9592

• UCREFRP Catalog Number: 9592
• Author: Mueller, G. A., J. Carpenter and P. C. Marsh.
• Title: Cibola High Levee Pond Annual Report 2004.
• USFW Year: 2004.
• USFW - Doc Type: \
• Copyright Material: NO

12
i _ Jan-27
10 - Feb-24
~ 8 -- _ Mar-1 0
6 - *- Apr-26
_ May-4
) 4 - May-19
2 --+-- Jun-23
- Jul-27
0
/ " 1- '?J
Depth (m)

Figure 4. Dissolved oxygen concentrations (mg/L) measured at various depths
within the water column at Cibola High Levee Pond during 2004.

2. PRELIMARY ANALYSIS OF RECAPTURE DATA

Size Distribution

Bony tail- Small (<200 mm) bonytail were far more abundant than larger fish. Thousands of
small :fry were observed following spawning. Schools of small juveniles (<50 mm) were
commonly concealed amongst shoreline and submerged vegetation and in beaver dens along the
bank. Figure 5 shows the size distribution as a percentage ofbonytail caught in 2001-2004.
However, the data are biased by an artifact of greater numbers of juveniles captured by ~-inch
trammel nets used in 2001 and 2002. Small trammel nets were extremely effective in capturing
small fish. Unfortunately, a large percentage of these small fish were 'gilled'; as a preventative
measure, we switched to large minnow traps and hoop nets in 2003 and 2004. These sampling
methods proved to be less stressful but regrettably they were also far less effective, and very few
small bonytail were captured.

Razorback Sucker - Size distribution of razorback suckers is'just the opposite of bony tail;
large fish were more abundant than their young. Sampling revealed larger (300- 400 mm)
suckers were advancing into the adult population in 2001 and 2002; however, this size class was
not present in 2003 and 2004 (Figure 6). Juveniles (<300 mm) that were absent in 2001 and
2002 appear in both 2003 and 2004, indicating that suckers successfully recruited.

~

Large trammel nets are extremely effective in capturing large suckers, however, their young have
proved difficult to collect. The problem is compounded by the fact that they are relatively rare
and are both cover- and benthic-oriented. Figure 6 suggests recruitment during 2003 and 2004
was <5%, however, we consider that to be very conservative due to sampling bias. The actual
recruitment figure could be closer to 15-20% due to our reluctance to use small trammel nets in
2003 and 2004.

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