Key Highlights

2007 Adult Migration Monitoring

2007/06 Juvenile Migration Monitoring

San Joaquin River Conditions

Delta Exports

Key Highlights:

2007 Adult Migration Monitoring. Monitoring at the Stanislaus River Weir concluded on January 2, 2008. A total of 408 Chinook and two O. mykiss were recorded passing upstream of the weir during the 2007/08 adult migration monitoring period.

For the San Joaquin Basin, the preliminary 2007 fall-run Chinook escapement estimate is 1,158 individuals, which is only 20% of the number estimated in 2006 (5,672). Escapement estimates in individual tributaries for 2007 ranged from a low of 180 (Tuolumne River) to a high of 573 (Merced River).

2007/08 Juvenile Migration Monitoring. Daily O. mykiss catch decreased in the Calaveras River decreased during the sampling period, with a total of seven individuals captured compared to 90 during the previous reporting period.

San Joaquin River Conditions. San Joaquin River flows averaged 1,400 cfs during the reporting period. Water temperatures continued to decrease during this reporting period as a result of cooler ambient air temperatures. Dissolved oxygen (DO) at Mossdale averaged 11.1 mg/L while DO in the deep water ship channel averaged 9.3 mg/L during the reporting period.

Delta Exports. Combined exports ranged from 2,389 cfs to 7,212 cfs during the reporting period. Export rates at the federal pumping facility decreased from a high around 3,700 cfs to a low near 1,000 cfs during the reporting period. Export rates at the state pumping facility remained constant for the first part of the reporting period then fluctuated for the remainder of the period, averaging 2,047 cfs.

We encourage subscribers to contribute any relevant information for future issues of the newsletter (e.g., additional monitoring studies, announcements of upcoming meetings and events, etc). If you would like to contribute, please contact Chrissy Sonke. If you have any questions please contact Doug Demko at 530-342-9262 or by e-mail at dougdemko@fishbio.com.

To view a print version of this newsletter, click here.

December 17, 2007 - January 6, 2008

Upcoming Events

Jan. 17: VAMP Meeting
Jan. 17: SRFG Meeting

Featured Links

San Francisco Bay Hydrodynamics

Related Links

Tuolumne River Technical Advisory Committee
Calaveras River Fish Group
Stanislaus River Fish Group
San Joaquin River Group Authority
San Joaquin River Management Program

Stanislaus River Weir:

Monitoring at the Stanislaus River Weir (RM 31.4) concluded on January 2, 2008. The weir was subsequently removed from the river and will be re-installed in early September to monitor the 2008/09 fall-run Chinook and O. mykiss escapement.

For the 2007/08 season (September 22, 2007 through January 2, 2008), total of 408 fall-run Chinook were recorded passing upstream of the weir. Passage included nine (2.2%) adipose fin clipped Chinook (i.e., indicating fish was of hatchery origin). The 2007/08 fall-run escapement consisted of approximately 41% female, 38% male, and 21% unknown sex. The average length (TL) of Chinook passing upstream of the weir was 748 mm (range: 363 mm to 1,068 mm).

Only two O. mykiss were recorded passing upstream of the Stanislaus River Weir during the 2007/08 monitoring period. Additionally, zero spawned out carcasses were recovered from the weir.

Other species recorded passing upstream of the weir included one channel catfish (Ictalurus punctatus), six largemouth bass (Micropterus salmoides), 64 Sacramento suckers (Catostomus occidantalis), one Sacramento blackfish (Orthodon microlepidotus), one smallmouth bass (Micropterus dolomieu), and one white catfish (Ameiurus catus).

During the monitoring period, releases from Goodwin Dam (GDW; RM 58.4) ranged between 151 cfs and 805 cfs (avg: 328 cfs); flow at Orange Blossom Bridge (OBB; RM 46.9) ranged between 185 cfs and 576 cfs (avg: 277 cfs); and flow at Ripon (RIP; RM 15.7) ranged between 236 cfs and 657 cfs (avg: 341 cfs). Turbidity at the weir site ranged from 0.29 NTU to 4.4 NTU and DO ranged between 8.3 mg/L and 12.2 mg/L. DO downstream of the weir at Ripon (RPN; RM 15.7) ranged from 7.6 mg/L to 11.2 mg/L (avg: 9.2 mg/L). Daily instantaneous water temperature at the Stanislaus River weir ranged from 45 ºF to 63 ºF (avg: 53.5 ºF).

Tributary Carcass Surveys:

Carcass surveys concluded on the Stanislaus, Tuolumne and Merced rivers during the week of December 24. Preliminary estimates of fall-run Chinook in each of the tributaries were calculated using the adjusted Petersen method. A total of 1,158 fall-run Chinook were estimated to have spawned in the San Joaquin Basin during 2007, including 405 returning to the Stanislaus River, 167 returning to the Tuolumne River, and 573 returning to the Merced River. Final estimates prepared by CDFG will be available at the end of January. Comparisons to escapement estimates in the San Joaquin Basin since 2000 are provided in the table below.

Table 1. Escapement estimates of fall-run Chinook in the San Joaquin Basin tributaries, 2000-2007. Source: CDFG GrandTab database (2000-2006) and Tim Ford (2007 preliminary estimates).

Thirty-six female Chinook were spawned at the Merced River Hatchery (MRH) this year yielding only 275,475 eggs available for fertilization. Last year, 402,000 eggs were taken resulting in minimal number of juveniles provided for San Joaquin Basin studies (i.e., only 1,000 study fish released in 2007 for VAMP's acoustic tag study and zero fish released for other studies such as tributary smolt survival studies, rotary screw trap efficiency releases, trawl efficiency releases, and VAMP smolt survival experiments). It is likely that fish will not be available for San Joaquin Basin studies outside of the Merced River this year since production is much lower than last year.

2007/08 Juvenile Migration Monitoring

The Calaveras River rotary screw trap at Shelton Road (RM 29) sampled nine out of 21 days between December 17, 2007 and January 6, 2008. Sampling was temporarily suspended during the last three days of the sampling period ( January 4 through January 6) due to a series of storms that delivered over 4.5 inches of rain at New Hogan Dam.

O. mykiss catch at Shelton Road decreased during the sampling period with only seven captured compared to 90 captured during the previous two weeks. A total of one young-of-year (YOY; less than or equal to 100 mm) and six Age 1+ (greater than 100 mm) O. mykiss were captured. The YOY was 99 mm and weighed 10.0 g. Individual lengths of Age 1+ ranged from 111 mm to 212 mm (avg: 157.2 mm) and weights ranged from 24.5 g to 98.8 g (avg: 51.3 g). Only one of the O. mykiss captured were smolting (212 mm) while the others were rated as a parr (n=3) or silvery parr (n=3). Parr are likely redistributing themselves into downstream habitat and not actively migrating. It is unknown whether silvery parr are actively migrating or redistributing into other habitats as they transition to the smolting stage.

Instantaneous temperature taken at the trap ranged from 42ºF and 49ºF, and turbidity ranged from 0.46 NTU to 2.76 NTU. Daily average flow at New Hogan Dam (NHG) fluctuated between 30 cfs to 87 cfs, flows at Cosgrove (COS) ranged from 0 cfs to 185 cfs, and flows at Bellota (MRS) ranged between 54 cfs and 228 cfs.

San Joaquin River Conditions

During the reporting period, flow in the San Joaquin River at Vernalis ranged from 1,290 cfs to 1,513 cfs (avg: 1,409 cfs). Note: data was unavailable between January 4 and January 6 when a series of storm events passed through the San Joaquin Basin. Water temperatures in the San Joaquin River continued a steady decline that began in early September as a result of cooling ambient air temperatures. Water temperature in the San Joaquin ranged from 44.9 °F to 51.4 °F (avg: 47.4 °F) at Vernalis; from 45.3 °F to 51.5 °F (avg: 47.8°F) at Mossdale; and from 45.0 °F to 49.9 °F (avg: 47.8 °F) at Rough 'n Ready Island. Dissolved oxygen (DO) in the San Joaquin River at Mossdale fluctuated between 10.3 mg/L and 11.6 mg/L (avg: 11. mg/L). Meanwhile, DO in the deep water ship channel (measured at Rough 'n Ready Island) continued to improve since the last reporting period and fluctuated between 8.4 mg/L and 10.2 mg/L (avg: 9.3 mg/L).

Delta Exports

Mean daily pumping at the C.W. Jones Pumping Plant (federal pumps previously known as Tracy Pumping Plant) decreased throughout the reporting period and ranged from 3,769 cfs to 1,024 cfs. Mean daily pumping at the Harvey O. Banks Pumping Plant (state pumps) remained fairly constant at 3,300 cfs between December 17 and December 22 then fluctuated between 1,325 cfs and 3,988 cfs (avg: 2,047 cfs) for the remainder of the reporting period.

© 2007 FISHBIO Environmental, LLC • 3188 Wood Creek Drive, Chico, CA 94928

Data Disclaimer:  The data displayed on the sanjoaquinbasin.com website are courtesy of Stockton East Water District (SEWD), California Department of Fish & Game (CDFG), U.S. Fish & Wildlife Service (USFWS), Tri-dam, Turlock Irrigation District (TID), Modesto Irrigation District (MID) and FISHBIO.  Data are intended to be current, but are preliminary and are not guaranteed to be accurate.  Source data compiled and provided by FISHBIO, from whom further information can be obtained.  Use or reproduction of this data is prohibited without prior permission of SEWD, CDFG, USFWS, Tri-dam, TID, MID and/or FISHBIO.