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P. G. Bajer and M. L. Wildhaber. 2007. Population viability analysis of Lower Missouri River shovelnose sturgeon with initial application to the pallid sturgeon. Journal of Applied Ichthyology 23(4):457-464.

Demographic models for the shovelnose (Scaphirhynchus platorhynchus) and pallid (S. albus) sturgeons in the Lower Missouri River were developed to conduct sensitivity analyses for both populations. Potential effects of increased fishing mortality on the shovelnose sturgeon were also evaluated. Populations of shovelnose and pallid sturgeon were most sensitive to age-0 mortality rates as well as mortality rates of juveniles and young adults. Overall, fecundity was a less sensitive parameter. However, increased fecundity effectively balanced higher mortality among sensitive age classes in both populations. Management that increases population-level fecundity and improves survival of age-0, juveniles, and young adults should most effectively benefit both populations. Evaluation of reproductive values indicated that populations of pallid sturgeon dominated by ages ≥35 could rapidly lose their potential for growth, particularly if recruitment remains low. Under the initial parameter values portraying current conditions the population of shovelnose sturgeon was predicted to decline by 1.65% annually, causing the commercial yield to also decline. Modeling indicated that the commercial yield could increase substantially if exploitation of females in ages ≤12 was highly restricted.

P. J. Braaten and D. B. Fuller. 2007. Growth rates of young-of-year shovelnose sturgeon in the Upper Missouri River. Journal of Applied Ichthyology 23(4):506-515.

Information on growth during the larval and young-of-year life stages in natural river environments is generally lacking for most sturgeon species. In this study, methods for estimating ages and quantifying growth were developed for field-sampled larval and young-of-year shovelnose sturgeon Scaphirhynchus platorhynchus in the upper Missouri River. First, growth was assessed by partitioning samples of young-of-year shovelnose sturgeon into cohorts, and regressing weekly increases in cohort mean length on sampling date. This method quantified relative growth because ages of the cohorts were unknown. Cohort increases in mean length among sampling dates were positively related (P < 0.05, r2 > 0.59 for all cohorts) to sampling date, and yielded growth rate estimates of 0.80–2.95 mm day1 (2003) and 0.44–2.28 mm day1 (2004). Highest growth rates occurred in the largest (and earliest spawned) cohorts. Second, a method was developed to estimate cohort hatch dates, thus age on date of sampling could be determined. This method included quantification of post-hatch length increases as a function of water temperature (growth capacity; mm per thermal unit, mm TU1), and summation of mean daily water temperatures to achieve the required number of thermal units that corresponded to post-hatch lengths of shovelnose sturgeon on sampling dates. For six of seven cohorts of shovelnose sturgeon analyzed, linear growth models (r2 = 0.65, p<0.0001) or Gompertz growth models (r2 = 0.83, p<0.0001) quantified length-at-age from hatch through 55 days post-hatch (98–100 mm). Comparisons of length-at-age derived from the growth models indicated that length-at-age was greater for the earlier-hatched cohorts than later-hatched cohorts. Estimated hatch dates for different cohorts were corroborated based on the dates that newly-hatched larval shovelnose sturgeon were sampled in the drift. These results provide the first quantification of growth dynamics for field-sampled age-0 shovelnose sturgeon in a natural river environment, and provide an accurate method for estimating age of wild-caught individuals. Methods of age determination used in this study have applications to sturgeons in other regions, but require additional testing and validation.

P. J. Braaten, D. B. Fuller and N. D. McClenning. 2007. Diet composition of larval and young-of-year shovelnose sturgeon in the Upper Missouri River. Journal of Applied Ichthyology 23(4):516-520.

Obtaining food following the transition from endogenous to exogenous feeding and during the first year of life is a critical event that strongly influences growth and survival of young-of-year fishes. For shovelnose sturgeon Scaphirhynchus platorhynchus, limited information is available on food habits during the first year of life. The objective of this study was to quantify diet components of shovelnose sturgeon during the transition from endogenous to exogenous feeding and during the young-of-year life stage in the North Dakota and Montana portions of the Missouri River. Young-of-year shovelnose sturgeon were sampled between early August and early September 2003. Shovelnose sturgeon initiated exogenous feeding by 16 mm, and individuals 16–140 mm fed exclusively on two macroinvertebrate orders (Diptera and Ephemeroptera). Young-of-year shovelnose sturgeon exhibited an apparently high feeding success as 99 of 100 individuals contained food in the gut. The number of organisms in the gut increased exponentially with fish length for larval Diptera (r2 = 0.73, P < 0.0001) and linearly (r2 = 0.12, P = 0.0006) for larval Ephemeroptera, but the number of Diptera pupae in the gut was not significantly related (P = 0.55) to length of young-of-year shovelnose sturgeon. The length of ingested prey was linearly related to fish length for Diptera larvae (r2 = 0.20, P = 0.002), whereas the relationship between lengths of ingested Ephemeroptera larvae and lengths of young-of-year shovelnose sturgeon was best described by a power function (r2 = 0.50, p<0.0001). These results provide the first quantification of feeding dynamics for young-of-year shovelnose sturgeon in a natural river environment.

(91485) W. G. Brumbaugh, T. W. May, J. M. Besser, A. L. Allert and C. J. Schmitt. 2007. Assessment of elemental concentrations in streams of the New Lead Belt in Southeastern Missouri, 2002-05. U.S. Geological Survey, Scientific Investigations Report 2007-5057.

Concerns about possible effects of lead-mining activities on the water quality of federally protected streams located in southeastern Missouri prompted a suite of multidisciplinary studies to be conducted by the U.S. Geological Survey. As part of this investigation, a series of biological studies were initiated in 2001 for streams in the current mining region and the prospecting area. In this report, results are examined for trace elements and other selected chemical measurements in sediment, surface water, and sediment interstitial (pore) water sampled between 2002 and 2005 in association with these biological studies.

(91496) J. A. Bryan, M. L. Wildhaber, D. M. Papoulias, A. J. DeLonay, D. E. Tillitt and M. L. Annis. 2007. Estimation of gonad volume, fecundity, and reproductive stage of shovelnose sturgeon using sonography and endoscopy with application to the endangered pallid sturgeon. Journal of Applied Ichthyology, 23(4): 411-419.

Most species of sturgeon are declining in the Mississippi River Basin of North America including pallid (Scaphirhynchus albus F. and R.) and shovelnose sturgeons (S. platorhynchus R.). Understanding the reproductive cycle of sturgeon in the Mississippi River Basin is important in evaluating the status and viability of sturgeon populations. We used non-invasive, non-lethal methods for examining internal reproductive organs of shovelnose and pallid sturgeon. We used an ultrasound to measure egg diameter, fecundity, and gonad volume; endoscope was used to visually examine the gonad. We found the ultrasound to accurately measure the gonad volume, but it underestimated egg diameter by 52%. After correcting for the measurement error, the ultrasound accurately measured the gonad volume but it was higher than the true gonad volume for stages I and II. The ultrasound underestimated the fecundity of shovelnose sturgeon by 5%. The ultrasound fecundity was lower than the true fecundity for stage III and during August. Using the endoscope, we viewed seven different egg color categories. Using a model selection procedure, the presence of four egg categories correctly predicted the reproductive stage ± one reproductive stage of shovelnose sturgeon 95% of the time. For pallid sturgeon, the ultrasound overestimated the density of eggs by 49% and the endoscope was able to view eggs in 50% of the pallid sturgeon. Individually, the ultrasound and endoscope can be used to assess certain reproductive characteristics in sturgeon. The use of both methods at the same time can be complementary depending on the parameter measured. These methods can be used to track gonad characteristics, including measuring Gonadosomatic Index in individuals and/or populations through time, which can be very useful when associating gonad characteristics with environmental spawning triggers or with repeated examinations of individual fish throughout the reproductive cycle.

(91474) R. S. Carr. 2007. Final Report on methods comparison and toxicity testing of sediments from Boundary Bay, Bellingham Bay and Samish Bay, Washington PSAMP 2006. Submitted to Washington State Department of Ecology, Pudget Sound Assessment and Monitoring Program, Olympia, Washington.

A. J. DeLonay, D. M. Papoulias, M. L. Wildhaber, M. L. Annis, J. L. Bryan, S. A. Griffith, S. H. Holan and D. E. Tillitt. 2007. Use of behavioral and physiological indicators to evaluate Scaphirhynchus sturgeon spawning success. Journal of Applied Ichthyology 23(4):428-435.

Thirty gravid, female shovelnose sturgeon (Scaphirhynchus platorhynchus) were captured in the Lower Missouri River in March 2004 to evaluate the effectiveness of physiology, telemetry and remote sensor technology coupled with change point analysis in identifying when and where Scaphirhynchus sturgeon spawn. Captured sturgeons were instrumented with ultrasonic transmitters and with archival data storage tags (DST) that recorded temperature and pressure. Female sturgeon were tracked through the suspected spawning period. Thereafter, attempts were made to recapture fish to evaluate spawning success. At the time of transmitter implantation, blood and an ovarian biopsy were taken. Reproductive hormones and cortisol were measured in blood. Polarization indices and germinal vesicle breakdown were assessed on the biopsied oocytes to determine readiness to spawn. Behavioral data collected using telemetry and DST sensors were used to determine the direction and magnitude of possible spawning-related movements and to identify the timing of potential spawning events. Upon recapture observations of the ovaries and blood chemistry provided measures of spawning success and comparative indicators to explain differences in observed behavior. Behavioral and physiological indicators of spawning interpreted along with environmental measures may assist in the determination of variables that may cue sturgeon reproduction and the conditions under which sturgeon successfully spawn.

(91484) A. M. Farag, D. A. Nimck, B. A. Kimball, S. E. Church, D. A. Harper and W. G. Brumbaugh. 2007. Concentrations of metals in water, sediment, biofilm, benthic macroinvertebrates, and fish in the Boulder River Watershed, Montana, and the role of colloids in Metal Uptake. Archives of Environmental Contamination and Toxicology, 52(3): 397-409.

To characterize the partitioning of metals in a stream ecosystem, concentrations of trace metals including As, Cd, Cu, Pb, and Zn were measured in water, colloids, sediment, biofilm (also referred to as Aufwuchs), macroinvertebrates, and fish collected from the Boulder River watershed, Montana. Median concentrations of Cd, Cu, and Zn in water throughout the watershed exceeded the U.S. EPA acute and chronic criteria for protection of aquatic life. Concentrations of As, Cd, Cu, Pb, and Zn in sediment were sufficient in the tributaries to cause invertebrate toxicity. The concentrations of As, Cu, Cd, Pb, and Zn in invertebrates from lower Cataract Creek (63, 339, 59, 34, and 2,410 μg/g dry wt, respectively) were greater than the concentrations in invertebrates from the Clark Fork River watershed, Montana (19, 174, 2.3, 15, and 648 μg/g, respectively), that were associated with reduced survival, growth, and health of cutthroat trout fed diets composed of those invertebrates. Colloids and biofilm seem to play a critical role in the pathway of metals into the food chain and concentrations of As, Cu, Pb, and Zn in these two components are significantly correlated. We suggest that transfer of metals associated with Fe colloids to biological components of biofilm is an important pathway where metals associated with abiotic components are first available to biotic components. The significant correlations suggest that Cd, Cu, and Zn may move independently to biota (biofilm, invertebrates, or fish tissues) from water and sediment. The possibility exists that Cd, Cu, and Zn concentrations increase in fish tissues as a result of direct contact with water and sediment and indirect exposure through the food chain. However, uptake through the food chain to fish may be more important for As. Although As concentrations in colloids and biofilm were significantly correlated with As water concentrations, As concentrations in fish tissues were not correlated with water. The pathway for Pb into biological components seems to begin with sediment because concentrations of Pb in water were not significantly correlated with any other component and because concentrations of Pb in the water were often below detection limits.

(91483) N. K. Frohnauer, C. L. Pierce and L. W. Kallemeyn. 2007. Population dynamics and angler exploitation of the unique muskellunge population in Shoepack Lake, Voyageurs National Park, Minnesota. North American Journal of Fisheries Management, 27(1):63-76.

A unique population of muskellunge Esox masquinongy inhabits Shoepack Lake in Voyageurs National Park, Minnesota. Little is known about its status, dynamics, and angler exploitation, and there is concern for the long-term viability of this population. We used intensive sampling and mark–recapture methods to quantify abundance, survival, growth, condition, age at maturity and fecundity and angler surveys to quantify angler pressure, catch rates, and exploitation. During our study, heavy rain washed out a dam constructed by beavers Castor canadensis which regulates the water level at the lake outlet, resulting in a nearly 50% reduction in surface area. We estimated a population size of 1,120 adult fish at the beginning of the study. No immediate reduction in population size was detected in response to the loss of lake area, although there was a gradual, but significant, decline in population size over the 2-year study. Adults grew less than 50 mm per year, and relative weight (Wr) averaged roughly 80. Anglers were successful in catching, on average, two fish during a full day of angling, but harvest was negligible. Shoepack Lake muskellunge exhibit much slower growth rates and lower condition, but much higher densities and angler catch per unit effort (CPUE), than other muskellunge populations. The unique nature, limited distribution, and location of this population in a national park require special consideration for management. The results of this study provide the basis for assessing the long-term viability of the Shoepack Lake muskellunge population through simulations of long-term population dynamics and genetically effective population size.

(91478) N. K. Frohnauer, C. L. Pierce and L. W. Kallemeyn. 2007. Simulated effects of recruitment variability, exploitation, and reduced habitat area on the Muskellunge population in Shoepack Lake, Voyageurs National Park, Minnesota. North American Journal of Fisheries Management, 27(1): 77-88.

A unique population of muskellunge Esox masquinongy inhabits Shoepack Lake in Voyageurs National Park, Minnesota. Little is known about its status, dynamics, and angler exploitation, and there is concern for the long-term viability of this population. We used intensive sampling and mark–recapture methods to quantify abundance, survival, growth, condition, age at maturity and fecundity and angler surveys to quantify angler pressure, catch rates, and exploitation. During our study, heavy rain washed out a dam constructed by beavers Castor canadensis which regulates the water level at the lake outlet, resulting in a nearly 50% reduction in surface area. We estimated a population size of 1,120 adult fish at the beginning of the study. No immediate reduction in population size was detected in response to the loss of lake area, although there was a gradual, but significant, decline in population size over the 2-year study. Adults grew less than 50 mm per year, and relative weight (Wr) averaged roughly 80. Anglers were successful in catching, on average, two fish during a full day of angling, but harvest was negligible. Shoepack Lake muskellunge exhibit much slower growth rates and lower condition, but much higher densities and angler catch per unit effort (CPUE), than other muskellunge populations. The unique nature, limited distribution, and location of this population in a national park require special consideration for management. The results of this study provide the basis for assessing the long-term viability of the Shoepack Lake muskellunge population through simulations of long-term population dynamics and genetically effective population size.

D. Gaeuman and R. B. Jacobson. 2007. Quantifying fluid and bed dynamics for characterizing benthic physical habitat in large rivers. Journal of Applied Ichthyology 23(4):359-364.

Sturgeon use benthic habitats in and adjacent to main channels where environmental conditions can include bedload sediment transport and high near-bed flow velocities. Bed velocity measurements obtained with acoustic Doppler instruments provide a means to assess the concentration and velocity of sediment moving near the streambed, and are thus indicative of the bedload sediment transport rate, the near-bed flow velocity, and the stability of the substrate. Acoustic assessments of benthic conditions in the Missouri River were conducted at scales ranging from the stream reach to individual bedforms. Reach-scale results show that spatially-averaged bed velocities in excess of 0.5 m s1 frequently occur in the navigation channel. At the local scale, bed velocities are highest near bedform crests, and lowest in the troughs. Low-velocity zones can persist in areas with extremely high mean bed velocities. Use of these low-velocity zones may allow sturgeon to make use of portions of the channel where the average conditions near the bed are severe. To obtain bed velocity measurements of the highest possible quality, it is necessary to extract bottom-track and GPS velocity information from the raw ADCP data files on a ping-by-ping basis. However, bed velocity measured from a point can also be estimated using a simplified method that is more easily implemented in the context of routine monitoring. The method requires only the transect distance and direction data displayed in standard ADCP data-logging software. Bed velocity estimates obtained using this method are usually within 5–10% of estimates obtained from ping-by-ping processing.

(91486) J. E. Hinck, V. S. Blazer, G. M. Denslow, M. S. Myers, T. S. Gross and D. E. Tillitt. 2007. Biomarkers of contaminant exposure in Northern Pike (Esox lucius) from the Yukon River Basin, Alaska. Archives of Environmental Contamination and Toxicology, 52(4): 549-562.

As part of a larger investigation, northern pike (n = 158; Esox lucius) were collected from ten sites in the Yukon River Basin (YRB), Alaska, to document biomarkers and their correlations with organochlorine pesticide (total p,p’-DDT, total chlordane, dieldrin, and toxaphene), total polychlorinated biphenyls (PCBs), and elemental contaminant (arsenic, cadmium, copper, lead, total mercury, selenium, and zinc) concentrations. A suite of biomarkers including somatic indices, hepatic 7-ethoxyresorufin O-deethylase (EROD) activity, vitellogenin concentrations, steroid hormone (17B- ustradiol and 16-kebtestosteront) concentrations, splenic macrophage aggregates (MAs), oocyte atresia, and other microscopic anomalies in various tissues were documented in YRB pike. Mean condition factor (0.50 to 0.68), hepatosomatic index (1.00% to 3.56%), and splenosomatic index (0.09% to 0.18%) were not anomalous at any site nor correlated with any contaminant concentration. Mean EROD activity (0.71 to 17.51 pmol/min/mg protein) was similar to basal activity levels previously measured in pike and was positively correlated with selenium concentrations (r = 0.88, P < 0.01). Vitellogenin concentrations in female (0.09 to 5.32 mg/mL) and male (<0.0005 to 0.097 mg/mL) pike were not correlated with any contaminant, but vitellogenin concentrations >0.01 mg/mL in male pike from multiple sites indicated exposure to estrogenic compounds. Mean steroid hormone concentrations and percent oocyte atresia were not anomalous in pike from any YRB site. Few site differences were significant for mean MA density (1.86 to 6.42 MA/mm2), size (812 to 1481 μm2), and tissue occupied (MA-%; 0.24% to 0.75%). A linear regression between MA-% and total PCBs was significant, although PCB concentrations were generally low in YRB pike (≤63 ng/g), and MA-% values in female pike (0.24% to 0.54%) were lower than in male pike (0.32% to 0.75%) at similar PCB concentrations. Greater numbers of MAs were found as zinc concentrations increased in YRB female pike, but it is unlikely that this is a causative relationship. Histological abnormalities observed in gill, liver, spleen, and kidney tissues were not likely a result of contaminant exposure but provide information on the general health of YRB pike. The most common histologic anomalies were parasitic infestations in various organs and developing nephrons and nephrocalcinosis in posterior kidney tissues. Overall, few biomarker responses in YRB pike were correlated with chemical contaminant concentrations, and YRB pike generally appeared to be healthy with no site having multiple anomalous biomarker responses.

(91482) J. E. Hinck, V. S. Blazer, N. D. Denslow, K. R. Echols, T. S. Gross, T. W. May, P. J. Anderson, J. J. Coyle and D. E. Tillitt. 2007. Chemical contaminants, health indicators, and reproductive biomarker responses in fish from the Colorado River and it's tributaries. Science of the Total Environment, 378(3): 376-402.

Common carp (Cyprinus carpio), black bass (Micropterus spp.), and channel catfish (Ictalurus punctatus) were collected from 14 sites in the Colorado River Basin (CRB) to document spatial trends in accumulative contaminants, health indicators, and reproductive biomarkers. Organochlorine residues, 2,3,7,8-tetrachlorodibenzo-p-dioxin-like activity (TCDD-EQ), and elemental contaminants were measured in composite samples of whole fish, grouped by species and gender, from each site. Selenium (Se) and mercury (Hg) concentrations in fish were elevated throughout the CRB, and pesticide concentrations were greatest in fish from agricultural areas in the Lower Colorado River and Gila River. Selenium concentrations exceeded toxicity thresholds for fish (> 1.0 μg/g ww) at all CRB sites except the Gila River at Hayden, Arizona. Mercury concentrations were elevated (> 0.1 μg/g ww) in fish from the Yampa River at Lay, Colorado; the Green River at Ouray National Wildlife Refuge (NWR), Utah and San Rafael, Utah; the San Juan River at Hogback Diversion, New Mexico; and the Colorado River at Gold Bar Canyon, Utah, Needles, California, and Imperial Dam, Arizona. Concentrations of p,p′-DDE were relatively high in fish from the Gila River at Arlington, Arizona (> 1.0 μg/g ww) and Phoenix, Arizona (> 0.5 μg/g ww). Concentrations of other formerly used pesticides including toxaphene, total chlordanes, and dieldrin were also greatest at these two sites but did not exceed toxicity thresholds. Currently used pesticides such as Dacthal, endosulfan, γ-HCH, and methoxychlor were also greatest in fish from the Gila River downstream of Phoenix. Total polychlorinated biphenyls (PCBs; > 0.11 μg/g ww) and TCDD-EQs (> 5 pg/g ww) exceeded wildlife guidelines in fish from the Gila River at Phoenix. Hepatic ethoxyresorufin O-deethylase (EROD) activity was also relatively high in carp from the Gila River at Phoenix and in bass from the Green River at Ouray NWR. Fish from some sites showed evidence of contaminant exposure as indicated by fish health indicators and reproductive biomarker results. Multiple health indicators including altered body and organ weights and high health assessment index scores may be associated with elevated Se concentrations in fish from the Colorado River at Loma, Colorado and Needles. Although grossly visible external or internal lesions were found on most fish from some sites, histopathological analysis determined many of these to be inflammatory responses associated with parasites. Edema, exophthalmos, and cataracts were noted in fish from sites with elevated Se concentrations. Intersex fish were found at seven of 14 sites and included smallmouth bass (M. dolomieu), largemouth bass (M. salmoides), catfish, and carp and may indicate exposure to endocrine disrupting compounds. A high proportion of smallmouth bass from the Yampa River at Lay (70%) was intersex but the cause of this condition is unknown. Male carp, bass, and catfish with low concentrations of vitellogenin were common in the CRB. Comparatively high vitellogenin concentrations (> 0.2 mg/mL) were measured in male bass from the Green River at Ouray NWR and the Colorado River at Imperial Dam and indicate exposure to estrogenic or anti-androgenic chemicals. Anomalous reproductive biomarkers including low GSI and gonadal abnormalities (calcifications, edema, and parasites) observed in fish downstream of Phoenix are likely related to the poor water-quality of the Gila River in this area.

(91494) M. S. Laustrup, R. B. Jacobson and D. G. Simpkins. 2007. Distribution of Potential Spawning Habitat for Sturgeon in the Lower Missouri River, 2003-06. U.S. Geological Survey, Open File Report 2007-1192.

We surveyed the Lower Missouri River downstream from Gavins Point Dam near Yankton, South Dakota, to St. Louis, Missouri, during low water conditions in 2003-06 to identify and map coarse substrate deposits and bedrock exposures that might serve as spawning areas for sturgeon and other fishes. More than 330 deposits were identified, including tributary fans, bars, and habitat-enhancement projects. The location and extent of riverside bedrock exposures immediately adjacent to the channel also were mapped. Field surveys identified 48 bedrock exposures whereas the analysis of aerial orthophotographs identified an additional 65 exposures for a total of 113. Maps illustrating the distribution of deposits and their density were developed to aid researchers studying reproductive ecology of sturgeon and other lithophilic fishes.

(91488) T. W. May and W. G. Brumbaugh. 2007. Determination of total mercury in fillets of sport fishes collected from Folsom and New Melones Reservoirs, California, 2004. U.S. Geological Survey, Open-File Report 2007-1077.

This report presents the results of a study by the U.S. Geological Survey, done in cooperation with the Bureau of Reclamation, to determine mercury concentrations in selected sport fishes from Folsom and New Melones Reservoirs in California. Fillets were collected from each fish sample, and after homogenization and lyophilization of fish fillets, mercury concentrations were determined with a direct mercury analyzer utilizing the process of thermal combustion-gold amalgamation atomic absorption spectroscopy. Mercury concentrations in fish fillets from Folsom Reservoir ranged from 0.09 to 1.16 micrograms per gram wet weight, and from New Melones Reservoir ranged from 0.03 to 0.94 microgram per gram wet weight. Most of the fish fillets from Folsom Reservoir (87 percent) and 27 percent of the fillets from New Melones Reservoir exceeded the U.S. Environmental Protection Agency's fish consumption advisory of 0.30 microgram per gram wet weight.

(91487) T. W. May and W. G. Brumbaugh. 2007. Determination of total mercury in fillets of sport fishes collected from Folsom Reservoir, California, 2006. U.S. Geological Survey, Open-File Report 2007-1078.

This report presents the results of a study by the U.S. Geological Survey, done in cooperation with the Bureau of Reclamation, to determine mercury concentrations in selected sport fishes from Folsom Reservoir in California. Fillets were collected from each fish sample, and after homogenization and lyophilization of fish fillets, mercury concentrations were determined with a direct mercury analyzer utilizing the process of thermal combustion-gold amalgamation atomic absorption spectroscopy. Mercury concentrations in fillets ranged from 0.031 to 0.20 micrograms per gram wet weight in rainbow trout (Oncorhynchus mykiss) samples and 0.071 to 0.16 micrograms per gram wet weight in bluegill (Lepomis macrochirus) samples. Mercury concentration was 0.98 microgram per gram wet weight in a single spotted bass (Micropterus punctulatus) sample, which was the only one in the sample set which exceeded the U.S. Environmental Protection Agency's fish consumption advisory of 0.30 microgram per gram wet weight.

(91489) T. W. May and W. G. Brumbaugh. 2007. Determination of total mercury in whole-body fish and fish muscle plugs collected from the South Fork of the Humboldt River, Nevada, September 2005. U.S. Geological Survey, Open File Report 2007-1059.

This report presents the results of a study by the U.S. Geological Survey, done in cooperation with the Bureau of Reclamation, to determine mercury concentrations in whole-body fish and fish muscle plugs from the South Fork of the Humboldt River near Elko in the Te-Moak Indian Reservation. A single muscle plug was collected from beneath the dorsal fin area in each of the three whole-body fish samples. After homogenization and lyophilization of the muscle plugs and whole-body fish samples, mercury concentrations were determined with a direct mercury analyzer utilizing the process of thermal combustion-gold amalgamation atomic absorption spectroscopy. Mercury concentrations in whole-body fish ranged from 0.048 to 0.061 microgram per gram wet weight, and 0.061 to 0.082 microgram per gram wet weight in muscle plugs. All sample mercury concentrations were well below the U.S. Environmental Protection Agency's fish consumption advisory of 0.30 microgram per gram wet weight.

(91493) B. C. Poulton, T. J. Rasmusssen and C. J. Lee. 2007. Assessment of Biological Conditions at Selected Stream Sites in Johnson County, Kansas, and Cass and Jackson Counties, Missouri, 2003 and 2004. U.S. Geological Survey, Scientific Investigations Report 2007-5108.

Macroinvertebrate samples were collected at 15 stream sites representing 11 different watersheds in Johnson County, Kansas, in 2003 and 2004 to assess biological conditions in streams and relations to environmental variables. Published data from an additional seven stream sites, one in Johnson County, Kansas, and six others in adjacent Cass and Jackson Counties in Missouri also were evaluated. Multimetric scores, which integrated a combination of measures that describe various aspects of biological community abundance and diversity, were used to evaluate and compare the biological health of streams. In addition, for 15 of 16 Johnson County stream sites, environmental data (streamflow, precipitation, and land use) and water- and sediment-quality data (primarily nutrients, indicator bacteria, and organic wastewater compounds) were used in statistical analyses to evaluate relations between macroinvertebrate metrics and variables that may affect them. The information is useful for defining current conditions, evaluating conditions relative to State aquatic-life support and total maximum daily load requirements, evaluating effects of urbanization, developing effective water-quality management plans, and documenting changes in biological condition and water quality.

(91490) C. J. Schmitt, W. G. Brumbaugh and T. W. May. 2007. Accumulation of metals in fish from lead–zinc mining areas of southeastern Missouri, USA Ecotoxicology and Environmental Safety, 67(1):14-30.

The potential effects of proposed lead–zinc mining in an ecologically sensitive area were assessed by studying a nearby mining district that has been exploited for about 30 yr under contemporary environmental regulations and with modern technology. Blood and liver samples representing fish of three species (largescale stoneroller, Campostoma oligolepis, n=91; longear sunfish, Lepomis megalotis, n=105; and northern hog sucker, Hypentelium nigricans, n=20) were collected from 16 sites representing a range of conditions relative to lead–zinc mining and ore beneficiation in southeastern Missouri. Samples were analyzed for lead, zinc, and cadmium, and for a suite of biomarkers (reported in a companion paper). A subset of the hog sucker (n=9) representing three sites were also analyzed for nickel and cobalt. Blood and liver lead concentrations were highly correlated (r=0.84–0.85, P<0.01) in all three species and were significantly (ANOVA, P<0.01) greater at sites <10 km downstream of active lead–zinc mines and mills and in a historical lead–zinc mining area than at reference sites, including a site in the area proposed for new mining. Correlations between blood and liver cadmium concentrations were less evident than for lead but were nevertheless statistically significant (r=0.26–0.69, P <0.01–0.07). Although blood and liver cadmium concentrations were highest in all three species at sites near mines, within-site variability was greater and mining-related trends were less evident than for lead. Blood and liver zinc concentrations were significantly correlated only in stoneroller (r=0.46, P<0.01) and mining-related trends were not evident. Concentrations of cobalt and nickel in blood and liver were significantly higher (ANOVA, P<0.01) at a site near an active mine than at a reference site and a site in the historical lead–zinc mining area. These findings confirm previous studies indicating that lead and other metals are released to streams from active lead–zinc mines and are available for uptake by aquatic organisms.

(91491) C. J. Schmitt, J. J. Whyte, A. P. Roberts, M. L. Annis, T. W. May and D. E. Tillitt. 2007. Biomarkers of metals exposure in fish from lead-zinc mining areas of Southeastern Missouri, USA Ecotoxicology and Environmental Safety, 67(1):31-47.

The potential effects of proposed lead-zinc mining in an ecologically sensitive area were assessed by studying a nearby mining district that has been exploited for about 30 y under contemporary environmental regulations and with modern technology. Blood and liver samples representing fish of three species (largescale stoneroller, Campostoma oligolepis, n=91; longear sunfish, Lepomis megalotis, n=105; and northern hog sucker, Hypentelium nigricans, n=20) from 16 sites representing a range of conditions relative to mining activities were collected. Samples were analyzed for metals (also reported in a companion paper) and for biomarkers of metals exposure [erythrocyte δ-aminolevulinic acid dehydratase (ALA-D) activity; concentrations of zinc protoporphyrin (ZPP), iron, and hemoglobin (Hb) in blood; and hepatic metallothionein (MT) gene expression and lipid peroxidation]. Blood lead concentrations were significantly higher and ALA-D activity significantly lower in all species at sites nearest to active lead-zinc mines and in a stream contaminated by historical mining than at reference or downstream sites. ALA-D activity was also negatively correlated with blood lead concentrations in all three species but not with other metals. Iron and Hb concentrations were positively correlated in all three species, but were not correlated with any other metals in blood or liver in any species. MT gene expression was positively correlated with liver zinc concentrations, but neither MT nor lipid peroxidase differences among fish grouped according to lead concentrations were statistically significant. ZPP was not detected by hematofluorometry in most fish, but fish with detectable ZPP were from sites affected by mining. Collectively, these results confirm that metals are released to streams from active lead-zinc mining sites and are accumulated by fish.

(91492) M. L. Wildhaber, A. J. DeLonay, D. M. Papoulias, D. L. Galat, R. B. Jacobson, D. G. Simpkins, P. J. Braaten, C. E. Korschgen and M. J. Mac. 2007. A conceptual life-history model for pallid and shovelnose sturgeon. U.S. Geological Survey, Circular 1315.

Intensive management of the Missouri and Mississippi Rivers has resulted in dramatic physical changes to these rivers. These changes have been implicated as causative agents in the decline of pallid sturgeon. The pallid sturgeon, federally listed as endangered, is endemic to the turbid waters of the Missouri River and the Lower Mississippi River. The sympatric shovelnose sturgeon historically was more common and widespread than the pallid sturgeon. Habitat alteration, river regulation, pollution, and over-harvest have resulted in the now predictable patterns of decline and localized extirpation of sturgeon across species and geographic areas. Symptomatic of this generalized pattern of decline is poor reproductive success, and low or no recruitment of wild juveniles to the adult population. The purpose of this report is to introduce a conceptual life-history model of the factors that affect reproduction, growth, and survival of shovelnose and pallid sturgeons. The conceptual model provided here was developed to organize the understanding about the complex life history of Scaphirhynchus sturgeons. It was designed to be used for communication, planning, and to provide the structure for a population-forecasting model. These models are intended to be dynamic and responsive to new information and changes in river management, thereby providing scientists, stakeholders, and managers with ways to improve understanding of the effects of management actions on the ecological requirements of Scaphirhynchus sturgeons. As new scientific knowledge becomes available, it could be included in the model in many ways at various integration levels.

M. L. Wildhaber, D. M. Papoulias, A. J. DeLonay, D. E. Tillitt, J. L. Bryan and M. L. Annis. 2007. Physical and hormonal examination of Missouri River shovelnose sturgeon reproductive stage: a reference guide. Journal of Applied Ichthyology 23(4):382-401.

From May 2001 to June 2002 Wildhaber et al. (2005) conducted monthly sampling of Lower Missouri River shovelnose sturgeon (Scaphirhynchus platorhynchus) to develop methods for determination of sex and the reproductive stage of sturgeons in the field. Shovelnose sturgeon were collected from the Missouri River and ultrasonic and endoscopic imagery and blood and gonadal tissue samples were taken. The full set of data was used to develop monthly reproductive stage profiles for S. platorhynchus that could be compared to data collected on pallid sturgeon (Scaphirhynchus albus). This paper presents a comprehensive reference set of images, sex steroids, and vitellogenin (VTG, an egg protein precursor) data for assessing shovelnose sturgeon sex and reproductive stage. This reference set includes ultrasonic, endoscopic, histologic, and internal images of male and female gonads of shovelnose sturgeon at each reproductive stage along with complementary data on average 17-ß estradiol, 11-ketotestosterone, VTG, gonadosomatic index, and polarization index.

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