FISHERIES OF ALASKA, 1908. 



55 



be separated by bending the tail. These fish were probably dying 

 from disease. The Atlantic salmon in Europe is subject to a disease 

 uniformly characterized by fungus, which was supposed by Huxley 

 to be the cause. Later it was found to be a bacterial disease, the 

 fimgus attacks l^eing secondary. It was impossible to make a 

 bacterial examination of the Wood River salmon, but it was difficult 

 to account for the injuries as due alone to external causes. The 

 mortalit}^ here referred to has nothing to do with the natural death 

 of salmon after spawning. 



Wliile salmon with abraded and bleeding surfaces frequently or 

 usually become fungused, many salmon showed white patches on 

 head or body which resembled fungus while the fish was in the water, 

 but which on close inspection seemed to be merely white areas ap- 

 parently caused by rubbing against stones on the bottom of the 

 stream. This explanation, however, is not entirely satisfactory, as 

 it is not understood why salmon still green, as many were, should have 

 occasion so far from spawnmg grounds to perform movements which 

 irritate the skin so extensively. Migrating salmon do not usually 

 permit their bodies to come in contact with any solid surface, not 

 even with each other, provided lack of space does not compel them 

 to crowd together. In the spawning streams they may, of course, 

 mass themselves in intimate contact. 



The latter part of July, as the run decreased rapidly, the percentage 

 of fish, which, from their appearance as they passed the gate or tun- 

 nels were classed as "injured fish,',' was seen to be increasing. From 

 July 22 to 26 a tally of such fish was made at intervals, and from 21 

 to 35 per cent were found to be thus "injured." This tally takes in 

 any fish showing white patches (whether fungused or not), ragged 

 skin, or white or broken snouts. 



The injuries to the snout or nose were quite common late in the 

 season and some of these may have been caused by constant jamming 

 of the head into the meshes of the web. 



Daily Tally of Red Salmon into Lake Aleknagik during the Summer op 



1908. 



