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February 20 through March 5, 2006, Report No.
3
Waterford:
A total of
1,595 juvenile Chinook salmon were captured at Waterford
between February 20 and March 5, increasing the season total
to 6,779. Daily catch ranged from 27 to 393 Chinook (Figure
2). Average forklength was 34.7 mm and ranged from 30 mm to
140 mm. Average weight was 0.4 g and ranged from 0.2 g to
32.4 g.
Three yearling Chinook salmon were
captured at the Waterford site during this sample period,
but were not included in the total catch or in calculations
for mean length or weight. Yearling forklengths ranged
between 121 mm and 141 mm, and weights ranged from 20.5 g to
32.4 g.
No O. mykiss were captured in the rotary screw trap
during this sampling period.
Figure 1. Rotary
screw trap near Waterford on the Tuolumne River.
Figure 2. Chinook
salmon catch at Waterford versus flow at La Grange (LGN).
No trap efficiency tests were conducted at Waterford during
this sample period due to low catch numbers.
Grayson:
A total of 341 juvenile
Chinook salmon were captured at Grayson between February 20
and March 5, increasing the season total to 1,194.
Daily catch ranged from 2 to 93 Chinook (Figure 4).
Average forklength was 37.6 mm and ranged from 30 mm to 76
mm. Average weight was 0.7 g and ranged from 0.2 g to 4.8
g.
No O.
mykiss were captured in the rotary screw trap during
this sampling period.
Figure 3. Rotary screw trap near
Waterford on the Tuolumne River.
Figure 4. Chinook
salmon catch at Grayson versus flow at Modesto (MOD).
One trap
efficiency test was conducted at Grayson during this sample
period on March 3 with an estimated trap
efficiency of 4.5% (Table 1).
Table 1. Trap efficiency test
conducted at Grayson on March 3.
|
Date |
Number Released |
Number Recaptured |
Estimated Efficiency |
Mean Length at
Release (mm) |
Mean Length at
Recapture (mm) |
Turbidity (NTU) |
Flow at MOD (cfs) |
|
3/3/06 |
89 |
4 |
4.5% |
34.8 |
36.0 |
4.97 |
4,261 |
Environmental Data:
Instantaneous water temperature taken at the Waterford trap
ranged between 48.9°F and 51.9°F, while temperature at
Grayson ranged between 50.0°F and 54.2°F. Turbidity ranged
from 1.42 NTU to 3.92 NTU at Waterford and from 1.78 NTU to
15.9 NTU at Grayson. During the sampling period, flows at
La Grange ranged between 1,718 cfs and 4,948 cfs, while
flows at Modesto ranged between 2,281 cfs and 4,813 cfs.
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