Stanislaus River Weir Update                                                                    November 22, 2006

November 6 through November 19, 2006
 

A total of 1,127 Chinook passed upstream of the weir between November 6 and November 19 increasing the season total to 2,621. Chinook daily passage counts ranged from 4 to 596 fish. A large school of 830 Chinook passed the weir on the 13^th and continued on into the early hours of the 14^th. Total-lengths ranged from 273 mm to 1071 mm (avg = 782 mm). Other fish species observed included Sacramento sucker, Sacramento pikeminnow, and Sacramento blackfish. 

 Figure 1.   Adult Chinook Passage at the Stanislaus River weir, 2003 to 2006.

A total of 7 ad-clipped Chinook (i.e., indicating presence of coded wire tag) passed upstream of the weir during this sample period. Total lengths ranged from 609 mm to 1004 mm (Table 1).

Table 1.  Date, total length and sex of ad-clipped Chinook passing upstream of the weir between November 6 and November 19, 2006.
 

Livebox trapping continued during this sample period. 33 Chinook were captured, processed, and released in good condition upstream of the weir during this sample period (Figure 2).

Figure 2.  Fisheries Technician John Montgomery holding a large male Chinook salmon captured in the upstream livebox on November 12^th.  This fish had a depth of 310mm and a total length of 1100mm.

It is getting to be that time of year again when we start to see spawned out Chinook carcasses float downstream and land on top of the weir. We recovered three such carcasses (all male) during this sample period (Figure 3). All three carcasses are now in the possession of CDFG.

Figure 3.  A spawned out male Chinook carcass (Depth: 165mm, TL: 660mm) found on November 16^th.

One O. mykiss passed the weir during this sample period. The fish passed on November 13^th at 7:33 am and had a depth of 105mm and a total length of 441mm. The fish was not ad-clipped and the sex is unknown.

Environmental conditions fluctuated at the weir site during the sampling period. Flow at Orange Blossom Bridge (OBB) ranged from 566 cfs to 627 cfs, and flow at Ripon (RIP) ranged from 640 cfs to 718 cfs. Turbidity ranged between 0.18 NTU and 1.29 NTU; and dissolved oxygen (DO) ranged between 9.41 mg/L and 10.62 mg/L. DO at Rough 'n Ready Island (RRI) in the San Joaquin River's Deep Water Ship Channel ranged from 7.66 mg/L to 8.54 mg/L. Daily instantaneous water temperature at the Stanislaus River weir ranged from 51.2ºF to 55.7ºF.

For more details on 2006 Stanislaus River adult Chinook passage at the weir and how it relates to San Joaquin and Stanislaus environmental conditions, visit the webpage at www.stanislausriver.com/weir/data.htm. 

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