My WebLink
|
Help
|
About
|
Sign Out
Home
Browse
Search
8003
CWCB
>
UCREFRP
>
Public
>
8003
Metadata
Thumbnails
Annotations
Entry Properties
Last modified
7/14/2009 5:02:32 PM
Creation date
6/1/2009 12:41:50 PM
Metadata
Fields
Template:
UCREFRP
UCREFRP Catalog Number
8003
Author
Haynes, C. M. and R. T. Muth.
Title
Identification of Habitat Requirements and Limiting Factors for Colorado Squawfish and Humpback Chubs (January 1, 1981 to June 30, 1982).
USFW Year
1982.
USFW - Doc Type
SE-3-4,
Copyright Material
NO
There are no annotations on this page.
Document management portal powered by Laserfiche WebLink 9 © 1998-2015
Laserfiche.
All rights reserved.
/
42
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
9 <br /> <br />RESULTS AND DISCUSSION <br />General <br />I. Sampling Bias/Selectivity <br />Several sources of sampling bias are inherent in the design of this study <br />and should be acknowledged. <br />A. Gear Selectivity. Built-in bias against the capture of adults <br />of larger species is inherent in the use of relatively short <br />(3.0 and 1.0 m) seins of small mesh (0.79 and 1.6 mm). However, <br />gear selection is consistent with the objective of sampling <br />young-of-the-year (YOY) fishes. <br />B. Habitat Selectivity. Design and size of sampling gear is biased <br />against the sampling of deeper swifter sites. Such sites could <br />be more efficiently sampled with electrofishing and/or passive <br />netting techniques; however, these methods would not capture <br />YOY forms and most juveniles. <br />C. Seining Efficiency. Efficiency varies according to both width <br />and depth of the individual sein haul and substrate. This study <br />is not designed to account for sein efficiency variability. <br />II. Yampa River Study Area. <br />A total of 422 samples were collected during March - August, 1981 (Table 1). <br />Laboratory processing and computer storage of these data has been <br />completed, as well as a preliminary data analysis. A total of 103 samples <br />have been collected during April - June, 1982; however, these samples <br />will be processed during fall-winter, 1982. A total of 18 species have <br />been identified from 1981 samples, of which seven were native (Table 2). <br />Unidentified YOY chubs (Gila spp.) await taxonomic clarification and are <br />listed here as a single taxon. Several specimens of immature minnows <br />and suckers could not be positively identified due to their early stage <br />of development and are listed as "unidentified Cyprinidae" and "unidentified <br />Catastomidae", respectively. <br />For the Yampa River study area as a whole, 19,058 fishes were identified <br />in 1981. Of these, the introduced red shiner (Notropis lutrensis) <br />was the predominant species (7563 individuals) and native unidentified <br />chubs (Gila spp.) were the second most numerous (5823). The number of <br />individuals of native species was slightly smaller (9398) than introduced <br />species (9660). Based on a length-frequency analysis for YOY Yampa <br />fishes (Appendix C), 1981 spawning periods for the eight most abundant <br />species were determined (Figure 2). Species-habitat associations have <br />not been completed and these will hopefully be conducted utilizing the <br />MANAGE program. <br />III. Colorado River Study Area <br />A total of 354 samples were collected during April - July, 1981 (Table 3). <br />Sample number per habitat type has not been compiled, nor has computer <br />
The URL can be used to link to this page
Your browser does not support the video tag.