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October 3 through October 16, 2005
Weir Update:
A total of 380 Chinook (daily
range: 0 to 79) passed upstream of the weir between October 3
and October 16 increasing the season total to 513
Chinook. Whereas, a total of 1,755 and 776 Chinook passed the
weir by the same date in 2003 and 2004, respectively. The first
O. mykiss (480
mm; female) of the season passed the weir on October 15 (Figure
1). Based on the recent modifications to the livebox, we are
confident that we can continue to distinguish
O. mykiss from Chinook.
Other species observed included Sacramento sucker,
Sacramento pikeminnow, striped bass, carp, and black bass.
Figure 1. A
480 mm female O. mykiss
that passed through the Vaki on October 15, 2005.
Environmental conditions
fluctuated slightly at the weir site during the sampling
period. Daily instantaneous measurements of turbidity, DO, and
water temperature ranged between 1.0 and 3.6 NTU; 8.9 mg/L and
10.0 mg/L; and 56.2ºF and 58.8ºF, respectively. DO at Rough 'n
Ready Island (RRI) in the San Joaquin River's Deep Water Ship
Channel ranged from 5.4 mg/L to 7.7 mg/L and water temperature
ranged from 65.4ºF to 69.6ºF.
Releases from Goodwin Dam
fluctuated between 352 cfs and 371 cfs between October 3 and
October 16. Fall attraction flows on the Stanislaus River are
currently underway. Releases from Goodwin Dam were increased to
1,000 cfs over a two-day period (October 18-19) and will remain
elevated until October 28, when releases will return back to
approximately 350 cfs.
Trapping:
Three trapping events were
conducted during the sampling period to collect biological data
(i.e., length, body depth, scales, etc.). The measurements
obtained will be used to calibrate the Vaki system. Recall, the
Vaki calculates the length of a fish based on the body
depth/length ratio of each species. As more information is
obtained, we will re-calculate this ratio and apply it to the
data collected by the Vaki system.
During the three trapping events,
a total of 33 Chinook were captured increasing the season's
cumulative total to 44. The length of Chinook captured to date
ranged from 555 mm to 1,000 mm (avg=779 mm). Fifty-nine percent
of the Chinook were female (26), thirty-six percent were male
(16) and five percent were unknown (2). Seven percent (3
Chinook) were grilse (<600 mm) and two percent (1 Chinook) were
ad-clipped.
Figure 2. A
950 mm male ad-clipped Chinook captured in the livebox on
October 14, 2005. Note the absence of the adipose fin (ad-clip)
in the photo on the right.
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