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Cramer Fish Sciences
March 5 - 25, 2007, Summary
Postcard No. 4
Caswell:
A total of 199 juvenile Chinook salmon were captured at
Caswell State Park between March 5th and March 25th
increasing the season total to 921. Daily catch ranged from
1 to 32 Chinook. Individual forklengths ranged from 23
mm to 138 mm (Figure 1). Mean length for captured
Chinook during this sampling period was 39 mm and mean
weight was 1.3 grams. The contribution of the season
total catch for each trap are 387 for the north trap, 323
for the south trap, and 211 for the lower trap. The lower trap captured 43 of
the 199 juvenile Chinook salmon yielding 22% of the total
catch for the sampling period and 23% of the total catch for
the season thus far (Figure 2).
Figure 1. Photo of a 31 mm Chinook salmon fry (bottom) and a 83 mm Chinook salmon smolt (top). [click on the photo for
enlarged view]
Figure 2. Total daily catch contributions of the North,
South, and Lower rotary screw traps at Caswell State Park (RM
8).
One O. mykiss
was captured in the South rotary screw trap during this
sampling period. (Table 1, Figure 3).
|
Trap
|
Date
|
Time
|
Fork
length(mm)
|
Total
length(mm)
|
Weight
(g)
|
Smolt
Index
|
|
South
|
3/16/07
|
09:30
|
226
|
245
|
111.4
|
5
|
Table 1. Trap location,
date, time, forklength, total length, weight, and smolt
index of captured O. mykiss at Caswell State Park (RM
8).
Figure 3. Photo of an O.mykiss
captured on March 16th (FL: 226 mm, W:
111.4 g). [click on the photo for
enlarged view]
Four trap efficiency tests were conducted during this
sampling period; 73 upper caudal fin-clipped, 37 caudal
fin pink, 27 caudal fin yellow, and 35 caudal fin green
wild juvenile Chinook salmon were released on March 6th,
8th, 10th, and 12th
respectively. The trap efficiencies (for all traps
combined) ranged between 5.4% and 8.6%. During the
trap efficiency tests, the flow at Ripon (RIP; RM 15.8)
ranged between 1,221 cfs and 1,375 cfs (Table 2).
|
Date |
Mark |
#Released |
#Recaptured North/South Traps |
North/South Trap Efficiency |
#Recaptured Lower Trap |
Combined Traps Efficiency |
RIP Flow (cfs) |
|
March 6th |
Upper Caudal Fin-clip |
73 |
4 |
5.5% |
0 |
5.5% |
1,364 |
|
March 8th |
Caudal Fin Pink |
37 |
2 |
5.4% |
0 |
5.4% |
1,375 |
|
March 10th |
Caudal Fin Yellow |
27 |
1 |
3.7% |
1 |
7.4% |
1,364 |
|
March 12th |
Caudal Fin Green |
35 |
2 |
5.7% |
1 |
8.6% |
1,221 |
|
|
Totals |
172 |
9 |
5.2% |
2 |
6.4% |
|
Table 2. Trap efficiency
data for the North/South traps, Lower trap, and all the
traps combined at Caswell State Park (RM
8) and flow at Ripon (RIP; RM 15.8).
During the sampling period fourteen incidental species were captured, including white catfish, bluegill sunfish, tule
perch, prickly sculpin,
hardhead, bigscale logperch, Sacramento sucker, western mosquitofish,
black crappie, brown bullhead, goldfish, Sacramento blackfish,
Sacramento pikeminnow and unidentified lamprey (Figure 4).
Figure 4. Photo of a bigscale logperch captured on Feb. 24th
(FL: 83 mm).
[click on the photo for
enlarged view]
Coded Wire Tagging (CWT):
Please see the
Caswell
Coded Wire Tagging Summary Update #4 for detailed
information and data on the project.
Environmental
Data:
Instantaneous water
temperature taken at the Caswell rotary screw trap ranged
from 52.0°F to 58.0°F. Turbidity at Caswell ranged
from 1.4 NTU to 3.9 NTU. During the sampling period
releases from Goodwin Dam (GDW) ranged from 502 cfs to 1,511 cfs.
Flows at Orange Blossom Bridge (OBB; RM 46.9) ranged from
494 cfs to 1,166 cfs and at Ripon (RIP; RM 15.8) from 674 cfs
to 1,381 cfs. Click here if you need Adobe Acrobat
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