Relationships Between Fish Species Distribution and Habitat in the Willamette River Drainage in Western Oregon
Relationships Between Fish Species Distribution and Habitat in the Willamette River Drainage in Western Oregon

Author: Amy Ellen Kruse

Publisher:

Published: 1988

Total Pages: 192

ISBN-13:

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The objectives of this study were to (1) describe physical environmental conditions and species composition at several sites along an Upstream/downstream gradient in a number of tributaries of the Willamette River in western Oregon; and (2) identify possible relationships between species distributional patterns and physical habitat parameters using detrended correspondence analysis (DCA), graphical techniques, and contingency table analysis. Study sites that contained both pools and riffles were selected at various locations on seven streams. At each site 13 physical environmental parameters were measured, and fish species composition and abundance were determined by snorkeling and electroshocking techniques. Associations between environmental conditions and species composition and abundances were hypothesized using the results of DCA. The DCA analysis revealed three habitat gradients, each of which represents a composite of several physical habitat variables. Axis one was interpreted as a habitat gradient from pools to riffles based upon observations of temperature, depth, and percent gravel and bedrock. Axis two appeared to be a gradient of habitat cover types; instream cover (undercut banks, root wads and boles, woody debris, and rooted vegetation) typified one end of the axis and other cover types (riparian vegetation, large substrate composition, and swift water velocities) were indicative of the opposite end of the axis. Axis three seemed to be gradient of stream discharge. Species scores differed along each axis due to the variation in specific responses to these different physical habitat gradients. A three-dimensional graph of species scores for all three axes was used to predict fish community responses to potential human perturbations of the Willamette River drainage given known effects of these perturbations on the physical parameters underlying the three gradients.

Habitat Relationships of Native and Non-native Fishes of the Willamette River, Oregon
Habitat Relationships of Native and Non-native Fishes of the Willamette River, Oregon

Author: Joshua Everett Williams

Publisher:

Published: 2014

Total Pages: 125

ISBN-13:

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The Willamette River flows north between the Cascade Mountains and Coast Range of western Oregon within a 29,728-km2 basin. The fish community in the geologically young basin consists of 36 native species, but introductions of non-native fishes have added 33 additional species for a total of 69 fish species. During the summers of 2011-2013, fish distributions were sampled from the confluence of the McKenzie River downstream to the confluence of the Columbia River to assess: (1) fish community composition, (2) differences in community composition between mainstem river and slough habitats, and (3) relationships between native and non-native fish species and physical habitat characteristics. In addition, a 182-ha seasonally inundated floodplain habitat along the middle Willamette River was sampled during winter 2011 through spring 2012 to assess: (1) fish community composition, (2) spawning and rearing, and (3) timing of use and movement by fish species. Throughout the three years of longitudinal sampling, 36,586 fish were collected comprising 41 species, 22 native and 19 non-native. Overall, native fish represented 93% of the total fish sampled. Higher numbers of fish were collected in the upper river, and higher proportions of those fish were native species. Though non-native fish were more common in slough habitats than mainstem sties, the majority of fish collected in both habitat types were native. The strongest environmental predictors of fish community were quantitative measures of longitudinal distance, velocity, depth, percent macrophyte cover and percent embeddedness. Habitat type (slough versus mainstem) was also a significant predictor. Native fish species exhibited greater variability in habitat relationships than non-native fishes, though several native species were strongly associated with specific environmental attributes. Non-native species were more associated with slough habitats and sites with high amount of macrophyte growth and embedded substrates. Overall, 25 species had a high fidelity to mainstem or slough habitats. Equal numbers of native species showed a fidelity to either mainstem or slough sites, but non-native species were significantly related only to slough habitats. In the seasonally inundated floodplain habitat, an estimated 43,000 fish were collected comprising 23 species; 12 native and 11 non-native. Of these 98.1% were native. The most common native species were threespine stickleback Gasterosteus aculeatus and peamouth Mylocheilus caurinus while the most common non-native species were bluegill Lepomis macrochirus and western mosquitofish Gambusia affinus. Several species used the inundated floodplain for spawning and rearing, particularly threespine stickleback, peamouth and western mosquitofish. With the exception of young-of-year threespine stickleback, native species were collected mostly in the beginning and middle of the sampling period while non-native species were collected in the latter portion of the sampling. The Willamette River Basin has a long history of environmental modification. Understanding relationships of a broad range of species to their environment and to each other provides a technical foundation for ecosystem based management by state and federal agencies, local municipalities, and private landowners. The need for ecosystem based management is vital for future conservation and recovery of large river floodplain ecosystems.

Fish and Amphibian Use of Intermittent Streams Within the Upper Willamette Basin, Oregon
Fish and Amphibian Use of Intermittent Streams Within the Upper Willamette Basin, Oregon

Author: Randall William Colvin

Publisher:

Published: 2005

Total Pages: 228

ISBN-13:

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In the fall through spring of 2002/03 and 2003/04, the composition of fish and amphibian communities were examined in intermittent streams in the upper Willamette river basin in western Oregon. I recorded standard aquatic habitat variables and water nutrient concentrations (nitrate and phosphate) and correlated them with fish and amphibian communities present. Fish and amphibian communities were also compared between seasons (winter and spring), capture method (minnowtrap and backpack electrofishing) and channel morphology (incised and gently sloping channels). Fish were tagged with visual implant elastomer to assess movement and distribution. Fourteen species of fish and five species of amphibians were present in these habitats over two field seasons. Fish and amphibian species composition and abundance was correlated with characteristics of the upper Willamette basin. The regional characteristics associated with the differences were a) the amount of the watershed covered in forest and b) upstream slope; whereas mean maximum water velocity separated fish dominated communities from amphibian dominated communities. Approximately 99% of fish and amphibian species caught were native to the Willamette river basin and the number of fish species decreased as the sampling distance from perennial water increased. Significant differences were found in fish and amphibian community composition between winter and spring and between capture methods. Surface/mid-water feeding fish were more abundant in gently sloping channels than benthic feeding fishes. Only 2.6% of the 498 tagged fish were recaptured between December and April. In the fall through spring 2003/04, the composition of fish communities and their invertebrate diets were compared between 12 sites on four intermittent streams. The distance between consecutive sites was approximately 900 to 1500-m. Two intermittent streams had incised channels, confining high flows to a narrow channel. The remaining two streams had gently sloping channels, where flood waters had access to the floodplain. Two hundred and thirty individual diets were sampled from cutthroat trout, northern pikeminnow, redside shiner, sculpin, speckled dace, threespine stickleback in both winter and spring. About 60% of the stomach samples contained invertebrates and approximately 90% of them were aquatic species. There was a significant difference in the numbers of invertebrates consumed by redside shiners, sculpins and speckled dace. These three fish species fed most often on benthic invertebrates compared to surf ace/midwater invertebrates, but only sculpins and redside shiners were significantly different. However, the proportions of benthic and surface/midwater invertebrates in the diet of these fish species were not significantly different between seasons or channel types. This thesis inventories fish and amphibian species found in intermittent stream habitats of the upper Willamette basin, and identifies the main habitat features that influence the distribution of those species. It also examines the diet composition of a subset of widely distributed fish species. The findings of this study can be used to understand how land uses, such as grass seed agriculture, affect intermittent streams, and to design future studies on the effectiveness of habitat enhancement conservation practices (such as grassed waterways, residue management, filter strips, streambank protection, etc.) to improve and/or protect these important seasonal habitats in the upper Willamette basin.

Field Guide to Common Fish of the Willamette Valley Floodplain
Field Guide to Common Fish of the Willamette Valley Floodplain

Author: Joshua Everett Williams

Publisher:

Published: 2014

Total Pages: 44

ISBN-13:

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This book contains descriptions of 15 native and 16 nonnative fish (including origin, distribution, key characteristics, size, distinguishing features, color, diet, and other remarks) found in the Willamette River Basin's seasonal watercourses, with over a hundred photos to aid in identification. It also offers a succinct explanation of the Willamette River Basin's aquatic ecosystems and seasonal watercourses, and instructions for using the field guide and how to report a sighting.

Comparisons of Fish Assemblages and Habitat Associations in Littoral Zones of Reservoirs in the Willamette Basin, Oregon
Comparisons of Fish Assemblages and Habitat Associations in Littoral Zones of Reservoirs in the Willamette Basin, Oregon

Author: Paul Michael Bennett

Publisher:

Published: 2002

Total Pages: 396

ISBN-13:

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The littoral zones of seven reservoirs in the southern Willamette Valley of Oregon were sampled with a boat electroshocker during the summer months of 1995 and 1996. Shoreline substrates were inventoried before sampling sites were randomly selected. Sampling sites consisted of 9 of 12 possible habitat types including four substrate types (bedrock, fines, gravel to small boulders, and large boulders), each with or without overlying vegetation or wood. Fish assemblages occupying these specific habitat types were compared. Various aspects of substrate distribution and dimensions were utilized to help explain differences in fish assemblages. Significant differences in richness, diversity, mean length, mean weight, and catch per unit effort (CPUE) of fish assemblages occupying the specific habitat types were found. Fish assemblages using vegetated substrates were greatest in richness, diversity, and CPUE, while bedrock and unvegetated fines were lowest. Gravel to small boulder substrates tended to be intermediate for these variables. Large boulder substrates were consistently on the higher end of the range of these values. The largest and oldest fish occupied habitats with wood and large boulder substrates; smaller, younger individuals tended to be found in fine substrates with vegetation. Largemouth bass, bluegill, and coarsescale suckers were well distributed across habitat types. Other species such as the yellow bullhead, white crappie, reticulate sculpin, longnose dace, and speckled dace were much more restricted in their use of habitat. Overlying structure tended to increase fish diversity and richness for fine but not for coarse size substrates. Comparison of fish species between reservoirs, using regression analysis, was also performed. Fish sampled in Lookout Point Reservoir showed the overall greatest weight for length values, whereas, fish from Hills Creek and Green Peter Reservoirs were lowest in these values of the seven study reservoirs. Regression analysis of specified substrate parameters to fish species richness and diversity indicated bedrock was generally a negative influence. The occurence of gravel to small boulder substrate was a positive influence over the range of segment sizes encountered. Large expanses of fines resulted in depressed richness and diversity. Conversely, smaller segments of fine habitat appear to have a strong positive effect on fish richness and diversity. Large boulders were found in too small a quantity to impact reservoir littoral zone fish assemblages. The exotic/native ratio of fish abundance averaged about 3/1 in all habitats sampled except fine substrates without overlying structure. Only here were native fish more abundant than exotics.

Wildlife-habitat Relationships in Oregon and Washington
Wildlife-habitat Relationships in Oregon and Washington

Author: David H. Johnson

Publisher:

Published: 2001

Total Pages: 764

ISBN-13:

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This volume provides information about the terrestrial, freshwater, and marine habitats of Oregon and Washington and the wildlife that depend upon them; it also supports broader and more consistent conservation planning, management, and research. The 27 chapters identify 593 wildlife species, define some 300 wildlife terms, profile wildlife communities, review introduced and extirpated species and species at risk, and discuss management approaches. The volume includes color and bandw photographs, maps, diagrams, and illustrations; and the accompanying CD-ROM contains additional wildlife data (60,000 records), maps, and seven matrixes that link wildlife species with their respective habitat types. Johnson is a wildlife biologist, engineer, and habitat scientist; and O'Neill is director of the Northwest Habitat Institute; they worked together on this publication project as its managing directors. Annotation copyrighted by Book News Inc., Portland, OR