Some fall Chinook salmon Oncorhynchus tshawytscha initiate spawning in the Snake River downstream of Hells Canyon Dam at temperatures that exceed 138C and at intergravel dissolved oxygen concentrations that are less than 8 mg O 2 /L. Although water temperature declines and dissolved oxygen increases soon after spawning, the initial temperature and dissolved oxygen levels do not meet the water quality standards established by the states of Oregon and Idaho for salmonid spawning. Our objective was to determine whether temperatures from 138C to 178C and dissolved oxygen levels from 4 to more than 8 mg O 2 / L during the first 40 d of incubation followed by declining temperature and rising dissolved oxygen affected survival, development, and growth of Snake River fall Chinook salmon embryos, alevins, and fry. During the first 40 d of incubation, temperatures were experimentally adjusted downward approximately 0.28C/d and oxygen was increased in increments of 2 mg O 2 /L to mimic the thermal and oxygen regime of the Snake River where these fish spawn. At 40 d postfertilization, embryos were moved to a common exposure regime that followed the thermal and dissolved oxygen profile of the Snake River through emergence. Mortality of fall Chinook salmon embryos increased markedly at initial incubation temperatures of 178C or more, and a rapid decline in survival occurred between 16.58C and 178C; there were no significant differences in survival at temperatures up to 16.58C. Initial dissolved oxygen levels as low as 4 mg O 2 /L over a range of initial temperatures from 158C to 16.58C did not affect embryo survival to emergence. There were no significant differences in alevin and fry size at hatch and emergence across the range of initial temperature exposures. The number of days from fertilization to eyed egg, hatch, and emergence was highly related to temperature and dissolved oxygen; fish required from 6 to 10 d longer to reach hatch at 4 mg O 2 /L than at saturation and up to 24 d longer to reach emergence. In contrast, within each dissolved oxygen treatment, fish required about 20 d longer to reach hatch at 138C than at 16.58C (no data were available for 178C) and up to 41 d longer to reach emergence. Overall, this study indicates that exposure to water temperatures up to 16.58C will not have deleterious effects on survival or growth from egg to emergence if temperatures decline at a rate of 0.28C/d or more after spawning. Although fall Chinook salmon survived low initial dissolved oxygen levels, the delay in emergence could have significant long-term effects on their survival. Thus, an exemption to the state water quality standards for temperature-but not oxygen-may be warranted for the portions of the Snake River where fall Chinook salmon spawn.

No abstract

SummaryAt the request of the U.S. Army Corps of Engineers (USACE), Portland District, the Pacific Northwest National Laboratory (PNNL) conducted research to measure the concentration of total dissolved gas (TDG) in chum salmon (Oncorhynchus keta) spawning areas downstream of Bonneville Dam and to assess the impact of elevated dissolved gas on chum salmon survival. Spring spill at the dam occurs when chum salmon sac fry are still in the gravel. Prior to this study, no data existed on the concentration of TDG within the incubation habitat of riverbed gravels. Further, little research has been conducted recently on the effects of gas supersaturation on incubating and larval stages of salmonids. A literature review early in this study suggested that impacts to chum salmon sac fry could occur at gas levels as low as 103% TDG, but this had not been studied previously on this species. The overall goal of the study was to evaluate potential impacts on chum salmon survival and development from elevated TDG that occurs during spring spill operations at Bonneville Dam. Specifically, we were interested in learning whether chum salmon were impacted by TDG under a range of hydraulic conditions created downstream from Bonneville Dam and also in determining physiological response to a range of TDG levels.The study was conducted over a three-year period from 2006 through 2008 and included both a field and laboratory component. The field component consisted of measuring total dissolved gas levels in the riverbed at egg pocket depth as well as in the river at chum salmon spawning sites below Bonneville Dam in the Ives Island and Multnomah Falls areas. In addition, chum salmon sac fry were sampled from natural redds in 2007 and from artificial egg tubes in 2008 to determine if there was a physiological response to TDG that resulted from operations at Bonneville Dam. The laboratory component consisted of a two-year study (2007 and 2008) using toxicity tests on hatchery chum salmon fry at several static gas levels ranging up to 113% TDG; an additional incremental exposure to TDG levels up to 129% was conducted in 2008.Results from the field and laboratory components of this study conducted in 2006 and 2007 were submitted previously in annual reports to the USACE and, with the exception of occasional references to those results, will not be repeated here. This report covers the field and laboratory components of this study that were conducted in 2008. The 2008 research activities resulted in six key findings:• Chum salmon sac fry in the Ives Island area were exposed to depth-compensated TDG greater than 103% for up to 200 hours and greater than 105% for up to 100 hours. These exposure times represent up to 8% and 4%, respectively, of the total estimated 2008 incubation time.• Most exposure occurred prior to spring spill during 2008 when the Bonneville Dam corner collector was operating. This finding contrasts with previous years' monitoring when exposure to elevated TDG was distributed before and after the onset of spring spill.• Chu...

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Pacific Northwest National Laboratory (PNNL), one of the U.S. Department of Energy (DOE) Office of Science's 10 national laboratories, provides innovative science and technology development in the areas of energy and the environment, fundamental and computational science, and national security. DOE's Pacific Northwest Site Office (PNSO) is responsible for oversight of PNNL at its Campus in Richland, Washington, as well as its facilities in Sequim, Seattle, and North Bonneville, Washington, and Corvallis and Portland, Oregon.This site environmental report provides a synopsis of ongoing environmental management performance and compliance activities conducted during 2012. The report addresses the operations occurring on the PNNL Campus in Richland, Washington, which includes PNNL Site facilities, Battelle Land-Richland (Battelle privately owned land in Richland), Battelle-owned and -leased facilities, and DOE Office of Science-owned land and exclusive-use facilities. Environmental activities at other locations are also included if they are under PNNL's responsibility (e.g., a permitted waste storage and treatment unit on the Hanford Site). The report also includes environmental information regarding the PNNL Marine Sciences Laboratory (MSL) and Battelle Land-Sequim (Battelle privately owned land located near Sequim, Washington). It includes a description of the location and background for each facility; addresses compliance with all applicable DOE, federal, state, and local regulations and sitespecific permits; documents environmental monitoring efforts and status; presents potential radiation doses to staff and the public in the surrounding areas; and describes DOE-required data quality assurance methods used for data verification.