Fish And Invertebrates Of Revetments And Other Habitats In The Willamette River Oregon

Author : Randall William Colvin
Publisher :
ISBN 13 :
Total Pages : 228 pages
Book Rating : 4.:/5 (62 download)

DOWNLOAD NOW!

Download or read book Fish and Amphibian Use of Intermittent Streams Within the Upper Willamette Basin, Oregon written by Randall William Colvin and published by . This book was released on 2005 with total page 228 pages. Available in PDF, EPUB and Kindle. Book excerpt: 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.