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May 1
through May 14, 2006, Report No.
8
Oakdale:
A total of 1,939 juvenile
Chinook salmon were captured between May 1 and May 14,
increasing the season total to 49,362 (Figure 1). Daily
catch ranged from 10 to 365 Chinook. Average forklength was
80.9 mm and ranged from 34 mm to 112 mm. Average weight for
captured Chinook was 4.9 g and ranged from 3.4 g to 6.4 g.
Figure 1. Chinook
Catch at Oakdale versus Stanislaus River flow at Orange Blossom Bridge
(OBB).
One
O. mykiss fry
(42 mm; 0.9 g) was captured in the rotary screw trap on May
3.
Figure 2. A
42 mm O. mykiss captured at the Oakdale rotary screw
trap on May 3, 2006.
Two trap efficiency tests were
conducted at Oakdale using Chinook from Merced River
Hatchery on May 4 and May 11 with resulting efficiencies of
6.0% and 2.3%, respectively (Table 1).
Table 1. Trap efficiency
tests conducted at Oakdale between
May 1 and May 14,
2006.
|
Location |
Date |
Mark |
Number released |
Number recaptured |
Mean Length @ Release(mm) |
Mean Length @ Recapture (mm) |
Estimated
Efficiency |
Flow
(cfs)
at OBB |
|
Oakdale |
5/4/06 |
CFG |
821 |
49 |
69.1 |
70.9 |
6.0% |
4,844 |
|
Oakdale |
5/11/06 |
CFG |
681 |
16 |
80.4 |
78.1 |
2.3% |
4,473 |
Caswell:
The Caswell rotary screw traps
sampled nine out of 14 days between May 1 and May 14. A
total of 52 juvenile Chinook salmon were captured,
increasing the season total to 846 (Figure 3). Daily catch
ranged from zero to 17 Chinook. Average forklength was 94.5
mm and ranged from 78 mm to 108 mm. Average weight for
captured Chinook was 9.6 g and ranged from 7.3 g to 13.9 g.
Figure 3. Chinook
Catch at Caswell versus Stanislaus River flow at Ripon (RIP).
No O. mykiss
were captured during the sampling period.
Two trap efficiency tests were
conducted at Caswell using Chinook from Merced River
Hatchery on May 3 and May 10 with resulting efficiencies of
2.8% and 0.9%, respectively (Table 2).
Table 2. Trap efficiency
tests conducted at Caswell between May 1 and May 14,
2006.
|
Location |
Date |
Mark |
Number released |
Number recaptured |
Mean Length @ Release(mm) |
Mean Length @ Recapture (mm) |
Estimated
Efficiency |
Flow (cfs)
at RIP |
|
Caswell |
5/3/06 |
CFP |
1096 |
31 |
69.2 |
70.2 |
2.8% |
4,911 |
|
Caswell |
5/10/06 |
CFP |
670 |
6 |
78.2 |
82.8 |
0.9% |
4,325 |
Smolt Survival
Release:
The California Department of
Fish and Game released 75,000 coded-wired tagged (CWT)
Merced River Hatchery Chinook at Knight's Ferry on April 28
to evaluate survival in the lower Stanislaus River. A total
of 252 CWT fish (daily range: 1 to 109) were recaptured at
Oakdale (14.2
river miles downstream of release site) between April 28 and
May 14, and only three were recaptured at Caswell (45.7
river miles downstream of release site) during the same
sampling period (Table 3).
Table 3. Daily totals
of CWT Chinook recaptured in the Oakdale and Caswell rotary
screw traps between April 28 and May 14, 2006.
| Date |
Oakdale |
Caswell |
| 4/28/06 |
35 |
- |
| 4/29/06 |
109 |
- |
| 4/30/06 |
19 |
2 |
| 5/1/06 |
7 |
1 |
| 5/3/06 |
6 |
- |
| 5/4/06 |
1 |
- |
| 5/5/06 |
3 |
- |
| 5/6/06 |
11 |
- |
| 5/7/06 |
6 |
- |
| 5/8/06 |
6 |
- |
| 5/9/06 |
11 |
- |
| 5/10/06 |
15 |
- |
| 5/11/06 |
17 |
- |
| 5/12/06 |
6 |
- |
Environmental Data:
Instantaneous water
temperature fluctuated between 49.0°F and 52.0°F at Oakdale
and between 53.5°F and 55.0°F at Caswell. Turbidity ranged
from 1.1 NTU to 4.3 NTU at Oakdale and from 1.2 NTU to 2.6
NTU at Caswell. During the sampling period, releases from
Goodwin Dam (GDW) ranged between 4,243 cfs and 5,161 cfs.
Flows at Orange Blossom Bridge (OBB; RM 46.9) ranged from
4,288 cfs to 5,483 cfs and at Ripon (RIP; RM 15.8) from
4,321 cfs to 5,325 cfs.
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