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January 7 through
February 17 , 2008, Report No.
1
Waterford:
An 8-foot
rotary screw trap was installed on January 7, 2008 near the
town of Waterford (RM 30). The trap sampled continuously between January 7 and February 17. A total of
1,546 juvenile Chinook salmon were captured during the
sampling period. Daily catch ranged from one to 236 Chinook (Figure
1). Average forklength was 39.0 mm and ranged from 33 mm to
128 mm. Average weight was 1.0 g and ranged from 0.2 g to
21.2 g.
Five O. mykiss were captured in the rotary screw trap
during this sampling period. Individual lengths ranged from 105 mm to 268 mm (avg: 227 mm) and weights ranged from 87.4g to 173.0 g (avg: 115.5 g).
Figure 1. Chinook
salmon catch at Waterford versus flow at La Grange (LGN).
Seven
trap efficiency tests were conducted at Waterford using natural Chinook
captured from the trap with resulting efficiencies ranging from 8.4% to 34.4%.
Table 1. Trap efficiency tests conducted at Waterford between January 7 and February 17, 2008.
Release date |
Mark applied |
Number released |
Number recaptured |
Estimated efficiency |
Length at release (mm) |
Length at recapture (mm) |
Flow at LGN (cfs) |
Turbidity (NTU) |
|
|
|
|
|
37.0 |
|
|
5.0 |
|
|
|
|
|
|
|
|
151.0 |
|
|
|
|
|
|
|
|
75.2 |
|
|
|
|
|
|
|
|
9.6 |
|
|
|
|
|
|
|
|
6.8 |
|
|
|
|
|
|
|
|
14.0 |
|
|
|
|
|
|
|
167 |
2.6 |
Instantaneous water temperature taken at the Waterford trap
ranged between 46.0 °F and 52.8 °F; turbidity ranged from
1.3 NTU to 411.0 NTU; and flows at La Grange ranged between
164 cfs and 178 cfs.
Grayson:
The Grayson traps were installed at the same location as previous years (i.e., RM 5) on January 28, 2008 and sampling began immediately. A total of 26 juvenile Chinook salmon were captured between January 28 and February 17. Daily catch ranged from zero to 13 Chinook (Figure
2). Average forklength was 43.4 mm and ranged from 35 mm to
104 mm. Average weight was 1.3 g and ranged from 0.3 g to
12.0 g.
Zero O. mykiss were captured in the rotary screw traps
during this sampling period.
Figure 2. Chinook
salmon catch at Grayson versus flow at Modesto (MOD).
Zero trap efficiency tests were conducted during the sampling period due to insufficient number of Chinook captured in the traps.
Instantaneous temperature taken at the trap ranged between 46.7 °F and 54.8 °F, and turbidity ranged from 2.8 NTU to 95.7 NTU. Daily average flow at Modesto (MOD) fluctuated between 280 cfs and 1,249 cfs. |
