8180

• UCREFRP Catalog Number: 8180
• Author: Hamilton, S. J.
• Title: Hypothesis of Historical Effects From Selenium on Endangered Fish in the Colorado River Basin.
• USFW Year: 1999.
• USFW - Doc Type: \
• Copyright Material: YES

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Table 1. ~ events in the decline of endangered f'1sh in the Colorado River basin. (continued)

Date Event

1978 WiJtzius (J 978) concludes endangered fish declined before dams.

1978-81 Elevated selenium in fish from six sites in Colorado River basin as part of the National Contaminant Biomonitoring

1979-81
::c
c
? 1979-87
rr1
I"l
~ 1980
Z?
'" 1984
~
~
~ 1985-94
'"
~
~ 1986-87
.Ut 1986-87
Z
~
'? 1986-89
-
<.0
<.0
<.0

Program (NCBP) (Lowe el al., 1985).

Razorback sucker found at Walter Walker State Wildlife Area (WWSW A) and Clifton Pond in Grand Valley -- all are old

fish (Valdez el al., 1982).

::z:
~
0-
1:1

Razorback sucker stage at Stewart Lake outlet and Ashley Creek on Green River (Tyus, 1987).

Bony tail listed as endangered by the U.S. Fish and Wildlife Service (USFWS, 1980).

Elevated selenium in fish from six sites in Colorado River basin as part of the NCBP (Schmitt and Brumbaugh, 1990).

31 kg per day of selenium loading from Gwmison River to Colorado River (Engberg, 1999).

Ashley Creek and Stewart Lake outlet have elevated selenium in water, sediments, and biota (Stephens el al., 1988, 1992).

Selenium elevated in water, sediment, and biota in lower Colorado River basin (Radtke el a/.. 1988).

Razorback suckers found at WWSW A and Clifton Pond in Grand Valley (Osmundson and Kaeding, 1989).