Calaveras River Juvenile Migration Monitoring continued at the Shelton Road (RM 28) rotary screw trap and a total of 21 O. mykiss were captured, increasing the

Stanislaus River Juvenile Migration Monitoring at Oakdale (RM 40) began on January 1, and a total of 2,273 Chinook salmon fry and 3 O. mykiss were captured. Monitoring at Caswell (RM 4) began on December 17, and a total of 51 Chinook salmon and 10 O. mykiss were captured. 

Tuolumne River Juvenile Migration Monitoring at Waterford (RM 30) and at Grayson (RM 5) began on January 2. No Chinook salmon were captured.

Mokelumne River Juvenile Migration Monitoring at Vino Farms (RM 54) began on December 17 and a total of 736 Chinook salmon were captured.

Stanislaus River Weir Monitoring continued with a total of 23 Chinook salmon passing upstream through the weir between December 17 and January 6, increasing the total to 7,042.

Tuolumne River Weir Monitoring continued with a total of 30 Chinook salmon passing upstream through the weir between December 17 and January 6, increasing the total to 2,105.

Mokelumne River Woodbridge Dam Fish Ladder Monitoring continued with a total of 13 Chinook salmon passed upstream of the dam between December 17 and January 6, increasing the total to 12,088.

San Joaquin Basin Escapement Surveys. Annual carcass surveys conducted by California Department of Fish and Game (CDFG) continued through the week of December 31 and spawning activity has been decreasing since the peak in mid-November.

San Joaquin River Conditions. San Joaquin River flow at Vernalis ranged from 1,365 cfs to 3,507 cfs. Daily average water temperature in the San Joaquin River ranged from 45.6�F to 50.7�F at Vernalis, and from 46.1�F to 50.7�F at Mossdale. Daily average dissolved oxygen (DO) in the San Joaquin River ranged from 9.7 mg/L to 11.1 mg/L at Mossdale, and from 7.0 mg/L to 9.9 mg/L in the deep-water ship channel (measured at Rough 'n Ready Island).

The Stanislaus River rotary screw trap at Oakdale (RM 40) began on January 1 and operated continuously through the end of the reporting period. A total of 2,273 Chinook salmon were captured during the reporting period. Average forklengths and weights of all Chinook salmon are provided in Table 2. Most of the fish measured were fry (n = 361), but one captured Chinook salmon was greater than 100 mm and rated a smolt.

 

Table 2. Biosampling data for Chinook salmon captured and measured at Oakdale between January 1 and January 6, 2013. Parentheses indicate range.

Three O. mykiss were captured during the reporting period and rated as silvery parr (n=1) and smolt (n=2).

 

Instantaneous temperature taken at the trap ranged from 46.5�F to 49.4�F, and turbidity ranged from 3.76 NTU to 7.80 NTU. Daily average flow at Goodwin Dam (GDW) ranged from 279 cfs to 299 cfs, and flow ranged from 332 cfs to 391 cfs at Ripon (RIP) (Figure 2).

 

One trap efficiency experiment was conducted during the reporting period with naturally spawned juvenile Chinook salmon marked caudal fin green (CFG). The preliminary estimated capture efficiency was 6.8% at a flow of 284 cfs (Table 3).

 

Figure 2. Daily Chinook salmon catch at Oakdale and Stanislaus River flow recorded at Goodwin Dam (GDW) and Ripon (RIP) in 2013.

  

The Stanislaus River rotary screw traps at Caswell (RM 4) began operating December 17 and sampled for 21 days through January 12. A total of 50 Chinook salmon fry and one smolt were captured.  

  

One O. mykiss was captured (218 mm).  

  

Instantaneous temperature taken at the trap ranged from 44.8�F to 50.4�F, and instantaneous turbidity ranged from 1.51 NTU to 31.70 NTU. Instantaneous dissolved oxygen measured at the trap ranged from 11.03 mg/L to 14.55 mg/L. 

The Tuolumne River rotary screw trap at Waterford (RM 30) began operating on January 2 and no Chinook salmon or O. mykiss were captured during the reporting period.

Instantaneous temperature taken at the trap ranged from 46.2�F to 48.0�F, and turbidity ranged from 1.42 NTU to 6.22 NTU. Daily average flow at La Grange (LGN) was stable between 170 cfs and 178 cfs (Figure 3).

Figure 3. Daily Chinook salmon catch at Waterford and Tuolumne River flow recorded at La Grange (LGN) and Modesto (MOD) between December 1, 2012, and January 6, 2013.

 

The Tuolumne River rotary screw traps at Grayson (RM 5) began operating on January 2. No Chinook salmon were captured during the reporting period. 

 

Instantaneous temperature taken at the trap ranged from 44.0�F to 47.8�F, and turbidity ranged from 3.12 NTU to 9.13 NTU. Daily average flow at Modesto (MOD) fluctuated during the reporting period due to a couple freshet events, ranging between 212 cfs and 1,400 cfs.

The Mokelumne River rotary screw trap at Vino Farms (RM 54) began on December 17 and was sampled intermittently during the reporting period. A total of 736 juvenile Chinook salmon were captured.

 

Average daily flow from Camanche Reservoir (CMN) ranged from 258 cfs to 503 cfs (Figure 4). Instantaneous temperature ranged between 49.5�F and 53.8�F, and instantaneous turbidity ranged between 2.09 NTU and 6.68 NTU.

 

Figure 4. Daily juvenile Chinook catches at Vino Farms and Mokelumne River flow recorded at Camanche Reservoir (CMN), between December 1, 2012, and January 6, 2013.

  

Between December 17 and January 6 a total of 23 Chinook salmon were detected by the Vaki Riverwatcher as they passed upstream of the Stanislaus River weir. The total passage to-date of 7,042 is the highest observed at the Stanislaus weir since monitoring began in 2003 (Figure 5; Table 4). Daily passage has decreased during the reporting period, ranging between 0 and 5 Chinook salmon (Figure 6).

  

Instantaneous water temperature measured at the weir ranged between 45.3˚F and 52.7˚F, and daily average water temperature at Ripon (RPN; RM 15) ranged between 47.1˚F and 52.8˚F (Figure 7). Instantaneous turbidity ranged between 0.9 NTU and 106.0 NTU (Figure 8). Instantaneous dissolved oxygen at the weir ranged between 10.30 mg/L and 13.28 mg/L, and daily average dissolved oxygen at Ripon (RPN; RM 15) ranged from 9.16 mg/L to 10.60 mg/L (Figure 9).

  

Daily average flows in the Stanislaus River at Goodwin Dam (GDW; RM 58) ranged from 278 cfs to 318 cfs. Flows at Ripon (RIP; RM 15) ranged from 315 cfs to 705 cfs. Note: flows downstream of Goodwin Dam may differ from dam releases due to irrigation, precipitation and other factors.

  

Table 4. Annual fall-run Chinook passage at the Stanislaus River weir prior to January 6, 2003-2012.

 

 

Figure 5. Cumulative passage of fall-run Chinook salmon recorded at the Stanislaus River weir from 2003-2012.

Figure 7. Daily upstream Chinook passage recorded at the Stanislaus River weir in relation to instantaneous water temperature recorded at the weir, and daily average water temperature recorded in the Stanislaus River at Ripon (RPN), and in the San Joaquin River at Vernalis (VER), Mossdale (MSD) and Rough & Ready (RRI) in 2012. 

Fall-run Chinook salmon returning to the Mokelumne are counted annually by East Bay Municipal Utility District (EBMUD) as they ascend the fish ladder at Woodbridge Dam. A total of 13 Chinook salmon were observed passing upstream of the dam between December 17 and January 6, increasing the total for the season to 12,088. Daily passage ranged between 0 and 2 Chinook (Figure 15).

Figure 15. Daily upstream Chinook passage recorded at the Woodbridge Dam fish ladder in relation to daily average flows (cfs) recorded in the Mokelumne River at Camanche Reservoir (CMN) in 2012.  

Annual carcass surveys conducted by CDFG continued through the week of December 31. The number of live fish and redds observed on all rivers continued to decrease during recent weeks since peak spawning in mid-November. Live counts during the week of December 31st were 0 on the Stanislaus River, 0 on the Tuolumne River and 3 on the Merced River.