Studies were conducted to determine the distribution and elimination of imidacloprid (IMI) in rainbow trout. Animals were injected with a low (47.6 μg/kg), medium (117.5 μg/kg) or high (232.7 μg/kg) dose directly into the bloodstream and allowed to depurate. The fish were then sampled to characterize the loss of IMI from plasma and its appearance in expired water (all dose groups) and urine (medium dose only). In vitro biotransformation of IMI was evaluated using trout liver S9 fractions. Mean total clearance (CLT) values determined by non-compartmental analysis of plasma time-course data were 21.8, 27.0 and 19.5 mL/h/kg for the low, medium and high dose groups, respectively. Estimated half-lives for the same groups were 67.0, 68.4 and 68.1 h, while fitted values for the steady-state volume of distribution (VSS) were 1.72, 2.23 and 1.81 L/kg. Branchial elimination rates were much lower than expected, suggesting that IMI is highly bound in blood. Renal clearance rates were greater than measured rates of branchial clearance (60% of CLT in the medium dose group), possibly indicating a role for renal membrane transporters. There was no evidence for hepatic biotransformation of IMI. Collectively, these findings suggest that IMI would accumulate in trout in continuous waterborne exposures.

Habitat variables were correlated with scaled quail (Callipep/,a squamata) whistle counts on 133 (24-km) random transects in Texas. Whether or not a particular habitat variable was correlated with whistle counts appeared to depend upon abundance and distribution of other habitat types and structural features. If >= 1 requisite for quail survival and reproduction (food, water, cover, nest sites) was limited, habitat types and structural features were usually positively correlated with whistle counts (P < 0.10). Conversely, abundant habitat types which did not provide all of these requisites were usually negatively correlated with whistle counts (P< 0.10). Correlations indicated breeding scaled quail selected the more dense, shorter shrub habitats. Mesquite (Prosopsis spp.) habitats were especially important to scaled quail in the Trans-Pecos region.

Aquatic herbicides are used to manage invasive emergent plants in and around wetlands. Metamorphic frogs that emerge during the aquatic weed management season may be at risk of herbicide exposure. Metamorphic northern red-legged frogs (Rana aurora) were exposed to a triclopyr tank mix labeled for control of broadleaf emergent aquatic weeds such as invasive purple loosestrife (Lythrum salicaria). The tank mix consisted of Renovate® 3 (triclopyr triethylamine salt 44.4%), the modified vegetable oil surfactant Competitor®, and the marker dye Hi-Light® . Metamorphs were exposed to the tank mix and a clean-water control for 96 h, and then reared in clean water for 60 d. Exposure to the tank mix resulted in no treatment-related mortalities, no effects on behavior immediately post exposure, and no effects on body or liver condition indices. Exposure to the tank mix resulted in lethargy during exposure and a 1-d delay in completion of metamorphosis. Deformities present in the rearing population confounded results for some endpoints. Observed effects were minimal, especially compared with the potential for ecological impacts from unmanaged invasive plants. Environ Toxicol Chem 2017;36:2316-2326. © 2017 SETAC.

Willapa Bay (Washington State, USA) has been 1 of the rare intertidal locations where large-scale pesticide applications occur. Until recently, carbaryl was applied to control burrowing shrimp that decrease commercial oyster productivity. The bay is a critical habitat for green sturgeon (Acipenser medirostris), an anadromous species listed as threatened under the US Endangered Species Act. However, the hazard that carbaryl poses is unknown. Surrogate seawater-acclimated white sturgeon (A. transmontanus) were exposed to 0gL(-1), 30gL(-1), 100gL(-1), 300gL(-1), 1000gL(-1), and 3000gL(-1) carbaryl for 6h, and brain acetylcholinesterase (AChE) and plasma butyrylcholinesterase (BChE) activities were measured. Enzyme recovery was measured in an additional cohort exposed to 1000gL(-1) carbaryl for 6h. Activity of AChE was reduced (p0.001) at concentrations100gL(-1) with recovery in the 1000gL(-1) cohort by 72h. Surprisingly, BChE activity was greater than controls at concentrations300gL(-1) (p>0.05), a finding confirmed in additional fish exposed to 3000gL(-1) for 6h (+30%, p < 0.001) with apparent recovery by 48h. Plasma samples were collected from free-living green sturgeon before and 4d to 5d after application of carbaryl in Willapa Bay. Activity of BChE after application was reduced 28% (p<0.001), indicating exposure to the pesticide. However, the lack of congruence between BChE and AChE activity in captive white sturgeon exposed to carbaryl indicates that further studies are needed to better understand the risk carbaryl exposure poses to green sturgeon. Environ Toxicol Chem 2016;35:2003-2015. (c) 2015 SETAC

Willapa Bay and Grays Harbor (WA, USA) comprise the largest region of commercial oyster cultivation on the Pacific Coast. The activities of 2 species of burrowing shrimp impair growth and survival of oysters reared on the intertidal mudflats. To maintain viable harvests, the oyster growers have proposed controlling the shrimp by applying the insecticide imidacloprid onto harvested beds. Green sturgeon (listed in the Endangered Species Act) forage on burrowing shrimp and could be exposed to imidacloprid in the sediment porewater and through consumed prey. Studies were conducted to evaluate the likelihood that green sturgeon would be exposed to imidacloprid and to characterize the subsequent environmental exposure. Comparisons between treated and untreated control beds following test application of the insecticide suggested that green sturgeon fed opportunistically on imidacloprid-impaired shrimp. The highest interpolated imidacloprid residue concentrations in field samples following chemical application were 27.8 µg kg(-1) and 31.4 µg kg(-1) in porewater and shrimp, respectively. Results from modeled branchial and dietary uptake, based on conservative assumptions, indicated that the porewater exposure route had the greatest contribution to systemic absorption of imidacloprid. The highest average daily uptake from porewater (177.9 µg kg(-1) body wt) was 9.5-fold greater than total dietary uptake (18.8 µg kg(-1) body wt). Concentrations and durations of exposure would be lower than the levels expected to elicit direct acute or chronic toxic effects.

Pesticides are frequently detected in urban streams, with concentrations often exceeding those reported in surface waters within agricultural areas. The authors studied growth, survival, and return rates of coho salmon (Oncorhynchus kisutch) smolts exposed to a pesticide mixture ("cocktail") representative of the pesticides most frequently reported within urban streams in western Washington State, USA, in fall through early spring. Exposure concentrations were selected to represent a reasonable worst-case scenario based on field monitoring data. Smolts were continuously exposed to pulses of the cocktail either from fertilization through swim-up (2007-2008) or from fertilization through smoltification (2007-2008 and 2008-2009), coded wire tagged, and released in 2008 and 2009. Pre-release endpoints (growth, survival, sex ratio, brain acetylcholinesterase activity, and gonado- and hepatosomatic indices) were not affected. However, the number of returning adults exposed to the cocktail to swim-up (0.90%, n = 42) was more than double that of unexposed controls (0.38%, n = 26) in 2008, whereas in 2009, fish exposed through smoltification returned in lower numbers (0.15%, n = 18) than controls (0.37%, n = 30). Variability in return rates among treatments between years was comparable to that observed in previous whole life cycle studies with Pacific salmon and other contaminants. Results suggest that exposure to pesticides in urban streams does not directly impair early life stages of coho salmon, and that additional studies incorporating releases of larger numbers of smolts across several years are necessary to adequately quantify effects on return rates. (C) 2014 SETAC

The listing of several runs of Pacific salmon as threatened or endangered and associated federal, state, and local efforts to restore/enhance salmon habitat in the Pacific Northwest make it imperative that the factors associated with these population declines are understood. Prespawn mortality (PSM) has been documented in coho salmon (Oncorhynchus kisutch) within urban streams in western Washington since the late 1990s and is characterized by a suite of neurological and respiratory symptoms with mortality occurring shortly thereafter. Mortality rates in returning adults have ranged between 17 and 100 %. The cause of PSM is not known, but the presence of pesticide residues within urban streams led to a hypothesis that PSM in coho salmon and pesticides in urban streams were linked. We exposed pairs of "green" (unripe) prespawn male and female coho salmon to a pesticide mixture ("cocktail") reported in urban streams in western Washington State, USA. Longevity, ripening in female salmon, and brain acetylcholinesterase were not significantly affected by continuous exposure to the maximum reported concentrations of the pesticides. Fertilization, hatching success, and growth of fry were also not affected when green adults were exposed to these concentrations for 96 h. The absence of effects suggests it is unlikely that pesticides within stormwater are singularly responsible for PSM in coho salmon or that they impair the reproductive capability of exposed adults.

Pesticides are frequently detected in urban streams and are believed to be primarily the result of homeowner use. Although concentrations in most cases are low (<1 mu g/L), there is concern that pesticide inputs threaten efforts to restore and enhance salmon habitat. The authors exposed early life stages of coho salmon (Oncorhynchus kisutch) to a pesticide mixture (cocktail) representative of those pesticides most frequently reported in urban streams in western Washington State, USA. Life stages were continuously exposed to pulses of the cocktail simulating those in urban streams in fall and winter when coho salmon eggs and sac fry are present. Nominal concentrations of eight herbicides, two insecticides, a fungicide, and a breakdown product were the maximum detected. Fertilization, hatching success, survival, deformities, and growth of fry were not significantly affected. A reduction in fertilization success (1925%) was not reproducible even when gametes were exposed to 100 times the maximum concentrations detected. Based on the end points examined in the present study, the results suggest that direct exposure to the pesticides most frequently detected in urban streams in western Washington does not impair early life stages of coho salmon and is not a major factor governing the recovery of salmon populations. The extent to which pesticide exposure would affect smoltification, outmigration, and ocean survival needs to be determined. Environ. Toxicol. Chem. 2013;32:920931. (c) 2013 SETAC

Carbaryl has been applied in Willapa Bay, Washington, for five decades to control burrowing shrimp (Neotrypaea californiensis and Upogebia pugettensis) on commercial oyster (Crassostrea gigas) beds. Concerns about effects on nontarget species, including fishes, have led to restrictions in use despite a lack of data on in situ exposure. We measured brain acetylcholinesterase (AChE) activity in adult Shiner perch (Cymatogaster aggregata) and juvenile Chinook salmon (Oncorhynchus tshawytscha) after operational applications. We hypothesized that exposure in Shiner perch would be greater than in juvenile Chinook salmon because of their greater site fidelity and benthic foraging. However, Shiner perch exhibited no statistically significant AChE inhibition. Enzyme activity was statistically decreased (≤14 %) in juvenile Chinook salmon after a second spray event; however, inhibition was less than that associated with overt effects and was similar to controls by 48 h after the spray. Diet analyses confirmed that Shiner perch were primarily feeding on benthic invertebrates and that juvenile Chinook salmon were feeding primarily within the water column. Composition of Shiner perch diets and amount of food consumed varied little among channels and time periods; however, Shiner perch on beds consumed more food 6 h after application than those at other time points and locations. There were no consistent differences in the diets of juvenile Chinook salmon within channels among time periods. Results suggest (1) that carbaryl applications pose little hazard to fish in the bay having habitat and dietary preferences similar to those of Shiner perch and juvenile Chinook salmon and (2) that quantification of direct exposure in the field is essential to adequately assess risk.

Sound management of large carnivore populations in wildland-urban environments requires accurate information regarding the ecology of these populations and factors contributing to their interactions with people. We quantified cougar (Puma concolor) residential use and interactions with people in western Washington from 2003 to 2008 to characterize the ecology and risks associated with an adaptable large carnivore residing in a wildland-urban environment. We fitted cougars with global positioning system and very-high-frequency radiocollars, quantified residential use, and tested for differences between demographic classes using analysis of variance fixed-effects and multiple-comparison models. We investigated interaction reports to quantify interaction rates and tested for differences among interaction levels for different cougar demographic classes. We captured 32 cougars (16 males and 16 females) and estimated 33 annual utilization distributions (UDs) for 27 individuals. Ninety-three percent of cougars (n = 27; 15 males and 12 females) used residential areas with an average UD overlap of 16.86% (SD = 17.05%, n = 33). There were no differences between male and female (F-1,F-29 = 0.77, P = 0.49) or resident and transient (F-1,F-29 = 0.0003, P = 0.99) use of residential areas, but subadult use was significantly higher than that of adults (F-1,F-29 = 7.20, P = 0.01). Twenty-nine percent of reports were confirmed (n = 73), with livestock depredations accounting for 67% of confirmed reports. The interaction rate for radiocollared cougars was low (1.6 interactions/1,000 radiodays) and all demographic classes were involved in similar numbers of interactions. Use of residential areas in western Washington appears to be a function of the adaptive and mobile nature of the cougar exploiting suitable habitat and resources within the matrix of residential development. Interaction appears to be a function of individual behavior. Management strategies that target problem individuals and maintain older age structures in local populations coupled with proactive landscape planning and public education in residential areas at the wildland-urban interface may provide an effective strategy for decreasing cougar-human interaction.

The neonicotinoid insecticide imidacloprid (IMI) has been proposed as an alternative to carbaryl for controlling indigenous burrowing shrimp on commercial oyster beds in Willapa Bay and Grays Harbor, Washington. A focus of concern over the use of this insecticide in an aquatic environment is the potential for adverse effects from exposure to non-target species residing in the Bay, such as juvenile Chinook (Oncorhynchus tshawytscha) and cutthroat trout (O. clarki). Federal registration and State permiting approval for the use of IMI will require confirmation that the compound does not adversely impact these salmonids following field applications. This will necessitate an environmental monitoring program for evaluating exposure in salmonids following the treatment of beds. Quantification of IMI residues in tissue can be used for determining salmonid exposure to the insecticide. Refinement of an existing protocol using liquid-chromatography mass spectrometry (LC-MS) detection would provide the low limits of quantification, given the relatively small tissue sample sizes, necessary for determining exposure in individual fish. Such an approach would not be viable for the environmental monitoring effort in Willapa Bay and Grays Harbor due to the high costs associated with running multiple analyses, however. A new sample preparation protocol was developed for use with a commercially available enzyme-linked immunosorbent assay (ELISA) for the quantification of IMI, thereby providing a low-cost alternative to LC-MS for environmental monitoring in Willapa Bay and Grays Harbor. Extraction of the analyte from the salmonid brain tissue was achieved by Dounce homogenization in 4.0 mL of 20.0 mM Triton X-100, followed by a 6 h incubation at 50-55 °C. Centrifugal ultrafiltration and reversed phase solid phase extraction were used for sample cleanup. The limit of quantification for an average 77.0 mg whole brain sample was calculated at 18.2 μg kg(-1) (ppb) with an average recovery of 79%. This relatively low limit of quantification allows for the analysis of individual fish. Using controlled laboratory studies, a curvelinear relationship was found between the measured IMI residue concentrations in brain tissue and exposure concentrations in seawater. Additonally, a range of IMI brain residue concentrations was associated with an overt effect; illustrating the utility of the IMI tissue residue quantification approach for linking exposure with defined effects.

Conflict between native amphibians and aquatic weed management in the Pacific Northwest is rarely recognized because most native stillwater-breeding amphibian species move upland during summer, when herbicide application to control weeds in aquatic habitats typically occurs. However, aquatic weed management may pose a risk for aquatic species present in wetlands through the summer, such as the Oregon spotted frog (OSF, Rana pretiosa), a state endangered species in Washington. Acute toxicity of herbicides used to control aquatic weeds tends to be low, but the direct effects of herbicide tank mixes on OSFs have remained unexamined. We exposed juvenile OSFs to tank mixes of the herbicide imazapyr, a surfactant, and a marker dye in a 96-h static-renewal test. The tank mix was chosen because of its low toxicity to fish and its effectiveness in aquatic weed control. Concentrations were those associated with low-volume (3.5?L/ha) and high-volume (7.0?L/ha) applications of imazapyr and a clean-water control. Following exposure, frogs were reared for two months in clean water to identify potential latent effects on growth. Endpoints evaluated included feeding behavior, growth, and body and liver condition indices. We recorded no mortalities and found no significant differences for any end point between the herbicide-exposed and clean-water control frogs. The results suggest that imazapyr use in wetland restoration poses a low risk of direct toxic effects on juvenile OSFs. Environ. Toxicol. Chem. 2013;32:228235. (c) 2012 SETAC

The Cougar (Puma concolor) is an apex predator whose occurrence and space- use patterns are closely tied to the abundance and vulnerability of ungulate prey. Deer (Odocoileus spp.) and Elk (Cervus elaphus) readily use residential portions of the landscape, but little is known of Cougar prey use within these environments. We used Global Positioning System and VHF relocation data from 20 Cougars to examine prey use in a wildland-urban landscape in western Washington. We tested for differences (α = 0.10) between wildland and residential prey compositions using the Chi-square test of homogeneity and used an ANOVA fixed-effects model to determine the potential influence of residential development on the duration of Cougar presence on kills. We located 304 kills throughout the study area with Black-tailed Deer (Odocoileus hemionus columbianus, 55.3%), Beaver (Castor canadensis, 22.0%), and Elk (8.8%) constituting the bulk of Cougar diet. Wildland and residential prey compositions were significantly different, with Cougars killing a higher proportion of Deer, Beavers, and Mountain Beavers (Aplodontia rufa) in wildland areas and more Coyotes (Canis latrans), Raccoons (Procyon lotor), Opossums (Didelphis virginiana), and domestic species close to residential development. Kill location did not have a significant effect on the duration of stay regardless of species killed, nor was the effect of location significant when comparing kills of the same species. Cougar diet in wildland-urban forests of western Washington is diverse, but Cougars do not appear to shift their space-use patterns to take advantage of non-ungulate prey close to residential development. However, long-term management of Cougars in wildland-urban environments may require an examination of ungulate presence in residential environments to ensure that these populations do not encourage Cougar presence in habitats close to people.

The wildland-urban interface lies at the confluence of human-dominated and wild landscapes, creating a number of management and conservation challenges. Because wildlife ecology, behavior, and evolution at this interface are shaped by both natural and human phenomena, this requires greater understanding of how diverse factors affect ecosystem and population processes. We illustrate the challenge of understanding and managing a frequent and often undesired inhabitant of the wildland-urban landscape, the cougar (Puma concolor). In wildland and residential areas of western Washington State, USA, we captured and radiotracked 27 cougars to model space use and understand the role of landscape features in interactions (sightings, encounters, and depredations) between cougars and humans. Resource utilization functions (RUFs) identified cougar use of areas with features that were probably attractive to prey, influential on prey vulnerability, and associated with limited or no residential development. Early-successional forest (+), conifer forest (+), distance to road ( ), residential density ( ), and elevation ( ) were significant positive and negative predictors of use for the population, whereas use of other landscape features was highly variable. Space use and movement rates in wildland and residential areas were similar because cougars used wildland-like forest patches, reserves, and corridors in residential portions of their home range. The population RUF was a good predictor of confirmed cougar interactions, with 72% of confirmed reports occurring in the 50% of the landscape predicted to be medium-high and high cougar use areas. We believe that there is a threshold residential density at which the level of development modifies the habitat but maintains enough wildland characteristics to encourage moderate levels of cougar use and maximize the probability of interaction. Wildlife managers trying to reduce interactions between cougars and people should incorporate information on spatial ecology and landscape characteristics to identify areas with the highest overlap of human and cougar use to focus management, education, and landscape planning. Resource utilization functions provide a proactive tool to guide these activities for improved coexistence with wildlife using both wildland and residential portions of the landscape.

Non-native fish and Bullfrogs (Lithobates catesbeianus) are frequently cited as contributing to the decline of ranid frogs in the western United States. Because of this, we hypothesized that non-native species, habitat, or a combination relate to the probability of local extinction for Northern Red-legged Frogs (Rana aurora) in western Oregon. In the first 5 y of an ongoing study, we found no support for the non-native species hypothesis. Instead, the probability of local extinction decreased with the extent of emergent vegetation and riparian forest.

S 21th Annual Western Aquatic Plant Management Society Meeting March 25-27, 2002

During 1999-2002, we studied the abundance of fish-eating birds, primarily Ring billed Gulls (Larus delawarensis) and California Gulls (L. californicus), and estimated their consumption of fish at Horn Rapids Dam and the Chandler Irrigation Canal return pipe on the Yakima River in eastern Washington. Earlier observations of gulls at these structures suggested a high level of predation of juvenile salmonids. The relationship between river flow, gull use at the sites and fish taken was also examined. Numbers of gulls (instantaneous counts of foraging and non-foraging individuals) at the structures varied daily between their arrival in late March-early April and departure in late June. Daily averages across the four years were 9.8 (SE +/- 1.5) and 19.1 (SE +/- 2.5) gulls at Horn Rapids and Chandler, respectively. Gull numbers at Horn Rapids peaked dramatically during the last two weeks in May, reaching maxima of 37 (SE +/- 2.2) to 133 (SE +/- 4.2) gulls/day. This increase appeared to be associated with the hatchery release of one to two million juvenile autumn Chinook (Oncorhynchus tshawytscha) above the dam. A comparable peak in gull abundance was not observed at Chandler. Diurnal patterns of gull abundance differed between sites and among years. Relationships between fish take and water flow also varied within and among years at the two sites. Low seasonal flows were associated with increased predation at Chandler, whereas high seasonal flows were associated with increased predation at Horn Rapids. Assuming all fish taken were salmonids, consumption at both sites combined was estimated to be <= 10.3% of the juvenile salmonids passing the two sites.