The sizes of salmonid spawning gravels

The availability of suitably sized spawning gravels limits salmonid (salmon and trout) populations in many streams. The authors compiles published and original size distribution data to determine distinguishing characteristics of spawning gravels and how gravel size varies with size of the spawning fish. Median diameters of 135 size distributions ranged from 5.4 to 78 mm, with 50% falling between 14.5 and 35 mm. All but three spawning gravel size distributions were negatively skewed (on a log-transformed basis), with 50% of the skewness coefficients falling between [minus]0.24 and [minus]0.39. Fewer than 20% of the distributions were bimodal. Although tending to be coarser, spawning gravels had sorting and skewness values similar to other fluvial gravels reported in the literature. The range of gravel sizes used by fish of a given species or length is great, but the relation between fish size and size of gravel can be described by an envelope curve. In general, fish can spawn in gravels with a median diameter up to about 10% of their body length. 53 refs., 8 figs., 2 tabs.

[1]  G. Kondolf,et al.  Modification of fluvial gravel size by spawning salmonids , 1993 .

[2]  D. T. Crisp,et al.  Observations on siting, dimensions and structure of salmonid redds , 1989 .

[3]  M. Sale,et al.  Distribution and Stability of Potential Salmonid Spawning Gravels in Steep Boulder-Bed Streams of the Eastern Sierra Nevada , 1991 .

[4]  K. Koski The survival of coho salmon (Oncorhynchus kisutch) from egg deposition to emergence in three Oregon coastal streams , 1965 .

[5]  K. Warner Natural Spawning Success of Landlocked Salmon, Salmo salar , 1963 .

[6]  Thomas E. Lisle,et al.  Sediment Transport and Resulting Deposition in Spawning Gravels, North Coastal California , 1989 .

[7]  Robert L. Folk,et al.  Petrology of Sedimentary Rocks , 1974 .

[8]  W. C. Krumbein Flood deposits of Arroyo Seco, Los Angeles County, California , 1942 .

[9]  James W. Burns SPAWNING BED SEDIMENTATION STUDIES IN NORTHERN CALIFORNIA STREAMS 1 , 1970 .

[10]  R. Beschta,et al.  Gravel Bed Composition in Oregon Coastal Streams1 , 1980 .

[11]  W. C. Krumbein Flood gravel of San Gabriel Canyon, California , 1940 .

[12]  J. Schlee UPLAND GRAVELS OF SOUTHERN MARYLAND , 1957 .

[13]  D. Inman,et al.  Measures for describing the size distribution of sediments , 1952 .

[14]  E. O. Salo,et al.  The effects of logging road landslide siltation on the salmon and trout spawning gravels of Stequaleho Creek and the Clearwater River basin, Jefferson Co., WA , 1979 .

[15]  Donald R. Orcutt,et al.  Characteristics of Steelhead Trout Redds in Idaho Streams , 1968 .

[16]  William J. Plumley,et al.  Black Hills Terrace Gravels: A Study in Sediment Transport , 1948, The Journal of Geology.

[17]  John W. Tukey,et al.  Exploratory Data Analysis. , 1979 .

[18]  M. Gross,et al.  Female Size and Nest Depth in Coho Salmon (Oncorhynchus kisutch) , 1984 .