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 Vol. 2, Issue 4: Dec. 3, 2007 |
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Key Highlights 2007 Adult Migration Monitoring 2007/08 Juvenile Migration Monitoring San Joaquin River Conditions Delta Exports |
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November 12 -December 2, 2007 |
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Key Highlights:2007 Adult Migration Monitoring. Daily passage at the Stanislaus River weir continues to remain consistently low. To date, passage is only 9-14% of the number of Chinook that passed the weir during the same time period in 2003-2006. Eight weeks of carcass surveys have been completed on the Merced, Tuolumne and Stanislaus Rivers. The number of carcasses tagged on each tributary is very low (10 to 27) and no tagged carcasses have been recovered. The low number of carcasses available for tagging this year may be attributed to a combination of low fish densities and the normal scavenging of carcasses that typically occurs along each river; since fish densities are already low, any loss of carcasses to scavenging animals significantly impacts the number of carcasses remaining for tagging studies. 2007/08 Juvenile Migration Monitoring. The Shelton Road rotary screw trap on the Calaveras River began sampling on November 12. The trap began sampling early this year to determine the extent of O. mykiss migration, if any, occurring in November. Few O. mykiss were captured and most were Age 1+ (greater than 100mm) that were not smolting which indicates that fish were not actively migrating but were likely redistributing themselves into downstream habitat. San Joaquin River Conditions. San Joaquin River flows gradually decreased during the sampling period. Water temperatures continued to decrease during this reporting period as a result of cooler ambient air temperatures. Dissolved oxygen (DO) at Mossdale remained constant, but DO in the deep water ship channel decreased to 6.3 mg/L by mid-November where it remained for a couple of days before increasing to 8.6 mg/L by December 2. Delta Exports. Combined exports ranged from 4,174 cfs to 7,892 cfs during the reporting period. Export rates at the state pumping facility increased from a rate near 1,400 cfs to a peak of 5,153 cfs during the same period when the federal pumping facility reduced to approximately 2,700 cfs for a 10-day period. By November 21, exports at the federal pumping facility increased by 1,000 cfs while export rates at the state pumping facility decreased by more than 2,000 cfs. |
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Upcoming EventsDec. 12: CALFED Ops Meeting
Featured LinksSacramento River Watershed Program
Related LinksTuolumne River Technical Advisory Committee |
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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. |
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2007 Adult Migration Monitoring Stanislaus River Weir: Between November 12 and December 2, a total of 103 Chinook were recorded passing upstream of the weir, increasing the season total to 383. Daily upstream passage ranged from one to 16 Chinook. One Chinook with a clipped adipose fin was observed on December 2, increasing the season total to nine (2.3% of total passage). Zero O. mykiss were detected during the sampling period. To date, Chinook passage at the weir remains significantly lower than recent years during the same period (13.9% of 2,765 observed in 2006, 9.9% of 3,882 observed in 2005, 8.8% of 4,334 observed in 2004, and 8.6% of 4,451 observed in 2003). Trapping was suspended during the sampling period as a precaution due to increased spawning activity in the vicinity of the weir. Similar activity has been reported each year during the same time period. Trapping may resume at the weir if daily passage numbers increase. During the sampling period, releases from Goodwin Dam (GDW; RM 58.4) remained consistent and ranged between 280 cfs and 287 cfs; flow at Orange Blossom Bridge (OBB; RM 46.9) ranged between 218 cfs and 313 cfs; and flow at Ripon (RIP; RM 15.7) ranged between 294 cfs and 333 cfs. Turbidity at the weir site ranged from 0.29 NTU to 2.28 NTU and DO averaged 10.1 mg/L. DO downstream of the weir at Ripon (RPN; RM 15.7) ranged from 7.9 mg/L to 10.9 mg/L (avg: 9.2 mg/L). Daily instantaneous water temperature at the Stanislaus River weir ranged from 45 ºF to 57 ºF (avg: 52.1 ºF). Tributary Carcass Surveys: Carcass surveys continued on the Stanislaus, Tuolumne and Merced Rivers. The number of live fish and redds observed on all three tributaries increased, but still remains extremely low compared to past years. Through the first eight weeks of suveys, only 513 redds were observed on the Stanislaus, 254 redds were observed on the Tuolumne, and 123 redds were observed on the Merced. Very few carcasses have been tagged (i.e., 10 on the Stanislaus, 20 on the Tuolumne, and 27 on the Merced) and zero tagged carcasses have been recovered on all three tributaries. Only 17 female Chinook have been spawned at the Merced River Hatchery (MRH) thus far. Last year, adult numbers were also low and only 77 females (402,000 eggs) were spawned resulting in a minimal amount of juveniles available for release outside of the Merced River for various 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). In years when hatchery production is sufficient, CWT Merced fish are released for various San Joaquin Basin studies, including tributary smolt survival studies, rotary screw trap efficiency releases, trawl efficiency releases, and VAMP smolt survival experiments. In 2007, approximately 300,000 coded-wire tagged (CWT) fish were released into the Merced River as part of the Merced River Smolt Survival Study (200,000 released at MRH and 100,000 at Hatfield State Park). Additionally, 8,000 MRH fish were marked and released for rotary screw trap efficiency releases near Hatfield State Park while the remaining 36,000 unmarked hatchery fish were released into the river upstream at the MRH. 2007/08 Juvenile Migration Monitoring
The trap sampled a total of 10 out of 21 days between November 12 and November 28. A total of 27 Age 1+ (greater than 100 mm) and two young-of year (YOY; less than or equal to 100 mm) O. mykiss were captured. Individual lengths of Age 1+ ranged from 102 mm to 166 mm (avg: 126 mm) and weights ranged from 10.6 g to 49.6 g (avg: 22.3 g). None of the O. mykiss captured were smolting and were rated as a parr (n=25) or silvery parr (n=4). Most fish were likely redistributing themselves into downstream habitat and not actively migrating. The two YOY O. mykiss were 85 mm and 92 mm and weighed 6.6g and 8.7 g, respectively. Zero Chinook were captured during the sampling period. The cone was raised on November 28 due to insufficient depth to sample the trap. Sampling will resume once flows increase to above 34 cfs. Instantaneous temperature taken at the trap ranged from 45ºF to 52ºF, and turbidity ranged from 0.03 NTU to 1.55 NTU. Daily average flow at New Hogan Dam (NHG) fluctuated between 29 cfs and 34 cfs, and flows at Bellota (MRS) ranged between 5 cfs and 17 cfs. Note: Flow data is not yet available after November 29.
San Joaquin River Conditions
Delta Exports
Mean daily pumping at the C.W. Jones Pumping Plant (federal pumps previously known as Tracy Pumping Plant) decreased to approximately 2,700 cfs on November 12 where it remained for a 10-day period. Pumping rates then increased for the remainder of the reporting period and ranged from 3,439 cfs to 3,762 cfs. Mean daily pumping at the Harvey O. Banks Pumping Plant (state pumps) increased from 1,416 cfs on November 12 to 5,153 cfs by November 20. Pumping rates then decreased for the remainder of the reporting period and ranged from 2,391 cfs to 4,182 cfs. To view newsletter archives, click here. |
Rotary screw trap operations on the lower Calaveras River began on November 12 just upstream of the Shelton Road Bridge (RM 29). This is the earliest that the trap has been operated since annual monitoring began in 2002. The trap began sampling early this year to determine the extent of O. mykiss migration, if any, occurring in November. As in past years, the trap will be operated on an intermittent schedule (i.e., 3-5 days/week) during the sampling season.
Flow in the San Joaquin River at Vernalis gradually decreased from 1,640 cfs to near 1,350 cfs during the reporting period. 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 48.8 °F to 60.4 °F (avg: 54.7 °F) at Vernalis; from 50.4 °F to 61.0 °F (avg: 56.1°F) at Mossdale; and from 53.6 °F to 61.4 °F (avg: 58.2 °F) at Rough 'n Ready Island. Dissolved oxygen (DO) in the San Joaquin River at Mossdale fluctuated between 8.0 mg/L and 10.7 mg/L (avg: 9.3 mg/L). DO in the deep water ship channel (measured at Rough 'n Ready Island) decreased to 6.3 mg/L by mid-November where it remained for a couple of days before gradually increasing to 8.6 mg/L by the end of the reporting period. Average DO in the deep water ship channel decreased by almost 1.0 mg/L as compared to the previous three weeks.
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© 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. |