Michael Saiki - Academia.edu (original) (raw)

Papers by Michael Saiki

Research paper thumbnail of Mean Bulk Index Method of Fish Food Analysis

Http Dx Doi Org 10 1577 1548 865938 55 Mbimof 2 0 Co 2, Jan 9, 2011

Various techniques for analyzing the stomach contents of fish are available to fishery biologists... more Various techniques for analyzing the stomach contents of fish are available to fishery biologists. The more popular methods (frequency of occurrence, enumeration, volumetric, and gravimetric) were discussed by and by Lagler (1956). Although these methods (except for frequency of occurrence) quantify the importance of different food items, they require tedious sorting and measuring, and are very time-consuming.

Research paper thumbnail of Mean Bulk Index Method of Fish Food Analysis

The Progressive Fish-Culturist, 1976

Various techniques for analyzing the stomach contents of fish are available to fishery biologists... more Various techniques for analyzing the stomach contents of fish are available to fishery biologists. The more popular methods (frequency of occurrence, enumeration, volumetric, and gravimetric) were discussed by and by Lagler (1956). Although these methods (except for frequency of occurrence) quantify the importance of different food items, they require tedious sorting and measuring, and are very time-consuming.

Research paper thumbnail of Elemental concentrations in fishes from the Salton Sea, Southeastern California

Water, Air, and Soil Pollution, 1990

The Salton Sea is a 93 000 ha saline lake fed by drainage water from more than 283 000 ha of irri... more The Salton Sea is a 93 000 ha saline lake fed by drainage water from more than 283 000 ha of irrigated lands in the Imperial and Coachella valleys of California. A total of 21 composite samples of four recreationally important fish species -bairdielta (Bairdiella icistia), orangemouth corvina (Cynoscion xanthulus), sargo (Anisotremus davidsoni), and Mozambique tilapia (Tilapia mossambica)collected there were analyzed for 14 elements. Twelve of these elements were detected in one or more of the samples: As, B, Co, Cu, Fe, Hg, Mo, Ni, Pb, Se, V, and Zn. Cadmium and T1 were not detected. The ranges in concentrations of elements in the skinless fillets of bairdiella, corvina, and sargo, and in whole bodies of all four fishes were comparable to levels that are typically measured in saltwater fishes. Only Se concentrations were elevated (as much as 14 ~xg g-~ dry weight in both fillets and whole bodies) in this series of samples. Elevated concentrations of Se have already led to public health advisories concerning the consumption of fish and might eventually cause the demise of fish populations from toxic effects.

Research paper thumbnail of Relation of length and sex to selenium concentrations in mosquitofish

Environmental Pollution, 1987

Analysis of mosquitofish, Gambusia affinis, has proven useful.for monitoring contaminant levels i... more Analysis of mosquitofish, Gambusia affinis, has proven useful.for monitoring contaminant levels in aquatic biota; however, the small size of this species often requires the compositing of several fish to provide sufficient biomass for selenium analysis. SuCh composites have usually been obtained without considering the length and sex of the individual fish. The present study found significant differences in mean lengths and sex ratios of mosquitofish sampled with small-mesh dip nets from five sites close to each other in the San Joaquin Valley, California. To test the effect of these different sample characteristics, fish from each site were divided by sex into five size classes (<20, 20-30, 31-45, 46-60, and > 60 mm total length) before analysis for total selenium. Altogether, fish .from the San Luis Drain and Kesterson Ponds 2 and 7 contained 65-360#gg-1 selenium (dry weight basis), or about 28-to 300fold more than concentrations in fish of the same length and sex from the Volta Wasteway and Volta Pond 26. Except for females 31-45 mm long from the San Luis Drain that had higher concentrations than either smaller or larger.females, selenium concentrations did not differ significantly among size classes. Although concentrations differed between sexes in samples from the San Luis Drain, Kesterson Pond 2, and Volta Pond 26, neither males nor females consistently had the higher concentrations. In the San Luis Drain, 20-30 and 31-45 mm long females had higher concentrations than did males of the same size classes; in Kesterson Pond 2 and Volta Pond 26, however, 20 30 mm long males had higher concentrations than did females of the same size class. Although no consistent patterns were observed, the occasional differences in selenium concentrations in fish of different length and sex indicate that these variables should be considered when surveys and monitoring studies are designed. 171 Environ. Pollut. 0269-7491/87/$03"50

Research paper thumbnail of Unusual Population Dynamics in Largemouth Bass, Micropterus salmoides (Lacepede), Caused by a Seasonally Fluctuating Food Supply

American Midland Naturalist, 1978

Research paper thumbnail of Evidence of Impaired Reproduction by Western Mosquitofish Inhabiting Seleniferous Agricultural Drainwater

Transactions of the American Fisheries Society, 1995

Western mosquitofish Gambusia affinis from the San Luis Drain (SLD), a major conveyance system fo... more Western mosquitofish Gambusia affinis from the San Luis Drain (SLD), a major conveyance system for seleniferous agricultural subsurface (tile) drainage water in the San Joaquin Valley, California, experienced lower reproductive success than did mosquitofish from a nearby reference area (Pond 26 at the Volta Wildlife Area, VOLTA) that had no history of receiving tile drainage. At birth, mean survival of SLD fry was 70% in 1984 and 77% in 1985, whereas mean survival of VOLTA fry was greater than 99% in 1984 and 97% in 1985. Measurements of total length (TL) of offspring born to SLD females in 1985 showed that stillborn fry (mean TL, 7.5 mm) were significantly shorter than live fry (mean TL, 9.4 mm). In addition, most stillborn fry were at earlier stages of development (contained prominent yolk sacs or occasionally resembled eyed embryos) than most live fry (yolk sacs were fully resorbed). In comparison, stillborn and live fry born to VOLTA females did not differ significantly in TL (mean for stillborn fry, 7.1 mm; mean for live fry, 7.5 mm), and nearly all fry had resorbed their yolk sacs. Mosquitofish from the SLD contained over 100 |Ag/g (whole-body concentration in dry weight) of selenium, whereas those from VOLTA averaged 1.5 jxg/g. Although experiments are still needed to establish cause and effect, the high incidence of abnormal births of mosquitofish from the SLD is seemingly a response to selenium toxicity.

Research paper thumbnail of Selenium and other elements in juvenile striped bass from the San Joaquin Valley and San Francisco Estuary, California

Archives of Environmental Contamination and Toxicology, 1990

Concentrations of selenium and other trace elements were determined in 55 whole body samples of j... more Concentrations of selenium and other trace elements were determined in 55 whole body samples of juvenile anadromous striped bass (Morone saxatilis) from the San Joaquin Valley and San Francisco Estuary, California. The fish (≤1 yr old-the predominant life stage in the San Joaquin Valley) were collected in September-December 1986 from 19 sites in the Valley and 3 sites in the Estuary, and analyzed for the following elements: aluminum (Al), arsenic (As), boron (B), barium (Ba), beryllium (Be), cadmium (Cd), chromium (Cr), copper (Cu), iron (Fe), mercury (Hg), magnesium (Mg), molybdenum (Mo), nickel (Ni), lead (Pb), selenium (Se), strontium (Sr), vanadium (V), and zinc (Zn). When compared to concentrations in whole freshwater fish measured by surveys from other waters, a few samples contained higher levels, of As, Cd, Cu, Pb, and Se. The median concentrations of Al, As, Cu, Fe, Mg, Se, and Sr also differed significantly (P[Symbol: see text]0.05) among sites. However, only Se concentrations were highest (up to 7.9 μg/g dry weight) in samples from Valley sites exposed to agricultural subsurface (tile) drainwater; concentrations were lower in samples collected elsewhere. Water quality variables-especially those strongly influenced by tile drainwater (conductivity, total dissolved solids, total alkalinity, and total hardness)-were also significantly correlated (P[Symbol: see text]0.05) with Se concentrations in fish. Selenium concentrations in striped bass from the Estuary were only one-fourth to one-half the concentrations measured in the most contaminated fish from the San Joaquin River.

Research paper thumbnail of Survey of fishes and environmental conditions in Abbotts Lagoon, Point Reyes National Seashore, California

California Fish and Game, 2001

Research paper thumbnail of Total Selenium and Selenium Species in Irrigation Drain Inflows to the Salton Sea, California, April and July 2008

Open File Report, 2009

Total Selenium and Selenium Species in Irrigation Drain Inflows to the Salton Sea, California, Oc... more Total Selenium and Selenium Species in Irrigation Drain Inflows to the Salton Sea, California, October 2008 and January 2009. Thomas W May, Michael J Walther, Michael K Saiki, William G Brumbaugh Open-File Report. US Geological Survey, US Geological Survey, 2009. ...

Research paper thumbnail of Total Selenium and Selenium Species in Irrigation Drain Inflows to the Salton Sea, California, October 2007 and January 2008

Open File Report, 2008

Total Selenium and Selenium Species in Irrigation Drain Inflows to the Salton Sea, California, Oc... more Total Selenium and Selenium Species in Irrigation Drain Inflows to the Salton Sea, California, October 2008 and January 2009. Thomas W May, Michael J Walther, Michael K Saiki, William G Brumbaugh Open-File Report. US Geological Survey, US Geological Survey, 2009. ...

Research paper thumbnail of Unusual Dominance by Desert Pupfish (Cyprinodon macularius) in Experimental Ponds within the Salton Sea Basin

Http Dx Doi Org 10 1894 F12 Cmt 06 1, Sep 1, 2011

Research paper thumbnail of Total Selenium in Irrigation Drain Inflows to the Salton Sea, California, April 2009

Research paper thumbnail of Year 3 Summary Report: Baseline Selenium Monitoring of Agricultural Drains Operated by the Imperial Irrigation District in the Salton Sea Basin

Research paper thumbnail of Effects of Ambient Water Quality on the Endangered Lost River Sucker in Upper Klamath Lake, Oregon

Http Dx Doi Org 10 1577 1548 8659128 2 0 Co 2, Jan 9, 2011

... 2 Barbara A. Martin a &amp;amp; Michael K. Saiki a pages 953-961. ... Sheepy Lake (Moyle ... more ... 2 Barbara A. Martin a &amp;amp; Michael K. Saiki a pages 953-961. ... Sheepy Lake (Moyle 197620. Moyle, PB 1976. Inland fishes of California Berkeley: University of California Press. View all references). Historically, this fish was widespread and abundant within the Upper Klamath Basin. ...

Research paper thumbnail of Total Selenium and Selenium Species in Irrigation Drain Inflows to the Salton Sea, California, April and July 2007

Open File Report, 2007

Total Selenium and Selenium Species in Irrigation Drain Inflows to the Salton Sea, California, Oc... more Total Selenium and Selenium Species in Irrigation Drain Inflows to the Salton Sea, California, October 2008 and January 2009. Thomas W May, Michael J Walther, Michael K Saiki, William G Brumbaugh Open-File Report. US Geological Survey, US Geological Survey, 2009. ...

Research paper thumbnail of Relation of desert pupfish abundance to selected environmental variables in natural and manmade habitats in the Salton Sea basin

Environmental Biology of Fishes, Jan 4, 2005

We assessed the relation between abundance of desert pupfish, Cyprinodon macularius, and selected... more We assessed the relation between abundance of desert pupfish, Cyprinodon macularius, and selected biological and physicochemical variables in natural and manmade habitats within the Salton Sea Basin. Field sampling in a natural tributary, Salt Creek, and three agricultural drains captured eight species including pupfish (1.1% of the total catch), the only native species encountered. According to Bray-Curtis resemblance functions, fish species assemblages differed mostly between Salt Creek and the drains (i.e., the three drains had relatively similar species assemblages). Pupfish numbers and environmental variables varied among sites and sample periods. Canonical correlation showed that pupfish abundance was positively correlated with abundance of western mosquitofish, Gambusia affinis, and negatively correlated with abundance of porthole livebearers, Poeciliopsis gracilis, tilapias (Sarotherodon mossambica and Tilapia zillii), longjaw mudsuckers, Gillichthys mirabilis, and mollies (Poecilia latipinna and Poecilia mexicana). In addition, pupfish abundance was positively correlated with cover, pH, and salinity, and negatively correlated with sediment factor (a measure of sediment grain size) and dissolved oxygen. Pupfish abundance was generally highest in habitats where water quality extremes (especially high pH and salinity, and low dissolved oxygen) seemingly limited the occurrence of nonnative fishes. This study also documented evidence of predation by mudsuckers on pupfish. These findings support the contention of many resource managers that pupfish populations are adversely influenced by ecological interactions with nonnative fishes.

Research paper thumbnail of Final Report: Baseline Selenium Monitoring of Agricultural Drains Operated by the Imperial Irrigation District in the Salton Sea Basin, California

Research paper thumbnail of Total mercury concentrations in fillets of bluegill, redear sunfish, largemouth bass, and other fishes from Lake Natoma, Sacramento County, California

California Fish and Game, 2005

Research paper thumbnail of Gut contents of juvenile chinook salmon from the upper sacramento river, California during spring 1998

California Fish and Game, 2001

Research paper thumbnail of Preliminary Assessment of the Effects of Selenium in Agricultural Drainage on Fish in the San Joaquin Valley

The Economics and Management of Water and Drainage in Agriculture, 1991

Research paper thumbnail of Mean Bulk Index Method of Fish Food Analysis

Http Dx Doi Org 10 1577 1548 865938 55 Mbimof 2 0 Co 2, Jan 9, 2011

Various techniques for analyzing the stomach contents of fish are available to fishery biologists... more Various techniques for analyzing the stomach contents of fish are available to fishery biologists. The more popular methods (frequency of occurrence, enumeration, volumetric, and gravimetric) were discussed by and by Lagler (1956). Although these methods (except for frequency of occurrence) quantify the importance of different food items, they require tedious sorting and measuring, and are very time-consuming.

Research paper thumbnail of Mean Bulk Index Method of Fish Food Analysis

The Progressive Fish-Culturist, 1976

Various techniques for analyzing the stomach contents of fish are available to fishery biologists... more Various techniques for analyzing the stomach contents of fish are available to fishery biologists. The more popular methods (frequency of occurrence, enumeration, volumetric, and gravimetric) were discussed by and by Lagler (1956). Although these methods (except for frequency of occurrence) quantify the importance of different food items, they require tedious sorting and measuring, and are very time-consuming.

Research paper thumbnail of Elemental concentrations in fishes from the Salton Sea, Southeastern California

Water, Air, and Soil Pollution, 1990

The Salton Sea is a 93 000 ha saline lake fed by drainage water from more than 283 000 ha of irri... more The Salton Sea is a 93 000 ha saline lake fed by drainage water from more than 283 000 ha of irrigated lands in the Imperial and Coachella valleys of California. A total of 21 composite samples of four recreationally important fish species -bairdielta (Bairdiella icistia), orangemouth corvina (Cynoscion xanthulus), sargo (Anisotremus davidsoni), and Mozambique tilapia (Tilapia mossambica)collected there were analyzed for 14 elements. Twelve of these elements were detected in one or more of the samples: As, B, Co, Cu, Fe, Hg, Mo, Ni, Pb, Se, V, and Zn. Cadmium and T1 were not detected. The ranges in concentrations of elements in the skinless fillets of bairdiella, corvina, and sargo, and in whole bodies of all four fishes were comparable to levels that are typically measured in saltwater fishes. Only Se concentrations were elevated (as much as 14 ~xg g-~ dry weight in both fillets and whole bodies) in this series of samples. Elevated concentrations of Se have already led to public health advisories concerning the consumption of fish and might eventually cause the demise of fish populations from toxic effects.

Research paper thumbnail of Relation of length and sex to selenium concentrations in mosquitofish

Environmental Pollution, 1987

Analysis of mosquitofish, Gambusia affinis, has proven useful.for monitoring contaminant levels i... more Analysis of mosquitofish, Gambusia affinis, has proven useful.for monitoring contaminant levels in aquatic biota; however, the small size of this species often requires the compositing of several fish to provide sufficient biomass for selenium analysis. SuCh composites have usually been obtained without considering the length and sex of the individual fish. The present study found significant differences in mean lengths and sex ratios of mosquitofish sampled with small-mesh dip nets from five sites close to each other in the San Joaquin Valley, California. To test the effect of these different sample characteristics, fish from each site were divided by sex into five size classes (<20, 20-30, 31-45, 46-60, and > 60 mm total length) before analysis for total selenium. Altogether, fish .from the San Luis Drain and Kesterson Ponds 2 and 7 contained 65-360#gg-1 selenium (dry weight basis), or about 28-to 300fold more than concentrations in fish of the same length and sex from the Volta Wasteway and Volta Pond 26. Except for females 31-45 mm long from the San Luis Drain that had higher concentrations than either smaller or larger.females, selenium concentrations did not differ significantly among size classes. Although concentrations differed between sexes in samples from the San Luis Drain, Kesterson Pond 2, and Volta Pond 26, neither males nor females consistently had the higher concentrations. In the San Luis Drain, 20-30 and 31-45 mm long females had higher concentrations than did males of the same size classes; in Kesterson Pond 2 and Volta Pond 26, however, 20 30 mm long males had higher concentrations than did females of the same size class. Although no consistent patterns were observed, the occasional differences in selenium concentrations in fish of different length and sex indicate that these variables should be considered when surveys and monitoring studies are designed. 171 Environ. Pollut. 0269-7491/87/$03"50

Research paper thumbnail of Unusual Population Dynamics in Largemouth Bass, Micropterus salmoides (Lacepede), Caused by a Seasonally Fluctuating Food Supply

American Midland Naturalist, 1978

Research paper thumbnail of Evidence of Impaired Reproduction by Western Mosquitofish Inhabiting Seleniferous Agricultural Drainwater

Transactions of the American Fisheries Society, 1995

Western mosquitofish Gambusia affinis from the San Luis Drain (SLD), a major conveyance system fo... more Western mosquitofish Gambusia affinis from the San Luis Drain (SLD), a major conveyance system for seleniferous agricultural subsurface (tile) drainage water in the San Joaquin Valley, California, experienced lower reproductive success than did mosquitofish from a nearby reference area (Pond 26 at the Volta Wildlife Area, VOLTA) that had no history of receiving tile drainage. At birth, mean survival of SLD fry was 70% in 1984 and 77% in 1985, whereas mean survival of VOLTA fry was greater than 99% in 1984 and 97% in 1985. Measurements of total length (TL) of offspring born to SLD females in 1985 showed that stillborn fry (mean TL, 7.5 mm) were significantly shorter than live fry (mean TL, 9.4 mm). In addition, most stillborn fry were at earlier stages of development (contained prominent yolk sacs or occasionally resembled eyed embryos) than most live fry (yolk sacs were fully resorbed). In comparison, stillborn and live fry born to VOLTA females did not differ significantly in TL (mean for stillborn fry, 7.1 mm; mean for live fry, 7.5 mm), and nearly all fry had resorbed their yolk sacs. Mosquitofish from the SLD contained over 100 |Ag/g (whole-body concentration in dry weight) of selenium, whereas those from VOLTA averaged 1.5 jxg/g. Although experiments are still needed to establish cause and effect, the high incidence of abnormal births of mosquitofish from the SLD is seemingly a response to selenium toxicity.

Research paper thumbnail of Selenium and other elements in juvenile striped bass from the San Joaquin Valley and San Francisco Estuary, California

Archives of Environmental Contamination and Toxicology, 1990

Concentrations of selenium and other trace elements were determined in 55 whole body samples of j... more Concentrations of selenium and other trace elements were determined in 55 whole body samples of juvenile anadromous striped bass (Morone saxatilis) from the San Joaquin Valley and San Francisco Estuary, California. The fish (≤1 yr old-the predominant life stage in the San Joaquin Valley) were collected in September-December 1986 from 19 sites in the Valley and 3 sites in the Estuary, and analyzed for the following elements: aluminum (Al), arsenic (As), boron (B), barium (Ba), beryllium (Be), cadmium (Cd), chromium (Cr), copper (Cu), iron (Fe), mercury (Hg), magnesium (Mg), molybdenum (Mo), nickel (Ni), lead (Pb), selenium (Se), strontium (Sr), vanadium (V), and zinc (Zn). When compared to concentrations in whole freshwater fish measured by surveys from other waters, a few samples contained higher levels, of As, Cd, Cu, Pb, and Se. The median concentrations of Al, As, Cu, Fe, Mg, Se, and Sr also differed significantly (P[Symbol: see text]0.05) among sites. However, only Se concentrations were highest (up to 7.9 μg/g dry weight) in samples from Valley sites exposed to agricultural subsurface (tile) drainwater; concentrations were lower in samples collected elsewhere. Water quality variables-especially those strongly influenced by tile drainwater (conductivity, total dissolved solids, total alkalinity, and total hardness)-were also significantly correlated (P[Symbol: see text]0.05) with Se concentrations in fish. Selenium concentrations in striped bass from the Estuary were only one-fourth to one-half the concentrations measured in the most contaminated fish from the San Joaquin River.

Research paper thumbnail of Survey of fishes and environmental conditions in Abbotts Lagoon, Point Reyes National Seashore, California

California Fish and Game, 2001

Research paper thumbnail of Total Selenium and Selenium Species in Irrigation Drain Inflows to the Salton Sea, California, April and July 2008

Open File Report, 2009

Total Selenium and Selenium Species in Irrigation Drain Inflows to the Salton Sea, California, Oc... more Total Selenium and Selenium Species in Irrigation Drain Inflows to the Salton Sea, California, October 2008 and January 2009. Thomas W May, Michael J Walther, Michael K Saiki, William G Brumbaugh Open-File Report. US Geological Survey, US Geological Survey, 2009. ...

Research paper thumbnail of Total Selenium and Selenium Species in Irrigation Drain Inflows to the Salton Sea, California, October 2007 and January 2008

Open File Report, 2008

Total Selenium and Selenium Species in Irrigation Drain Inflows to the Salton Sea, California, Oc... more Total Selenium and Selenium Species in Irrigation Drain Inflows to the Salton Sea, California, October 2008 and January 2009. Thomas W May, Michael J Walther, Michael K Saiki, William G Brumbaugh Open-File Report. US Geological Survey, US Geological Survey, 2009. ...

Research paper thumbnail of Unusual Dominance by Desert Pupfish (Cyprinodon macularius) in Experimental Ponds within the Salton Sea Basin

Http Dx Doi Org 10 1894 F12 Cmt 06 1, Sep 1, 2011

Research paper thumbnail of Total Selenium in Irrigation Drain Inflows to the Salton Sea, California, April 2009

Research paper thumbnail of Year 3 Summary Report: Baseline Selenium Monitoring of Agricultural Drains Operated by the Imperial Irrigation District in the Salton Sea Basin

Research paper thumbnail of Effects of Ambient Water Quality on the Endangered Lost River Sucker in Upper Klamath Lake, Oregon

Http Dx Doi Org 10 1577 1548 8659128 2 0 Co 2, Jan 9, 2011

... 2 Barbara A. Martin a &amp;amp; Michael K. Saiki a pages 953-961. ... Sheepy Lake (Moyle ... more ... 2 Barbara A. Martin a &amp;amp; Michael K. Saiki a pages 953-961. ... Sheepy Lake (Moyle 197620. Moyle, PB 1976. Inland fishes of California Berkeley: University of California Press. View all references). Historically, this fish was widespread and abundant within the Upper Klamath Basin. ...

Research paper thumbnail of Total Selenium and Selenium Species in Irrigation Drain Inflows to the Salton Sea, California, April and July 2007

Open File Report, 2007

Total Selenium and Selenium Species in Irrigation Drain Inflows to the Salton Sea, California, Oc... more Total Selenium and Selenium Species in Irrigation Drain Inflows to the Salton Sea, California, October 2008 and January 2009. Thomas W May, Michael J Walther, Michael K Saiki, William G Brumbaugh Open-File Report. US Geological Survey, US Geological Survey, 2009. ...

Research paper thumbnail of Relation of desert pupfish abundance to selected environmental variables in natural and manmade habitats in the Salton Sea basin

Environmental Biology of Fishes, Jan 4, 2005

We assessed the relation between abundance of desert pupfish, Cyprinodon macularius, and selected... more We assessed the relation between abundance of desert pupfish, Cyprinodon macularius, and selected biological and physicochemical variables in natural and manmade habitats within the Salton Sea Basin. Field sampling in a natural tributary, Salt Creek, and three agricultural drains captured eight species including pupfish (1.1% of the total catch), the only native species encountered. According to Bray-Curtis resemblance functions, fish species assemblages differed mostly between Salt Creek and the drains (i.e., the three drains had relatively similar species assemblages). Pupfish numbers and environmental variables varied among sites and sample periods. Canonical correlation showed that pupfish abundance was positively correlated with abundance of western mosquitofish, Gambusia affinis, and negatively correlated with abundance of porthole livebearers, Poeciliopsis gracilis, tilapias (Sarotherodon mossambica and Tilapia zillii), longjaw mudsuckers, Gillichthys mirabilis, and mollies (Poecilia latipinna and Poecilia mexicana). In addition, pupfish abundance was positively correlated with cover, pH, and salinity, and negatively correlated with sediment factor (a measure of sediment grain size) and dissolved oxygen. Pupfish abundance was generally highest in habitats where water quality extremes (especially high pH and salinity, and low dissolved oxygen) seemingly limited the occurrence of nonnative fishes. This study also documented evidence of predation by mudsuckers on pupfish. These findings support the contention of many resource managers that pupfish populations are adversely influenced by ecological interactions with nonnative fishes.

Research paper thumbnail of Final Report: Baseline Selenium Monitoring of Agricultural Drains Operated by the Imperial Irrigation District in the Salton Sea Basin, California

Research paper thumbnail of Total mercury concentrations in fillets of bluegill, redear sunfish, largemouth bass, and other fishes from Lake Natoma, Sacramento County, California

California Fish and Game, 2005

Research paper thumbnail of Gut contents of juvenile chinook salmon from the upper sacramento river, California during spring 1998

California Fish and Game, 2001

Research paper thumbnail of Preliminary Assessment of the Effects of Selenium in Agricultural Drainage on Fish in the San Joaquin Valley

The Economics and Management of Water and Drainage in Agriculture, 1991