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 December
4 through December 17, 2006
A total of 181 Chinook passed
upstream of the weir between December 4 and December 17
increasing the season total to 2,953 (Figure 1). Chinook
daily passage counts ranged from 1 to 23 fish. Total-lengths
ranged from 483 mm to 1063 mm (avg = 776 mm). Other fish
species observed included multiple Sacramento sucker, three
Sacramento pikeminnow, four Sacramento blackfish, and two
striped bass.
Figure 1.
Adult Chinook Passage at the Stanislaus River weir, 2003 to
2006.
One ad-clipped Chinook (i.e.,
indicating presence of coded wire tag) passed upstream of
the weir during this sample period.
Livebox trapping continued
during this sample period however due to high flows the last
day that we trapped was on December 9. Seven Chinook were
captured, processed, and released in good condition upstream
of the weir during this sample period (Figure 2).
Figure 2.
Fisheries Technician processing a female Chinook salmon
(FL: 745 mm; TL: 780 mm; D: 175mm) captured on December 9.
We recovered one spawned out
Chinook carcass during this sample period. The carcass was
processed and then passed downstream of the weir.
No
O. mykiss passed
the weir during this sample period.
Environmental conditions
fluctuated at the weir site during the sampling period. Flow
at Orange Blossom Bridge (OBB) ranged from 549 cfs to 927
cfs, and flow at Ripon (RIP) ranged from 592 cfs to 1090 cfs.
The weir is operating well under the current high flow
conditions with the effort of one cleaning per day (Figure
3). Turbidity ranged between 0.5 NTU and 3.5 NTU; and
dissolved oxygen (DO) ranged between 9.28 mg/L and 10.49
mg/L. DO at Rough 'n Ready Island (RRI) in the San Joaquin
River's Deep Water Ship Channel ranged from 8.2 mg/L to 8.9
mg/L. Daily instantaneous water temperature at the
Stanislaus River weir ranged from 48.7ºF to 52.3ºF.
 
Figure 3.
Weir operating under high flow conditions.
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