My WebLink
|
Help
|
About
|
Sign Out
Home
Browse
Search
8208
CWCB
>
UCREFRP
>
Public
>
8208
Metadata
Thumbnails
Annotations
Entry Properties
Last modified
7/14/2009 5:02:33 PM
Creation date
5/20/2009 10:21:35 AM
Metadata
Fields
Template:
UCREFRP
UCREFRP Catalog Number
8208
Author
Osmundson, D. B., P. Nelson, K. Fenton and D. W. Ryden.
Title
Relationships Between Flow and Rare fish Habitat in the '15-Mile Reach' of the Upper Colorado River.
USFW Year
1995.
USFW - Doc Type
\
Copyright Material
NO
Jump to thumbnail
< previous set
next set >
There are no annotations on this page.
Document management portal powered by Laserfiche WebLink 9 © 1998-2015
Laserfiche.
All rights reserved.
/
233
PDF
Print
Pages to print
Enter page numbers and/or page ranges separated by commas. For example, 1,3,5-12.
After downloading, print the document using a PDF reader (e.g. Adobe Reader).
Show annotations
View images
View plain text
was used in the discharge versus TWA regressions rather than the discharge on the day of mapping; <br />this was because TWA was calculated from the video prints rather than from the field maps. The <br />TWA for the discharge on the day of mapping was then predicted from the relationship and correc- <br />tion factors for habitat areas were derived by dividing this predicted TWA (for the day of mapping) <br />by the measured TWA (for the day of video) as before. Regression values and correction factors as <br />well as unadjusted and adjusted data are provided in Appendix V (tables V-VI). <br />Seasonal Partitioning of the Year <br />For management purposes, it is useful to group months into seasons so that a given flow recom- <br />mendation can be implemented for a block of months rather than on a month-by-month basis. In <br />addition, analyses involving a limited number of fish observations is greatly enhanced if observa- <br />tions made during different months can be pooled to increase sample size. To block months into <br />seasons, the habitat use patterns of each species were analyzed to identify changes in behavior that <br />would mark the beginning or end of seasons. Seasons were defined for each species by examining <br />the radiotelemetry data collected throughout the Grand Valley and identifying blocks of months <br />within which habitat utilization was similar. <br />Though this report focuses primarily on adult Colorado squawfish flow needs in the 15-mite reach <br />during summer and winter, the needs of squawfish in the 18-mile reach immediately downstream as <br />well as the summer and winter flow needs of razorback sucker there will need to be addressed in a <br />future report. Thus, consistency in seasonal partitioning between the two reaches is required be- <br />cause flows in the reaches will later need to be coordinated. <br />Previous studies by Osmundson and Kaeding (1989) indicated that Colorado squawfish and razor- <br />back sucker exhibit somewhat different annual behavior patterns in habitat use which results in a <br />somewhat different seasonal partitioning of months. These patterns were re-examined for this <br />study. If instream flows are to be managed on a seasonal basis in one river for two species, the year <br />must be partitioned in such a way that combines the season specific needs of both species. To do <br />this we averaged the monthly Colorado squawfish and razorback sucker percent use of each habitat <br />type (Appendix tables III and IV) and looked for major breaks in the averaged habitat use pattern. <br />Determining Preference For Habitat Type <br />To determine habitat frequency of use, we first partitioned the 1986-88 radiotelemetry data such <br />that only those fish locations made within the current study sites were included in the analysis. <br />Habitat data from the four sites were pooled into one composite; according to Gauch (1982), aver- <br />aging out differences among samples by forming a composite tends to raise the level of abstraction, <br />emphasizing broader features of the data (Kinsolving and Bain 1993). Pertinent location data <br />included river mile, date, and habitat type. Habitat use data were further partitioned by season and <br />percent use of each type was calculated for each fish. A seasonal frequency of use value was <br />calculated for each habitat type by averaging the percent values across all fish. This follows the <br />'aggregate percent method' recommended by Swanson et al. (1974) that greatly reduces biases <br />associated with unequal number of locations among sampled fish. <br />From the videography mapping data, overall habitat availability was also calculated. This was done <br />for each fish individually and then averaged across fish. Percent total area of each habitat type, <br />within study sites comprising the home range of a fish, was averaged over a range of seasonal flows <br />that were similar to those that occurred when the fish location data were collected. This average <br />13
The URL can be used to link to this page
Your browser does not support the video tag.