SC/61/JR4 (additional analysis -SC/J09/JR24)

Additional analyses of temporal trends and factors affecting
PCB levels in baleen whales from the western North Pacific
GENTA YASUNAGA AND YOSHIHIRO FUJISEThe Institute of Cetacean Research, 4-5, Toyomi-cho, Chuo-ku, Tokyo, 104-0055, Japan.
Contact e-mail: yasunaga@cetacean.jp

ABSTRACTThis short paper presents an additional analysis on PCB trend in common minke, Bryde’s and sei whales from thewestern North Pacific in response to some recommendations from the JARPN II review workshop. The review Panelrecommended that future studies on PCB must be carried out on a lipid weight basis. A total of fifteen whales in eachspecies were additionally analyzed for fat contents and this was converted into concentrations in fat wt. basis. Results ofthe statistical analysis on PCB level trends in these baleen whale species were consistent with those originally presented
by Yasunaga and Fujise (2009) (SC/J09/JR24).

INTRODUCTION
The International Whaling Commission’s Scientific Committee (IWC SC) carried out a Workshop to review theprogress made in the research conducted under the Japanese Whale Research Programme under Special Permit in theNorth Pacific-Phase II (JARPN II) in its first six years (2002-2007). The review was carried out by an Independent
Expert Panel (IEP) who examined primary papers related with the research objectives of JARPN II.

One of the objectives of the JARPN II is ‘Monitoring environmental pollutants in cetaceans and the marine ecosystem’
and regarding to this objective three primary papers were presented to the review workshop. Yasunaga and Fujise(2009) examined temporal trends and factors affecting PCB levels in baleen whales (common minke, Bryde’s and seiwhales) and environmental samples in the western North Pacific (SC/J09/JR24). Regarding whales yearly changes of
PCB levels were not observed in these whale species in the period 2002-2007. Results from previous studies had
suggested that PCB levels had been continually decreasing in this oceanic region (1980’s-1990’s). Results from theJARPN II analysis suggested that the level had stabilized since 2002 (Yasunaga and Fujise, 2009).

During the review workshop the IEP recommended that future studies must be carried out on a lipid weight basis (IWC,2009). Thus, an additional analysis was performed on fat content (%) of some whale samples in order to convert wet wt.
base levels into fat wt. base levels. This paper presents the results of the additional analyses.

MATERIALS AND METHODS

The sample size and body length of mature males of the common minke whales (Okhotsk Sea-West Pacific stock),
Bryde’s and sei whales used in this study are shown in Table 1. The samples were sent to the Japan Food ResearchLaboratories (Tokyo, Japan) for analysis of fat content (%) analyses. Analyses were performed according to the publicanalytical method of Japan (Science and Technology Agency, 2004). A detailed description of materials and methods of
the PCB analysis is provided in Yasunaga and Fujise (2009) (SC/J09/JR24).

In this study only mature male whales were used. Males of minke, Bryde's and sei whales were defined as sexuallymature by testis weight (larger side) of more than 290g, 560g and 1,090g, respectively (Bando et al., unpublished data).

As in the previous study, the yearly trend of PCB levels in blubber of whales was examined by a multiple linear
regression analyses (see Yasunaga and Fujise, 2009 for more details of the analytical procedure used).
RESULTS AND DISCUSSION
Table 1 shows the fat content, PCB levels (wet wt. basis and fat wt. basis) in blubbers of common minke, Bryde’s andsei whales and Figure 1 shows the relationships between PCB levels (fat wt. basis) in these whale species and sampling
year. For PCB levels (fat wt. basis) of common minke whales in sub-area 9, blubber thickness, sampling latitude,
sampling year and body length were significantly selected (Table 2) with a rank order of effects of blubber thickness(B:+1.564 ) > latitude (-1.514) > year (-0.576) > body length (+0.468). For Bryde’s whales from sub-areas 8 and 9(Table 3), sei whales from sub-area 9 (Table 4) no factor was significantly selected in the regression equation.

Yearly trend of PCB levels in Bryde’s and sei whales were not observed (Tables 3 and 4). The year would not be
important factor for PCB levels in minke whales from sub-area 9, because the sampling year was selected as third factor(Table 2). The results of the present analysis are consistent with the results of PCB levels based on wet wt. basis
presented by Yasunaga and Fujise (2009) (SC/J09/JR24, 2009).

REFERENCES

International Whaling Commission. 2009. The Report of the Expert Workshop to review the ongoing JARPN II
Programme. Document SC/61/xx presented to this meeting.
Science and Technology Agency. 2004. Standard tables of Food Composition in Japan. 464pp.
Yasunaga, G. and Fujise, Y. 2009. Temporal trends and factors affecting PCB levels in baleen whales andenvironmental samples from the western North Pacific. Paper SC/J09/JR24 presented to the JARPN II
Review Workshop, Tokyo, January 2009 (unpublished). 13pp.

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Table 1. Body length, PCB concentrations (ppm wet basis and fat basis) in blubber of common minke , Bryde's and sei
whales in the western North Pacific in 2002, 2004 and 2006.
speciesYear
sub areabody length
PCB (ppm wet) PCB (ppm fat) Fat content (%)
9ave±sd 7.41 ± 0.040.67 ± 0.09
0.88 ± 0.10
75.7 ± 3.99
common minke whal 2002
ragne ( 7.37 - 7.45 ) ( 0.58 - 0.79 ) ( 0.79 - 1.00 ) ( 71.50 - 80.70 )n44440.30 ± 0.110.46 ± 0.21
65.7 ± 7.12
2004
9ave±sd 7.29 ± 0.08
ragne ( 7.20 - 7.40 ) ( 0.13 - 0.43 ) ( 0.19 - 0.67 ) ( 55.10 - 75.00 )5n555
0.58 ± 0.42
0.91 ± 0.74
66.4 ± 6.32
2006
9ave±sd 7.41 ± 0.20
ragne ( 7.13 - 7.66 ) ( 0.24 - 1.30 ) ( 0.40 - 2.20 ) ( 59.80 - 74.80 )5555
n0.11 ± 0.06
0.19 ± 0.11
61.5 ± 6.93
Bryde's whale
2002
8ave±sd 12.67 ± 0.43
ragne ( 12.07 - 13.11 ) ( 0.05 - 0.21 ) ( 0.07 - 0.36 ) ( 54.50 - 72.00 )5555n0.13 ± 0.58
0.22 ± 0.14
60.1 ± 0.62
2004
8, 9 ave±sd 12.59 ± 0.36
ragne ( 12.06 - 13.01 ) ( 0.28 - 2.70 ) ( 0.32 - 0.75 ) ( 0.54 - 2.30 )5555n
0.07 ± 0.03
0.11 ± 0.04
62.8 ± 11.88
2006
8ave±sd 12.36 ± 0.47
ragne ( 11.90 - 12.88 ) ( 0.04 - 0.11 ) ( 0.06 - 0.15 ) ( 43.10 - 73.70 )555n
50.14 ± 0.18
0.27 ± 0.36
57.9 ± 4.92
Sei whale20029
ave±sd 13.60 ± 0.16
ragne ( 13.42 - 13.86 ) ( 0.03 - 0.47 ) ( 0.05 - 0.91 ) ( 51.60 - 64.80 )n55550.12 ± 0.07
0.21 ± 0.17
59.3 ± 8.57
2004
9ave±sd 13.61 ± 0.04
ragne ( 13.55 - 13.66 ) ( 0.04 - 0.22 ) ( 0.07 - 0.49 ) ( 44.60 - 65.00 )n55550.09 ± 0.06
0.14 ± 0.10
64.6 ± 6.97
2006
9ave±sd 13.84 ± 0.51
ragne ( 13.23 - 14.48 ) ( 0.04 - 0.19 ) ( 0.06 - 0.30 ) ( 53.80 - 72.40 )n55553

Table 2. Results of multiple linear regression analyses with "PCB levels in blubbers ofcommon minke whales from sub-areas 9" as the dependent variable.
a) Model of regression
Model1R
0.936

R20.876

R2'0.769b) Analysis of Variance TableModel
Sum of Squares
Regression
11.386
Residual
1.614
Total
13.000DF6713

Mean Square
1.898
0.231

F value
8.23

P value
0.007c) Variables
ModelConstant
year
date
latitudelongitude
body length
blubber thickness

SE0.128
0.189
0.178
0.352
0.334
0.151
0.273B'T
0.000-3.054-0.682-4.302-0.432
3.094
5.668

P value
1.000
0.018
0.517
0.004
0.679
0.017
0.001

B
3.27E-10-0.576-0.122-1.514-0.1440.468
1.546-0.576-0.122-0.1514-0.1440.468
1.546

Table 3. Results of multiple linear regression analyses with "PCB levels in blubbers ofBryde's whales from sub-areas 8 and 9" as the dependent variable.
a) Model of regression
Model
1R
0.722

R20.522

R2'0.163b) Analysis of Variance TableModel
Sum of SquaresRegression7.305
Residual
6.695
Total
14.000DF6814

Mean Square
1.218
0.837

F value
1.455

P value
0.304c) Variables
Model
Constant
year
date
latitudelongitude
body length
blubber thickness

SE
0.236
0.317
1.311
0.977
1.192
0.264
0.290

B'T
0.000
-1.8010.576-1.0720.891
1.073-0.291

P value
1.000
0.109
0.580
0.315
0.399
0.315
0.778

B-2.55E-10-0.5710.755-1.0471.062
0.283-0.008-0.5710.755-1.0471.062
0.283-0.084

Table 4. Results of multiple linear regression analyses with "PCB levels in blubbers ofsei whales from sub-areas 9" as the dependent variable.
a) Model of regression
Model
1R
0.659

R20.434

R2'0.010b) Analysis of Variance TableModel
Sum of Squares
Regression
6.082
Residual
7.918
Total
14.000DF
6814

Mean Square
1.014
0.990

F value
1.024

P value
0.473c) Variables
Model
Constant
year
date
latitudelongitude
body length
blubber thickness

SE
0.257
0.511
0.719
0.898
0.389
0.378
0.506

B'T
0.000
-1.7011.512-1.4190.291-0.398-0.044

P value
1.000
0.127
0.169
0.194
0.779
0.701
0.966

B
-1.68E-10-0.8701.087-1.2730.113-0.150-2.22E-02-0.8701.087-1.2730.113-0.150-0.0224b) Bryde's whale (mature male, sub areas 8, 9)a) Common minke whale (mature male, O stock, sub area 9)
PCB conc. in blubber (ppm fat)

PCB conc. in blubber (ppm fat)

5.0
4.0
3.0
2.0
1.0
0.02001

2002

2003

2004

2005

2006

1.0
0.8
0.6
0.4
0.20.02001

2007

2002

2003

2004

2005

2006

2007

yearyear

PCB conc. in blubber (ppm fat)c) Sei whale (mature male, sub area 9)
1.0
0.8
0.6
0.4
0.2
0.0
2001

2002

2003

2004

2005

2006

2007

year

Figure 1. PCB levels (ppm fat wt.) in blubber of a) common minke, b) Bryde’s and c) sei whales from sub-areas 8 and 9
in 2002, 2004 and 2006.

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