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THE INFLUENCE OF ENGINEERING DESIGN AND OPERATION AND OTHER ENVIRONMENTAL FACTORS ON RESERVOIR FISHERY RESOURCES 1
Author(s) -
Jenkins Robert M.
Publication year - 1970
Publication title -
jawra journal of the american water resources association
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.957
H-Index - 105
eISSN - 1752-1688
pISSN - 1093-474X
DOI - 10.1111/j.1752-1688.1970.tb00443.x
Subject(s) - thermocline , standing crop , environmental science , shore , hydrology (agriculture) , surface water , fishery , oceanography , geology , environmental engineering , biology , geotechnical engineering , biomass (ecology)
The apparent effect of selected reservoir environmental variables‐including surface area, mean depth, outlet depth, thermocline depth, water level fluctuation, storage ratio, shore development, total dissolved solids, growing season and age of reservoir–on fish standing crop in 140 large impoundments has been explored through partial correlation and multiple regression analyses. The sample was partitioned into 25 subsamples based on reservoir use type, water exchange rate, thermocline formation and water chemistry. Fish standing crops were estimated by summer rotenone sampling of coves or open water areas enclosed by blockoff net. Logarithmic partial correlation revealed highly significant (0.01 confidence shore development and dissolved solids on At the 0.20 confidence level, the crop of storage ratio and shore level) positive effects of outlet depth, total standing crop in the entire sample. all sport fishes is positively influenced by outlet depth, development and negatively by mean depth. In 54 hydropower reservoirs with a stable thermocline, positive effects of increased storage ratio and dissolved solids on t o t a l crop are evident at the 0.05 confidence interva. Increase in thermocline depth has a negative effect. In 25 hydropower reservoirs without a stable thermocline, clupeid (shad) crop is negatively correlated with surface area, mean depth and fluctuation. Reservoirs with a thermocline have higher standing crops than those without. At the species or species group level, partial correlation of nine environmental variables a t the 0.05 confidence interval reveals: Positive effect of surface area on pike and pickerel; buffalo‐fishes, white crappie and total sport fish crop; positive effect of outlet depth on largemouth bass, catfishes, total sport fish crop and buffalofishes; a negative effect of water level fluctuation on pike and pickerel, redear sunfish and gizzard shad; a positive relationship between storage ratio and channel catfish and bull‐ heads and a negative one with flathead catfish and suckers; a positive effect of total dissolved solids on black and whit basses, catfishes, gizzard shad, carpsuckers and carp. A morphoedaphic expression, total dissolved solids divided by mean depth, provides a useful index t o reservoir fish production. The relationship is curvilinear, with maximum crops expected at index values of 5 t o 30.The index accounts for 62 percent of the variability in hydropower storage reservoir crops. Several multivariable regressions have been derived f o r predictive purposes. Examples are included, with R values of 35 t o 60.