and have even in some places 

 become^more productive. From most places, however, it is reported 

 that the freshwater fisheries, even in localities where formerly they were 

 very productive and furnished profitable employment to a large class 

 of our people, have declined to such a degree as to make them unprof- 

 itable. The causes of this state of affairs vary very considerably. 

 Through the sinking and draining of lakes the fisheries have in some 

 places undergone considerable changes ; the area of fishing waters has 

 decreased, while the area of cultivated ground, and with it the popula- 

 tion, has increased. In several localities the fisheries have become less 

 productive through the constantly increasing rafting, as thereby it has 

 become difficult and even sometimes impossible for the fish to go to 

 their accustomed spawning places. Saw-mills and other industrial es- 

 tablishments have also had an injurious influence on the fisheries, both 

 by the construction of dikes and by the refuse which is thrown into the 

 water and renders it uninhabitable for fish. 



Many complaints come from the district of Gefleborg that both the. 

 sea and river fisheries have decreased, especially the salmon fisheries, 

 owing to the increased rafting in the rivers. The same applies to the 

 sea fisheries in the districts of Westemorrland, Westerbotten, and Norr- 

 botten. From all the northern districts it is reported that the fisheries 

 have decreased, and among the causes is mentioned the increased num- 

 ber of saw-mills, which, especially the smaller ones, throw considerable 

 quantities of sawdust into the water, so as sometimes to cover the bottom 

 entirely. 



At Atrau (in the district of Halland) the salmon fisheries, which in 

 1875, according to a report made by Maj. M.Kilman, yielded an income 

 of $0,51)5.77, have now declined to such a degree as only to yield $2,282,50 

 in ISO. As the cause of this there is assigned the disturbing of the 

 spawning places by excessive quantities of bark from lumber which is 

 rafted dowu the river, which rafting has been going on for years and 

 is on the increase. 



The lake fisheries of the Kalmar district. — It is reported 

 from Jareda, in the county of Aspeland, that in the river Em, which 

 Hows through the .Jam Lake, many salmon were caught in former times, 



'* Om tlmmerjlotl nivgens skadlighet pa insjS- och flqdfislcet." From Report of theSwe- 

 lish Fish Commission, March 3,1883. Translated from the Swedish hy Herman 

 •acc^son. 



