71 results on '"Northern pikeminnow"'
Search Results
2. A Field-based Bioenergetics Model for Estimating Time-Varying Food Consumption and Growth.
- Author
-
van Poorten, Brett T., Walters, Carl J., and Taylor, Nathan G.
- Subjects
BIOENERGETICS ,FISH growth ,FISH feeds ,ESTIMATION theory ,FISH populations ,NORTHERN pikeminnow - Abstract
Bioenergetics models are often used to describe the implications of changes in growth and consumption of specific wild populations, and yet most parameters are derived from a variety of laboratory studies on other populations or species, leading to questions regarding the validity of predictions. A novel bioenergetics approach was recently developed where many parameters are estimated from the population being modeled, but growth and consumption are assumed invariant over time, which would not hold true when manipulations to the system are known or suspected. In the present paper, a bioenergetics model with many key parameters estimated from field data are presented where temporal deviations in growth rates were directly estimated. A series of rainbow trout Oncorhynchus mykiss and northern pikeminnow Ptychocheilus oregonensis populations, which have undergone various population manipulations, were used to evaluate the model. Further, the model was fit to a series of rainbow trout size-classes stocked into each of the study lakes to compare with their wild counterparts and evaluate intercohort differences in growth and consumption. We found the model with time-varying consumption was more parsimonious compared with models where growth and consumption were assumed to be constant over time. Our field data demonstrated how the model can detect different patterns in growth and consumption across populations and species. The model detected highly variable growth and consumption in rainbow trout over time and between populations but did not seem to be particularly influenced by past population manipulations. By contrast, northern pikeminnow demonstrated differences between lakes, but showed little temporal variation in growth and consumption. Stocked rainbow trout demonstrated similar growth rates to their wild counterparts, helping to validate growth estimates. Our bioenergetics model moves beyond existing ones by allowing measurement and process errors to be explicitly represented, while also permitting growth and consumption to vary over time. Received October 24, 2011; accepted February 22, 2012 [ABSTRACT FROM PUBLISHER]
- Published
- 2012
- Full Text
- View/download PDF
3. Prey naivety in the behavioural responses of juvenile Chinook salmon ( Oncorhynchus tshawytscha) to an invasive predator.
- Author
-
KUEHNE, LAUREN M. and OLDEN, JULIAN D.
- Subjects
- *
CHINOOK salmon , *PREDATION , *AQUATIC animals , *PREDATORY animals , *SMALLMOUTH bass , *NORTHERN pikeminnow - Abstract
1. Non-native predators might inflict proportionally higher mortality on prey that have no previous experience of them, compared to species that have coexisted with the predator for some time. 2. We tested whether juvenile Chinook salmon ( Oncorhynchus tshawytscha) were less able to recognise a non-native than a native predator, by investigating behavioural responses to the chemical cues of the invasive smallmouth bass ( Micropterus dolomieu) and the native northern pikeminnow ( Ptychocheilus oregonensis) in both laboratory and field experiments. 3. Laboratory results demonstrated strong innate antipredator responses of individual juvenile Chinook salmon to northern pikeminnow; fish spent 70% of time motionless and exhibited 100% greater panic response than in controls. By contrast, antipredator responses to the chemical cues of smallmouth bass did not differ from controls. 4. These results were supported by similar differences in recognition of these predator odours by groups of juvenile Chinook salmon in fully natural conditions, though responses reflected a greater range of antipredator behaviours by individuals. In field trials, responses to northern pikeminnow odour resulted in increased flight or absence, reductions in swimming and foraging, and increased time spent near the substratum, compared to smallmouth bass odour. 5. Given that survival of juvenile fish is facilitated by predator recognition, our results support the hypothesis that naivety may be an important factor determining the effect of non-native predators on prey populations. Efforts to manage the effect of native and non-native predators may benefit by considering complex behavioural interactions, such as these at the individual and group levels. [ABSTRACT FROM AUTHOR]
- Published
- 2012
- Full Text
- View/download PDF
4. ECOSYSTEM-BASED MANAGEMENT OF PREDATOR-PREY RELATIONSHIPS: PISCIVOROUS BIRDS AND SALMONIDS.
- Author
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Wiese, Francis K., Parrish, Julia K., Thompson, Christopher W., and Maranto, Christina
- Subjects
RIVERS ,WILDLIFE management ,PREDATORY animals ,WATER birds ,SEA birds ,SALMONIDAE ,SALMON - Abstract
The article reports on the research conducted by Francis K. Wiese and colleagues on management of predator-prey relationship of birds and salmonids in the Columbia River basin. It shows that predator-prey relationships are altered as a result of human activities. In Columbia River basin, piscivorous predators have been implicated in contributing to lack of recovery of several endangered anadromous salmonids and control systems are instituted against piscine and avian species. Researchers employed the use of bioenergetics approach to estimate the consumption of salmonid smolts by waterbirds. Studies reveal that smolts survival could be maximized by deterring birds from the river when smolts are present, allowing bird presence after the diet switch to act as a tool for predator control.
- Published
- 2008
- Full Text
- View/download PDF
5. Vulnerability of Young White Sturgeon, Acipenser transmontanus, to Predation in the Presence of Alternative Prey.
- Author
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Gadomski, Dena M. and Parsley, Michael J.
- Subjects
PREDATION ,ACIPENSER ,WHITE sturgeon ,PREDATORS of fishes ,EFFECT of predators on fishes ,COHO salmon ,ONCORHYNCHUS ,NORTHERN pikeminnow ,ECOLOGY - Abstract
We conducted laboratory trials to test the vulnerability of young white sturgeon, Acipenser transmontanus, to predation when an alternative prey was available. In trials with two species of predators, we observed two feeding patterns. When equal numbers of white sturgeon and goldfish, Carassius auratus, were available, prickly sculpins, Cottus asper, ingested more white sturgeon. Conversely, northern pikeminnow, Ptychocheilus oregonensis, ate more juvenile coho salmon, Oncorhynchus kisutch, than white sturgeon in three out of four sets of trials, but ate more white sturgeon in one set of trials. White sturgeon size and the availability of cover did not affect the proportions of prey species ingested. Our results indicate that predation may be affecting survival of white sturgeon larvae and juveniles in the wild and could be one factor limiting recruitment of young-of-the-year white sturgeon in some locations. [ABSTRACT FROM AUTHOR]
- Published
- 2005
- Full Text
- View/download PDF
6. Patterns of fish deformities and their association with trematode cysts in the Willamette River, Oregon.
- Author
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Cunningham, Michael E., Markle, Douglas F., Watral, Virginia G., Kent, Michael L., and Curtis, Larry R.
- Subjects
ABNORMALITIES in animals ,NORTHERN pikeminnow ,MINNOWS ,SKELETON ,BONE abnormalities ,TREMATODA ,FISHES - Abstract
We described skeletal deformities in Willamette River fishes from larval and juvenile specimens collected in 2002 and 2003. Deformities were found in most taxa examined but were more frequent in native broadcast spawners, especially minnows and suckers, than in native or exotic nest builders. Caudal deformities were uniformly distributed throughout the river, but precaudal deformities were more localized near the towns of Newberg and Salem (Wheatland Ferry). In northern pikeminnow,Ptychocheilus oregonensis, deformities were dependent on relative hatch date, with early season fish having about three times the deformity load as late season fish. In a subsample of northern pikeminnow and chiselmouth,Acrocheilus alutaceus, number of deformities was directly related to number of trematode metacercariae and precaudal deformities were twice as likely as caudal deformities to be associated with metacercariae. Based on a logistic regression, the probability of a precaudal deformity was dependent on number of metacercariae and geographic area with the area effect disappearing as the number of cysts increased. A separate analysis showed that some types of deformities were unlikely to be associated with metacercariae. However, even in cases where metacercariae were unlikely to be associated with deformities, metacercariae were usually present elsewhere in the fish and an indirect effect could not be dismissed. The taxonomic, spatial and temporal patterns of skeletal deformities in Willamette River fishes may be due to differences in intermediate host (snail or fish) resistance or susceptibility to parasites, to differences in life history ecology, or to anthropogenic effects that are manifest in increased precaudal deformities near Newberg and Wheatland Ferry or decreased rates elsewhere. [ABSTRACT FROM AUTHOR]
- Published
- 2005
- Full Text
- View/download PDF
7. Predation by Northern Pikeminnow and Tiger Muskellunge on Juvenile Salmonids in a High‐Head Reservoir: Implications for Anadromous Fish Reintroductions
- Author
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David A. Beauchamp, Andrew C. Wilson, Erin D. Lowery, Kristin A. Connelly, Adam G. Hansen, and Mark H. Sorel
- Subjects
0106 biological sciences ,Ptychocheilus ,education.field_of_study ,Fish migration ,biology ,010604 marine biology & hydrobiology ,Population ,04 agricultural and veterinary sciences ,Tiger muskellunge ,Aquatic Science ,Northern pikeminnow ,biology.organism_classification ,01 natural sciences ,Predation ,Fishery ,040102 fisheries ,0401 agriculture, forestry, and fisheries ,education ,computer ,Ecology, Evolution, Behavior and Systematics ,Esox ,Pike ,computer.programming_language - Abstract
The feasibility of reintroducing anadromous salmonids into reservoirs above high-head dams is affected by the suitability of the reservoir habitat for rearing and the interactions of the resident fish with introduced fish. We evaluated the predation risk to anadromous salmonids considered for reintroduction in Merwin Reservoir on the North Fork Lewis River in Washington State for two reservoir use-scenarios: year-round rearing and smolt migration. We characterized the role of the primary predators, Northern Pikeminnow Ptychocheilus oregonensis and tiger muskellunge (Northern Pike Esox lucius × Muskellunge E. masquinongy), by using stable isotopes and stomach content analysis, quantified seasonal, per capita predation using bioenergetics modeling, and evaluated the size and age structures of the populations. We then combined these inputs to estimate predation rates of size-structured population units. Northern Pikeminnow of FL ≥ 300 mm were highly cannibalistic and exhibited modest, seasonal, per c...
- Published
- 2016
8. Growth and mortality of age-0 northern squawfish, Ptychocheilus oregonensis, rearing in shoreline habitats of a Columbia River reservoir.
- Author
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Barfoot, Craig A., Gadomski, Dena M., and Wertheimer, Robert H.
- Subjects
NORTHERN pikeminnow ,PIKEMINNOWS ,FISH growth ,FISH mortality ,FISH habitats - Abstract
We investigated growth and mortality of age-0 northern squawfish during early rearing in shallow shoreline habitats. Larvae and juveniles (n = 22914) were collected by weekly seining at three sample sites in the upper John Day Reservoir, Columbia River, during June through early September 1994-1996. Using a length-based ageing method, it was estimated that the exponential growth rate (C) for a common growth stanza (10-28 mm standard length SL) was significantly higher in 1994 (G = 0.047) than in 1996 (G = 0.037). Growth rate in 1995 could not be estimated, but was probably intermediate between 1994 and 1996 based on mean standard lengths of fish collected at the end of each sampling season (46.3, 40.0, and 32.0 mm SL in 1994, 1995, and 1996, respectively). For many fish species, variations in early growth can influence survival through size-selective mortality processes. Consistent with this possibility, our estimates of instantaneous mortality rates (Z) demonstrated that larvae and juveniles had significantly higher mortality in 1996 than in 1994 (Z = 0.103 in 1994, versus Z = 0.138 in 1996). Enhanced growth and lower mortality in 1994 were associated with a number of interrelated environmental conditions - comparatively low flows and turbidities, abundant instream vegetative cover, and high near-shore water temperatures. [ABSTRACT FROM AUTHOR]
- Published
- 1999
- Full Text
- View/download PDF
9. Diel and distributional abundance patterns of fish embryos and larvae in the lower Columbia and Deschutes rivers.
- Author
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Gadomski, Dena M. and Barfoot, Craig A.
- Subjects
FISH embryos ,AMERICAN shad ,NORTHERN pikeminnow - Abstract
Diel and distributional abundance patterns of free embryos and larvae of fishes in the lower Columbia River Basin were investigated. Ichthyoplankton samples were collected in 1993 during day and night in the main-channel and a backwater of the lower Columbia River, and in a tributary, the Deschutes River. Fish embryos and larvae collected in the main-channel Columbia River were primarily (85.6%) of native taxa (peamouth Mylocheilus caurinus, northern squawfish Ptychocheilus oregonensis, suckers Catostomus spp., and sculpins Cottus spp.), with two introduced species (American shad Alosa sapidissima and common carp Cyprinus carpio) comprising a smaller percentage of the catch (13.3%). Similarly, in the Deschutes River native taxa [lampreys (Petromyzontidae), minnows (Cyprinidae), and suckers Catostomus spp.] dominated collections (99.5% of the catch). In contrast, 83.5% of embryos and larvae in the Columbia River backwater were of introduced taxa [American shad, common carp, and sunfishes (Centrarchidae)]. In all locations, all dominant taxa except sculpins were collected in significantly greater proportions at night. Taxon-specific differences in proportions of embryos and larvae collected at night can in some instances be related to life history styles. In the main-channel Columbia River, northern squawfish and peamouth were strongly nocturnal and high proportions still had yolksacs, suggesting that they had recently hatched and were drifting downriver to rearing areas. In contrast, sculpin abundances were similar during day and night, and sculpins mostly had depleted yolksacs, indicating sculpins were feeding and rearing in offshore limnetic habitats. Taxon-specific diel abundance patterns and their causes must be considered when designing effective sampling programs for fish embryos and larvae. [ABSTRACT FROM AUTHOR]
- Published
- 1998
- Full Text
- View/download PDF
10. Fish Assemblage Structure and Habitat Associations in a Large Western River System
- Author
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Michael C. Quist, Christopher D. Smith, and Ryan S. Hardy
- Subjects
0106 biological sciences ,Perch ,biology ,Ecology ,010604 marine biology & hydrobiology ,Northern pikeminnow ,biology.organism_classification ,010603 evolutionary biology ,01 natural sciences ,Mylocheilus caurinus ,Prosopium ,Lepomis ,Fishery ,Mountain whitefish ,Electrofishing ,Animal ecology ,Environmental Chemistry ,General Environmental Science ,Water Science and Technology - Abstract
Longitudinal gradients of fish assemblage and habitat structure were investigated in the Kootenai River of northern Idaho. A total of 43 500-m river reaches was sampled repeatedly with several techniques (boat-mounted electrofishing, hoop nets and benthic trawls) in the summers of 2012 and 2013. Differences in habitat and fish assemblage structure were apparent along the longitudinal gradient of the Kootenai River. Habitat characteristics (e.g. depth, substrate composition and water velocity) were related to fish assemblage structure in three different geomorphic river sections. Upper river sections were characterized by native salmonids (e.g. mountain whitefish Prosopium williamsoni), whereas native cyprinids (peamouth Mylocheilus caurinus, northern pikeminnow Ptychocheilus oregonensis) and non-native fishes (pumpkinseed Lepomis gibbosus, yellow perch Perca flavescens) were common in the downstream section. Overall, a general pattern of species addition from upstream to downstream sections was discovered and is likely related to increased habitat complexity and additions of non-native species in downstream sections. Assemblage structure of the upper sections were similar, but were both dissimilar to the lower section of the Kootenai River. Species-specific hurdle regressions indicated the relationships among habitat characteristics and the predicted probability of occurrence and relative abundance varied by species. Understanding fish assemblage structure in relation to habitat could improve conservation efforts of rare fishes and improve management of coldwater river systems. Copyright © 2015 John Wiley & Sons, Ltd.
- Published
- 2015
11. Detection Probabilities of Electrofishing, Hoop Nets, and Benthic Trawls for Fishes in Two Western North American Rivers
- Author
-
Ryan S. Hardy, Michael C. Quist, and Christopher D. Smith
- Subjects
Ptychocheilus ,Ecology ,biology ,Sampling (statistics) ,Northern pikeminnow ,biology.organism_classification ,Fishery ,Electrofishing ,Habitat ,Benthic zone ,Juvenile ,%22">Fish ,Animal Science and Zoology ,Ecology, Evolution, Behavior and Systematics ,Nature and Landscape Conservation - Abstract
Research comparing different sampling techniques helps improve the efficiency and efficacy of sampling efforts. We compared the effectiveness of three sampling techniques (small-mesh hoop nets, benthic trawls, boat-mounted electrofishing) for 30 species in the Green (WY, USA) and Kootenai (ID, USA) rivers by estimating conditional detection probabilities (probability of detecting a species given its presence at a site). Electrofishing had the highest detection probabilities (generally greater than 0.60) for most species (88%), but hoop nets also had high detectability for several taxa (e.g., adult burbot Lota lota, juvenile northern pikeminnow Ptychocheilus oregonensis). Benthic trawls had low detection probabilities (
- Published
- 2015
12. Effects of Summer Drawdown on the Fishes and Larval Chironomids in Beulah Reservoir, Oregon
- Author
-
Matthew G. Mesa and Brien P. Rose
- Subjects
Fishery ,Ptychocheilus ,Catostomus ,biology ,Ecology ,Fishing ,Rhinichthys ,Northern pikeminnow ,Catch per unit effort ,biology.organism_classification ,Chironomidae ,Ecology, Evolution, Behavior and Systematics ,Richardsonius balteatus - Abstract
Summer drawdown of Beulah Reservoir, Oregon, could adversely affect fish and invertebrate production, limit sport fishing opportunities, and hinder the recovery of threatened species. To assess the impacts of drawdown, we sampled fish and Chironomidae larvae in Beulah Reservoir in the springs of 2006 to 2008. The reservoir was reduced to 68% of full pool in 2006 and to run-of-river level in 2007. From spring 2006 to spring 2007, the catch per unit effort (CPUE) of fyke nets decreased significantly for dace [Rhinichthys spp.] and northern pikeminnow [Ptychocheilus oregonensis], increased significantly for suckers [Catastomus spp.] and white crappies [Pomoxis nigromaculatus], and was similar for redside shiners [Richardsonius balteatus]. CPUE of gillnets either increased significantly or remained similar depending on genera, and the size structure of redside shiners, suckers, and white crappies changed appreciably. From 2007 to 2008, the CPUE of northern pikeminnow, redside shiners, suckers, and wh...
- Published
- 2013
13. A Field-based Bioenergetics Model for Estimating Time-Varying Food Consumption and Growth
- Author
-
Nathan G. Taylor, Brett T. van Poorten, and Carl J. Walters
- Subjects
Ptychocheilus ,education.field_of_study ,Bioenergetics ,biology ,Ecology ,Field data ,Population ,Food consumption ,Aquatic Science ,Northern pikeminnow ,biology.organism_classification ,Statistics ,Rainbow trout ,Field based ,education ,Ecology, Evolution, Behavior and Systematics - Abstract
Bioenergetics models are often used to describe the implications of changes in growth and consumption of specific wild populations, and yet most parameters are derived from a variety of laboratory studies on other populations or species, leading to questions regarding the validity of predictions. A novel bioenergetics approach was recently developed where many parameters are estimated from the population being modeled, but growth and consumption are assumed invariant over time, which would not hold true when manipulations to the system are known or suspected. In the present paper, a bioenergetics model with many key parameters estimated from field data are presented where temporal deviations in growth rates were directly estimated. A series of rainbow trout Oncorhynchus mykiss and northern pikeminnow Ptychocheilus oregonensis populations, which have undergone various population manipulations, were used to evaluate the model. Further, the model was fit to a series of rainbow trout size-classes sto...
- Published
- 2012
14. Prey naivety in the behavioural responses of juvenile Chinook salmon (Oncorhynchus tshawytscha) to an invasive predator
- Author
-
Lauren M. Kuehne and Julian D. Olden
- Subjects
Ptychocheilus ,biology ,Ecology ,Oncorhynchus ,Juvenile ,Micropterus ,Juvenile fish ,Aquatic Science ,Northern pikeminnow ,biology.organism_classification ,Predator ,Predation - Abstract
SUMMARY 1. Non-native predators might inflict proportionally higher mortality on prey that have no previous experience of them, compared to species that have coexisted with the predator for some time. 2. We tested whether juvenile Chinook salmon (Oncorhynchus tshawytscha) were less able to recognise a non-native than a native predator, by investigating behavioural responses to the chemical cues of the invasive smallmouth bass (Micropterus dolomieu) and the native northern pikeminnow (Ptychocheilus oregonensis) in both laboratory and field experiments. 3. Laboratory results demonstrated strong innate antipredator responses of individual juvenile Chinook salmon to northern pikeminnow; fish spent 70% of time motionless and exhibited 100% greater panic response than in controls. By contrast, antipredator responses to the chemical cues of smallmouth bass did not differ from controls. 4. These results were supported by similar differences in recognition of these predator odours by groups of juvenile Chinook salmon in fully natural conditions, though responses reflected a greater range of antipredator behaviours by individuals. In field trials, responses to northern pikeminnow odour resulted in increased flight or absence, reductions in swimming and foraging, and increased time spent near the substratum, compared to smallmouth bass odour. 5. Given that survival of juvenile fish is facilitated by predator recognition, our results support the hypothesis that naivety may be an important factor determining the effect of non-native predators on prey populations. Efforts to manage the effect of native and non-native predators may benefit by considering complex behavioural interactions, such as these at the individual and group levels.
- Published
- 2012
15. Trophic Ecology of Olympic Mudminnow (Novumbra hubbsi) in Lake Ozette, Washington
- Author
-
Lauren M. Kuehne, Julian D. Olden, and Amaryllis K. Adey
- Subjects
0106 biological sciences ,education.field_of_study ,biology ,Ecology ,010604 marine biology & hydrobiology ,media_common.quotation_subject ,Population ,Northern pikeminnow ,biology.organism_classification ,010603 evolutionary biology ,01 natural sciences ,Competition (biology) ,Predation ,Geography ,Novumbra hubbsi ,Sculpin ,education ,Cottus asper ,Ecology, Evolution, Behavior and Systematics ,media_common ,Trophic level - Abstract
Washington State's only endemic fish, Olympic mudminnow (Novumbra hubbsi), was listed as state “Sensitive” in 1999 due to a small range and concern about population declines and threats, including impacts from nonnative competitors and predators. We investigated the trophic ecology of Olympic mudminnow to identify habitat and foraging specialization across three sites in Lake Ozette (Olympic National Park, Washington), and evaluate evidence for resource interactions with sympatric fish species. Stable isotopes of carbon and nitrogen from dominant co-occurring fish—yellow perch (Percaflavescens), prickly sculpin (Cottus asper), and northern pikeminnow (Ptychocheilus oregonensis)—were evaluated for evidence of competition with and predation on Olympic mudminnow using trophic niche overlap and stable isotope mixing models. Evidence from co-occurrence and isotope analyses supported spatial and trophic segregation of Olympic mudminnow, and reduced likelihood of competitive and predatory relationships. Of the sympatric fish examined, prickly sculpin may be the most likely to experience biotic interactions with Olympic mudminnow. These results are consistent with other research demonstrating strong habitat and microhabitat specialization by Olympic mudminnow and suggest that access to these favored habitats may be an important mediating factor in defining the potential for biotic interactions with other species, including nonnative fishes.
- Published
- 2018
16. Biotic and Abiotic Factors Related to Redband Trout Occurrence and Abundance in Desert and Montane Streams
- Author
-
James A. Lamansky, Kevin A. Meyer, and Daniel J. Schill
- Subjects
Abiotic component ,Ptychocheilus ,Ecology ,biology ,Redband trout ,Micropterus ,STREAMS ,Northern pikeminnow ,biology.organism_classification ,Substrate (marine biology) ,Environmental science ,Rainbow trout ,Ecology, Evolution, Behavior and Systematics - Abstract
Redband trout Oncorhynchus mykiss gairdneri in the Columbia River Basin of western North America occupy desert and montane streams with variable habitat conditions. In general, desert streams are lower in gradient and elevation, contain less large substrate and more silt substrate, are less shaded by overhead vegetation, and have higher summer water temperature than montane streams. Consequently, we assessed whether the relationships between biotic and abiotic factors and the occurrence and abundance of redband trout in southwestern Idaho differed between desert and montane streams (
- Published
- 2010
17. Estimation of Bioenergetics Parameters for a Stunted Northern Pikeminnow Population of South Central British Columbia
- Author
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Nathan G. Taylor and Carl J. Walters
- Subjects
Estimation ,education.field_of_study ,geography ,Plateau ,geography.geographical_feature_category ,biology ,Bioenergetics ,Ecology ,media_common.quotation_subject ,Field data ,Population ,Q10 ,Northern pikeminnow ,biology.organism_classification ,Fishery ,Environmental science ,Reproduction ,education ,media_common - Abstract
We estimate bioenergetics parameters using length-age and mark-recapture data for a stunted population of Northern pikeminnow on the Bonaparte plateau, British Columbia using a seasonal reproduction, skeletal allocation model. We show that using field data alone it was possible to estimate food consumption rates, standard metabolic rate and metabolic Q10 parameters, the proportional increase in feeding rate per 10 o C increase (Qc), but that prior parameter ranges must be specified. Using the estimated parameter set, we predict body sizes using warmer water temperatures from Cultis Lake, British Columbia and the John Day Reservoir, Columbia River. We show that surface temperature differ- ences between the Bonaparte plateau, John Day reservoir and Cultus Lake alone are insufficient to explain very large un- der-predictions of body size for these areas. In addition to diet differences, fish are likely choosing between fine-scale temperature and food-density environments to optimize capture and metabolism of food.
- Published
- 2010
18. Polyphyly of the Pikeminnows (Teleostei: Cyprinidae) Inferred Using Mitochondrial DNA Sequences
- Author
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Derek D. Houston, Dennis K. Shiozawa, Michael F. Whiting, and T. Heath Ogden
- Subjects
Ptychocheilus ,Genetics ,Mitochondrial DNA ,Mylopharodon conocephalus ,biology ,Cytochrome b ,Sacramento pikeminnow ,Aquatic Science ,Northern pikeminnow ,biology.organism_classification ,Monophyly ,Evolutionary biology ,Polyphyly ,Ecology, Evolution, Behavior and Systematics - Abstract
The phylogenetic relationships of the Colorado pikeminnow Ptychocheilus lucius, northern pikeminnow P. oregonensis, Sacramento pikeminnow P. grandis, Umpqua pikeminnow P. umpquae, and hardhead Mylopharodon conocephalus were examined by using molecular data to investigate monophyly of the genus Ptychocheilus. Phylogenies generated using DNA sequence data from the cytochrome b and 16S ribosomal DNA genes of the mitochondrial genome reveal that Ptychocheilus is a polyphyletic genus and suggest that the taxonomy of the group is in need of further revision. These data yield insights into the evolution of the pikeminnows and help place the significant evolutionary events in context with the geological history of parts of western North America (e.g., ancient drainage connections that may have allowed for dispersal, followed by speciation once those connections were broken).
- Published
- 2010
19. Factors Affecting the Age-0 Resident Fish Community Along Shorelines of the Hanford Reach of the Columbia River
- Author
-
Dena M. Gadomski and Paul G. Wagner
- Subjects
Ptychocheilus ,Catostomus ,biology ,Ecology ,Vegetation ,Northern pikeminnow ,biology.organism_classification ,Mylocheilus caurinus ,Water level ,Fishery ,Shiner ,Environmental science ,Ecology, Evolution, Behavior and Systematics ,Richardsonius balteatus - Abstract
The Hanford Reach is one of the few remaining unimpounded sections of the Columbia River. However, because of flow management at upstream dams, there are often large fluctuations in water level. To determine how environmental conditions might affect age-0 resident fishes in the Hanford Reach, we evaluated species composition, distribution, abundance, and standard lengths of larval and juvenile fishes along shoreline habitats during July and August 1998, 1999, and 2000. Catches in beach seine hauls during all three years were highly variable. The four most abundant taxa collected were three cyprinids, peamouth (Mylocheilus caurinus), northern pikeminnow (Ptychocheilus oregonensis), and redside shiner (Richardsonius balteatus); and suckers (Catostomus spp.). Highest overall catches were in sloughs of the Hanford Reach in 1999, a year with high flows, lower water level fluctuations, and more vegetation. Mean shoreline summer water temperatures were higher in 1998 than in 1999 and 2000, and mean leng...
- Published
- 2009
20. Northern squawfish (Ptychocheilus oregonensis) for surimi production.
- Author
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Lin, D. and Morrissey, M.T.
- Subjects
- *
NORTHERN pikeminnow , *SURIMI - Abstract
Investigates the feasibility of using Northern squawfish, or Ptychocheilus oregonensis, kept in ice over an extended period, for surimi processing. Processing parameters; Stress and strain results; Fish freshness' effect on initial surimi gel strength and color; Variable effects on loss of gel strength during frozen storage.
- Published
- 1995
- Full Text
- View/download PDF
21. PCDDs, PCDFs, PCBs, OC pesticides and mercury in fish and osprey eggs from Willamette River, Oregon (1993, 2001 and 2006) with calculated biomagnification factors
- Author
-
James L. Kaiser, Robert A. Grove, and Charles J. Henny
- Subjects
Polychlorinated Dibenzodioxins ,Polymers ,Health, Toxicology and Mutagenesis ,Biomagnification ,Population ,Polychlorinated dibenzodioxins ,Management, Monitoring, Policy and Law ,Toxicology ,Oregon ,chemistry.chemical_compound ,Rivers ,Hydrocarbons, Chlorinated ,Animals ,education ,Falconiformes ,Benzofurans ,Ovum ,education.field_of_study ,Geography ,biology ,Mercury in fish ,Fishes ,Pesticide Residues ,Mercury ,General Medicine ,Northern pikeminnow ,Pesticide ,biology.organism_classification ,Polychlorinated Biphenyls ,Congener ,chemistry ,Environmental chemistry ,Environmental science ,Environmental Pollutants ,Polychlorinated dibenzofurans ,Environmental Monitoring - Abstract
The osprey (Pandion haliaetus) population nesting along the main stem Willamette River and lower Santiam River was first studied to evaluate contaminants and reproductive rates in 1993 when 78 occupied nests were present. By 2001, the population increased to 234 occupied nests, a 13.7% annual rate of population increase. A sample egg was collected from each of a series of nests along the Upper River (river mile 55-187) in 1993, 2001 and 2006 to evaluate trends of persistent contaminants (organochlorine [OC] pesticides, polychlorinated biphenyls [PCBs], polychlorinated dibenzo-p-dioxins [PCDDs], and polychlorinated dibenzofurans [PCDFs]). Nearly all OC pesticide residues decreased significantly, e.g., p, p'-DDE (DDE) from 2,350 to 1,353 to 210 microg/kg wet weight (ww). PCBs followed a similar pattern over time, e.g., SigmaPCBs 688 to 245 to 182 microg/kg ww, while PCDDs and PCDFs showed a more precipitous decline (often 85-95%) between 1993 and 2001, with no egg analyses warranted in 2006. During 2001-2002, sample osprey eggs were also collected from nests at three Headwater Reservoirs and two lower reaches (Newberg Pool and Tidal Portland) of the Willamette River, as well as the lower portion of the Santiam River to evaluate spatial residue patterns. Significant differences were seldom detected among the different sampling areas for OC pesticides (probably due to small sample sizes), although higher concentrations were often seen in the lower reaches, e.g., DDE 901 microg/kg ww (Headwater Reservoirs), 1,353 (Upper River), 1,384 (Newberg Pool) and 2,676 (Tidal Portland). PCB congener concentrations in eggs were usually higher in the Tidal Portland reach than at other locations and often significantly higher than at the Headwater Reservoirs or Upper River. Mercury (first analyzed in eggs in 2001), PCDDs and PCDFs were extremely low in 2001/2002 with no significant spatial patterns. Whole fish composite samples of largescale sucker (Catastomus macrocheilus) and northern pikeminnow (Ptychocheilus oregonensis), which account for about 90% of the biomass in the diet of this osprey population, were also collected from the Willamette River in 1993 and 2001 and analyzed for the same contaminants as osprey eggs. Contaminant residues in fish from the Upper River decreased between 1993 and 2001, paralleling findings for osprey eggs. Likewise, spatial patterns for fish residues paralleled findings for osprey eggs from the different reaches in 2001. A second empirical estimate of biomagnification factors (BMFs) from fish to osprey eggs for OC pesticides, PCBs, PCDDs and PCDFs (ww and lipid weight [lw] basis) was calculated based on residue data collected in 2001. The two independent BMF estimates (1993 and 2001) for each contaminant from the Upper River provide a measure of consistency, e.g., DDE (ww) 87 and 79, (lw) 103 and 112; SigmaPCBs (ww) 11 and 8.4, (lw) 13 and 12. Mercury did not biomagnify from fish to osprey eggs (BMF = 0.60). Legacy contaminants investigated had limited (perhaps only DDE), if any, effects on reproductive success of the increasing osprey population nesting along the Willamette River by 2001.
- Published
- 2008
22. Bypass System Modification at Bonneville Dam on the Columbia River Improved the Survival of Juvenile Salmon
- Author
-
Rachel E. Reagan, Benjamin P. Sandford, Lyle G. Gilbreath, Noah S. Adams, Edward B. Meyer, John W. Ferguson, and Richard D. Ledgerwood
- Subjects
endocrine system ,Chinook wind ,biology ,Juvenile fish ,Aquatic Science ,Northern pikeminnow ,biology.organism_classification ,Predation ,Fishery ,Plasma cortisol ,Oncorhynchus ,Juvenile ,%22">Fish ,Ecology, Evolution, Behavior and Systematics - Abstract
From 1987 to 1992, we evaluated a fish bypass system at Bonneville Dam Powerhouse 2 on the Columbia River. The survival of subyearling Chinook salmon Oncorhynchus tshawytscha released into the system ranged from 0.774 to 0.911 and was significantly lower than the survival of test fish released into turbines and the area immediately below the powerhouse where bypass system flow reentered the river. Yearling and subyearling Chinook salmon and yearling coho salmon O. kisutch released into the bypass system were injured or descaled. Also, levels of blood plasma cortisol and lactate were significantly higher in yearling and subyearling Chinook salmon that passed through the bypass system than in fish released directly into a net located over the bypass exit. This original system was then extensively modified using updated design criteria, and the site where juvenile fish reentered the river was relocated 2.8 km further downstream to reduce predation on bypassed fish by northern pikeminnow Ptychocheilu...
- Published
- 2007
23. Predation on the Invasive Copepod, Pseudodiaptomus forbesi, and Native Zooplankton in the Lower Columbia River: An Experimental Approach to Quantify Differences in Prey-Specific Feeding Rates
- Author
-
John G. Bishop, Stephen M. Bollens, and Jesse B. Adams
- Subjects
0106 biological sciences ,Food Chain ,lcsh:Medicine ,Introduced species ,010603 evolutionary biology ,01 natural sciences ,Zooplankton ,Predation ,Copepoda ,Rivers ,Animals ,14. Life underwater ,lcsh:Science ,Multidisciplinary ,biology ,Ecology ,010604 marine biology & hydrobiology ,lcsh:R ,Fishes ,Stickleback ,Northern pikeminnow ,biology.organism_classification ,Crustacean ,Cyclopidae ,Predatory Behavior ,lcsh:Q ,Introduced Species ,Copepod ,Research Article - Abstract
Invasive planktonic crustaceans have become a prominent feature of aquatic communities worldwide, yet their effects on food webs are not well known. The Asian calanoid copepod, Pseudodiaptomus forbesi, introduced to the Columbia River Estuary approximately 15 years ago, now dominates the late-summer zooplankton community, but its use by native aquatic predators is unknown. We investigated whether three species of planktivorous fishes (chinook salmon, three-spined stickleback, and northern pikeminnow) and one species of mysid exhibited higher feeding rates on native copepods and cladocerans relative to P. forbesi by conducting `single-prey' feeding experiments and, additionally, examined selectivity for prey types with `two-prey' feeding experiments. In single-prey experiments individual predator species showed no difference in feeding rates on native cyclopoid copepods (Cyclopidae spp.) relative to invasive P. forbesi, though wild-collected predators exhibited higher feeding rates on cyclopoids when considered in aggregate. In two-prey experiments, chinook salmon and northern pikeminnow both strongly selected native cladocerans (Daphnia retrocurva) over P. forbesi, and moreover, northern pikeminnow selected native Cyclopidae spp. over P. forbesi. On the other hand, in two-prey experiments, chinook salmon, three-spined stickleback and mysids were non- selective with respect to feeding on native cyclopoid copepods versus P. forbesi. Our results indicate that all four native predators in the Columbia River Estuary can consume the invasive copepod, P. forbesi, but that some predators select for native zooplankton over P. forbesi, most likely due to one (or both) of two possible underlying casual mechanisms: 1) differential taxon-specific prey motility and escape responses (calanoids > cyclopoids > daphnids) or 2) the invasive status of the zooplankton prey resulting in naivety, and thus lower feeding rates, of native predators feeding on invasive prey.
- Published
- 2015
24. Ontogenetic Trophic Interactions and Benthopelagic Coupling in Lake Washington: Evidence from Stable Isotopes and Diet Analysis
- Author
-
Nathanael C. Overman, Jenifer K. McIntyre, David A. Beauchamp, and Michael M. Mazur
- Subjects
Perch ,biology ,Benthic zone ,Ecology ,Pelagic zone ,δ15N ,Aquatic Science ,Northern pikeminnow ,biology.organism_classification ,Ecology, Evolution, Behavior and Systematics ,Food web ,Apex predator ,Trophic level - Abstract
Stable isotopes of nitrogen and carbon and stomach content analysis were used to determine the trophic position and relative importance of benthic and pelagic pathways for different life stages and species of the major fishes and invertebrate prey in Lake Washington. Significant coupling of the benthic and pelagic pathways was evident in this complex food web across seasons and fish ontogenies. Among apex predators, cutthroat trout Oncorhynchus clarkii and northern pikeminnow Ptychocheilus oregonensis shifted ontogenetically from benthic omnivory to pelagic piscivory, whereas yellow perch Perca flavescens shifted from pelagic zooplanktivory to benthic piscivory. Apex predators continued to rely on benthic prey seasonally, particularly in winter and spring. Benthic pathways were less important to the current diets of apex predators than they were during the recovery from eutrophication in the 1970s. Surprisingly, the δ15N values for copepods during winter and for zooplanktivorous longfin smelt Spi...
- Published
- 2006
25. Update on the Distribution of the Invasive Asian Fish Tapeworm, Bothriocephalus acheilognathi, in the U.S. and Canada
- Author
-
Rebecca A. Cole, Elizabeth M. Charipar, Scott A. Bonar, Patrick A. Nelson, James R. Hodgson, and Anindo Choudhury
- Subjects
Ptychocheilus ,biology ,Ecology ,White bass ,Northern pikeminnow ,Minnow ,biology.organism_classification ,Bothriocephalus acheilognathi ,Fishery ,Stocking ,biology.animal ,Parasitology ,Morone ,Pimephales promelas ,Ecology, Evolution, Behavior and Systematics - Abstract
The documented range of the invasive and potentiallypathogenicAsianfish tapeworm,Bothriocephalus acheilognathi Yamaguti, 1934 in the United States and Canada is updated based on examination of museum depo- sitions and original field collections. Gravid specimens of B. acheilognathi were collected from the fathead minnow Pimephales promelas Rafinesque in Peter Lake, at the University of Notre Dame Environmental Research Center (UNDERC) Land o' Lakes, Wisconsin. A single immature specimen of the parasite was collected from a white bass, Morone chrysops (Rafinesque) in Lake Winnipeg, Manitoba, Canada. This is the first record of B. acheilognathi in Canada and extends its northern range in the interior of the continent by more than 600 miles over the last documented record. The previous record of B. acheilognathi in Canada, from the northern pikeminnow, Ptychocheilus oregonensis in British Columbia, is a misidentification of Eubothrium tulipai. Examination of selected records of intestinal cestodes from native cyprinids, in the Harold W. Manter Laboratory of Parasitology (HWML, n ¼ 9) collection and in the United States National Parasite Collection (USNPC, n¼8), provided evidenceof theparasite in Nebraska and possiblyin the upper Colorado River basin. Introductions into Wisconsin- Michigan were due to the stocking of goldenshiners,whereas the source of the introduction in Manitoba remains unknown.
- Published
- 2006
26. ASPECTS OF SACRAMENTO PIKEMINNOW BIOLOGY IN NEARSHORE HABITATS OF THE SACRAMENTO–SAN JOAQUIN DELTA, CALIFORNIA
- Author
-
Frederick Feyrer, Randall D. Baxter, and Matthew L. Nobriga
- Subjects
Delta ,Ptychocheilus ,geography ,geography.geographical_feature_category ,Ecology ,Floodplain ,biology ,Estuary ,Sacramento pikeminnow ,Northern pikeminnow ,biology.organism_classification ,Cyprinidae ,San Joaquin ,Ecology, Evolution, Behavior and Systematics - Abstract
We documented distribution, relative abundance, diet composition, and body condition of Sacramento pikeminnow Ptychocheilus grandis during 2001 and 2003 at 5 sites in the Sacramento-San Joaquin Delta, California. Sacramento pikeminnow densities in nearshore habitats were higher in 2003 than 2001. In both years, spatial distribu- tion of beach seine densities was similar. There were no significant differences in density among sampling sites except for the southernmost site where the catch was near zero. Based on rotary screw-trap data from a 6th site, we found rela- tive abundance of Sacramento pikeminnow entering the Delta via an artificial floodplain was positively correlated with flow. Most individuals collected using all 3 gear types were age 1 or older, and appeared to grow quickly based on data from previous studies. Sacramento pikeminnow had diverse diets composed of freshwater and estuarine invertebrate and fish taxa. Incidence of piscivory was only 2% of the diet of individuals
- Published
- 2006
27. Vulnerability of Young White Sturgeon, Acipenser transmontanus, to Predation in the Presence of Alternative Prey
- Author
-
Dena M. Gadomski and Michael J. Parsley
- Subjects
Fishery ,Ptychocheilus ,Sturgeon ,biology ,Acipenser transmontanus ,Oncorhynchus ,Juvenile ,Aquatic Science ,Northern pikeminnow ,biology.organism_classification ,Cottus asper ,Ecology, Evolution, Behavior and Systematics ,Predation - Abstract
We conducted laboratory trials to test the vulnerability of young white sturgeon, Acipenser transmontanus, to predation when an alternative prey was available. In trials with two species of predators, we observed two feeding patterns. When equal numbers of white sturgeon and goldfish, Carassius auratus, were available, prickly sculpins, Cottus asper, ingested more white sturgeon. Conversely, northern pikeminnow, Ptychocheilus oregonensis, ate more juvenile coho salmon, Oncorhynchus kisutch, than white sturgeon in three out of four sets of trials, but ate more white sturgeon in one set of trials. White sturgeon size and the availability of cover did not affect the proportions of prey species ingested. Our results indicate that predation may be affecting survival of white sturgeon larvae and juveniles in the wild and could be one factor limiting recruitment of young-of-the-year white sturgeon in some locations.
- Published
- 2005
28. Laboratory Studies on the Vulnerability of Young White Sturgeon to Predation
- Author
-
Michael J. Parsley and Dena M. Gadomski
- Subjects
Ptychocheilus ,Larva ,animal structures ,Ecology ,fungi ,Management, Monitoring, Policy and Law ,Aquatic Science ,Biology ,Northern pikeminnow ,biology.organism_classification ,Predation ,Fishery ,Sturgeon ,Acipenser transmontanus ,Ictalurus ,Ecology, Evolution, Behavior and Systematics ,Catfish - Abstract
Despite evidence of annual spawning by white sturgeon Acipenser transmontanus in rivers of the northwestern United States and Canada, in some years and locations little or no recruitment of age-0 white sturgeon has been observed. We examined the vulnerability of white sturgeon larvae and juveniles to predation to further understand possible causes of mortality. We were particularly interested in the vulnerability of older larvae and juveniles because at about 25 mm total length (TL) white sturgeon develop sharp dorsal and lateral scutes that may act as a morphological defense. In the laboratory, white sturgeon ranging from newly hatched larvae to about 170-mm TL juveniles were exposed to predatory fishes they might encounter in the natural environment. We found that channel catfish Ictalurus punctatus (mean TL = 464 mm) and northern pikeminnow Ptychocheilus oregonensis (mean TL = 472 mm) ate white sturgeon up to mean sizes of 121 and 134 mm TL, respectively. Conversely, similarly sized walleyes S...
- Published
- 2005
29. A Digenean Metacercaria (Apophallussp.) and a Myxozoan (Myxobolussp.) Associated with Vertebral Deformities in Cyprinid Fishes from the Willamette River, Oregon
- Author
-
L. R. Curtis, D. F. Markle, Jan M. Spitsbergen, Charles D. Criscione, Michael L. Kent, J. R. Heidel, M. E. Cunningham, Virginia Watral, and Christopher M. Whipps
- Subjects
Ptychocheilus ,Chiselmouth ,biology ,Anatomy ,Aquatic Science ,Northern pikeminnow ,Acrocheilus ,biology.organism_classification ,Myxobolus sp ,Clearance ,Apophallus ,Mylocheilus caurinus - Abstract
A high prevalence of vertebral deformities has been observed in various fishes, especially cyprinids, from certain regions of the Willamette River for many years. One proposed source of these deformities is exposure to toxicants. Histological evaluation of affected chiselmouth Acrocheilus alutaceus revealed that all lesions associated with vertebrae were associated with metacercariae of digenean trematodes. Approximately half of the northern pikeminnow Ptychocheilus oregonensis had infections in which metacercariae were associated with these lesions. Metacercariae were also associated with vertebral lesions in three of four affected peamouth Mylocheilus caurinus. Many metacercariae that were present within the vertebral bodies were associated with bony dysplasia and bony proliferation in all three species. We also evaluated the association of the metacercariae with the vertebral deformities, using intact fish that had been cleared with trypsin. Fish from the affected regions had a much higher pre...
- Published
- 2004
30. Mercury in fish from the Pinchi Lake Region, British Columbia, Canada
- Author
-
John E. Elliott, Anton M. Scheuhammer, S.A. Weech, and Kimberly M. Cheng
- Subjects
Ptychocheilus ,Aging ,Geologic Sediments ,Health, Toxicology and Mutagenesis ,Zoology ,chemistry.chemical_element ,Fresh Water ,Toxicology ,Fish measurement ,Species Specificity ,Animals ,Trophic level ,British Columbia ,biology ,Mercury in fish ,Ecology ,Mercury ,General Medicine ,Northern pikeminnow ,biology.organism_classification ,Pollution ,Mercury (element) ,Trout ,chemistry ,Oncorhynchus mykiss ,Esocidae ,Environmental science ,Rainbow trout ,Water Pollutants, Chemical ,Environmental Monitoring - Abstract
Water, surface sediments, and40 cm rainbow trout (Oncorhynchus mykiss) and northern pikeminnow (Ptychocheilus oregonensis) were collected from Pinchi Lake, British Columbia, and from several nearby reference lakes. Hg concentrations in sediment samples from Pinchi L. were highly elevated compared to sediments from reference lakes, especially in sites adjacent to and downstream of a former Hg mine. In both fish species examined, Hg concentration was positively related to age and/or fork length. In northern pikeminnow, Hg concentrations were also positively related to trophic level (deltaN). Hg concentrations in both fish species were highest in Pinchi L., and were higher in pikeminnow than in rainbow trout of similar size. Average Hg concentrations in small rainbow trout from all lakes, including Pinchi L., were lower than dietary levels reported to cause reproductive impairment in common loons (Gavia immer); however, Hg levels in small pikeminnow from Pinchi L. were sufficiently high to be of concern. The risk for Hg toxicity in the study area is greatest for animals that consume larger piscivorous fish such as larger northern pikeminnow or lake trout, which are known from previous studies to contain higher Hg concentrations.
- Published
- 2004
31. Evacuation of Passive Integrated Transponder (PIT) Tags from Northern Pikeminnow Consuming Tagged Juvenile Chinook Salmon
- Author
-
Craig A. Barfoot and James H. Petersen
- Subjects
Ptychocheilus ,Chinook wind ,Ecology ,biology ,Management, Monitoring, Policy and Law ,Aquatic Science ,Northern pikeminnow ,biology.organism_classification ,Transponder (aeronautics) ,Predation ,Fishery ,Forage fish ,Environmental science ,Oncorhynchus ,Juvenile ,Ecology, Evolution, Behavior and Systematics - Abstract
Prey fish implanted with passive integrated transponder (PIT) tags can be used in predation studies if the timing of tag evacuation from the predators is understood. Laboratory experiments were conducted to determine how PIT tags in juvenile Chinook salmon Oncorhynchus tshawytscha that were consumed by northern pikeminnow Ptychocheilus oregonensis were evacuated in relation to various parameters. The rate of evacuation was directly related to temperature, while predator size and the number of prey consumed had less effect on the timing of tag evacuation. A power model was fitted to predict the proportion of tags expected to be evacuated at different intervals after ingestion. These results could be used in planning field or laboratory predation experiments with PIT-tagged prey fish.
- Published
- 2003
32. Predation by Northern Pikeminnow on Hatchery and Wild Coho Salmon Smolts in the Chehalis River, Washington
- Author
-
Kurt L. Fresh, Mark I. Carr, and Steven L. Schroder
- Subjects
Fishery ,Ptychocheilus ,Ecology ,biology ,Oncorhynchus ,%22">Fish ,Management, Monitoring, Policy and Law ,Aquatic Science ,Northern pikeminnow ,biology.organism_classification ,Ecology, Evolution, Behavior and Systematics ,Hatchery ,Predation - Abstract
One explanation for the low smolt-to-adult survival rates of hatchery and wild coho salmon Oncorhynchus kisutch originating from the Chehalis River, Washington, is predation by northern pikeminnow Ptychocheilus oregonensis. To evaluate this hypothesis, we studied predation by northern pikeminnow on emigrating coho salmon smolts in the undammed, lower main-stem Chehalis River (river kilometers (rkm) 27-82) during Apr and May of 1988 and 1989. Where only wild coho salmon smolts were available, we estimated that northern pikeminnow ate 0.2% of the 1,100,000 wild coho salmon smolts migrating through this reach in 1989. In the reach where both hatchery and wild fish were present, northern pikeminnow ate about 0.9% of the hatchery and wild coho salmon available in this area in 1989. Thus, the total estimated loss of coho salmon smolts due to northern pikeminnow predation in the lower main-stem Chehalis River in 1989 was approximately 18,200 fish. This was about two orders of magnitude less than the los...
- Published
- 2003
33. Assessment of a Constructed Fish Migration Barrier Using Radio Telemetry and Floy Tagging
- Author
-
James S. Baxter, Gary J. Birch, and W. R. Olmsted
- Subjects
Ptychocheilus ,Catostomus ,Fish migration ,Ecology ,biology ,Management, Monitoring, Policy and Law ,Aquatic Science ,Northern pikeminnow ,biology.organism_classification ,Fishery ,Radio tracking ,Telemetry ,parasitic diseases ,Sucker ,Environmental science ,Salmo ,Ecology, Evolution, Behavior and Systematics - Abstract
We assessed the effectiveness of a constructed fish migration barrier in the Salmo River, British Columbia, Canada, 10 years after it was constructed. The barrier was initially installed to prevent an expected increase in upstream migration of suckers Catostomus spp. and northern pikeminnow Ptychocheilus oregonensis into the Salmo River following the creation of Seven Mile Reservoir on the Pend d'Oreille River. To determine the effectiveness of the barrier, we applied radio and Floy tags to these species in Seven Mile Reservoir to assess whether upstream migration over the barrier was occurring. After sampling below the barrier, 5 largescale suckers C. macrocheilus and 5 northern pikeminnow were radio-tagged, whereas 124 suckers and 11 northern pikeminnow were Floy-tagged. Radio tracking surveys confirmed that most radio-tagged suckers and northern pikeminnow made migrations only within the reservoir, but one sucker was tracked above the barrier. This movement occurred after the peak of annual di...
- Published
- 2003
34. Innate and enhanced predator recognition in hatchery-reared chinook salmon
- Author
-
A. L. LaRae, E. P. Tezak, and Barry A. Berejikian
- Subjects
education.field_of_study ,biology ,business.industry ,Population ,Aquatic Science ,Northern pikeminnow ,biology.organism_classification ,Hatchery ,Fishery ,Aquaculture ,Juvenile ,Oncorhynchus ,business ,education ,Predator ,Ecology, Evolution, Behavior and Systematics ,Salmonidae - Abstract
We used a laboratory behaviour assay to investigate how innate predator recognition, handling stress, retention time, and number of conditioning events might affect chemically mediated anti-predator conditioning for hatchery-reared chinook salmon, Oncorhynchus tshawytscha. Juvenile chinook salmon with no prior exposure to predatory stimuli exhibited innate fright responses to northern pikeminnow, Ptychocheilis oregonensis, odour, regardless of whether the salmon came from a population that exists in sympatry or allopatry with northern pikeminnows. Juvenile chinook salmon exhibited enhanced predator recognition following a single conditioning event with conspecific extract and northern pikeminnow odour. Handling similar to what hatchery salmon might experience prior to release did not substantially reduce the conditioned response. When we conditioned juvenile chinook salmon in hatchery rearing vessels, fish from tanks treated once exhibited a conditioned response to northern pikeminnow odour in aquaria, but only for one behaviour (feeding response), and fish treated twice did not respond. The results suggest that enhanced recognition of predator stimuli occurs quickly, but may be to some extent context-specific, which may limit conditioned fright responses after release into the natural environment.
- Published
- 2003
35. Observations on the Plerocercoid Stage of the TapewormLigulain Three Species of Fish from the Lower Crooked River of Central Oregon
- Author
-
Barbara A. Shields and Kristy L. Groves
- Subjects
Ptychocheilus ,Catostomus ,biology ,Chiselmouth ,Ecology ,Bridgelip sucker ,Plerocercoid ,Aquatic Science ,Northern pikeminnow ,Ligula intestinalis ,biology.organism_classification ,Catostomidae - Abstract
Tapeworms in the genus Ligula are cosmopolitan parasites whose plerocercoid stages are found worldwide in fishes of the families Cyprinidae and Catostomidae. Examination of chiselmouth Acrocheilus alutaceus, northern pikeminnow Ptychocheilus oregonensis, and bridgelip sucker Catostomus columbianus revealed the presence of Ligula in the lower Crooked River system of central Oregon. This represents the first report of Ligula intestinalis in two of these host species: chiselmouth and bridgelip sucker. Although most hosts appeared healthy, large external lesions were noted on some bridgelip suckers in close association with a Ligula plerocercoid. The largest plerocercoid recovered was 101.5 cm relaxed length and may represent the longest plerocercoid of Ligula reported from North America.
- Published
- 2001
36. Density, aggregation, and body size of northern pikeminnow preying on juvenile salmonids in a large river
- Author
-
James H. Petersen
- Subjects
Ptychocheilus ,biology ,Ecology ,Oncorhynchus ,Juvenile ,Aquatic Science ,Northern pikeminnow ,biology.organism_classification ,Predator ,Population density ,Ecology, Evolution, Behavior and Systematics ,Salmonidae ,Predation - Abstract
Predation by northern pikeminnow Ptychocheilus oregonensis on juvenile salmonids Oncorhynchus spp. occurred probably during brief feeding bouts since diets were either dominated by salmonids (>80% by weight), or contained other prey types and few salmonids (
- Published
- 2001
37. Early Life History of the Northern Pikeminnow in the Lower Columbia River Basin
- Author
-
Craig A. Barfoot, Thomas P. Poe, Jennifer M. Bayer, and Dena M. Gadomski
- Subjects
Ptychocheilus ,Larva ,geography.geographical_feature_category ,biology ,fungi ,Drainage basin ,Aquatic Science ,Northern pikeminnow ,biology.organism_classification ,Population density ,Fishery ,Geography ,Habitat ,Tributary ,Cyprinidae ,Ecology, Evolution, Behavior and Systematics - Abstract
The northern pikeminnow Ptychocheilus oregonensis is a large, native cyprinid in the Columbia River basin that has persisted in spite of substantial habitat alterations. During the months of June to September 1993–1996, we investigated the temporal and spatial patterns of northern pikeminnow spawning, along with describing larval drift and characterizing larval and early juvenile rearing habitats in the lower Columbia River (the John Day and Dalles reservoirs and the free-flowing section downstream of Bonneville Dam) as well as in the lower sections of two major tributaries (the John Day and Deschutes rivers). The density of newly emerged drifting larvae was higher in dam tailraces (a mean of 7.7 larvae/100 m3 in surface tows) than in the lower reservoirs (0.3 larvae/100 m3), indicating that tailraces were areas of more intense spawning. Density was particularly high in the Bonneville Dam tailrace (15.1 larvae/100 m3), perhaps because adult northern pikeminnow are abundant below Bonneville Dam an...
- Published
- 2001
38. Biological Characteristics of Northern Pikeminnow in the Lower Columbia and Snake Rivers before and after Sustained Exploitation
- Author
-
Christopher J. Knutsen and David L. Ward
- Subjects
Ptychocheilus ,Biomanipulation ,biology ,Ecology ,Mortality rate ,Aquatic Science ,Northern pikeminnow ,Fecundity ,biology.organism_classification ,Fish measurement ,Fishery ,Density dependence ,Cyprinidae ,Ecology, Evolution, Behavior and Systematics - Abstract
We describe the response of northern pikeminnow Ptychocheilus oregonensis to a sustained removal program in the lower Columbia and Snake rivers. We compared catch rates of fish 250 mm fork length and larger before and after implementation of removals and examined relationships between catch rates and year-class strength. We also describe the response of mortality rates, relative weight, growth, and fecundity to sustained removals. Although annual exploitation of northern pikeminnow at least 250 mm long averaged 12.1% from 1991 to 1996, we found no evidence that surviving northern pikeminnow compensated for removals. In some areas, catch rates decreased in response to removals; however, we found no trend of increased relative weight, growth, or fecundity. Estimates of mortality were higher than those reported prior to removals, and variations in mortality generally corresponded to variations in annual exploitation rates. Our estimates of relative weight, growth, and fecundity were similar to estim...
- Published
- 1999
39. Response of Smallmouth Bass to Sustained Removals of Northern Pikeminnow in the Lower Columbia and Snake Rivers
- Author
-
Mark P. Zimmerman and David L. Ward
- Subjects
Ptychocheilus ,food.ingredient ,biology ,Micropterus ,Aquatic Science ,Northern pikeminnow ,biology.organism_classification ,Fish measurement ,Population density ,Fishery ,Bass (fish) ,food ,Ecology, Evolution, Behavior and Systematics ,Salmonidae ,Centrarchidae - Abstract
We describe the response of smallmouth bass Micropterus dolomieu density, year-class strength, consumption of juvenile salmonids Oncorhynchus spp., mortality, relative weight, and growth to sustained removals of northern pikeminnow Ptychocheilus oregonensis in the lower Columbia and Snake rivers. Although fishery exploitation of northern pikeminnow (250 mm fork length and larger) averaged 12.1% annually from 1991 to 1996, we detected no response by smallmouth bass. Density of smallmouth bass varied among years, but we found no evidence of increased density concurrent with removals of northern pikeminnow. Year-class strength of smallmouth bass also varied, and variations were similar among areas; however, we found no trend of increasing year-class strength. Consumption of juvenile salmonids by smallmouth bass was zero for 74 of our 104 estimates and did not appear to increase over time. Estimates of mortality varied among areas, but we found no differences among years for any area. Relative weight...
- Published
- 1999
40. Food Habits of Smallmouth Bass, Walleyes, and Northern Pikeminnow in the Lower Columbia River Basin during Outmigration of Juvenile Anadromous Salmonids
- Author
-
Mark P. Zimmerman
- Subjects
Ptychocheilus ,Fishery ,Fish migration ,Percidae ,biology ,Micropterus ,Aquatic Science ,Northern pikeminnow ,biology.organism_classification ,Crayfish ,Ecology, Evolution, Behavior and Systematics ,Centrarchidae ,Salmonidae - Abstract
I compared the diets of adult smallmouth bass Micropterus dolomieu, walleyes Stizostedion vitreum, and northern pikeminnow Ptychocheilus oregonensis collected in impounded and unimpounded reaches of the lower Columbia and lower Snake rivers during the outmigration of juvenile anadromous salmonids Oncorhynchus spp. from 1990 to 1996. Gravimetric proportions of fish, crayfish, and other prey consumed by each predator in spring and summer differed among the three river reaches for each predator species. Fish prey were generally the largest dietary component for all three predator species, although crayfish were also prevalent in the diets of smallmouth bass and, to a lesser extent, northern pikeminnow. Numerical proportions of salmonids, cottids, and other fish prey differed among predator species and among study reaches. Juvenile salmonids formed the majority of fish prey consumed by northern pikeminnow, whereas cottids, cyprinids, catostomids, and percopsids were more commonly consumed by smallmou...
- Published
- 1999
41. Index of Predation on Juvenile Salmonids by Northern Pikeminnow in the Lower Columbia River Basin, 1994–1996
- Author
-
David L. Ward and Mark P. Zimmerman
- Subjects
Ptychocheilus ,geography ,geography.geographical_feature_category ,biology ,Ecology ,Drainage basin ,Aquatic Science ,Northern pikeminnow ,biology.organism_classification ,Predation ,Abundance (ecology) ,Oncorhynchus ,Relative species abundance ,Ecology, Evolution, Behavior and Systematics ,Salmonidae - Abstract
We estimated relative abundance of northern pikeminnow Ptychocheilus oregonensis and relative consumption of juvenile salmonids Oncorhynchus spp. by northern pikeminnow at standardized sites in the lower Columbia and lower Snake rivers from 1994 to 1996. Indexes of abundance and consumption were compared with indexes measured from 1990 to 1993 to evaluate changes in predation concurrent with a predator control program in the lower Columbia basin. Reductions in indexes of northern pikeminnow abundance, consumption, or both resulted in mean 1994–1996 predation index values that were 44–91% lower than mean 1990–1993 values throughout the lower Columbia basin. Consumption of juvenile salmonids by surviving northern pikeminnow has not increased in response to predator control efforts. Spatial patterns were consistent among years, being greatest downstream from Bonneville Dam, intermediate in lower Columbia River reservoirs, and lowest at Snake River sites. Reductions in relative predation were consist...
- Published
- 1999
42. Development and Corroboration of a Bioenergetics Model for Northern Pikeminnow Feeding on Juvenile Salmonids in the Columbia River
- Author
-
David L. Ward and James H. Petersen
- Subjects
Ptychocheilus ,biology ,Bioenergetics ,Ecology ,Aquatic Science ,Northern pikeminnow ,Seasonality ,biology.organism_classification ,medicine.disease ,Predation ,medicine ,Oncorhynchus ,Environmental science ,Predator ,Ecology, Evolution, Behavior and Systematics ,Salmonidae - Abstract
A bioenergetics model was developed and corroborated for northern pikeminnow Ptychocheilus oregonensis, an important predator on juvenile salmonids in the Pacific Northwest. Predictions of modeled predation rate on salmonids were compared with field data from three areas of John Day Reservoir (Columbia River). To make bioenergetics model estimates of predation rate, three methods were used to approximate the change in mass of average predators during 30-d growth periods: Observed change in mass between the first and the second month, predicted change in mass calculated with seasonal growth rates, and predicted change in mass based on an annual growth model. For all reservoir areas combined, bioenergetics model predictions of predation on salmon were 19% lower than field estimates based on observed masses, 45% lower than estimates based on seasonal growth rates, and 15% lower than estimates based on the annual growth model. For each growth approach, the largest differences in field-versus-model pr...
- Published
- 1999
43. Management of Northern Pikeminnow and Implications for Juvenile Salmonid Survival in the Lower Columbia and Snake Rivers
- Author
-
Thomas A. Friesen and David L. Ward
- Subjects
Ptychocheilus ,Ecology ,biology ,Range (biology) ,Management, Monitoring, Policy and Law ,Aquatic Science ,Northern pikeminnow ,biology.organism_classification ,Fish measurement ,Predation ,Fishery ,Oncorhynchus ,Juvenile ,Ecology, Evolution, Behavior and Systematics - Abstract
Predation by large northern pikeminnow (formerly northern squawfish) Ptychocheilus oregonensis is a major source of mortality for juvenile salmonids Oncorhynchus spp. in the lower Columbia and Snake rivers. Large-scale, agency-operated fisheries have been implemented in this area since 1990 to harvest northern pikeminnow with a goal of 10–20% exploitation. We used indirect methods to analyze the success of the fisheries, and examined benefits to salmonid populations. From 1991 to 1996, three fisheries (sport-reward, dam-angling, and gill-net) harvested approximately 1.1 million northern pikeminnow that were 250 mm in fork length or longer, with the sport-reward fishery contributing 86.5% of the total catch. Total exploitation averaged 12.0% (range, 8.1–15.5) for 1991–1996 and met program goals in all years except 1993. Gill-net and dam-angling fisheries harvested larger northern pikeminnow (which consume a greater number of juvenile salmonids) than the sport-reward fishery. Modeling results indic...
- Published
- 1999
44. Variability in Biological Characteristics of Northern Squawfish in the Lower Columbia and Snake Rivers
- Author
-
Mark P. Zimmerman, David L. Ward, and Robert M. Parker
- Subjects
Ptychocheilus ,biology ,Ecology ,Population structure ,Relative weight ,Aquatic Science ,Northern pikeminnow ,Fecundity ,Fish measurement ,biology.organism_classification ,Fishery ,Fish weight ,Pooled data ,Ecology, Evolution, Behavior and Systematics - Abstract
We described and compared population structure, growth, mortality, and reproduction of northern Squawfish Ptychocheilus oregonensis among four reservoirs of the lower Columbia River and among four reservoirs of the lower Snake River. We also pooled data for comparisons among three larger areas: Columbia River reservoirs, Snake River reservoirs, and the unimpounded Columbia River downstream from Bonneville Dam. Females made up 76–100% of northern squawfish 380 mm fork length or greater in individual reservoirs, and 87–99% of fish 380 mm or greater in the three combined areas. Females lived longer and grew faster than males in all reservoirs and areas and had lower annual mortality rates in all but two reservoirs. Proportional stock density was highest and annual mortality rates were generally lowest in Columbia River reservoirs. Northern Squawfish downstream from Bonneville Dam had a lower mean relative weight and higher relative fecundity (eggs per unit fish weight) than populations in impoundmen...
- Published
- 1995
45. Index of Predation on Juvenile Salmonids by Northern Squawfish in the Lower and Middle Columbia River and in the Lower Snake River
- Author
-
James H. Petersen, John J. Loch, and David L. Ward
- Subjects
Ptychocheilus ,Index (economics) ,biology ,Ecology ,Aquatic Science ,Catch per unit effort ,Northern pikeminnow ,biology.organism_classification ,Predation ,Fishery ,Turnover time ,Abundance (ecology) ,Juvenile ,Ecology, Evolution, Behavior and Systematics - Abstract
We developed a predation index to describe the relative magnitude of predation on juvenile salmonids by northern squawfish Ptychocheilus oregonensis throughout the lower and middle Columbia River and lower Snake River. The predation index was the product of an abundance index and a consumption index. We evaluated various catch indices and found that catch per unit effort best reflected differences among northern squawfish abundances. Northern squawfish abundance was higher in the lower Columbia River than in the middle Columbia or lower Snake rivers and was highest in Bonneville Reservoir and the Columbia River downstream from Bonneville Dam. The consumption index was based on the concept of meal turnover time for a sample of northern squawfish. Variables needed to calculate the consumption index (CI) were water temperature (T), mean weight of the northern squawfish (W), mean number of salmonids in each gut (S), and mean weight of the gut contents (GW): CI = 0.0209·T 1.60·W 0.27·(S·GW−0.61). Gene...
- Published
- 1995
46. Predation on Juvenile Salmonids by Smallmouth Bass and Northern Squawfish in the Columbia River near Richland, Washington
- Author
-
Thomas P. Poe, Roger A. Tabor, and Rip S. Shively
- Subjects
Ptychocheilus ,Fish migration ,Chinook wind ,food.ingredient ,Ecology ,biology ,Micropterus ,Management, Monitoring, Policy and Law ,Aquatic Science ,Northern pikeminnow ,biology.organism_classification ,Crayfish ,Fishery ,Bass (fish) ,food ,Oncorhynchus ,Ecology, Evolution, Behavior and Systematics - Abstract
The importance of juvenile salmonids in the diet of smallmouth bass Micropterus dolomieu and northern squawfish Ptychocheilus oregonensis was examined at a 6-km stretch of the Columbia River. Piscivorous fish were sampled with electrofishing gear on 4 d (May 2–3 and June 20–21, 1990) during emigration of juvenile anadromous salmonids. Sixty-two smallmouth bass and 69 northern squawfish were collected for diet analysis. Juvenile salmonids made up 59% of smallmouth bass diet by weight and were present in 65% of the stomachs of smallmouth bass. By a meal turnover method, smallmouth bass were estimated to consume from 1.4 (May 2–3) to 1.0 (June 20–21) salmonids per predator daily. Crayfish were the dominant prey item (41.4% by weight) of northern squawfish, but juvenile salmonids (28.8%) were also important. Northern squawfish consumed from 0.55 (May 2–3) to 0.34 (June 20–21) salmonids per predator daily. Smallmouth bass and northern squawfish consumed mostly subyearling Chinook salmon Oncorhynchus t...
- Published
- 1993
47. Report on the Predation Index, Predator Control Fisheries, and Program Evaluation for the Columbia River Basin Experimental Northern Pikeminnow Management Program, 2008 Annual Report
- Author
-
Russell . Porter
- Subjects
Ptychocheilus ,geography ,education.field_of_study ,geography.geographical_feature_category ,biology ,Ecology ,Fishing ,Population ,Drainage basin ,Wildlife ,Annual report ,Northern pikeminnow ,biology.organism_classification ,Predation ,Fishery ,Environmental science ,education - Abstract
This report presents results for year seventeen in the basin-wide Experimental Northern Pikeminnow Management Program to harvest northern pikeminnow1 (Ptychocheilus oregonensis) in the Columbia and Snake Rivers. This program was started in an effort to reduce predation by northern pikeminnow on juvenile salmonids during their emigration from natal streams to the ocean. Earlier work in the Columbia River Basin suggested predation by northern pikeminnow on juvenile salmonids might account for most of the 10-20% mortality juvenile salmonids experience in each of eight Columbia River and Snake River reservoirs. Modeling simulations based on work in John Day Reservoir from 1982 through 1988 indicated that, if predator-size northern pikeminnow were exploited at a 10-20% rate, the resulting restructuring of their population could reduce their predation on juvenile salmonids by 50%. To test this hypothesis, we implemented a sport-reward angling fishery and a commercial longline fishery in the John Day Pool in 1990. We also conducted an angling fishery in areas inaccessible to the public at four dams on the mainstem Columbia River and at Ice Harbor Dam on the Snake River. Based on the success of these limited efforts, we implemented three test fisheries on a system-wide scale in 1991 - amore » tribal longline fishery above Bonneville Dam, a sport-reward fishery, and a dam-angling fishery. Low catch of target fish and high cost of implementation resulted in discontinuation of the tribal longline fishery. However, the sport-reward and dam-angling fisheries were continued in 1992 and 1993. In 1992, we investigated the feasibility of implementing a commercial longline fishery in the Columbia River below Bonneville Dam and found that implementation of this fishery was also infeasible. Estimates of combined annual exploitation rates resulting from the sport-reward and dam-angling fisheries remained at the low end of our target range of 10-20%. This suggested the need for additional effective harvest techniques. During 1991 and 1992, we developed and tested a modified (small-sized) Merwin trapnet. We found this floating trapnet to be very effective in catching northern pikeminnow at specific sites. Consequently, in 1993 we examined a system-wide fishery using floating trapnets, but found this fishery to be ineffective at harvesting large numbers of northern pikeminnow on a system-wide scale. In 1994, we investigated the use of trap nets and gillnets at specific locations where concentrations of northern pikeminnow were known or suspected to occur during the spring season (i.e., March through early June). In addition, we initiated a concerted effort to increase public participation in the sport-reward fishery through a series of promotional and incentive activities. In 1995, 1996, and 1997, promotional activities and incentives were further improved based on the favorable response in 1994. Results of these efforts are subjects of this annual report. Evaluation of the success of test fisheries in achieving our target goal of a 10-20% annual exploitation rate on northern pikeminnow is presented in Report C of this report. Overall program success in terms of altering the size and age composition of the northern pikeminnow population and in terms of potential reductions in loss of juvenile salmonids to northern pikeminnow predation is also discussed in Report C. Program cooperators include the Pacific States Marine Fisheries Commission (PSMFC), Oregon Department of Fish and Wildlife (ODFW), and Washington Department of Fish and Wildlife (WDFW), and the U. S. Department of Agriculture (USDA), Animal Damage Unit as a contractor to test Dam Angling. The PSMFC was responsible for coordination and administration of the program; PSMFC subcontracted various tasks and activities to ODFW and WDFW based on the expertise each brought to the tasks involved in implementing the program and dam angling to the USDA.« less
- Published
- 2009
48. Lake Roosevelt Fisheries Evaluation Program; Evaluation of Limiting Factors for Stocked Kokanee and Rainbow Trout in Lake Roosevelt, Washington, 1999 Annual Report
- Author
-
Casey Baldwin and Matt Polacek
- Subjects
Fishery ,Fish migration ,Trout ,biology ,Ecology ,Oncorhynchus ,Environmental science ,Micropterus ,Rainbow trout ,Northern pikeminnow ,biology.organism_classification ,Limnetic zone ,Piscivore - Abstract
Hatchery supplementation of kokanee Oncorhynchus nerka and rainbow trout O. mykiss has been the primary mitigation provided by Bonneville Power Administration for loss of anadromous fish to the waters above Grand Coulee Dam (GCD). The hatchery program for rainbow trout has consistently met management goals and provided a substantial contribution to the fishery; however, spawner returns and creel survey results for kokanee have been below management goals. Our objective was to identify factors that limit limnetic fish production in Lake Roosevelt by evaluating abiotic conditions, food limitations, piscivory, and entrainment. Dissolved oxygen concentration was adequate throughout most of the year; however, levels dropped to near 6 mg/L in late July. For kokanee, warm water temperatures during mid-late summer limited their nocturnal distribution to 80-100 m in the lower section of the reservoir. Kokanee spawner length was consistently several centimeters longer than in other Pacific Northwest systems, and the relative weights of rainbow trout and large kokanee were comparable to national averages. Large bodied daphnia (> 1.7 mm) were present in the zooplankton community during all seasons indicating that top down effects were not limiting secondary productivity. Walleye Stizostedion vitreum were the primary piscivore of salmonids in 1998 and 1999. Burbot Lota lota smallmouth bass Micropterus dolomieui, and northern pikeminnow Ptychocheilus oregonensis preyed on salmonids to a lesser degree. Age 3 and 4 walleye were responsible for the majority (65%) of the total walleye consumption of salmonids. Bioenergetics modeling indicated that reservoir wide consumption by walleye could account for a 31-39% loss of stocked kokanee but only 6-12% of rainbow trout. Size at release was the primary reason for differential mortality rates due to predation. Entrainment ranged from 2% to 16% of the monthly abundance estimates of limnetic fish, and could account for 30% of total mortality of limnetic fishes, depending on the contribution of littoral zone fishes. Inflow to GCD forebay showed the strongest negative relationship with entrainment whereas reservoir elevation and fish vertical distribution had no direct relationship with entrainment. Our results indicate that kokanee and rainbow trout in Lake Roosevelt were limited by top down impacts including predation and entrainment, whereas bottom up effects and abiotic conditions were not limiting.
- Published
- 2009
49. Rates of Consumption of Juvenile Salmonids and Alternative Prey Fish by Northern Squawfish, Walleyes, Smallmouth Bass, and Channel Catfish in John Day Reservoir, Columbia River
- Author
-
Thomas P. Poe, Steven Vigg, Linda A. Prendergast, and Hal C. Hansel
- Subjects
Fishery ,Ptychocheilus ,biology ,Ictalurus ,Forage fish ,Oncorhynchus ,Micropterus ,Aquatic Science ,Northern pikeminnow ,biology.organism_classification ,Ecology, Evolution, Behavior and Systematics ,Predation ,Catfish - Abstract
Adult northern squawfish Ptychocheilus oregonensis, walleyes Stizostedion vitreum, smallmouth bass Micropterus dolomieu, and channel catfish Ictalurus punctatus were sampled from four regions of John Day Reservoir from April to August 1983–1986 to quantify their consumption of 13 species of prey fish, particularly seaward-migrating juvenile Pacific salmon and steelhead (Oncorhynchus spp.). Consumption rates were estimated from field data on stomach contents and digestion rate relations determined in previous investigations. For each predator, consumption rates varied by reservoir area, month, time of day, and predator size or age. The greatest daily consumption of salmonids by northern squawfish and channel catfish (0.7 and 0.5 prey/predator) occurred in the upper end of the reservoir below McNary Dam. Greatest daily predation by walleyes (0.2 prey/predator) and smallmouth bass (0.04) occurred in the middle and lower reservoir. Consumption rates of all predators were highest in July, concurrent w...
- Published
- 1991
50. Estimated Loss of Juvenile Salmonids to Predation by Northern Squawfish, Walleyes, and Smallmouth Bass in John Day Reservoir, Columbia River
- Author
-
Raymond C. Beamesderfer, Steven Vigg, Bruce E. Rieman, and Thomas P. Poe
- Subjects
Ptychocheilus ,Fishery ,Chinook wind ,biology ,Juvenile ,Micropterus ,Aquatic Science ,Northern pikeminnow ,biology.organism_classification ,Ecology, Evolution, Behavior and Systematics ,Salmonidae ,Piscivore ,Predation - Abstract
–We estimated the loss of juvenile salmonids Oncorhynchus spp. to predation by northern squawfish Ptychocheilus oregonensis, walleyes Stizostedion vitreum, and smallmouth bass Micropterus dolomieu in John Day Reservoir during 1983–1986. Our estimates were based on measures of daily prey consumption, predator numbers, and numbers of juvenile salmonids entering the reservoir during the April–August period of migration. We estimated the mean annual loss was 2.7 million juvenile salmonids (95% confidence interval, 1.9–3.3 million). Northern squawfish were responsible for 78% of the total loss; walleyes accounted for 13% and smallmouth bass for 9%. Twenty-one percent of the loss occurred in a small area immediately below McNary Dam at the head of John Day Reservoir. We estimated that the three predator species consumed 14% (95% confidence interval, 9–19%) of all juvenile salmonids that entered the reservoir. Mortality changed by month and increased late in the migration season. Monthly mortality estim...
- Published
- 1991
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