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November
14 through November 27, 2005
Note: Data is preliminary and subject to revision. Data
presented in this report are only from the Vaki RiverWatcher and
numbers may increase after the data on the back up system is
analyzed and compared. Weir Update:
A total of 493 Chinook (daily
range: 3 to 77) passed upstream of the weir between November 14
and November 27 increasing the season total to 3,327
Chinook. Whereas, a total of 4,222 and 4,314 Chinook passed the
weir by the same date in 2003 and 2004, respectively. Past data
suggests that the fall Chinook run abundance decreases
significantly during the month of December. Based on this
trend, it looks as if the 2005 escapement will be at least 1,000
Chinook fewer than the past two years. No
O. mykiss were
observed passing the weir or in the daily snorkel surveys during
the sampling period. Other species observed included catfish
spp., Sacramento sucker, and striped bass.
Figure 1.
(Top) photo series of an otter going through the Vaki on
November 18, 2005; (bottom) photo series of a 662 mm (TL) silver
female Chinook passing through the Vaki on November 16, 2005.
Environmental conditions
fluctuated at the weir site during the sampling period.
Releases from Goodwin Dam fluctuated between 352 cfs and 359 cfs.
Daily instantaneous measurements of turbidity, DO, and water
temperature ranged between 0.1 and 1.9 NTU; 10.1 mg/L and 10.8
mg/L; and 49.1ºF and 52.6ºF, respectively. DO at Rough 'n Ready
Island (RRI) in the San Joaquin River's Deep Water Ship Channel
ranged from 5.8 mg/L to 7.8 mg/L and water temperature ranged
from 56.1ºF to 58.3ºF. DO at RRI decreased each day between
November 24 and November 27 from 7.3 mg/L to 5.8 mg/L.
Trapping:
Three trapping events were
conducted at the Stanislaus weir during the sampling period and
a total of 37 Chinook were captured increasing the season total
to 266. The length of Chinook captured to date ranged from 470
mm to 1,080 mm (avg=789 mm). Fifty-six percent of the Chinook
were female (148 Chinook), forty-four percent were male (116
Chinook), and less than one percent were unknown gender (2
Chinook). Eleven percent (30 Chinook) were grilse (<600 mm) and
five percent (13 Chinook) were ad-clipped.
Figure 3.
Photos taken of Chinook during trapping periods (left to right):
985 mm (TL) female Chinook; removing scales from a 860 mm (TL)
male Chinook; 575 mm (TL) male grilse. |
