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Fishery Bulletin 108(2) 
Table 1 
Estimates of biomass of Pacific sardine ( Sardinops sagax), biomass-related parameters for each survey (stratum 1, stratum 2 
[with latitude 125°W as the dividing line between them], and the entire survey area), and confidence intervals for biomass and 
recruits: incoming year class (fish <120 mm standard length) in tons (t). Either the coefficient of variation (CV) or number of 
positive (pos) trawls is in parentheses. 
Stratum 1 
Stratum 2 
Entire survey area 
July 2003 
Mean density (kg/m 3 ) 
2.41e-° 04 
2.2e-° 06 
4.85e-° 05 
Biomass (t) (CV) 
192,801(0.57) 
7207(0.85) 
200,008(0.56) 
No of trawls 1 (pos) 
38(34) 
10(2) 
48(36) 
No of trawls used for biomass (positive) 
17(14) 
5(2) 
22(16) 
Survey area (km 2 ) (% of entire survey area) 
40,043(19) 
166,333(81) 
206,377(100) 
Bootstrap results 
Biomass (t) (CV) 
193,946(0.53) 
7406(0.82) 
201,360(0.51) 
Mean square error (MSE) 1/2 
102,174 
6094 
102,378 
Bias-corrected 
Confidence interval (t) 
191,656 
7009 
198,656 
44,286-421,321 
March 2004 
Mean density(kg/m 3 ) 
2.6e-° 05 
4 6 e -° 08 
5.2e-° 06 
Biomass (t) (CV) 
21,243(0.83) 
155(0.7) 
21,398(0.82) 
Recruits (t)( CV ) 
21,030(0.83) 
69(1.0) 
21,099(0.83) 
No of trawls (pos) 
25(7) 
34(2) 
59(9) 
Survey area (km 2 ) (%) 
40,043(19) 
166,334(81) 
206,377(100) 
Bootstrap results 
Biomass (t) (CV) 
22,494(0.81) 
155(0.69) 
22,650(0.8) 
MSE 1/2 
18,260 
106 
18260 
Bias-corrected 
Confidence interval (t) 
19,992 
155 
20,147 
0-63,017 
Recruits (t)(CV) 
21,629(0.81) 
69(1.02) 
21,698(0.81) 
MSE 1/2 
17,576 
70 
17,578 
Bias-corrected 
Confidence interval (t) 
20,432 
69 
20,501 
4749-45,808 
July 2004 
Mean density (kg/m 3 ) 
9.0e -005 
2.3e-° 06 
2 ie-°° 5 
Biomass (t) (CV) 
72,206(0.405) 
6989(0.992) 
79,194(0.379) 
No of trawls 1 (pos) 
20(16) 
38(11) 
58(27) 
No of trawls used for biomass (pos) 
17(15) 
30(14) 
47(19) 
Survey area (km 2 ) (%) 
40,043(21) 
150,932(79) 
190,975(100) 
Bootstrap results 
Biomasst t) (CV) 
73,186(0.41) 
7299(0.95) 
80,485(0.38) 
MSE 1/2 
29,723 
6928 
30,605 
Bias-corrected 
Confidence interval (t) 
71,226 
6678 
77,903 
30,474-146,176 
March 2005 
Mean density (kg/m 3 ) 
3.7e-° 05 
2.3e- 007 
7.9e~ 006 
Biomass (t)(CV) 
29,488(0.69) 
700(0.57) 
30,188(0.68) 
Recruits (t) (CV) 
55(1.0) 
0(0) 
54.80(1.0) 
No of trawls (pos) 
15(11) 
34(9) 
49(20) 
Survey area (km 2 ) (%) 
40,043(21) 
150,932(79) 
190,976(100) 
Bootstrap results 
Biomass (t)(CV) 
29,573(0.73) 
705(0.57) 
30,278(0.72) 
MSE 1/2 
21,713 
402 
21,714 
Bias-corrected 
Confidence interval (t) 
29,403 
695 
30,098 
1800-86,035 
Recruits (t) (CV) 
56.6(0.98) 
0(0) 
57(0.98) 
MSE 1/2 
56 
0 
56 
Bias-corrected 
Confidence interval (t) 
53 
0 
53 
70-1640 
1 During the July 2003 cruise, data from 22 out of 48 trawls were used for biomass computation. The total 48 trawls included 38 (34 with sardine) 
in stratum 1 and 10 (2 with sardine) in stratum 2. During the July 2004 cruise, only data from the first 47 trawls out of 58 trawls were used. The 
total 58 trawls included 20 trawls (16 with sardine) in stratum 1 and 38 trawls (11 with sardine) in stratum 2. 
