Multiple stressors in the Sacramento River watershed

Hinton, David E.

doi:10.1007/978-3-0348-8853-0_9

Cited by 8 publications

(5 citation statements)

References 34 publications

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“…Simultaneous exposure to Se and other major stressors in the S.F. Bay-Delta including Cd 2+ , Cu 2+ , Zn 2+ , Hg 2+ , herbicides, pesticides, temperature, water diversions and pumps, and exotic species are necessary to determine the composite response of white sturgeon to ecologically relevant stressors (Hinton 1998).…”

Section: Discussionmentioning

confidence: 99%

Influence of dietary l-selenomethionine exposure on the survival and osmoregulatory capacity of white sturgeon in fresh and brackish water

Tashjian

Cech

Hung

2007

Fish Physiol Biochem

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Near simultaneous exposure to selenium and salinity stress is an environmental reality faced by white sturgeon juveniles in the San Francisco Bay-Delta, having the potential for adverse synergistic impacts on juveniles during seaward migration. White sturgeon juveniles (36-132 g) were transferred into higher salinities (15-20 ppth) after exposure to dietary selenium (0.4, 9.6, 20.5, 41.7, 89.8, or 191.1 lg Se/g diet) in the form of L-selenomethionine (SeMet) for 8 weeks in freshwater (0 ppth). White sturgeon fed above 41.7 lg Se/g diet experienced significant (P < 0.05) declines in survival relative to sturgeon fed between 0.4 and 41.7 lg Se/g diet when transferred into brackish water (15 ppth salinity) for 3 days. Plasma osmolality and ionic concentrations in white sturgeon after abrupt transfer correlated positively with dietary Se concentrations. Transfer of white sturgeon fed above 41.7 lg Se/g diet into 20 ppth brackish water for 1 day resulted in significant declines in survival relative to white sturgeon fed 0.4-41.7 lg Se/g diet. Hematocrit and dehydrational weight loss were significantly correlated with dietary Se concentrations while plasma osmolality and ion concentrations were not. The transfer of sturgeon into 20 ppth water for 3 days resulted in severe survival declines in all treatment groups. The results of this study suggest that the previously established threshold for Se toxicity (10-20 lg Se/g) is sufficient to protect white sturgeon from the adverse interactive affects resulting from increases in dietary Se and ambient water salinity.

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Section: Discussionmentioning

confidence: 99%

Influence of dietary l-selenomethionine exposure on the survival and osmoregulatory capacity of white sturgeon in fresh and brackish water

Tashjian

Cech

Hung

2007

Fish Physiol Biochem

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“…It is important to note that allowing more San Joaquin River water to enter the Delta may have consequences in addition to increasing organic matter supply. The San Joaquin receives pesticide-laden agricultural drainage, as well as high selenium loads (Hinton, 1998). An increased loading of these materials to the Delta may have unforeseen effects on selected components of the food web.…”

Section: Isolated Diversion Channelmentioning

confidence: 99%

Organic matter sources and rehabilitation of the Sacramento-San Joaquin Delta (California, USA)

Jassby

Cloern

2000

Aquatic Conserv: Mar. Freshw. Ecosyst.

139

181

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1. The Sacramento-San Joaquin River Delta, a complex mosaic of tidal freshwater habitats in California, is the focus of a major ecosystem rehabilitation effort because of significant long-term changes in critical ecosystem functions. One of these functions is the production, transport and transformation of organic matter that constitutes the primary food supply, which may be sub-optimal at trophic levels supporting fish recruitment. A long historical data set is used to define the most important organic matter sources, the factors underlying their variability, and the implications of ecosystem rehabilitation actions for these sources.2. Tributary-borne loading is the largest organic carbon source on an average annual Delta-wide basis; phytoplankton production and agricultural drainage are secondary; wastewater treatment plant discharge, tidal marsh drainage and possibly aquatic macrophyte production are tertiary; and benthic microalgal production, urban run-off and other sources are negligible.3. Allochthonous dissolved organic carbon must be converted to particulate form -with losses due to hydraulic flushing and to heterotroph growth inefficiency -before it becomes available to the metazoan food web. When these losses are accounted for, phytoplankton production plays a much larger role than is evident from a simple accounting of bulk organic carbon sources, especially in seasons critical for larval development and recruitment success. Phytoplankton-derived organic matter is also an important component of particulate loading to the Delta. 4. The Delta is a net producer of organic matter in critically dry years but, because of water diversion from the Delta, transport of organic matter from the Delta to important, downstream nursery areas in San Francisco Bay is always less than transport into the Delta from upstream sources.5. Of proposed rehabilitation measures, increased use of floodplains probably offers the biggest increase in organic matter sources.6. An isolated diversion facility-channelling water from the Sacramento River around the Delta to the water projects-would result in substantial loading increases during winter and autumn, but little change in spring and summer when food availability probably matters most to developing organisms.7. Flow and fish barriers in the channel could have significant effects, especially on phytoplankton sources and in dry years, by eliminating 'short-circuits' in the transport of organic matter to diversion points.8. Finally, productivity of intentionally flooded islands probably would exceed that of adjacent channels because of lower turbidity and shallower mean depth, although vascular plants rather than phytoplankton could dominate if depths were too shallow.

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“…Declines of anadromous salmonid populations have been attributed to many factors, including construction and operation of dams, loss of marshlands and estuaries, river‐water allocation for cities and farms, overfishing, and pollution [6]. The delta region of California, USA, formed by the confluence of the San Joaquin and Sacramento rivers, is one area where fish populations have declined severely because of anthropogenic activities [7]. All natural chinook salmon ( Oncorhynchus tshawytscha ) populations have declined in California, some even to extinction [6], and are now provided access to only 20% of their historical spawning and rearing habitat in the Sacramento‐San Joaquin watershed [8].…”

Section: Introductionmentioning

confidence: 99%

Synergistic effects of esfenvalerate and infectious hematopoietic necrosis virus on juvenile chinook salmon mortality

Clifford

Eder

Werner

et al. 2005

Enviro Toxic and Chemistry

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Sublethal concentrations of pollutants may compromise fish, resulting in increased susceptibility to endemic pathogens. To test this hypothesis, juvenile chinook salmon (Oncorhynchus tshawytscha) were exposed to sublethal levels of esfenvalerate or chlorpyrifos either alone or concurrently with infectious hematopoietic necrosis virus (IHNV). Three trials were performed with fish exposed to concentrations of IHNV between 0.8 x 10(2) and 2.7 x 10(6) plaque-forming units/ml and to 5.0 microg/L of chlorpyrifos or 0.1 microg/L of esfenvalerate. The presence and concentration of IHNV in dead fish were assayed by virus isolation and plaque assay techniques, respectively. Among groups exposed to both esfenvalerate and IHNV, 83% experienced highly significant (p < 0.001) mortality, ranging from 20 to 90% at 3 d post-virus exposure, and cumulatively died from 2.4 to 7.7 d sooner than fish exposed to IHNV alone. This trend was not seen in any other treatment group. Virus assays of dead fish indicate a lethal synergism of esfenvalerate and IHNV. Chlorpyrifos had no observed effect on total mortality or IHNV susceptibility. The present results suggest that accepted levels of pollutants may be seemingly nonlethal to fish but, in fact, be acting synergistically with endemic pathogens to compromise survivorship of wild fish populations through immunologic or physiologic disruption.

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Multiple stressors in the Sacramento River watershed

Cited by 8 publications

References 34 publications

Influence of dietary l-selenomethionine exposure on the survival and osmoregulatory capacity of white sturgeon in fresh and brackish water

Influence of dietary l-selenomethionine exposure on the survival and osmoregulatory capacity of white sturgeon in fresh and brackish water

Organic matter sources and rehabilitation of the Sacramento-San Joaquin Delta (California, USA)

Synergistic effects of esfenvalerate and infectious hematopoietic necrosis virus on juvenile chinook salmon mortality

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