SC/65a/SH30

THIS PAPER CAN BE CITED ONLY IN THE CONTEXT OF THE IWC SC MEETINGS

Mixing rates of humpback whales of Stocks D, E and F in the
Antarctic feeding grounds based on mitochondrial DNA
analyses
Luis A. Pastene1, Toshihide Kitakado2, Mutsuo Goto1 and Naohisa Kanda1
1

The Institute of Cetacean Research, 4-5 Toyomi-cho, Chuo-ku, Tokyo 104-0055, JapanTokyo University of Marine Science and Technology, Konan 4-5-7, Minato-ku, Tokyo 108-0075, Japan

2

ABSTRACT
Genetic samples from 575 humpback whales obtained in the Antarctic during surveys of the
JARPA/JARPA II and IDCR/SOWER, and from 1,057 whales from low latitude localities of theSouth Pacific and eastern Indian Ocean were analyzed to describe the distribution and mixing ofbreeding stocks in the Antarctic feeding grounds. Genetic samples from breeding grounds wereobtained mainly by biopsy sampling but also from sloughed skin and beachcast whales: Western
Australia (WA, n= 167, 1990-2002; n=185, 2007), Eastern Australia (Eden, Tasmania) (EA, n= 104),
New Caledonia (NC, n= 243), Tonga (TG, n= 240), Cook Islands (CI, n= 56) and French Polynesia(FP, n= 62). In the Antarctic feeding grounds, samples were obtained only by biopsy sampling: Areas
IIIE (n= 106), IV (n= 231), V (n= 171) and VI (n= 67). Genetic samples of both data sets were
examined for approximately the first half of the mtDNA control region. Duplicated samples were
excluded from the analysis. In the case of mother/calf pairs only one sequence was used. Sequencesfrom both data sets were aligned to produce a single data set comprising 137 haplotypes. Two kindsof analyses were conducted: mixing proportion and Fst under two stock structure hypotheses (sixstocks and four stocks). In general results were consistent with the geography. Under the six-stock
hypothesis, the largest proportion in Area IIIE was of the WA stock. However this results was notconsistent with the Fst analysis. A better interpretation of the results in Area IIIE would be possible if
the analysis includes baseline samples from the eastern Indian Ocean. The largest proportion in Areas
IVW and IVE was of the WA stock, and this was consistent with the Fst analysis. The largest
proportion in Area VW was of the EA stock, and this result was consistent with the Fst analysis. The
largest proportion in Area VE was of the NC stock. However this result was not consistent with the
Fst analysis. The stock with the largest proportion in Area VI was the TG stock, and this result wasconsistent with the Fst analysis. None of the Antarctic Areas investigated was represented by whalesof the FP and CI stocks, or just with a limited representation in Area VI (case of the CI stock). This
result was consistent with the Fst analysis.

KEYWORDS: ANTARCTIC, FEEDING GROUNDS, BREEDING GROUNDS, GENETICS,HUMPBACK WHALE
INTRODUCTION
Humpback whales, Megaptera novaeangliae, are found worldwide in all major oceans. Like other
Balaenopterid species, humpback whales migrate between summer feeding grounds in mid- and highlatitudinal waters and winter breeding grounds in tropical or subtropical waters. Animals occur primarily
in coastal and continental shelf waters. Regarding the Southern Hemisphere, Mackintosh (1965) showedthat humpback whales tend to gather into five or six distinct feeding concentrations in the Antarctic
during the austral summer season. These feeding concentrations were denominated as Groups I-V (with aGroup IIa and IIb) corresponding roughly to IWC Management Areas I-VI. The Groups most documented
are Groups IV and V.
More recently the IWC SC described the hypothetical stock structure and migratory corridors forSouthern Hemisphere humpback whales based mainly on information such as Discovery tags, photo-id,1genetics and satellite track (IWC, 2005). There are seven breeding stocks named from A to G. Some ofwhich (B, C, E and F) are further subdivided into sub-stocks. There are genetic evidences that humpback
whales are genetically structured in the Southern Hemisphere and this evidence comes mainly fromgenetic analysis on samples in breeding grounds and migratory corridors (Baker et al., 1998; Olavarria etal., 2007; Schmitt et al., 2012). In the feeding grounds genetic differences have been found among Areas
IIIE, IV, V and VI (Pastene et al., 2006).
In 2007 the IWC SC recommended that genetic data from breeding grounds be compared with genetic
data from their associated feeding grounds in order to determine the levels of stock mixing on feeding
grounds and to assist with allocation of catches. A preliminary analysis was conducted by Pastene et al.
(2011) based on mtDNA control region sequences and samples from Western Australia (Stock D), New
Caledonia (Stock E2), Tonga (Stock E3), Cook Island (Stock F1) and French Polynesia (Stock F2)(breeding grounds), and Antarctic Areas IIIE, IV, V and VI (feeding grounds). Results were discussed atthe 2011 and 2012 IWC SC meetings. In 2012 the IWC SC agreed that genetic data presented in Pastene
et al. (2011) could be used to inform relative proportions of mixing in the feeding grounds. The IWC SC
noted that these data missed samples from Eastern Australia (E1) and recommended that new analyses arecarried out incorporating samples from that locality (IWC, 2013).
The objective of this study therefore was to investigate the pattern of distribution and mixing ofbreeding stocks D, E1, E2, E3, F1 and F2 in the Antarctic feeding grounds of Areas IIIE, IV, V and VI.
This objective is directly related with the recommendations from the IWC SC in 2012. Previous studies
on baleen whales have used ‘baseline’ stock samples to estimate the mixing proportion of stocks in thefeeding grounds or migratory corridors e.g. common minke whales (Pastene et al., 1998).
MATERIALS AND METHODS
Samples
Skin biopsy samples were obtained from free-ranging whales along the sighting surveys of the JARPA
and JARPA II and IDCR/SOWER surveys in Areas IIIE, IV, V and VI, on an opportunistic basis. Biopsy
samples in JARPA were collected using an air gun described in Kasamatsu et al. (1991) and more
recently using a Paxarm system. Biopsy samples in IDCR/SOWER were collected using several methods
including Paxarm system, crossbows and Larsen gun. At the laboratory all biopsy samples were checked
for the possibility of re-sampling (two or more samples taken from a same individual) by comparing the
genotype profiles produced by a set of six microsatellites. When mother/calf pairs were sampled, only thegenetic information of the mother was used for the analysis (nine cases in Area V).
Genetic samples from breeding grounds were obtained mainly by biopsy sampling but also fromsloughed skin and beachcast whales (see details in Olavarria et al., 2007 and Schmitt et al., 2012). At thelaboratory the biopsy samples were checked for the possibility of re-sampling, within each of thesestudies (but not between the two studies).
Samples representing the Eastern Australia stock (E1) were obtained in the localities of Eden andTasmania (Schmitt et al., 2012). Samples representing the Western Australia were available from two
periods, 1990-2002 (Olavarria et al., 2007) and 2007 (Schmitt et al., 2012). Because the possibility of
duplicate samples between the two sampling periods, these two WA samples were treated separately inthe analyses.
Table 1 shows the number of samples used in the present analysis by sampling locality. A total of 1,057
samples were used from the breeding grounds and 575 from the feeding grounds. Figure 1 shows thebreeding ground localities and the geographical distribution of samples in the feeding grounds of Areas
IIIE, IV, V and VI.
Molecular genetic analysis
Extraction of DNA and mtDNA control region sequencing
Details of the genomic DNA extraction and sequencing of samples from breeding and feeding grounds
are given in Olavarria et al. (2007); Schmitt et al. (2012), and Pastene et al. (2006), respectively.

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MtDNA control region sequences from low latitude areas were provided to us through the Data
Availability Group (DAG) under data access Protocol B (courtesy of Dr. C.S. Baker, acting Data
Administrator, on behalf of the South Pacific Whale Research Consortium in case of Stock D, E2, E3, F1
and F2, and Dr. M. Double, Australian Antarctic Division, in the case of Stock D and E1).
All sequences were aligned by eye. The aligned sequences involved a common segment of 329bp of the
mtDNA control region. A total of 137 unique sequences (haplotypes) were determined in the common
data set of 1,632 whales.
Data analysis
Baseline stocks
During the Workshop on the Comprehensive Assessment of Southern Hemisphere humpback whales(IWC, 2006), animals from Western Australia were considered as part of a single stock (D). Regarding to
Stocks E and F the Workshop listed a total of six stock structure hypotheses and assigned them different
ranks of plausibility (Figure 2). In the present study we did not attempt to carry out additional analyses on
stock structure on breeding grounds samples. Rather ‘baseline’ breeding ground samples in our analyses
were defined according to some of those hypotheses.
Samples from Western Australia were considered a baseline sample for Stock D. Baseline samples for
Stocks E and F were defined according to the specifications of Hypotheses 1 (medium plausibility) and 3(high plausibility) in Figure 2, (IWC, 2006), adapted to the availability of samples:
Hypothesis 1 (medium): Eastern Australia (E1), New Caledonia (E2), Tonga (E3), Cook Islands (F1) and
French Polynesia (F2) are separate stocks.
Hypothesis 3 (high): Eastern Australia+New Caledonia, Tonga+Cook Island and French Polynesia areseparated stocks
In the feeding grounds, samples were grouped a) by Areas, and b) by Sectors (e.g. IIIE, IVW, IVE, VW,
VE, VI).
Statistical analyses
Two kinds of analyses were conducted.
Fst analysis
The first analysis involved the estimation of Fst between the baseline stocks and samples of humpback
whales in Areas IIIE, IV, V and VI, according to the two stock structure hypotheses and for both, Area
and Sector in the Antarctic. Fst values were estimated using the AMOVA (Excoffier et al., 1992). The
significance of the Fst values was estimated using 10,000 random permutations of the data matrix.
Mixing proportion analysis
The second analysis involved the estimation of mixing proportion of the baseline stocks in the samples of
humpback whales in Areas IIIE, IV, V and VI, according to the two stock structure hypotheses and forboth Area and Sector in the Antarctic. For this aim the method so-called "conditional likelihood method
given the observed haplotype frequencies of the baseline populations" was used. The SE is slightly
underestimated because the method did not take into account the estimation uncertainty for baseline
haplotype frequencies, but the extent of underestimation should not be serious.
RESULTSFst analysis
Results for the comparisons involving WA ‘old’ and WA ‘new’ were very similar. Results are shown
only for the latter.
Analysis by Antarctic Areas
Table 2A shows the estimates of Fst under Hypothesis 1, by Antarctic Areas. Larger and significant Fst
values were found in the comparison between WA and Areas IIIE, V and VI. A smaller and nonsignificant Fst value was found in the comparison WA and Area IV. EA whales were significantly3different from all Antarctic Areas although the Fst in the comparison with Area V was smaller. NC
whales were significant different from all Antarctic Areas except Area VI. A same pattern was observed
for TG whales. Whales from CI and FP were significantly different from all Antarctic Areas. The Fst
values of the comparisons involving FP whales were particularly large.
Table 2B shows the estimates of Fst under Hypothesis 3, by Antarctic Area. For the case of EA+NC
significant differences were found in the comparisons with Areas IIIE, IV and V (although the Fst value
in the comparison with V was smaller). No significant difference was found in the comparison with Area
VI. A similar pattern was observed in the comparisons for TG+CI. In this case the comparison with Area
V showed a larger Fst value.
Analysis by Antarctic Sectors
Table 3A shows the estimates of Fst under Hypothesis 1, by Antarctic Sector. The pattern found under
this hypothesis was similar to that based on Areas (Table 2A). New information is that EA whales weresignificantly different from Area VE, however, no significant differences were observed in thecomparison with Area VW.
Table 3B shows the estimates of Fst under Hypothesis 3, by Antarctic Sector. The pattern found under
this hypothesis was similar to that based on Areas (Table 2B).
Mixing proportion analysis
Results for the comparisons involving WA ‘old’ and WA ‘new’ were very similar. Results are shown
only for the latter.
Analyses by Antarctic Areas
Table 4A shows the results of mixing proportion of stocks in the feeding grounds under Hypothesis 1, by
Antarctic Area. The largest representation in Area IIIE is from WA stock (0.7112); in Area IV from WA
stock (0.8351). The largest representation in Area V is from the EA (0.5011) and NC (0.4584) stocks. The
largest representation in Area VI is from TG (0.4331) and NC (0.3711) stocks.
Table 4B shows the results of mixing proportion of stocks in the feeding grounds under Hypothesis 3,
by Antarctic Area. In this case the largest representation in Area V is from the EA+NC stock (0.9565) andthe largest representation in Area VI is from the TG+CI stock (0.7050).
Analyses by Antarctic Sectors
Tables 5A shows the results of mixing proportion of stocks in the feeding grounds under Hypothesis 1, by
Antarctic Sector. The largest representation in Areas IVW is from the WA Stock (0.8450); in Area IVEfrom the WA stock (0.7590). The largest representation in Area VW is from the EA (0.6465) stock. The
largest representation in Area VE is from the NC stock (0.8392).
Tables 5B shows the results of mixing proportion of stocks in the feeding grounds under Hypothesis 3,
by Antarctic Sector. In this case the largest representation in Area VW is from the EA+NC stock (0.9412),
and the same stock is the best represented in Area VE (1.0000).
DISCUSSION
The present study on southern humpback whale stock structure was one of the few cases among baleen
whales in which genetic data were available from both low latitude breeding areas and high latitude
feeding areas. The attainment of this comprehensive data set was possible thanks to several whale
research projects being conducted on humpback whale in Australia, Oceania and the Antarctic, and accessto those data was possible thanks to the IWC SC data access protocol.
Following recommendations from the IWC SC we conducted a mtDNA analysis on humpback whale
samples from low and high latitudes of Breeding Stocks D, E and F to investigate distribution and mixing
proportion of those stocks in the feeding grounds. The data set and analyses were similar to those used by(Pastene et al., 2011). This new study incorporated samples for Eastern Australia (E1), which were notavailable in the 2011 study.

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We summarized here the main results of mixing proportion under the two hypotheses (baseline) used,
noting the cases of agreement or disagreement with the Fst analysis.
Hypothesis 1
1) The largest proportion in Area IIIE was of the WA stock. However the Fst analysis indicatedsignificant differences between WA and Area IIIE. A better interpretation of the results in Area
IIIE would be possible if the analysis includes baseline samples from the eastern Indian Ocean,which were not available for this study.
2) The largest proportion in Areas IVW and IVE was of the WA stock, and this was consistent with
the Fst analysis.
3) The largest proportion in Area VW was of the EA stock, and this result was consistent with the
Fst analysis.
4) The largest proportion in Area VE was of the NC stock, followed by the EA stock. However thisresult was not consistent with the Fst analysis, which suggested significant differences between
NC and Area VE.
5) The stock with the largest proportion in Area VI was the TG stock, and this result was consistent
with the Fst analysis.
6) None of the Antarctic Areas was represented by whales of the FP and CI stocks, or just with alimited representation in Area VI (case of the CI stock). This result was consistent with the Fst
analysis.
Hypothesis 3
1) The largest proportion in Areas VW and VE was of the EA+NC stock. However this result was
not consistent with the Fst analysis. Significant differences were found in the Fst analysis
between EA+NC and Areas VW and VE.
2) The largest proportion in Area VI was of the TG+CI stock and this result was consistent with the
Fst analysis.
In general there was a good correlation between geographical areas and genetic signal with whales from
Western Australia represented mainly in Area IV, whales from Eastern Australia represented mainly in
Area VW, whales from New Caledonia represented mainly in Area VE and VI, whales from Tonga
represented mainly in Area VI and whales from Cook Island and French Polynesia not represented or
poorly represented in the research area investigated.
Results of the mixing proportion estimated by genetic markers in this study were consistent withprevious studies on distribution and mixing based on non-genetic markers. Omura (1953) examined the
distribution of humpback whale in the feeding grounds of Areas IV and V based on catch data. He
suggested that two populations occur in these Areas with a boundary around 130°-142°E. He did notdiscard the possibility of intermingling between these two populations in the feeding ground. He also
examined the pattern of distribution by month and suggested that for the month where more data wereavailable (November-March) the boundary between these two populations changed from 120°-130°E in
November to eastside of 140°E in December and to 120°-140°E in January.
Dawbin (1966) summarize the distribution and seasonal migratory movement of humpback whales fromGroups IV and V, as demonstrated by mark-recapture data (Discovery-type marks). Whales from GroupIV move mainly between Antarctic Area IV and Western Australia while whales from Group V move
between Antarctic Area V and Eastern Australia and along the coast of New Zealand and southwest
Pacific islands. Interchange of a few individuals between Groups IV and V was reported. Dawbin (1966)
also reported that the boundary of Groups IV and V in the Antarctic do not correspond to the actual
boundary between Areas IV and V and that some whales marked in Area VI were recovered in eastern
Australia.
Previous genetic analyses in the feeding grounds have shown different pattern of distribution by sex
with males being more mobile than females (Pastene et al., 2006). Future analyses of distribution andmixing in the feeding grounds similar to those conducted in this study should be conducted separately formales and females.

5Distribution of stocks in the feeding grounds could change yearly according to oceanographic
conditions which in turn determine the distribution of krill. Analyses on a year basis (or groups of years)
in the Antarctic samples would be useful. This could be possible for Areas where sample sizes are larger(e.g. Area IV). Finally the collection of additional genetic samples from Area VI and IW arerecommended to further understand the pattern of distribution and mixing of Stock F (Cook Island andFrench Polynesia).
ACKNOWLEDGEMENTS
We thank all the researchers and crew members of JARPA/JARPA II and IDCR/SOWER surveys
involved in the sampling of the Antarctic biopsy samples used in this study. The response to the data
request (for Western Australia, New Caledonia, Tonga, Cook Islands and French Polynesia) andsubsequent data transfer were communicated by C.S. Baker, acting Data Administrator, on behalf of theSouth Pacific Whale Research Consortium (SPWRC). The response to the data request (for Western andEastern Australia), and subsequent data transfer were communicated by M. Double, Australia Antarctic
Division. We thank researchers and other personnel involved in biopsy sampling and analyses of samples
from those localities. Data provided by the Australian Antarctic Division and SPWRC were all based
upon non-lethal samples collected under an animal ethics protocols approved by a registered ethic
committee. These data were provided by the Australian Antarctic Division and SPWRC for the purposeof advancing the ‘Comprehensive Assessment of southern hemisphere humpback whales’ rather than fora collaborative investigation. Data access was possible under the IWC SC Data Access Procedure B.
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Baker, CS., Florez-Gonzalez, L., Abernethy, B., Rosenbaum, HC, Slade, RW, Capella, J. and Bannister,JL. 1998. Mitochondrial DNA variation and maternal gene flow among humpback whales of theSouthern Hemisphere. Mar. Mamm. Sci. 14:721-737.
Dawbin, W.H. 1966. The seasonal migratory cycle of humpback whales. In: Whales, dolphins andporpoises, Norris, K.S. (ed.). University of California Press, Berkerley. pp. 145-171.
Excoffier, L., Smouse, P.E. and Quattro, J.M. 1992. Analysis of molecular variance inferred from metricdistances among DNA haplotypes: application to human mitochondrial DNA restriction data.
Genetics 131:479-491.
International Whaling Commision. 2005. Report of the Sub-Committee on Other Southern Hemisphere
Whale Stocks. J. Cetacean Res. Manage. (Suppl) 7:235-244.
International Whaling Commission 2006. Report of the Workshop on the Comprehensive Assessment ofSouthern Humpback Whales. Paper SC/58/Rep 5 presented to the IWC Scientific Committee, June
2006 (unpublished). 77pp.
International Whaling Commission. 2013. Report of the Scientific Committee. J. Cetacean Res. Manage.
(Suppl) 14:
Kasamatsu, F., Iwata, S. and Nishiwaki, S. 1991. Development of biopsy skin sampling system for fastswimming whales in pelagic waters. Rep int Whal Commn 41:555-557.
Mackintosh, N.A. (1965). The stocks of whales. Fishing News (Books) Ltd., London. 232pp.
Olavarria, C., Baker, C.S., Garrigue, C., Poole, M., Hauser, N., Caballero, S., Flores-Gonzalez, L.,
Brasseur, M., Bannister, J., Capella, J., Clapham, P., Dodemont, R., Donoghue, M., Jenner C.,
Jenner, M.N., Moro, D., Oremus, M., Paton, D, Rosenbaum, H. and Russell, K. 2007. Population
structure of South Pacific humpback whales and the origin of the eastern Polynesian breeding
grounds. Mar Ecol Prog Ser 330:257-268.
Omura, H. 1953. Biological study on humpback whales in the Antarctic whaling areas IV and V. Sci Rep
Whales Res Inst Tokyo 8:81-102.
Pastene, L.A., Goto, M., Kishino, H. 1998. An estimate of the mixing proportion of ‘J’ and ‘O’ stocks
minke whales in sub-area 11 based on mitochondrial DNA haplotype data. Rep. Int. Whal. Commn
48:471-474.
Pastene, L.A., Goto, M., Nishiwaki, S., Yoshida, H. and Kanda, N. 2006. Genetic characteristics andpopulation structure of humpback whales in the Antarctic feeding ground as revealed by
mitochondrial DNA control region seqwuencing and microsatellite analyses. Paper SC/D06/J31
presented to the JARPA Review Workshop, December 2006 (unpublished). 14pp.

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Pastene, L.A., Goto, M., Kanda, N., Kitakado, T. and Palsboll, P.J. 2011. Preliminary mitochondrial DNA
analysis of low and high latitude humpback whales of Stocks D, E and F. Paper SC/63/SH9
presented to the IWC Scientific Committee, June 2011 (unpublished). 16pp.
Schmitt, N.T., Double, M.C., Baker, C.S., Steel, D., Jenner, K.C.S., Jenner, M-N.M., Paton, D., Gales, R.,
Jarman, S.N., Gales, N., Marthick, J.R., Polanowski, A.M. and Peakall, R. 2012. Low levels ofgenetic differentiation characterize Australian humpback whale (Megaptera novaeangliae)
populations. Paper SC/64/SH15 presented to the IWC Scientific Committee, June 2012
(unpublished). 47pp.

Table 1. Number of samples of the humpback whale used in the present mtDNA analysis.

WA
‘old’
167

WA
‘new’
185

EA

Breeding grounds
NC
TG
CI

104

243

240

56

FP

Total

IIIE

Feeding grounds
IV
V
VI

Total

62

1,057

106

231

575

171

67

Table 2A. Fst values between breeding stocks (under Hypothesis 1) and feeding grounds samples
grouped by Area (significant p values are shown in bold).
WA new(n=185)0.0127EA(n=104)0.0186NC(n=243)0.0213TG(n=240)0.0245CI(n=56)
0.0379FP(n=62)
0.0452IIIE(n=106)IV
0.00010.01210.01350.01280.01950.0336(n= 231)V
0.01750.00440.00580.01130.02790.0422(n=171)VI
0.00030.00100.01090.01160.01070.0320(n= 67)
WA= Western Australia; EA= Eastern Australia; NC= New Caledonia; TG= Tonga; CI= Cook Islands;
FP= French Polynesia
Table 2B. Fst values between breeding stocks (under Hypothesis 3) and feeding grounds samples
grouped by Area (significant p values are shown in bold).
WA new

EA+NC
TG+CI
FP
(n=347)(296)
IIIE
0.01270.01790.02450.0452IV
0.00010.01060.01150.0336
V
0.01750.00280.01190.0422VI
0.00110.00010.01090.0320
WA= Western Australia; EA= Eastern Australia; NC= New Caledonia; TG= Tonga; CI= Cook Islands;
FP= French Polynesia

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Table 3A. Fst values between breeding stocks (under Hypothesis 1) and feeding grounds samples
grouped by Sector (significant p values are shown in bold).
WA new
EA
NC
TG
CI
FP
IIIE
0.01270.01860.02130.02450.03790.0452IVW
0.00150.01320.01580.01560.02320.0340(n=145)IVE-0.0015
0.01120.01050.00880.01450.0346(n=86)
VW
0.00130.01860.00930.01400.02970.0413(n=110)VE
0.02220.01680.00620.01320.03240.0519(n= 61)VI
0.00030.00100.01090.01160.01070.0320
WA= Western Australia; EA= Eastern Australia; NC= New Caledonia; TG= Tonga; CI= Cook Islands;
FP= French Polynesia

Table 3B. Fst values between breeding stocks (under Hypothesis 3) and feeding grounds samples
grouped by Sector (significant p values are shown in bold).
WA new
EA+NC
TG+CI
FP
IIIE
0.01270.01790.02450.0452IVW
0.00150.01250.01450.0340IVE-0.0015
0.00810.00730.0346VW
0.01860.00440.01440.0413VE
0.02220.00670.01420.0519VI
0.00110.00010.01090.0320
WA= Western Australia; EA= Eastern Australia; NC= New Caledonia; TG= Tonga; CI= Cook Islands;
FP= French Polynesia

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9

10

New Caledonia

N=243

N=185
Eastern Australia
N=104

Figure 1: Geographical distribution of humpback whale samples from breeding and feeding grounds
analyzed in this study.

Figure 2. Schematic diagram showing possible models for stock structure in the South Pacific. N=
number of breeding stocks and Rank, l= low, m= medium and h= high (taken from IWC, 2006). Samples
from Eastern Australia (Eden and Tasmania), New Caledonia, Tonga, Cook Islands and French Polynesia(in addition to Western Australia), were available for the present mtDNA study.

11