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FISHERY BULLETIN OF FISH AND WILDLIFE SERVICE 



Alaska. At maturity they average about 9K 

 pounds in weight and about 24 inches in length. 



In the upper Toutle and Green River tribu- 

 taries of the Columbia, the silver salmon occupied 

 many of the same spawning areas as the fall 

 chinooks, and the two species were found spawn- 

 ing at the same time. 



In general, the sUver salmon apparently prefered 

 small streams flowing only 3 or 4 cubic feet a 

 second and were present in a number of localities 

 not occupied by the chinook salmon. A compari- 

 son of the nesting habits of the two species was 

 obtained at a point where the Toutle River is 

 divided by a large bar into a broad and a narrow 

 channel. The small, 3-foot-wide watercourse was 

 populated exclusively by silver salmon. The 

 wider run, nearly 60 feet across, contained only 

 fall-chinook salmon. In the shallower upper 

 reaches of the Green River tributary, the two 

 species spawned virtually side by side. 



The silver salmon demonstrated a redd-building 

 versatility that was not equalled by other species. 

 In the small Beaver Creek tributary of the Green 

 River, a stream of less than 2 cubic feet a second, 

 the bottom was composed of flat chunks of slate- 

 shale rubble that defied classification by the usual 

 gravel standards. The silvers were paired off 

 and spawning in stream-width redds that were end 

 to end for a distance of nearly 2 miles. In the 

 Toutle River, immediately below Spirit Lake, 

 silver-salmon redds assumed bizarre shapes, both 

 in surface outline and in bottom contour, as the 

 fish dug around embedded boulders and fallen 

 trees. This was the only salmon of the four 

 species whose redds contained up to 10 percent 

 mud. The gravel composition of silver-salmon 

 redds is shown in figure 56 and the size frequency 

 of the redds is shown in figure 7. 



CHUM SALMON 



Chum salmon are found in rivers of the Pacific 

 coast from Oregon to the Arctic Ocean and in 

 streams of the northern Japanese islands. In the 

 Columbia River these salmon spawn mainly in 

 the small tributaries only a short distance from 

 the sea. They average 26 inches in length and 

 weigh about 10 pounds at maturity. 



The streams selected for a study of chum- 

 salmon spawning, Germany Creek, Abernethy 

 Creek, Elokomin River, and Grays River, are 

 tributaries of the lower Columbia River and only 



a few miles apart. The chum salmon did not 

 migrate far upstream, and in Abernethy Creek 

 some spawned in tidal water so that the redds were 

 uncovered and dry at the surface during a part of 

 each day. Several of the redds were examined 

 when exposed, and live ova were found in the 

 damp gravel of the nest. At high water, these 

 redds were occupied by spawners, but it was not 

 determined whether they were the original 

 occupants. 



Chum salmon were also found spawning in 

 water just deep enough to cover the lateral line of 

 the fish. When distm-bed they would dash out 

 of the water onto the banks and flop back into the 

 stream. In thickly populated sections, the redds 

 were ill-defined and overlapped from end to end 

 and laterally. The riffles contained hundreds of 

 opaque dead eggs and a few lives ones. Because 

 of the abundance of spawners and the overlapping 

 of nests, it was necessary to select redds for study 

 on the basis of their individuality of outline and 

 apparent maturity. These salmon were more 

 easily frightened than the other species so that it 

 was difficult to determine whether the females 

 were in continuous possession of their redds. In 

 a few instances it was definitely determined that 

 the same females occupied their nests for at least 

 3 days. 



Of 66 chum-salmon redds measured, the average 

 size was 2.7 square yards (fig. 5b, circle J). The 

 proportions of large, medium, and small gravel 

 were similar to the proportions for most of the 

 other species. Chum salmon, even more than 

 other species, avoided firmly cemented gravel 

 bottom and spawned in sections of moderately 

 bound rubble where subgravel flow or percolation 

 was evident. 



BLUEBACK SALMON 



Blueback salmon is the name applied to the 

 species 0. nerka within the Columbia River System 

 and a few neighboring streams. In Puget Sound 

 and British Columbia they are called sockeye, 

 and in Alaska, red salmon. In the Columbia 

 River, blueback salmon average 3 pounds in 

 weight and 20 inches in length. 



The blueback salmon differs from all the other 

 species in that the spawning redds, with few 

 exceptions, are made only in streams tributary 

 to lakes or along lake shores. The young salmon, 

 on emerging from the gravel of the nest, descend 



