392 



REPORT OF COMMISSIONER OF FISH AMD FISHERIES. [30] 



ing the average yield of fisheries and their actual vahie, for avseertainiiij;- 

 the iudemuity to be paid for any damage done to the fishing waters, and 

 such matters. ^ 



It is exceedingly important to be able to decide whether an increase 

 or decrease in the yield of fisheries is to be considered as a continual 

 increase or decrease in the quantity of fish, or is simi)ly caused by the 

 changes to which all fisheries seem to be subject ; and, if so, if any pe- 

 riodicity in the course of the fisheries can be observed. In certain cases 

 it will be easy to show unniistokable causes of a decrease in fisheries, 

 but in most cases this will be exceedingly difficult, and even impossible, 

 without statistical data. As an exceedingly interesting exajnplc of the 

 changes to which fisheries are subject, I give below^ a table showing 

 the quantity of salmon caught in a hixpata (a sort of salmou-trai)) at 

 Svarto, on the Lulea River. The laxpata is a contrivance consisting 

 of piles and nets, w^here the salmon enters and is taken out with special 

 nets. These traps are set in the rivers in spring as soon as the depth 

 of the water Avill alloAV it. The Svarto fishing station is near the mouth 

 of the Lulea River, and is therefore not influenced by fisheries further 

 down the stream. 



Tahlc shoivuio the ji^ihintj -season, a7i(l the quantity of salmon caught at the Svarto fish in ij 

 station during the period 1804 to 1880. 



1 ILvnuiul n/iiiala ab^ut 18.0 DOnndu. 



