XIV.— IS SAWDUST INJURIOUS TO THE FISHERIES? 



[From report of Mr. A. Landmark, iuspector of fisheries, on the condition of the Nor- 

 wegian fresh-water fisheries during the years 1376-1879.]* 



Before giving an account of the Norwegian river fisheries during the 

 years 1876-1879 and reporting the result of the salmon fisheries during 

 the same period, I must briefly dwell on some injurious influences to 

 which our salmon and sea trout fisheries are exposed, and which hith- 

 erto have either not at all or but insufficiently been reached by legis- 

 lation. 



Among these injurious influences I must first of all mention the very 

 general custom of throwing sawdust and other refuse from the saw-mills 

 into the river. It is well known that at present our fishery laws con- 

 tain no provision prohibiting this practice. Those prohibitory regula- 

 tions which have been made in the interest of navigation (laws of Au- 

 gust 12, 1848, August 26, 1854, and March 24, 1860) are of no practical 

 benefit to the fisheries, because they exempt the owners of saw-mills 

 from the duty incumbent upon all other manufacturers of gathering 

 their refuse, and merely compel them to contribute something towards 

 the expenses of dredging the rivers, which benefits navigation only. 

 This arrangement is very unsatisfactory as far as the fisheries are con- 

 cerned, for the refuse from saw- mills, and more especially the sawdust 

 proper, is, in various ways, injurious to the fisheries. Sawdust gradu- 

 ally sinks to the bottom, and thus fills the very place where the fish eggs 

 are to develop with impure and injurious matter. Salmon eggs, to which 

 we here have special reference, require for their development a clean 

 bottom, covered with small stones, pebbles, or sand. When brought 

 into contact with sawdust or any other rotting wooden matter for any 

 length of time, the eggs are overgrown by a species of fungus, which 

 invariably kills the germ contained in the o.gg, and is all the more inju- 

 rious because it spreads very rapidly from one egg to the other. It is 

 true that it is scarcely probable that very large masses of sawdust will 

 gather in those parts of the rivers where the salmon spawn, because in 

 these places the current is generally ver y rapid; but still a considerable 



* " Om Sagflisens Skadelighed for Fiskerierne." From "Iudberetning fra Fiskeii- 

 Inspectoren angaaende hvad der til Fcrskvandstiskeri ernes Fremme er udf ort og om 

 disses Tilstand i Aarene 187(5-1879." Chriatiania, 1881.— Translated by Herman 

 Jacobson. ggg 



S. Miss. 59 40 



