My WebLink
|
Help
|
About
|
Sign Out
Home
Browse
Search
7354
CWCB
>
UCREFRP
>
Public
>
7354
Metadata
Thumbnails
Annotations
Entry Properties
Last modified
8/11/2009 11:32:56 AM
Creation date
8/10/2009 3:26:31 PM
Metadata
Fields
Template:
UCREFRP
UCREFRP Catalog Number
7354
Author
Wydoski, R. S.
Title
Biological Review of Endangered or Imperiled Fish in the Upper Colorado River Basin.
USFW Year
1985.
USFW - Doc Type
Washington, D. C.
Copyright Material
NO
There are no annotations on this page.
Document management portal powered by Laserfiche WebLink 9 © 1998-2015
Laserfiche.
All rights reserved.
/
29
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
<br />ponds provided ample food and space. Since a direct positive <br />correlation has been established between survival and size of <br />a number of stocked species, the survival of 200 mm squawfish <br />can be expected to be much higher than for smaller fish that <br />are produced naturally. A wild 200 mm squawfish that is <br />reared in the river would be about 3 years of age. In <br />addition, the razorback sucker can be raised very easily <br />under these conditions based upon work that has been done at <br />hatcheries and experimental facilities at universities. <br />Considerations - Ponds that have been formed by gravel mining <br />along the Colorado River provide excellent habitat for <br />introduced species that are predators such as the largemouth <br />bass and green sunfish. Such predators would have to be <br />removed before the rare species are stocked. In addition, <br />the productivity of such ponds is not known. Therefore, the <br />limnology of the ponds should be studied so that the ponds <br />can be managed (i.e., fertilized to increase productivity) to <br />provide an adequate food source. These ponds are located on <br />private land so that permission would have to be obtained <br />from the landowners. Also, the ponds may have to be altered <br />so that the fish could be easily collected for stocking into <br />the river. The fish could be released at different sizes to <br />determine the relation between;size and survival. Marking <br />techniques may have to be developed unless that fish are <br />raised to a size that would allow the use of Carlin dangler <br />tags. The external recognition of individual fish would have <br />to be a prerequisite for separating recaptures so that <br />analyses can be made. Since there is concern among many <br />biologists that hatchery-reared fish from a small broodstock <br />might spawn with wild fish and alter the genotypes of the <br />wild stock, mature wild fish should be collected near the <br />site of the pond, injected with hormones if necessary to <br />induce spawning, and spawned artificially to obtain young <br />fish for stocking "grow-out" ponds. Since the ponds would be <br />near the release site for such fish, the phenomena of <br />imprinting and homing could be studied by analyses of <br />recaptured fish. There would be little cost for rearing such <br />fish after the initial studies were completed and progeny of <br />wild stocks would be released into given reach that should <br />have a higher survival rate and, therefore, augment <br />recruitment into the wild stock. <br />o Evaluate stocking of hatchery-reared rare fish as a management tool to re- <br />establish populations in parts of their former range. <br />- Expand broodstock of rare fish species to increase genetic <br />heterogenity. <br />Evaluate the relation between size of hatchery-reared fish and survival <br />from stocking. <br />13
The URL can be used to link to this page
Your browser does not support the video tag.