|Document Type:||Journal Article|
|Title:||Characteristics of spawning nests of Columbia River salmon|
|Author:||Clifford J. Burner|
One of the many problems in the relocation of salmon is that of determining how many spawners should be placed in each new stream. A study was made of the spawning habits of four species of Pacific salmon of the genus Oncorhynchus in the Columbia River watershed; 850 nests of chinook, silver, chum, and blueback salmon were measured. Mechanics of redd building, average size and depth or nests, size of gravel used, and stream conditions that modify these, are described in this report.
In general, the salmon chose stream-bed areas composed of gravel less than 6 inches in greatest diameter; percolation of water through the gravel appeared to be a requisite. In square yards, sizes of the redds were 6.1 for summer and fall chinook, 3.9 for spring chinook, 3.4 for silver, 2.7 for chum, and 2.1 for blueback. Spacing between redds was about three times the size of the redds. A conservative estimate of the number of salmon that may satisfactorily spawn in a stream can be made by dividing the stream area suitable for spawning by four times the average redd area.