Doubling sockeye salmon production in the Fraser River—Is this sustainable development?

We evaluate a proposal to double sockeye salmon production from the Fraser River and conclude that significant changes will be required to current management processes, particularly the way available catch is allocated, if the plan is to be consistent with five major principles embodied in the concept of sustainable development. Doubling sockeye salmon production will not, in itself, increase economic equity either regionally or globally. Developing nations may actually be hindered in their attempts to institute other, nonsalmon fisheries in the North Pacific Ocean as a result of the possible interception of salmon. Further, other users of the Fraser River basin will have to forgo opportunities so that salmon habitat can be conserved. If doubling sockeye salmon production is to meet the goal of doing more with less, it will be necessary to develop more efficient technologies to harvest the fish. If increasing salmon production is to reflect the integration of environmental and economic decision making at the highest level, then a serious attempt must be made to incorporate environmental assets into national economic accounting. Finally, to promote biodiversity and cultural self-sufficiency within the Fraser River basin, it will be important to safeguard the small, less-productive salmon stocks as well as the large ones and to allocate a substantial portion of the increased production to the Native Indian community.     

SALMONID SMOLT SURVIVAL RELATIVE TO TURBINE EFFICIENCY AND ENTRAINMENT DEPTH IN HYDROELECTRIC POWER GENERATION1

ABSTRACT: The hypotheses that fish survival probabilities may be lower (1) at less than peak operating turbine efficiency; (2) at deeper entrainment depth; and (3) with the deployment of extended‐length intake guidance screens, are not supported by results on yearling chinook salmon smolts (Oncorhynchus tshawytscha) at Lower Granite Dam, Snake River, Washington. Estimated 96 h survival probabilities for the six test conditions ranged from 0.937 to 0.972, with the highest survival at turbine operating towards the lower end of its efficiency. A blanket recommendation to operate all Kaplan type turbines within ± 1 percent of their peak efficiency appears too restrictive. Cavitation mode survival (0.946) was comparable to that at peak operating efficiency mode (0.937), as was the survival between upper (0.947) and mid depths (0.937). Survival differed only slightly among three turbine intake bays at the same depth (0.937 to 0.954), most likely due to differential flow distribution. Extended‐length intake fish guidance screens did not reduce survival. However, the sources of injury somewhat differed with depth; probable pressure and shear‐related injuries were common on fish entrained at mid‐depth, and mechanically‐induced injuries were common at upper depth. Operating conditions that reduce turbulence within the turbine environment may enhance fish survival; however, controlled experiments that integrate turbine flow physics and geometry and the path entrained fish traverse are needed to develop specific guidance to further enhance fish passage survival.     

Caddis flies (Trichoptera) in the benthos and food of fish from streams of the Pechora-Ilych State Biosphere Reserve, the northern Urals

Data on the numbers and biomass of caddis fly species (Trichoptera) in the benthos and in the diets of fish from streams of the Pechora-Ilych State Reserve (the northern Urals) are provided. In the diets of grayling and juvenile Atlantic salmon caught in the rivers of the reserve, 17 and 10 species of caddis flies have been identified. As a rule, one to three species (in most cases, two species) prevail in the diet of fish.     

A TECHNIQUE FOR MEASURING SCOUR AND FILL OF SALMON SPAWNING RIFFLES IN HEADWATER STREAMS1

A 30 x 0.9 cm piece of steel rod bent in the shape of an “L” and attached by hose clamps to a 15 x 3.2 cm section of plastic pipe sliding on an 86 x 1.9 cm steel shaft was tested for use in measuring scour and fill of salmon spawning riffles. Installed along channel cross-sections, results of tests at four sites on two hydraulically different streams showed the device to be useful in monitoring event specific scour and fill. Measurement error was estimated to be ± 10 mm.