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May 15 through May 28, 2006, Report No.
9
Waterford:
The Waterford rotary screw
trap sampled eight out of 14 days between May 15 and May
28. A total of 315 juvenile Chinook salmon were captured,
increasing the season total to 8,432. Daily catch ranged
from one to 72 Chinook (Figure 1). Average forklength was
93.6 mm and ranged from 33 mm to 115 mm. Average weight was
8.2 g and ranged from 5 g to 11.3 g.
Figure 1. Chinook
salmon catch at Waterford versus flow at La Grange (LGN).
No O.
mykiss were captured in the rotary screw trap during
this sampling period.
Two trap efficiency tests were
conducted at Waterford on May 17 and May 26 using Chinook
from the Merced River Hatchery with a resulting efficiency
of 0.5% and 0.1%, respectively (Table 1).
Table 1. Trap efficiency
tests conducted at Waterford between May 15 and May 28,
2006.
|
Location |
Date |
Mark |
Number released |
Number recaptured |
Mean Length @ Release(mm) |
Mean Length @ Recapture (mm) |
Estimated
Efficiency |
Flow (cfs)
at LGN |
|
Waterford |
5/17/06 |
CFO |
2,442 |
11 |
83.1 |
82.8 |
0.5% |
8,235 |
|
Waterford |
5/26/06 |
TCO |
2,326 |
3 |
85.9 |
73.7 |
0.1% |
6,669 |
Grayson:
The Grayson rotary screw traps
sampled eight out of 14 days between May 15 and May 28. A
total of 40 juvenile Chinook salmon were captured,
increasing the season total to 1,502. Daily catch ranged
from one to eight Chinook (Figure 2). Average forklength
was 97.4 mm and ranged from 81 mm to 111 mm. Average weight
was 11.1 g and ranged from 9.5 g to 13.2 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 May 25 using Chinook from the Merced
River Hatchery with a resulting efficiency of 0.1% (Table 2).
Table 2. Trap efficiency
test conducted at Grayson between May 15 and May 28,
2006.
|
Location |
Date |
Mark |
Number released |
Number recaptured |
Mean Length @ Release(mm) |
Mean Length @ Recapture (mm) |
Estimated
Efficiency |
Flow (cfs)
at MOD |
|
Grayson |
5/25/06 |
TCG |
1,532 |
2 |
83.7 |
69.5 |
0.1% |
6,537 |
Environmental Data:
Instantaneous water
temperature ranged between 52.0°F and 56.0°F at Waterford,
and between 54.8°F and 58.2°F at Grayson. Turbidity
fluctuated between 1.0 NTU and 1.7 NTU at Waterford, and
from 1.4 NTU to 2.6 NTU at Grayson. During the sampling
period, flows at La Grange ranged between 6,119 cfs and
8,495 cfs, while flows at Modesto ranged between 6,043 cfs
and 7,791 cfs.
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