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January 17-30, 2005, Report No.
2
Oakdale:
A total of 93,701 juvenile
Chinook were captured between January 17 and January 30
increasing the season total to 102,179. Daily catch ranged
from 209 to 39,137 Chinook (Figure 1). The majority of the
Chinook (90,573 or 97%) were captured during a four-day
period following a temporary increase in flow and turbidity
that was correlated with a rain event. Average forklength
was 34.9 mm
and ranged from 30 mm to 50 mm. Average weight for captured
Chinook was 0.3 g and ranged from
0.1 g to 0.5 g.
Two
O. mykiss were
captured on January 21 and January 29 measuring 366 mm
(total length) and 475 mm (forklength), respectively. Only
the total length was obtained from the
O. mykiss
captured on January 21 due to the tail being eroded. Both
O. mykiss
appeared to have recently spawned.
Figure 1. Chinook
Catch at Oakdale versus flow at Orange Blossom Bridge.
Trap efficiency releases were
conducted on six nights between January 17 and January 26
and results of releases are presented in Table 1. Estimated
trap efficiencies are consistent with past year's data under
similar flow conditions, with the exception of the release
conducted on January 18
which was substantially lower.
Table 1. Release
and recapture data for trap efficiencies conducted at
Oakdale.
|
Date |
# Released |
# Recaptured |
Trap Efficiency |
Mean Length @ Release (mm) |
Mean Length @ Recapture (mm) |
Turbidity (NTU) |
Flow @ OBB |
| 1/17/05 |
403 |
148 |
36.7% |
33.8 |
34.1 |
5.32 |
269 |
| 1/18/05 |
500 |
42 |
8.4% |
33.9 |
35.0 |
5.73 |
266 |
| 1/19/05 |
268 |
92 |
34.3% |
34.0 |
34.2 |
4.58 |
265 |
| 1/20/05 |
212 |
63 |
29.7% |
34.3 |
33.9 |
4.8 |
265 |
| 1/25/05 |
268 |
74 |
27.6% |
34.5 |
35.9 |
3.7 |
257 |
| 1/26/05 |
382 |
110 |
28.8% |
35.8 |
36.9 |
3.7 |
274 |
Caswell:
A total of 4,911 juvenile
Chinook were captured between January 17 and January 30
increasing the season total to 5,835. Daily catch ranged
from 0 to 4,873 Chinook (Figure 2). A majority of Chinook
(4,873 or 99.2%) were captured the day after a temporary
increase in flow and turbidity that was correlated with a
rain event. Average forklength was
36.0 mm and
ranged from 30 mm to 45 mm. Average weight for captured
Chinook was 0.3 g and ranged from
0.2 g to 0.4 g.
No
O. mykiss were
captured during the sampling period.
Figure 2. Chinook
Catch at Caswell versus flow at Ripon.
One trap efficiency release
was conducted January 17 and the results are listed in
Table 2. Estimated trap efficiencies are consistent with
past year's data under similar flow conditions.
Table 2. Release
and recapture data for trap efficiency conducted at
Caswell.
|
Date |
# Released |
# Recaptured |
Trap Efficiency |
Mean Length @ Release (mm) |
Mean Length @ Recapture (mm) |
Turbidity (NTU) |
Flow @ RIP |
| 1/17/05 |
68 |
12 |
17.7% |
34.3 |
34.3 |
6.07 |
332 |
Environmental Data:
Two rain events occurred during
the sampling period causing environmental conditions to
fluctuate. Instantaneous temperature fluctuated between 44°F
and 51°F
at Oakdale and between 46°F
and 53°F
at Caswell. Turbidity ranged from 3.7 NTU to 30.3 NTU at
Oakdale and from 3.5 NTU to 39.8 NTU at Caswell. During the
sampling period, flow releases from Goodwin Dam (GDW)
fluctuated between 227 cfs and 243 cfs. Flows at Orange
Blossom Bridge (OBB; RM 46.9) ranged from 257 cfs to 599 cfs
and at Ripon (RIP; RM 15.8) from 279 cfs to 777 cfs. The
difference between the flow released at GDW and the recorded
values at OBB and RIP was a result of run-off produced by rain
events.
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