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January 31-February 13, 2005, Report No.
3
Oakdale:
A total of 18,138 juvenile
Chinook were captured between January 31 and February 13
increasing the season total to 120,317. Daily catch ranged
from 183 to 6,497 Chinook (Figure 1). Individual
forklengths ranged from 23 mm to 68 mm and daily mean
lengths ranged from 33 mm to 39 mm. Average weight for
captured Chinook was 0.4 g and ranged from
0.2 g to 1.9 g.
A 149 mm Chinook was also captured on February 10, but was
not included in the total catch or in calculations for mean
length or weight.
Three
O. mykiss were
captured on three separate dates: February 3, February 8, and February 10 measuring
260 mm, 275 mm and 252 mm, respectively. All three of
fish were rated as smolts (SI 5) based on their appearance.
Two of the three fish (260 mm and 252 mm) were retained and
will be provided to CDFG for analysis as part of a Distribution and Relationship of Resident and
Anadromous Central Valley Rainbow Trout project
currently being conducted by George Edwards at CDFG.
Up to 30 O. mykiss
captured in the rotary screw traps during the 2005 season
will be provided to CDFG for their studies.
Figure 1. Chinook
Catch at Oakdale versus flow at Orange Blossom Bridge.
Trap efficiency releases were
conducted on four nights between February 3 and February 9
and results of releases are presented in Table 1.
Estimated trap efficiencies are consistent with past year's
data under similar flow conditions.
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 |
|
02/03/05 |
565 |
231 |
40.9% |
36.3 |
35.6 |
3.9 |
269 |
|
02/04/05 |
557 |
105 |
18.9% |
35.3 |
36.6 |
4.1 |
263 |
|
02/08/05 |
184 |
51 |
27.7% |
34.5 |
35.2 |
3.7 |
261 |
|
02/09/05 |
452 |
179 |
39.6% |
35.0 |
36.4 |
2.6 |
259 |
Caswell:
A total of 8,446 juvenile
Chinook were captured between January 31 and February 13
increasing the season total to 14,281. Daily catch ranged
from 3 to 5,814 Chinook (Figure 2). The peak in catch
(5,814 Chinook) was correlated with a rain event that
occurred during the previous week. Average forklength was
36.4 mm and
ranged from 23 mm to 55 mm. Average weight for captured
Chinook was 0.4 g and ranged from
0.2 g to 1.7 g.
No
O. mykiss were
captured during the sampling period.
Figure 2. Chinook
Catch at Caswell versus flow at Ripon.
Trap efficiency releases
were conducted on February 1 and February 2 and the results are listed in
Table 2. Estimated trap efficiencies are consistent with
past year's data under similar flow conditions and fish
sizes.
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 |
|
02/01/05 |
527 |
44 |
8.4% |
36.0 |
35.9 |
15.5 |
343 |
|
02/02/05 |
486 |
48 |
9.9% |
35.8 |
36.2 |
7.54 |
318 |
Environmental Data:
Environmental conditions
fluctuated during the sampling period as flow and turbidity
continued to decrease following a significant rain event the
previous week. Instantaneous temperature fluctuated between
47°F
and 51°F
at Oakdale and between 48°F
and 54°F
at Caswell. Turbidity ranged from 2.6 NTU to 9.6 NTU at
Oakdale and from 2.4 NTU to 17.5 NTU at Caswell. During the
sampling period, flow releases from Goodwin Dam (GDW)
fluctuated between 225 cfs and 245 cfs. Flows at Orange
Blossom Bridge (OBB; RM 46.9) ranged from 237 cfs to 284 cfs
and at Ripon (RIP; RM 15.8) from 269 cfs to 382 cfs.
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