My WebLink
|
Help
|
About
|
Sign Out
Home
Browse
Search
Pallid Sturgeon Recovery Plan
CWCB
>
Water Supply Protection
>
DayForward
>
5001-6000
>
Pallid Sturgeon Recovery Plan
Metadata
Thumbnails
Annotations
Entry Properties
Last modified
4/8/2013 4:34:02 PM
Creation date
3/6/2013 2:34:12 PM
Metadata
Fields
Template:
Water Supply Protection
Description
related to the Platte River Endangered Species Partnership (aka Platte River Recovery Implementation Program or PRRIP),
State
NE
Basin
South Platte
Water Division
1
Date
11/7/1993
Author
Pallid Sturgeon Recovery Team, U.S. Fish and Wildlife Service
Title
Recovery Plan for the Pallid Sturgeon (Scaphirhynchus albus)
Water Supply Pro - Doc Type
Report/Study
There are no annotations on this page.
Document management portal powered by Laserfiche WebLink 9 © 1998-2015
Laserfiche.
All rights reserved.
/
64
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
It is also suspected that increased clarity of the Missouri River has affected <br />food availability by changing species composition and by making it more <br />difficult for pallid sturgeon, and other native species, to capture prey in <br />the clearer water environment. In the Missouri River, pelagic planktivores <br />and sight- feeding carnivores have increased in abundance, whereas species <br />specialized for life in the turbid, predevelopment river (like the pallid <br />sturgeon) have decreased in abundance (Pflieger and Grace 1987). This change <br />in community structure is less apparent where changes in the natural <br />hydrograph, temperature regime, and turbidity are less pronounced. <br />Flood flows were essential for the dynamic transport of sediment and the re- <br />arrangement of these sediments into natural morphological channel features <br />(fish habitat); it served to introduce and transport organic matter from the <br />floodplain; and to maintain turbidity. Flood flows were the principle method <br />for the introduction of large woody debris and carried nutrients to floodplain <br />plant communities, which determined floodplain forest composition and <br />structure. Invertebrate reproduction and behavioral migration was closely <br />tied to the natural hydrograph (Hesse and Mestl 1993c). <br />Nearly all snags were removed from the Missouri River between 1838 and 1950. <br />This, plus the cessation of flooding and meandering as a result of damming and <br />channelizing the river has reduced the availability of organic matter supplies <br />utilized by the aquatic invertebrate community (Hesse and Mestl 1993a). Snags <br />influence sediment routing, thus creating pools, gravel bars, and depositional <br />areas, which in turn reduce the rate of downstream transport of particulate <br />organic matter (Bilby and Ward 1991; Bilby and Likens 1980). <br />Snags also provide habitat for aquatic insects that make up a large proportion <br />of both the shovelnose and pallid sturgeon's diet. These insects are <br />collector - filterer- gatherers (Merritt and Cummins 1984). They cling to large <br />woody debris in high velocity areas, gathering drifting diatoms, algae, <br />.animals, and organic detritus. Mestl and Hesse (1993) documented a decline <br />in the abundance of snag insect production of more than 65 percent in <br />Nebraska's portion of the Missouri River between 1963 and 1980. <br />In spite of man's efforts to constrict and control the Missouri and <br />Mississippi Rivers with reservoirs, stabilized banks, jetties, dikes, levees <br />and reventments that result in impacts described above, remnant reaches of the <br />Missouri River and the Mississippi River from the Missouri River confluence to <br />the Gulf still provide habitat believed usable by pallid sturgeon. These <br />remnants described later as Recovery- Priority Management Areas are priority <br />areas for implementation of recovery actions. <br />Commercial Harvest: Historically, pallid, shovelnose, and lake sturgeon were <br />commercially harvested on the Missouri and Mississippi Rivers (Helms 1974). <br />The larger lake and pallid sturgeon were sought for their eggs which were sold <br />as caviar, whereas shovelnose sturgeon were destroyed as a bycatch. <br />Commercial harvest of all sturgeon has declined substantially since record <br />keeping began in the late 1800's. Most commercial catch records for sturgeon <br />have not differentiated between species. Combined harvests as high as <br />195,450 kg (430,889 lbs) were recorded in the Mississippi River in the early <br />1890's, but had declined to less than 9,100 kg (20,062 lbs) by 1950 (Carlander <br />13 <br />
The URL can be used to link to this page
Your browser does not support the video tag.