7203

• UCREFRP Catalog Number: 7203
• Author: Osmundson, D. B. and L. R. Kaeding.
• Title: Colorado Squawfish and Razorback Sucker Grow-Out Pond Studies as Part of Conservation Measures for the Green Mountain and Ruedi Reservoir Water Sales
• USFW Year: 1989.
• USFW - Doc Type: Final Report.
• Copyright Material: NO

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may have always had available to them portions of the pond containing
t adequate levels of dissolved oxygen. Water clarity in West Pond was
usually high, allowing us to view the pond bottom during most of the year
' (Fig. 7). However, after fertilizing the pond in early May 1987, algal
growth increased and Secchi disk visibility dropped to 0.8 m. Rapid
decomposition of organic matter after cessation of the algae bloom proba-
bly caused the depletion of oxygen. Clarity and DO again increased in mid
to late September.
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1
Limited winterkill was detected at ice-out in early 1988. We collected a
total of 25 dead squawfish from the surface and bottom of the pond during
3-9 March. Water samples collected from the north and south ends of the
pond at two depths (mid- and bottom) on 15 March revealed relatively high
levels of hydrogen sulfide (0.002-0.014 mg/L). Though the levels we
detected in West Pond with our limited sampling effort were lower than the
3.5
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1
3
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2.5
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0
U 1.5
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0.5
0 l I I 1 I 1 I I 1 I I I I 1 I I I 1 1 1 I I I
S 0 N D J F M A M J J A S O N D J F M A M J J A S O
1986 1987 1988
---- FISH CHALET - HUMPHREY - WEST
Figure 7. Water clarity, as measured by Secchi disk visibility, in three
study ponds, 1986-88.
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