The Suinrey 



1. Main Salmoa River* — (July 20-23, 1941; Bryant), The main 

 Salmon extends for approximately 400 miles. In the lower 200 miles 

 it flows through the second deepest oanyon on the North American con- 

 tinent. This part of the river has a fairly steep gradient and little 

 suitable spawning area. The upper terminus of the oanyon is near Shoup, 

 Idaho. 



The strecun gradient is modejrate above the oanyon, and a large 

 amo\mt of spawning area was found. The stream bed was heavily silted 

 for a distance of approximately 161 miles from Shoup to Stanley, and 

 many otherwise good spawning riffles in iiiis sirea were considered of 

 doubtful value for the development of salmon eggs. This condition was 

 due to mining operations, the principal source of silting being a large 

 gold dredge opei*ating on Yankee Fork, although there were other dredges 

 and mines on both the main stream and some of its tributaries which were 

 contributing to this condition. Among these were the mine on the North 

 Pork near Gibbonsville, the silver mine at Clayton on the main Salmon, 

 «uad the operations on Valley Creek near Stanley* 



The effects of turbid water and a heavily silted stream bed on 

 the migration and spawning activities of salmon have not been agreed 

 upon by all fisheries investigators. Many instances are recorded where 

 salmoB migrate through very turbid water with apparently no ill effects. 

 Salmon often have been observed spawning in silted streams, suid their 

 spawning activity has the effect of washing the gravel and making the 

 nests easily distinguishable from the remainder of the stream bed. The 

 subsequent silting of the nests however, may be very harmful to the 

 development of the eggs, depending in large measure on the extent to 

 iriiioh it occurs. This has been well demonstrated by Hobbs (1937)« 

 Shapovalov and Berrian (1940), Smith (1940), and others. In the Salmon 

 River, silting has been so extensive as to constitute a serious hazard 

 in the development of salmon eggs* There is no practical remedy for 

 this condition* 



There is excellent spawning area, free of pollution, for a distance 

 of about 35 miles above Stanley. There sre numerous small side ohemnels 

 in this area where flows of 5-6 o.f.s. are maintained by constant cold 

 springs, and which serve as perfect natural rearing places for salmonoid 

 fry. This area with its tributaries at present supports small, greatly 

 depleted runs of chinook and blue back salmon and a fair spring ran of 

 steelhead trout* There are several tributary lakes in the headwaters 

 that offer suitable habitats for bluebaok salmon. These include Alturas, 

 Pettit, Yellow Belly, Little Redfish, and Big Redfish lAkes, all of which 

 were studied by Bvermazm (1895, 1696, 1897). The main Salmon River was 



