74 Salmonidas 



July, just before the running season, therefore coming in from 

 the open sea. The great majority of the quinnat salmon, and 

 probaby all the blue-back salmon, enter the rivers in the spring. 

 The run of the quinnat begins generally at the last of March; 

 it lasts, with various modifications and interruptions, until 

 the actual spawning season in November, the greatest run being 

 in early June in Alaska, in July in the Columbia, The run 

 begins earliest in the northernmost rivers, and in the longest 

 streams, the time of running and the proportionate amount 

 in each of the subordinate runs varying with each different 

 river. In general the runs are slack in the summer and increase 

 with the first high water of autumn. By the last of August 

 only straggling blue-backs can be found in the lower course of 

 any stream; but both in the Columbia and in the Sacramento 

 the quinnat runs in considerable numbers at least till October. 

 In the Sacramento the run is greatest in the fall, and more run 

 in the summer than in spring. In the Sacramento and the 

 smaller rivers southward there is a winter run, beginning in 

 December. The spring quinnat salmon ascends only those 

 rivers which are fed by the melting snows from the mountains 

 and which have sufficient volume to send their waters well out 

 to sea. Those salmon which run in the spring are chiefly adults 

 (supposed to be at least three years old). Their milt and spawn 

 are no more developed than at the same time in others of 

 the same species which have not yet entered the rivers. It 

 would appear that the contact with cold fresh water, when 

 in the ocean, in some way causes them to run towards it, and 

 to run before there is any special influence to that end exerted 

 by the development of the organs of generation. High water 

 on any of these rivers in the spring is always followed by an 

 increased run of salmon. The salmon-canners think and this 

 is probably true that salmon which would not have run till 

 later are brought up by the contact with the cold water. The 

 cause of this effect of cold fresh water is not understood. We 

 may call it an instinct of the salmon, which is another way of 

 expressing our ignorance. In general it seems to be true that 

 in those rivers and during those years when the spring run is 

 greatest the fall run is least to be depended on. 



The blue-back salmon runs chiefly in July and early August, 



