temperature, dissolved oxygen content, veloc- 

 ity, mineral and waste metabolite content, 

 and osmotic pressure. Osmotic pressure is 

 especially important where spawning occurs 

 in intertidal areas of streams. 



To prosper, an embryo or larva must re- 

 ceive an ample supply of oxygenated water 

 of suitable temperature and free of toxic 

 substances. Thus, the quality of water within 

 a spawning bed may limitthenumber of salmon 

 produced. Size composition of bottom materials 

 greatly influences water quality by affecting 

 rates of flow within spawning beds and rates of 

 exchange between intragravel ^ and stream 

 water. 



The presence of fine particles in spawning 

 beds (viz, sands and silts) increases egg and 

 larval mortality of several salmonid species 

 (Harrison, 1923; Shapovalov, 1937; Shaw and 

 Maga, 1943;Shelton, 1955; Lucas, 1960; Andrew 

 and Geen, 1960; Cordone and Kelley, 1961). 

 The presence of fine materials in spawning 

 beds reduces their permeability, and according 

 to Wickett (1958), survival of pink and chum 

 (O.ket a) salmon eggs and larvae is related di- 

 rectly to permeability. 



Equipment has been developed to measure 

 permeability of salmon spawning beds in situ 

 (Terhune, 1958). There is a possibility that 

 the size composition of bottom materials in 

 spawning beds affords an equally satisfactory 

 index of streambed quality as it relates to 

 egg and larval survival. It is the purpose of 

 this report to (1) describe a method for meas- 

 uring size composition of bottom materials in 

 salmon spawning beds, (2) show a relationship 

 between content of fine materials and per- 

 meability of spawning beds, (3) describe dif- 

 ferences in size composition and permeability 

 of spawning beds in streams supporting low to 

 high densities of spawning adult pink salmon, 

 and (4) demonstrate the occurrence of tem- 

 poral variations in size composition associated 

 with spawning, logging, and flooding. 



effects of logging on pink salmon streams in 

 Alaska. Observations were made mostly in 

 streams located near HoUis on Prince of Wales 

 Island. Financial suport for these studies was 

 provided by the Bureau of Commercial Fish- 

 eries, U.S. Fish and Wildlife Service, with 

 Saltonstall-Kennedy Act funds. Assistance with 

 field sampling studies was given by the North- 

 ern Forest Experiment Station, U.S. Forest 

 Service, Juneau. 



FIELD MEASUREMENT OF SIZE 

 COMPOSITION 



Perhaps the simplest technique for deter- 

 mining size composition of spawning bed 

 materials was employed by Burner (1951), 

 who approximated visually the relative amounts 

 of large, medium, and small gravel in redds. 

 A more analytical classification of gravels in 

 Pacific salmon redds was undertaken by Cham- 

 bers, Allen, and Pressey (1955), who isolated 

 small areas of stream bottom from the in- 

 fluence of current with open cylinders. Gravel 

 was removed from within the cylinders with 

 a scoop, washed through a series of sieves, 

 and weighed. Hatch (1957) collected bottom 

 materials with a spade that had a hood enclos- 

 ing the upper section of blade. In a laboratory, 

 he analyzed bottom materials for sand, silt, 

 and clay content. 



Collecting Samples 



We developed a bottom sampler suitable 

 for use in shallow water and in gravel after 

 several types of samplers were tried and 

 found to have a common deficiency — none 

 retained silt going into suspension. Further- 

 more, samplers with mechanically operated 

 closures did not function successfully at all 

 times in coarse gravel and rubble, and certain 

 sampling techniques required the collection of 

 large quantities of bottom materials that could 

 not be sorted and classified quickly. 



The size composition of bottom materials 

 was studied as part of an investigation of the 



'The term "intragravel water" is used to describe 

 water occupying interstitial spaces within the stream- 

 bed. 



Samples of bottom materials were removed 

 from the streambed with the sampler (fig. 1). 

 The sampler is stainless steel and is round 

 in cross section. The tube of the sampler was 

 worked manually to a depth of 6 inches. Con- 

 tents of the tube were dug by hand and lifted 



