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June 12 through June 23, 2006, Report No.
11
Waterford:
The Waterford rotary screw
trap sampled seven out of 10 days between June 12 and June
21. A total of 19 juvenile Chinook salmon were captured,
increasing the season total to 8,524. Daily catch ranged
from zero to six Chinook (Figure 1). Average forklength was
91.3 mm and ranged from 77 mm to 108 mm. Average weight was
9.4 g and ranged from 8.4 g to 10.8 g.
Figure 1. Chinook
salmon catch at Waterford versus flow at La Grange (LGN).
One
O. mykiss (79
mm; 6.0 g; SI 3) was captured in the rotary screw trap on
June 12 increasing the season total to six.
One trap efficiency test was
conducted at Waterford on June 16 using Chinook from the
Merced River Hatchery with a resulting efficiency of 0.05%
(Table 1).
Table 1. Trap efficiency
tests conducted at Waterford between June 12 and June 21,
2006.
|
Location |
Date |
Mark |
Number released |
Number recaptured |
Mean Length @ Release(mm) |
Mean Length @ Recapture (mm) |
Estimated
Efficiency |
Flow (cfs)
at LGN |
|
Waterford |
6/16/09 |
TCO |
2,163 |
1 |
97.5 |
75.0 |
0.05% |
5,007 |
Sampling was terminated
for the season on June 21 due to consistently low catch
and the trap was removed on June 23.
Grayson:
The Grayson rotary screw traps
sampled eight out of 11 days between June 12 and June 22. A
total of 12 juvenile Chinook salmon were captured,
increasing the season total to 1,568. Daily catch ranged
from zero to four Chinook (Figure 2). Average forklength
was 93.0 mm and ranged from 75 mm to 113 mm. Average weight
was 10.6 g and ranged from 5.9 g to 14.2 g.
Figure 2.
Chinook salmon catch at Grayson versus flow at Modesto (MOD).
No
O. mykiss were
captured in the rotary screw trap during this sampling
period.
One trap efficiency test was
conducted at Grayson on June 14 using Chinook from the
Merced River Hatchery with a resulting efficiency of 0.13%
(Table 2).
Table 2. Trap efficiency
test conducted at Grayson between June 12 and June 22,
2006.
|
Location |
Date |
Mark |
Number released |
Number recaptured |
Mean Length @ Release(mm) |
Mean Length @ Recapture (mm) |
Estimated
Efficiency |
Flow (cfs)
at MOD |
|
Grayson |
6/14/06 |
TCY |
1,507 |
2 |
85.4 |
83.0 |
0.13% |
4,864 |
Sampling was terminated
for the season on June 22 due to consistently low
catch. The traps will be removed from the water as soon
as a TID boom truck is available to assist with the
removal in the next few weeks.
Environmental Data:
Instantaneous water
temperature ranged between 52.0°F and 56.0°F at Waterford,
and between 57.6°F and 60.0°F at Grayson. Turbidity
fluctuated between 0.6 NTU and 2.0 NTU at Waterford, and
from 1.6 NTU to 2.5 NTU at Grayson. During the sampling
period, flows at La Grange ranged between 3,856 cfs and
7,580 cfs, while flows at Modesto ranged between 3,958 cfs
and 6,210 cfs.
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