Report of the Review Meeting of the Japanese Whale
Research Program under Special Permit in the Antarctic(JARPA) called by the Government of Japan,
Tokyo, 18-20 January 20051
The JARPA Review Meeting called by the Government of Japan was held at the Institute of Cetacean
Research, Tokyo, on 18-20 January 2005. The Terms of Reference of the meeting were to review
available data and research results in light of the objectives of JARPA and to identify future researchneeds on the basis of this review. A total of 40 scientists from eight countries participated in themeeting. The list of participants is given in Annex A.
Masayuki Komatsu, Director for Research and Environmental Protection, Fishery Agency,
Government of Japan and Japan’s Alternate Commissioner to the IWC, welcomed the participants. He
noted that the IWC Scientific Committee will undertake a review of JARPA after the completion of the
16-year program. During the 2004 IWC Scientific Committee meeting Japan proposed to host ameeting reviewing JARPA results limited to the first 15 years of JARPA ,so that relevant
recommendations and comments from such a meeting could be taken into account in the JARPA II
proposal. Komatsu briefly outlined the JARPA research objectives and noted that a large amount ofvaluable data and samples had been accumulated and that the Scientific Committee had positively
evaluated JARPA in the Committee’s mid-term review conducted in 1997. He hoped that the meeting
would produce fruitful discussions in order to make the best use of JARPA information for
management of whale resources in the Antarctic.

1.

ELECTION OF CHAIR

Kato was elected Chairman.

2. APPOINTMENT OF RAPPORTEUR
Pastene agreed to act as rapporteur assisted by Mori, Murase and Kanda.

3. ADOPTION OF THE AGENDA
The meeting adopted the agenda shown in Annex B.

4. REVIEW OF DOCUMENTS
The documents available to the meeting are listed in Annex C and are available on the following web
site: www.icrwhale.org/eng-index.htm

5. REVIEW OF JARPA RESEARCH OBJECTIVES
JR1 reviews JARPA research objectives and the work on the JARPA tasks recommended by the IWC
Scientific Committee in 1997 (IWC, 1998). The Government of Japan has been conducting JARPA
since the 1987/88 austral summer season under Article VIII of the International Convention forRegulation of Whaling, as a long-term research project. The last survey of JARPA will be completed in
the 2004/05 season. The original objectives for the research had been:(1) estimation of the biological parameters to improve the stock management of the Southern
Hemisphere minke whale;(2) elucidation of the role of whales in the Antarctic marine ecosystem.
Subsequently, as part of the natural evolution of the program and in response to developing
requirements, two further objectives had been added:1This report is available in the following website: www.icrwhale.org/eng-index.htm

1(3) elucidation of the effect of environmental changes on cetaceans;(4) elucidation of the stock structure of Southern Hemisphere minke whales to improve stock
management.
The tasks recommended by the IWC Scientific Committee in 1997 were the following:(1) Abundance estimates(a) Development of method to correct bias of abundance estimate.
(2) Stock structure(a) Stock definition.
(b) Statistical analysis of mtDNA data considering inclusion of school size as a covariate.
(c) Pilot study on nuclear DNA on JARPA minke samples.
(d) Effort to obtain biological materials for genetic analysis from low latitude areas of theSouthern Hemisphere.
(e) External morphology/morphometry analysis.
(f) Examination of possible stock boundaries (geographical and temporal) in Areas IV and V.
(3) Biological parameters(a) Segregation study(b) Recalculation of biological parameters by biological stocks(4) Marine ecosystem and environmental change(a) Meso-scale survey plan
JR1 concluded that reasonable progress had been made on these tasks.
The meeting noted that the research objectives at the start of JARPA had been designed to meet
management needs at that particular time. Although these needs have changed, the meeting agreed that
JARPA work remains relevant for providing data important for management, for example for
estimating MSYR now compared to natural mortality M in the past, because the two are interrelated in
the interpretation of catch-at-age data.

6.

REVIEW OF JARPA SURVEY PROCEDURE AND DATA COLLECTED

6.1 Survey procedure
JR2 presents a review of the general methodology and survey procedures of JARPA. Following twoyear feasibility surveys in the austral summer seasons of 1987/88 and 1988/89, full JARPA surveys
have been conducted annually since the 1989/90 season. JARPA is designed to repeat surveys in the
Antarctic Areas IV and V in alternate years (Fig. 1). Although the whole research period was from theend of November to March, the primary research in Areas IV and V was concentrated in January andFebruary. Two or three sighting/sampling vessels (SSVs) conducted sighting and sampling surveys on apredetermined track-line with parallel sub-track lines. A dedicated sighting vessel (SV) was introduced
from the 1991/92 season and the SSVs followed the SV to avoid any influence of sampling activity on
the sighting survey. One or two Antarctic minke whales were sampled randomly from each primarysighting of a school by the SSVs. A total of 300 (with 10% allowance) Antarctic minke whales weretaken from Area IV or V in alternate seasons. From the 1995/96 season onwards, the survey area was
expanded into parts of Areas III and VI and 100 (with 10% allowance) further samples were added. A
summary of research procedures and results for each survey cruise were also provided in JR2.
A table showing an outline of the JARPA program was presented to the meeting. This included
summary information for each survey conducted from 1987/88 to 2003/04. Several suggestions toimprove the table were offered by the meeting. An improved version of the table is shown in Annex D.
It was suggested that three pieces of information, in addition to those presented in JR2, could be helpful
for the interpretation of abundance estimates from JARPA data: specification of the relationships
between searching effort (number and positioning of dedicated observers) on SV and SSVs in JARPA
in comparison to those in IDCR/SOWER surveys; more information on changes in the extent of2‘skipping’ in the JARPA track design for surveys over time and provision of information on observer
experience.
6.2 Data collected
A list of the data sets produced by JARPA was presented to the meeting. Several suggestions toimprove the list were offered by the meeting. An improved version of the list is shown in Annex E.

7.

REVIEW OF RESULTS IN THE LIGHT OF JARPA OBJECTIVES

7.1 Stock structure of Antarctic minke whale
7.1.1
Genetic analyses
JR3 presented the results of mtDNA RFLP (six restriction enzymes) and microsatellite (six loci)analyses for identifying stock structure from the samples of Antarctic minke whales obtained during
JARPA surveys from the 1987/88 to the 2003/04 austral summer seasons in Areas IIIE, IV, V and VIW.
The mtDNA and microsatellite analyses involved a total of 5,838 and 5,808 samples respectively.
Statistical analyses were based upon the geographical strata defined for the JARPA surveys. Bothanalyses showed substantial spatial heterogeneity in some of the comparisons between whales fromdifferent geographic strata. The general pattern of spatial variation was concordant among the two
approaches: a) no evidence for differences between the whales in Area IIIE and in Areas IVW and IVE,b) no evidence of differences between the whales in Area VIW and in Area VE, and c) evidence fordifferentiation between the whales in Areas IIIE, IVW, IVE and in Areas VE, VIW. These results were
therefore consistent with the hypothesis of two stocks that were possibly related to the proposed
breeding areas in the eastern Indian and the western South Pacific Ocean. A fine-scale mtDNA analysis
suggested a ‘soft’ boundary at 165°E.
The meeting considered that JR3 is an important paper given that elucidation of the stock structure of
the Antarctic minke whale is one of the objectives of JARPA.
Participants commented that the results presented in JR3 strongly rejected the scenario of a single stockin the JARPA research area. Questions were raised whether results presented also gave evidence ofmore than two stocks in this area. Pastene responded that the results presented are most readily
explained by the two-stock scenario. In this context Pastene briefly presented For Info 5 (Kasamatsu etal., 1995). This paper used sighting data derived from the Japanese sighting surveys in low latitudes
during 1976 to 1987 to attempt to locate breeding areas of Antarctic minke whales. The spatial
distribution in tropical and subtropical waters during the latter half of the conception period suggested
two breeding grounds in the eastern and western South Pacific and two in the eastern and western
Indian Ocean. Pastene suggested that the two stocks proposed in the JARPA research area could be
related to these breeding grounds suggested in the eastern Indian and western South Pacific Oceans.
Butterworth pointed out that from the geographical point of view there is the possibility that animals
from the western Indian Ocean breeding ground could contribute to the minke whales found in Area
IIIE. If so, a scenario with three stocks in the JARPA research area is possible.
Hatanaka believed that the two stocks hypothesis is more consistent with the results and asked if there
was a basis for the multiple stocks hypothesis. Walloe responded that although the two-stock
hypothesis was the simplest and most likely explanation, it was still premature to rule out thepossibility of more than two stocks.
Ohsumi noted that the sighting effort in the study by Kasamatsu et al. (1995) was very limited. He
presented information on the distribution of fetus size in relation to the migration distance frombreeding areas. Females with small (≤6cm) and large (≥280cm) fetuses are those which are close to
their breeding areas. Based on such information he suggested that there is the possibility of a single
breeding ground for minke whales in the central Indian Ocean; these then migrate to feeding areas from
Area IIIE to approximately 150-160°E, thus supporting the results and interpretation of the genetic data.
Hester asked about the actual age difference between a fetus of 6cm and one of 280cm. Ohsumi
responded that the difference might be about 9 and a half months, but depended on their growth rate.
The Chair added that based on a period of 70-75 days to reach 15cm, a fetus of 6cm would be 40 daysold.

3

Butterworth pointed out that the difference in sampling time in Areas IIIE and VIW should beconsidered in future analyses because small fetuses might have been preferentially obtained fromfemales collected early in the season. Ohsumi agreed to consider that factor in future analyses.
The Chair advised that a Russian scientist had found females with mummified fetuses in the Indian
Ocean, suggesting that this was one of the breeding areas for Antarctic minke whales. Ishikawa
commented that there were a few reports of fetus mummification in the JARPA samples, but noobvious linkages to breeding areas have been found thus far.
The meeting noted that the suggested boundary at 165°E was based on mtDNA only, and that the ‘soft’boundary concept suggested in JR3 could alternatively be interpreted as two stocks mixing near that
longitude. Hatanaka mentioned that the analysis of biological parameters also supported a boundary at
165°E.
In terms of setting a boundary, Butterworth suggested estimation of mixing proportions around thisboundary, treating the westernmost and the easternmost areas in JARPA as ‘pure’ stocks. Pastene
agreed to conduct such an analysis in future.
Walloe noted that the number of microsatellite loci used (6) in the analysis was smaller than that used
for the North Pacific minke whale (17).
Butterworth asked for an explanation on why females showed more structure than males in someanalyses. Pastene responded that one possible reason was sex difference in site fidelity.
7.1.2
Non-genetic analyses
JR3 also presented the results of an analysis of the stock structure of the Antarctic minke whales thatutilized the following non-genetic methods: mean body length of physically matured whales (n=2,323),
morphometrics (5,549) and distribution of the parasite Anisakis simplex (n=6,338). Samples obtained
during JARPA surveys from the 1987/88 to the 2003/04 austral summer seasons in Areas IIIE, IV, V
and VIW were used in the analyses. Grouping of samples in these analyses was the same as for the
genetics analyses. Similar to the genetic approaches, the results supported the hypothesis of two stocks
in the JARPA research area.
The meetingnoted that the pattern of stock structure found by non-genetic approaches was similar tothat found by the genetic approaches. There was a suggestion that the statistical analysis used for
examining morphometric data could be further elaborated. Genetic population structure in Anisakis
simplex has been studied in other areas. The question was therefore raised of whether any such studies
are included in JARPA. Pastene responded that no such study has been conducted at the ICR. Otani
added that a genetic research plan for Anisakis collected by JARPA was now being discussed. He
further introduced a phylogenetic study of Anisakis conducted in the North Pacific.
7.1.3
Summary of results
The meeting noted that the part of the JARPA program addressing issues of stock structure had been
designed in accordance with a number of studies that had concluded that the most effective way toaddress questions on stock identity is to consider results from several techniques. The meeting agreed
that JARPA has obtained useful results from a number of genetic and non-genetic analytical methods
applied to investigate the stock structure of the Antarctic minke whale, and that the aim of the JARPA
design to sample randomly had aided in obtaining representative samples from the research areas
covered. With regard to the tasks that needed to be pursued to facilitate interpretations of stock
structure from JARPA data that were recommended by the IWC Scientific Committee in 1997 (seesection 5), the meeting agreed that good progress had been achieved on all of these tasks. However, themeeting also stressed the importance of examination of samples from low latitudes for obtaining aclearer genetic delimitation of breeding stocks.
The results from the different techniques provide strong evidence to reject the hypothesis of a single
stock in the research area. The most parsimonious explanation of the results is that there are two stocks
present in the research area: an eastern Indian (I) and a western South Pacific (P) stock. These stocks
would mix across a soft boundary, which would probably best be placed near 165°E. Further analyses
could usefully estimate the proportion of I and P animals in an overlap area such as VW using amethod such as that applied in the case of North Pacific minke whales (IWC, 2003). However, the4possibility of more than two stocks cannot as yet be ruled out. For example there could be somepresence of a stock from the western Indian Ocean in the western most part of the research area(following the postulate of Kasamatsu et al. (1995) based on sighting rates in low latitudes of two
breeding stocks in the Indian Ocean). It was noted, however, that the study by Kasamatsu et al. (1995)
was based on limited searching effort thus there is uncertainty regarding the occurrence of two
breeding grounds in the Indian Ocean as proposed in that study. Information on distribution of fetus
length suggested that there is possibly only one breeding ground in the central Indian Ocean.
Overall the meeting agreed that these results suggested the need to revise the IWC’s current
specifications for management Area boundaries. The results will also assist in calculating abundanceand biological parameter values that relate more closely to biological stocks units. They will also
inform the specifications and testing of appropriate Combination Areas for cascading under the RMP.
7.2 Biological parameters of Antarctic minke whales
7.2.1
Unbiased estimation of abundance and trends
JR4 examined the effect of sampling activities, particularly closing mode, on the estimation ofabundance using the methods of Haw (1991). The bias originating from under-surveying in highdensity areas was examined. Correction factors were estimated by comparing uncorrected abundance
estimates among SSV, SV in closing mode and SV in passing mode. As significant differences between
estimates for these different modes were detected, abundances were adjusted using correction factors.
Corrected abundance estimates are not significantly different to those from IDCR surveys during CP II,
and are larger than those derived from spatial modeling. This last matter should be investigated further.
No significant trend in abundance was detected in either Area IV or Area V. The authors concluded
that the underestimation of abundance pointed out at the JARPA review meeting in 1997 is largely due
to the effects of closing mode and of sampling activity. Abundance estimates derived by the method
proposed can be used to estimate biological parameters with higher precision.
Butterworth commented that the two correction factors for the abundance estimates (R1: correction
factor between SSV and SV; R2: correction factor between SV closing mode and SV passing mode)
should be examined carefully, especially the R1 correction factor. The reason for this is that there had
been some change in “skipping” protocol over the course of the JARPA survey period. To examine theannual effect of this factor might be difficult because of data limitations; therefore Butterworth
suggested that it might instead be useful to categorize this factor as “large” or “small” and thenincorporate this into the model as a covariate. He emphasized that these abundance estimates are key
input to other analyses, and also raised the importance of conducting possible sensitivity tests to checkthe robustness of the estimates.
Hakamada responded that the reason why he did not consider skipping in this analysis is that in his
preliminary calculations, no significant difference was found in relation to skipping between the earlyand late surveys using ANOVA.
Butterworth commented that he was pleased that Hakamada has looked into this effect, but alsostressed the importance of considering Type II error. Even though there is no significant difference, hesuggested conducting the analysis with and without the skipping factor to ascertain the difference in theabundance estimates and their precision. Hakamada agreed to consider this effect in more detail in
future analyses.
Walloe pointed out that some of the detection functions shown in Figure 3 of JR4 do not fit the datawell, and suggested that these aspects should be re-examined.
Butterworth noted that due to considerable stratification of the data, some of the sample sizes in theanalysis have become small. This may lead to false impressions of the detection function and hence tobiased estimates of abundances. It might be important to conduct the analysis by first pooling the data
to see whether there are any significant differences between the covariates. He further commented thatthough pooling the data may not show different results to the analysis in JR4, it is important to showsuch results as sensitivity tests. He also noted that the R2 factor was appreciably lower than for the
IDCR surveys, and suggested that reasons for this be sought.
Hakamada expressed appreciation for these comments and agreed to consider them in future work.

5JR20 presented a study based on a spatial model of minke whales using JARPA data from 1990/1991
to 2000/2001 in Area V. A Horvitz-Thompson estimator was used to obtain estimates of the expectedschool size, by stratum, based on estimated detection probabilities which allow for the effects ofcovariates. Estimates of minke whale abundance, as well as abundance of schools of size 1 andabundance of individuals in schools of size greater than 1, were presented to use for estimation of
biological parameters. The resultant abundance estimates in Area V are notably lower than those in JR4.
Butterworth commented that a reason why the abundance estimates shown in this paper are smaller
than those of Hakamada is that this analysis considers the survey mode factor by year and omits it as
non-significant, whereas JR4 considers this effect in combination over all years and finds significancegiven the larger sample size. Butterworth suggested that the authors of JR20 should also consider theeffect of survey mode as in JR4, and then compare the results for the two methodologies.
Hakamada responded that it is possible to examine this effect. However, he also pointed out that at the2004 IWC Scientific Committee meeting, it was shown through simulation tests that spatial modelinggives unbiased results regardless of survey mode, and the JR20 analysis is based on that assumption.
The meeting noted that the methods presented in JR20 and JR4 used different assumptions and agreed
that it is important that these analyses are presented in a more comparable way so that valid
comparisons between these different analytical methods become possible. There is a need for further
discussion between the respective authors to achieve this.
7.2.2

Estimation of biological parameters

JR5 used materials collected by the JARPA surveys in Areas IIIE, IV, V and VIW in 1987/88 to
2003/04, to estimate some biological parameters of the Antarctic minke whales by incorporating a new
sample grouping at 165°E based on the new stock scenario (‘Eastern Indian Ocean Stock (I-stock)’ and‘Western South Pacific Stock (P-stock)’). These parameters included sex ratio, sexual maturity rate,
body length and age at sexual maturity, body length and age at physical maturity, proportion ofpregnant in matured female(PPF), foetal sex ratio and the occurrence of multiple births. Significant
differences were detected between the two stocks for sex ratio, sexual maturity rate for both sexes, PPF
and foetal sex ratio by application of the χ2-test and for body length at 50% sexual maturity forfemales, age at 50% sexual maturity for females and body length at 50% physical maturity for both
sexes by likelihood ratio analysis. Significant yearly trends were detected among males for thefollowing parameters by linear regression analysis: sexual maturity rate in the I-stock, body length andage at 50% sexual maturity in the I-stock and body length and age at 50% physical maturity in the Pstock. Year was also selected as an explanatory variable for age at physical maturity and body length at
physical maturity by use of stepwise logistic regression analysis, but for age and body length at sexual
maturity were not selected. These results suggest the possibility that expansion of the carrying capacity
for the minke whales has ceased and that the ecosystem begun to return towards the conditions thatexisted before the expansion had taken place.
Participants commented that the yearly trends of some biological parameters shown in this paper areinteresting, and it is important to discuss these trends together with the results from other studies (i.e.
minke VPA, abundance estimates).
JR6 provides a point estimate for the natural mortality coefficient for Antarctic minke whales using
JARPA data, by modifying the original method proposed by Tanaka (1990). Skewed age distributions
arising from mature/immature segregation were corrected using the maturity rate at age. Net rates ofnatural increase of stock sizes corresponding to the new interpretation of a stock boundary were
estimated by maximum likelihood. Under a zero increase rate for stock size (which corresponded to thestatistical model selected by the c-AIC criterion), the point estimates of the natural mortality coefficientwere 0.0486 (per year) for the Eastern Indian Ocean Stock and 0.0490 for the Western South Pacific
Stock.
Butterworth commented that it is very important to have this analysis in addition to VPA. He also
noted the importance of showing confidence intervals for the estimate of natural mortality (M) shownin Table 3 of JR6. He further suggested that results for the M estimate when the increase rate parameter(r) was estimated should also be shown in the Table, even if it was not selected by the model selection

6criterion, and that the sensitivity of the M estimates to different assumptions should be discussed in thepaper. Tanaka responded that at present bootstrap data to be able to calculate the confidence intervals
have still to be generated, but this is planned for future work. Tanaka also commented that once theinput data for the model are finalized, the estimates will be re-calculated.
JR7 examined longer term changes in the age at sexual maturity of Antarctic minke whales by counting
transition phase layers in earplugs using a total of 4,547 earplugs collected from the 1971/72 to the
1986/87 commercial whaling operations and from the 1987/88 to the 2003/04 special permit surveys
under the JARPA research program in Area IV. The paper incorporated the same correction methods forbiases due to the truncation and the ‘age-specific’ effects that were addressed in past debates. No
systematic ageing errors were detected between the two primary age readers. The present analysis
revealed again that the age at sexual maturity declined from around 12-13 years for the 1940s cohorts
to about 7 years for the late 1960s’. Using the new data set produced by JARPA, it was further foundthat the age at sexual maturity had remained about constant at 7 - 8 years, with perhaps a slight increasein cohorts from the early 1970s to the late 1980s.
The meeting welcomed this contribution. Walloe pointed out that it would be of interest to see the trend
in age at sexual maturity shown in Fig. 7 extended to more recent years, rather than to 1993 only as
shown in this figure. He further suggested using the median rather than the mean age, since this may
increase number of years for which an estimate can be made. Zenitani responded that the reason why
the results had been shown to 1990 only is because recent data suffer from truncation biases. Zenitani
expressed appreciation for the useful comments, and will consider using the median for future analyses.
Butterworth commented that this analysis is important for interpreting trends obtained from abundance
estimates. He also suggested that the analysis could provide estimates for more recent years using themodel of Thompson et al. (1999). The meeting recommended that future analyses of this kind be
carried out in collaboration between ICR and UCT.
Participants also commented that the effect of time lags should be considered when considering theresults in relation to abundance trends .
Butterworth commented that it may be useful if a plot similar to Fig.8 of JR7 showing the age at sexual
maturity from direct observations and the age at transition from the earplug for the same animal, could
be provided. This type of plot would help understand the relationship between transition phase andsexual maturity of the animal.
In JR21 Virtual Population Analyses were performed to infer natural mortality coefficients for
Antarctic minke whales in Areas IV and V using catch-at-age data from both commercial whaling(1971/2-1986/7) and scientific whaling (JARPA 1987/88-2003/2004). Abundance estimates from IWC
and JARPA surveys were used as tuning indices. Some sensitivity tests related to the estimation of thenatural mortality coefficients were also performed. A clear difference in the estimates of the natural
mortality coefficients between Areas IV and V was observed. Sensitivity analyses showed the estimateof the natural mortality coefficient in Area IV was slightly influenced by both grouping of data (such as
2-year-2-age and 3-year-3-age) and the assumption made for the maximum age used in the loglikelihood for the catch-at-age data, while the estimate in Area V was rather stable by comparison. In
addition, the amount of bias in the abundance estimates arising from setting g(0)=1 affected theestimates of the natural mortality coefficient in Area IV to some extent. As expected, the extent ofadditional variance did not impact the point estimates in either Area, but it did lessen their precision.
In JR18 the ADAPT-VPA assessment methodology of Butterworth et al. (1999) is applied toabundance estimates (from both IDCR/SOWER and JARPA surveys) and catch at age data (bothcommercial and scientific) for Areas IV and V. The methodology is extended to be able to take accountof inter-annual differences in the distribution of the population between the two Areas when they areassessed jointly. An important feature of these updated results is that revised JARPA estimates ofabundance are shown to be statistically comparable with estimates from the IDCR/SOWER program(i.e. calibration factor not significantly different from 1). The general pattern shown by results is of aminke whale abundance trend that increased over the middle decades of the 20th century to peak at
about 1970, and then declined for the next three decades. The recruitment trend is similar, though with
its peak slightly earlier. The factor to which the results are most sensitive is the value of natural
mortality M. The assessments do show retrospective patterns, primarily related to changes in the best7

estimate of M as time has progressed. This in turn seems linked to the IDCR/SOWER survey trends
suggesting higher, and the JAPRA survey trends lower estimates of M. For the assessment of the two
Areas combined, M is estimated at 0.068 with a CV of 0.12; this compares with CVs of typically 0.35
for the Area-specific assessment of Butterworth et al. (1999), which were based on eight seasons’fewer data. The paper reflects an account of work in progress, and suggestions are made of areas where
further analysis would be desirable.
In response to an enquiry about JR21, Kitakado commented that further sensitivity analyses to different
selectivity functions and to age-dependent natural mortality will be conducted. He also commented thatfrom preliminary calculations, he had found that assuming various functions for age-dependent natural
mortality led to unreasonable estimates because of a lack of information content in the data.
The meeting noted that the estimation of the coefficient of variation (CV) of M was greatly improved
compared to previous similar analyses. Two reasons for this improvement were given: (1) addition ofdata obtained from further JARPA cruises, and (2) the abundance estimates of Hakamada et al. (JR4)(which corrected for biases between survey modes) could now be treated as comparable to those fromthe IDCR/SOWER surveys.
Komatsu questioned whether it is really necessary to collect samples from young animals (i.e. age 1 or
2 years old) for which the estimation of M seems to be difficult. Zenitani responded that from an agedetermination point of view, it is difficult to distinguish ages 1 and 2 groups and thus these are often
not used for analyses. Ishikawa commented that from a sampling point of view, there is no difficulty incollecting young animals. Kitakado remarked that changes in selectivity pattern would introduce
additional estimable parameters in the model and their estimation may compromise precision.
Butterworth was also concerned that changed sampling patterns might complicate data interpretation,and urged careful consideration before any changes might be implemented.
Morishita enquired about the importance of conducting similar analysis for other Areas such as Area
IIIE and VIW for which JARPA data are also available. Butterworth responded that the extension of
the analysis at this stage to Areas IIIE and VIW will introduce some difficulties as the sampling design
was not random in those regions, so that it was likely best to postpone such initiatives for the moment
while concentrating on analyses for Areas IV and V.
Kawahara asked about estimating fishing mortality (F) in the analysis. The response to this query wasthat the main important results from the minke VPA are the population trend and the MSYR estimates(see below). The F matrix is calculated in the VPA and values can be provided if requested.
The meeting agreed that these analyses were valuable contributions toward the main objective of the
JARPA, which is the estimation of biological parameters. Participants offered several suggestions on
how these analyses could be further developed. For example, the suggestion was made to consider a U
shape function for age dependent M for future analyses. There was a further suggestion to conduct theanalysis on the basis of the proposed new stock structure scenario (the I and P stocks). Butterworth
responded that for future studies, various functions for age dependent M will be explored, but asKitakado had noted, due to lack of information content in the data, this may not lead to better
estimation overall. He also remarked that different scenarios for stock boundaries can be explored, but
extensive analyses on this matter might be better conducted after some feedback from the IWC
Scientific Committee had also been obtained.
JR22 analyzed the results of the Base Case assessment of Areas IV and V to better understand the
dynamics of Antarctic minke whales in the region. A stock-recruitment model of the Pella-Tomlinson
form was fit to recruitment and adult female abundance estimates. The underlying assumptions werethat carrying capacity of minke whales first increased, then later decreased during the 20th Century.
An initial attempt at this fit suggested that the carrying capacity increased about five fold from 1930 tothe mid-1960s, and then decreased again by about half. The estimated MSYR1+ for the model was 4.0%.
Kitakado thanked the authors for the analysis presented and suggested that in equation (6) of JR22, it
may be better to weight the observed recruitment data depending on the precision of the estimates. He
also suggested consideration of a smoother functional form for changes in carrying capacity (K) in themodel. Butterworth endorsed these comments and advised that further analysis would be conducted
incorporating these suggestions.

8

Kawahara asked what would be the consequences of taking account of changes in the age at sexual
maturity of minke whales by year for the stock-recruitment plot. Butterworth responded that
qualitatively, probably the stock recruitment plot shown in Fig. 1b of JR22would stretch toward theupper left side, in better agreement with the stock-recruitment function suggested. This would be
examined in further analyses.
The meeting was pleased to note that the approach in JR22 allowed for estimation of MSYR.
7.2.3
Summary of results
Incorporation of inter-mode calibration factors (cf. Haw, 1991) in design-based estimation (JR4) ofminke whale abundance from JARPA sighting surveys provides results that are comparable with thosefrom IDCR/SOWER surveys. The model-based abundance estimates (JR20) are appreciably lower, but
do not explicitly allow for the possibility of inter-mode differences; the meeting recommended thatpossibilities to make such allowance in the model-based approach be investigated to ascertain whether
this would lead to comparability between the results of the two approaches. Estimated annual increase
rates in abundance from the design-based results, together with associated 95% confidence intervals,
are 0.3% [-4.6%; 3.9%] for Area IV and 2.5% [-1.4%; 6.2%] for Area V, i.e. not significantly different
from zero, but also not excluding either positive or negative trends.
Time series of biological parameter values were reported on a biological stock basis, as requested by
the mid-term JARPA review meeting (specifically for the I and P stocks, with their boundary set at
165°E – see section 7.1.3). Some significant differences between the stocks were reported, and there
were significant recent increases in the age at physical maturity. Consistent with this, an examinationof the transition phase in earplugs for Area IV suggested a slight increase after the 1970 cohort
following an earlier appreciable decline.
Two different methods for estimating age-independent natural mortality M from catch-at-age andabundance data provided comparable results. The VPA method, for example, estimates M=0.068(CV=0.12) if both Areas IV and V are assessed in combination. The meeting noted that this reflects
much greater precision than obtained from earlier analyses, in part because of the further data now
available. The VPA results all broadly reflect both recruitment and abundance increasing until about
1970, and then declining. Initial fits of these results to a population model suggest that carrying
capacity for minke whales must have first increased, but subsequently declined during the 20th Century,
and also allow MSYR to be estimated. The meeting noted that the results reported reflected work inprogress, and identified the desirability of conducting VPA calculations assuming two stocks with a
165°E boundary.
The meeting also noted the broad consistency between trends in some biological parameters and inabundances predicted by VPA models, as discussed further under section 8 below.
7.3 Role of whales in the Antarctic marine ecosystem
7.3.1
Krill consumption and body condition of Antarctic minke whale
In JR8 feeding habits and prey consumption of Antarctic minke whales were examined using stomach
content data collected in JARPA. A total of ten prey species, including one amphipod, four euphausiids
and five fish species were identified. Antarctic krill (Euphausia superba) was the most important preyspecies throughout the survey period. The analyses of prey digestion showed that whales tended to feedon prey in the early morning and late evening. Daily prey consumption for the Antarctic minke whale
was estimated using two methods: a direct method (diurnal changes of stomach contents mass) and an
indirect method (energy requirements). Daily consumption estimates were similar between the two
methods and ranged from 3.6 to 5.3 % of body weight. Annual consumption of Antarctic krill from the
1990/2000 to the 2002/03 season was calculated as being equivalent to 4% and 26 % of the krill
biomass in Areas IV and V, respectively. These results indicate that Antarctic minke whales are one ofthe dominant top-predator species in Areas IV and V.
It was noted that the decreasing trends in the mean mass of stomach contents was consistent withresults that showed that the age at sexual and physical maturity has stabilized and then increased inrecent years. In response to a question from Ohsumi on why minke whales occur in the Ross Sea, aregion with low food availability, Tamura responded that this paradox is still unresolved. Vikingsson

9noted that energy intake, and consequently consumption estimates by the indirect method, might beunderestimated if residence times in the Antarctic exceed the four month period (December-March)covered in the study. It was suggested that an index related to the mean mass of stomach contents
should be defined to assess changes in food availability. Currently, daily food consumption is estimatedover combined areas because available samples are not sufficient to allow estimation by area.
Because area specific daily consumption rates are important to understand the change in foodavailability to Antarctic minke whales, the meeting agreed that this aspect should be considered infuture analyses.
JR9 presented an analysis of recent trends in blubber thickness and factors that affect this thickness in
Antarctic minke whales for both mature males and pregnant females in Areas IV and V. The results
showed that a decrease of blubber thickness occurred over the JARPA survey period. This indicatedthat food availability for those minke whales has decreased over this survey period, quite possibly
caused by either or a combination of intra- and inter-species competition among baleen whales.
The appropriate part of the animal at which to measure blubber thickness of baleen whales was
discussed. Previous JARPA workers examined several body parts for blubber thickness and concluded
that blubber thickness on the lateral side of the body was most practical to measure. The meeting
agreed that the appropriate part of the body for blubber thickness measurement would be species
specific.
Distribution and abundance trends of Antarctic minke and large (blue, fin and humpback)whales
JR10 investigated the distribution and abundance of large whales (blue, fin and humpback whales)
using JARPA data from 1989/90 to 2003/04. A shift in baleen whale dominance from the Antarctic
minke to humpback whales was evident in Area IV. In the 1989/90 season, the biomass of Antarctic
minke was higher (382,000 tons) than that of humpback whales (128,000 tons); but 15 years later, inthe 2003/04 season, the biomass of humpback (841,000 tons) was twice that of Antarctic minke whales(335,000 tons). Expansion of humpback whale distribution was also observed in Area IV between theearlier (1989/90-1996/97) and the later half of the surveys (1997/97-2002/03). Increases of fin whales
were also observed in Areas IIIE and IV. Current abundances of fin whales were estimated as 7,00011,000 in the 2001/02 and 2003/04 seasons. A preliminary estimate of the number of fin whales southof 40oS between 35°E and 130° E based on JARPA and Japanese Scouting Vessel (JSV) data was
21,000 (CV=0.27). Abundance of blue whales was still less than 1,000 (biomass: less than 80,000 tons
in the JARPA research area. The authors commented that long term cetacean sighting surveys are very
important for the management of baleen whales in the Antarctic.
7.3.2

Butterworth suggested that it would be important to investigate differences in the sighting rates of
humpback whales 1) between passing and closing modes and 2) between SV and SSV modes using
GLM. It is expected that, in comparison to minke whales, the effect for this species would not be strong(because these whales are bigger and hence easier to sight), but the results of such an exercise would be
important to provide justification as to why the bias correction is necessary in the case of Antarctic
minke whale abundance estimation but not necessary for humpbacks.
It was noted that during the 2004 IWC Scientific Committee meeting, several recommendations forfurther analyses of abundance of large whales were made (IWC, 2004). The meeting agreed thatconsiderable progress has been made in addressing them.
JR19 presented results of dynamic production model analyses of the West and East Australian
humpback breeding populations using the most recent JARPA survey abundance estimates as well as
data from Australian coastal surveys. The model incorporated the information on mixing of the twobreeding populations on the feeding grounds of Areas IV and V. Best estimates projected undercontinuing zero harvest indicated that the western population will approach its pristine level in some 10
years, and the more depleted eastern population in 15-20 years.
In the discussion Komatsu remarked that results of the analysis will be affected by how the carrying
capacity of humpback whales is defined. Butterworth advised that the context of the analysis is a“single species” one in which humpback population carrying capacities are assumed to remainunchanged over time. Pastene pointed out that the IWC Scientific Committee defined the Western

10Australian breeding stock as “Stock D” and the Eastern Australian breeding stock as “Stock E”. Hesuggested standardizing terminology among the reports.
The meeting agreed that the status of the western stock of humpback whales provided a unique
opportunity to study changes in biological parameters as a population approaches carrying capacity,with the eastern stock serving as a control.
7.3.3
Inter-species relationships
JR11 presented the results of krill biomass estimation using quantitative echo sounder surveys
conducted in JARPA since the 1998/99 season. This is to achieve one of the main objectives of JARPA,
which is elucidation of the role of whales in the Antarctic marine ecosystem. The surveys wereconducted concurrently with cetacean surveys. Similar biomass estimates were obtained in Area IV in
the 1999/2000 (36.4 million t) and 2001/2002 (36.1 million t) seasons. In Area V, biomass estimates in
the 2000/2001 (18.7 million t) and in the 2002/2003 (21.0 million t) seasons were similar, but biomass
in 1998/1999 (32.3 million t) was higher than for the other two years. Higher biomass in 1998/99 could
be explained by seasonal effects and area coverage differences. The biomass in Area IV was higher
than in Area V. Regional krill distribution pattern differences in response to the southerly shift of the
SB-ACC were observed in Area IV. Because krill biomass surveys in the whole of Areas IV and V
were rarely conducted in the past, krill data collected by JARPA provided especially valuable
informationto understand krill-baleen whale relationships in the Antarctic.
Butterworth commented that some of the values in the paper had large CVs, so that care should be
exercised in arguing evidence for temporal trends. He also raised concerns about target strength andanalyses without concurrent species identification. Kim also mentioned some concerns about the large
scale survey design and the species identification method for acoustic abundance estimation of small
prey species. Murase advised that JARPA and CCAMLR use the same procedures with regard to target
strength and species identification of krill. In future surveys species would be identified by conducting
concurrent net sampling from the Japanese fisheries research vessel, Kaiyo-Maru. This vessel joined
JARPA for the first time in 2004/2005, engaging in a krill and oceanographic survey. The outcome ofthe survey would contribute to improving future JARPA surveys and would address the concerns raised
by Butterworth and Kim.
It was noted that the Government of Japan is prepared to provide the Kaiyo-Maru on a regular basis for
future surveys in the Antarctic. The meeting agreed that this will provide an excellent opportunity to
conduct ecological and biological research in the area.
The meeting noted that density estimate differences between the Australian survey (BROKE) and
JARPA could be attributed to either or a combination of 1) actual inter-year fluctuations, and 2)
uncertainty associated with survey methodology problems and species identification of krill in JARPA.
These differences should be further investigated to attempt a more detailed explanation.
JR12 assessed the magnitude of food consumptionby Antarctic minke, humpback and fin whales, on
krill based on data collected by JARPA in Areas IV and V from 1999/2000 to 2002/2003. Three data
sets - whale abundance, daily krill consumption rate of whales and krill biomass - were used in theanalysis. All data used in this analysis were collected in situ except for the daily krill consumption rateof humpback and fin whales because of lack of biological information. Three baleen whales consumed
10-21% and 30-35% of the krill standing stock in Areas IV and V respectively. In Area IV, humpback
whales consumed about twice as much krill as Antarctic minke whales. The results indicated that the
krill surplus period for Antarctic minke whales in Area IV could now be at an end because of theincrease of humpback whales, though this point should be investigated quantitatively in future using
multi-species models which included both baleen whales and krill.
Butterworth commented that the overall distribution of fin whales did not overlap exactly with otherwhales considered in the paper and asked whether their consumption north of 60°S was also primarily
krill. In response, advice was provided that fin whales north of this latitude also consumed othereuphausid species, but that for the area south of 60°S the assumptions of the paper were reasonable.
JR 23 introduced a multi-species predator-prey model of whales, seals and krill in the Antarctic that iscurrently being developed, and illustrated some example results that had been obtained from the model.
Due to limited time, sensitivities of model outputs to various input parameter values and functional

11

response forms have not yet been investigated. This is planned for future work. Preliminary results
show the possible role of predator-prey interactions in influencing the dynamics of the Antarctic
species considered in the model.
It was suggested that consideration be given to including some of the biological parameters that wereobtained by JARPA in the model in future work. Mori responded that currently the biologicalparameters used in the model were static but she would try to use dynamic biological parameters in themodel in future. Butterworth suggested that it is premature to include those parameters in the model atthis stage: the current model uses a simple age-aggregated approach, and advance to age-structured
models which could take explicit account of such changes would better first await more progress withthe simpler form. The meeting encouraged the further development of multi-species models.
7.3.4
Summary of results
Feeding studies conducted during JARPA have confirmed Antarctic krill as the main prey of minke
whales, which in their turn remain a major predator of krill. However the mean mass of minke whale
stomach contents has declined appreciably over recent years, and there has been a coincident decreasein blubber thickness. Results from pollutant studies (see item 7.4.1) are also consistent with a recent
decline in per capita food consumption by minke whales.
Estimates of abundance from JARPA surveys indicate increases in both humpback and fin whale
populations, and population modeling of humpbacks taking account also of the results from coastal
surveys suggests that the breeding stock off Western Australia (stock “D” as defined by the IWC) has
already recovered to its MSY level.
Contrary to the situation at the start of the JARPA progam, estimates of krill consumption in recent
years by humpback whales in Area IV now exceed those for minke whales. Acoustic estimates of krill
biomass have been obtained during recent JARPA surveys, and estimates of krill consumption byminke, fin and humpback whales constitute an appreciable fraction of the krill abundance estimatesobtained.
Taken together, these results are indicative of possible growing competition for krill amongst thebaleen whale species in the region covered by the JARPA program. Initial multi-species population
modeling studies (which implicitly incorporate such competitive effects) are able to broadly reproduce
the various Antarctic whale population trends indicated by sighting surveys. These models need to be
developed further to ascertain whether closer correspondence can be attained, and hence whether suchapproaches might have utility as predictive tools for management purposes.
The meeting emphasized the value of the availability of the research vessel Kaiyo Maru for mesoscalestudies.
7.4 Effects of the environmental changes on cetaceans
7.4.1
Pollutant analysis
In JR13 the concentrations of Mn, Fe, Cu, Ni, Zn, Cd, Hg, and Pb were reported from the liver andprey species (krill) from the stomach contents of Antarctic minke whales taken from Antarctic Areas
IV and V during the 1988/89 to 2002/03 seasons. The ranges of concentrations for each compound
were, in µg/g wet wt: Mn, 1.4-7.4; Fe, 1.6-10591; Ni, <0.1-0.1; Cu, 3.1-10; Zn, 18-103; Cd, 0.10-66;
Hg, 0.004-0.43, Pb, <0.3-0.5. The levels of essential elements, such as Mn, Cu and Zn, in Antarctic
minke whales were comparable to those of other baleen and toothed whales in the Northern
Hemisphere. Hepatic Hg levels for Antarctic minke whales were one order of magnitude lower thanother baleen whales in the Northern Hemisphere, while their Fe levels were one order of magnitude
higher than for other whales elsewhere in the world. Hepatic Pb and Ni levels were close to the lower
limit of detectability. There were remarkable sex differences for hepatic Fe levels for Antarctic minke
whales. Before the 1995/96 season, no correlation with age was evident for Fe, Cd and Hgconcentrations in livers. However, in recent years, these concentrations showed increases with age.
Small changes of accumulation in Antarctic minke whales could be detected in the early 1990’s.
During discussion it was noted that obtaining separate values of methyl mercury and ionic mercury
concentrations would be informative. It was pointed out that while methyl mercury is toxic and12accumulates in e.g. brain tissue, the ionic form of mercury is secreted by the kidney and does not
represent a threat.
The global distribution and long range transport of mercury in the environment was discussed. Becauseof the transport of Atlantic deep water from the North Atlantic to the upwelling zone in the Antarctic, it
was suggested that the low values of Hg may only represent a delay compared to the relatively higher
concentration of Hg in the Northern Hemisphere. In response, it was explained that airborne particle
dispersion is the most important way of dispersing mercury in the environment, and following theindustrial revolution there was a rapid increase in mercury concentrations over large geographic
regions. However, Antarctica remained little influenced, and the remoteness from industrial centers andthe patterns of atmospheric circulation systems therefore seem to be the main reason for the continued
low concentration of mercury in Antarctic minke whales. It is therefore reasonable to assume that Hgconcentrations in Antarctic minke whales will continue to be very low.
JR14 examined environmental changes in the Antarctic Ocean through analysis of concentrations oforganochlorines (PCBs, DDTs, HCHs, HCB and CHLs) in blubber tissues of mature male Antarctic
minke whales (from 21 to 25 years) from the Antarctic Areas-IV and V. The ranges of concentrations
for each compound were, in ng/g fat wt: PCBs, 44.8-88.7; DDTs, 29-340; HCHs, 0.20-4.3; HCB, 75430; CHLs, 10-120. Residue levels of PCBs, and DDTs in blubber of Antarctic minke whales from theSouthern Ocean were apparently lower than those levels in other baleen whales from middle latitude
areas. Significant regional differences between Areas IV and V were observed in PCBs, HCHs, HCB
and CHLs levels in Antarctic minke whales. Furthermore, their HCHs and HCB levels decreased
significantly over the 1988/89 to 2002/03 austral summer seasons. The directions of trends in PCB and
DDT levels are unclear over the 1988/89 to 2002/03 austral summer seasons, suggesting that the trends
in levels of organochlorins may be near a turning point in the Antarctic Ocean.
The mechanisms for the very low concentrations in Antarctic minke whales compared to most othercetaceans globally were discussed. It was pointed out that organochlorines (OC’s) enter cetacean
tissues mainly through the food web. Therefore, both the pristine conditions of the Antarctic feeding
grounds due to the remoteness from sources of OC pollution, and the feeding ecology of Antarctic
minke whales may contribute to the low OC levels recorded in the tissue of whales sampled in the
JARPA program. While toothed whales and minke whales in other areas feed at higher trophic levels
on a mixed diet including e.g. fish, the Antarctic minke whales are at a low trophic level and feed only
on planktonic crustaceans. The effect of feeding on low trophic levels is also shown by the low OC
levels recorded in the plankton-feeding bowhead whales off the North Slope of Alaska.
It was further pointed out that not all OCs are toxic to humans, and that it is important to present values
for the different compounds included in the analysis.
The OC concentrations (except for DDTs) in Antarctic minke whales from Area IV (1987/88 to
2001/02 seasons) were significantly higher than those recorded from Area V (1988/89 to 2002/03
seasons), and the possibility of using contaminants as a supplement to stock identification evaluations
was suggested. In response it was pointed out that stock identification requires larger sample sizes andthat OC analyses are expensive and time consuming.
7.4.2
Environmental changes examined through oceanographic analysis
In JR15 oceanographic observation data obtained by JARPA were analyzed to clarify physicaloceanographic conditions in the JARPA area as a basis for understanding of characteristics of thehabitat of whales. Accumulated XBT, XCTD and CTD data were stored in the HydroBase format andutilized to describe the oceanographic features of the JARPA area. The Southern Boundary (SB) of the
Antarctic Circumpolar Current was clearly observed as a 0ºC temperature contour line on the 27.6
sigma-theta isopycnal surface. It is evident that the position of the SB is controlled by major featuresof bottom topography such as the Kerguelen Plateau and the Pacific-Antarctic ridge. The analyses
presented evidence for year-to-year variations in oceanographic conditions, including large year-toyear meridional shifts of the SB that were found east of the Kerguelen plateau. The JARPA data also
provided new evidence of Antarctic Bottom Water formation in the Prydz Bay region. Comparison
between the JARPA data and satellite-derived chlorophyll distribution indicates that the intensity of thewintertime cooling determines the primary productivity south of the SB in the following seasons.

13

In the discussion it was pointed out that the surveys were primarily designed to study minke whales andthe cruise lines therefore were not ideal for exploration of oceanographic conditions. However, theoceanographic data have revealed some interesting results, e.g. it was demonstrated that El Nino events
could be traced into Antarctic SST and temporarily impact the distribution of minke whales. It wasnoted that this information could be used to explain observed temporal differences in minke whale
abundance. Continuation of the oceanographic studies was therefore encouraged as a supplement tocollection of abundance estimation data.
In a discussion of the possibilities of using oceanographic conditions to define stock boundaries, it wasdemonstrated that the position of the southern boundary of the Antarctic Circumpolar Current is
controlled by the bottom topography: the current runs near the continent west of 150°E and then moves
away from the continent at about 150°-165°E following the Pacific Antarctic Ridge. These longitudes
coincide with the stock boundary for Antarctic minke whales suggested by genetic data.
7.4.3
Summary of results
The meeting noted that the most important findings of the environmental studies were the following:•••

The bottom topography may contribute to the explanation of minke whale stockboundaries through its effect on the southern boundary of the Antarctic Circumpolar
Current.
While Fe showed very high concentration in Antarctic minke whales, the Hg values werevery low.
The concentrations of OC in Antarctic minke whales were also documented to be very
low, also in comparison with concentrations recorded in minke whales harvested in othergeographic areas.

These results provided evidence of changes in the Antarctic cetacean habitat (the biologicalenvironment), which supplement the growing evidence of density dependent responses in the minke
whale population. These observations are possibly related to intra- and inter-specific competition for asingle food resource (krill). The meeting emphasized the importance of further studies of minke,
humpback and fin whale abundance, distribution and feeding ecology with concomitant continued
monitoring of biological and physical oceanography.
7.5 Other results
7.5.1
Stock structure of humpback and fin whales
JR16 presented the results of mtDNA and microsatellite (humpback whale only) analyses conductedon the biopsy samples of 287 humpback and 23 fin whales obtained during JARPA surveys. The
humpback whale samples from their feeding grounds were grouped according to the stock distribution
in the feeding grounds proposed by the IWC Scientific Committee’s comprehensive assessment of thespecies. Analysis of mtDNA control region sequences clearly discriminated the Stocks C, D, E, F and
G on the feeding grounds. However, analysis of the six microsatellite loci failed to discriminate thesestocks, although some degree of genetic heterogeneity among the samples was evident. These results
suggested a different degree of fidelity to breeding areas between females and males. Analysis of
mtDNA suggested that the historically mixed sector between the Stocks D and E at 110-130°E was
occupied in recent years mostly by the D stock. For the fin whales, the level of observed mtDNA
diversity was similar to that for the Antarctic minke whales. No significant differences were foundwhen comparing fin whales from Areas III+IV and V that correspond approximately to the Indian andwestern South Pacific Oceans populations respectively. However the lack of observed differences inthis study could be due to the small number of samples available.
The meeting welcomed this contribution. Walloe commented on possible differences in the pattern ofstock structure between North Atlantic and Southern Hemisphere humpback whales. He noted thatstructure in the Antarctic was more evident in mtDNA than microsatellites. Pastene responded that site
fidelity to either feeding, breeding, or both areas is less in males than in females, resulting in morestructure in mtDNA than in microsatellites.
Butterworth remarked that results in this paper are broadly consistent with those in JR19. He further
suggested the use of biopsy samples from lower latitudes, if available. Pastene responded that a limited
number of mtDNA control region sequences from the D and E stocks are available from low latitudes
and that these will be used in future analyses.

14Miyashita asked whether there was any photo-id matching based on JARPA material. Pastene
responded that there had been two matches thus far, one between photos taken from eastern Australia
and Area V and the other from IDCR/SOWER and JARPA surveys both in Area VI.
7.5.2

Other

No matters were raised under this Agenda item.
8. OVERVIEW OF RESULTS AND IDENTIFICATION OF FUTURE RESEARCH NEEDS
JR17 discussed changes in the Antarctic minke whale stocks based on various results from JARPA
including the age at sexual maturity, growth curve, blubber thickness, prey consumption, and ADAPTVPA assessments as well as results from research on mercury accumulation.
Following discussion of JR17, the meeting agreed that, viewed broadly, results from JARPA are
consistent with the behaviour to be expected of baleen whale populations competing for a dominant
single food resource, krill. Studies that allow extrapolation back to the middle decades of the lastcentury suggest that minke whales increased coincident with the reductions in the populations of larger
baleen whales that were subject to heavy whaling pressure. However, it seems that from about 1970
this situation began to change; some commercial catches of minke whales took place and, as the larger
baleen whale species started to recover, there are indications that there have been consequent negative
impacts on minke whales. JARPA has, over the period of the program, provided data from a number ofstudies which are all broadly consistent with this inference. For example:
•
•
•
•
•

abundance estimates from surveys indicate appreciable increases in humpback and fin
populations;
population models incorporating survey abundance estimates and catch-at-age data indicate
some decline in minke whale recruitment;
the age at physical maturity for minke whales has increased;
a number of indicators, including weights of stomach contents and measures of blubber
thickness, confirm deterioration in feeding conditions for minke whales; andannual consumption of krill by baleen whales contributes an appreciable fraction of estimatedkrill abundance.

This provides strong qualitative evidence that competition for prey (krill) plays an important role in the
dynamics of the Antarctic ecosystem. Modelling studies need to be developed further to ascertain
whether such competitive effects alone can fully explain the trends observed, or perhaps there is a needto postulate environmental shifts in addition. Nevertheless, the meeting agreed that the results
obtained provide clear support for the need to take species-interaction (ecosystem) effects into accountin understanding the dynamics of the baleen whale species in the Antarctic ecosystem, and in
predicting future trends in their abundance and population structure. Accordingly, management also
needs to be based on ecosystem approaches, rather than upon single species considerations alone, andfuture data collection plans need to take cognizance of such requirements.
Regarding stock structure the meeting agreed that the most parsimonious explanation of the results of
JARPA is that there are two minke whale stocks present in the research area. These stocks mix across asoft boundary, which would probably best be placed near 165°E. Further research is necessary toinvestigate a) whether this mixing region changes from year to year and b) possible additional structure
in Area III (e.g. determination of a western boundary for the I stock) (see item 7.1.3). The importanceof obtaining samples from low latitudes for developing a clearer genetic delimitation of breeding stocks
is stressed
The meeting also agreed that JARPA has provided valuable information to assist in understanding thephysical oceanography in the research area. Bottom topography, and therefore the southern boundaryof the Antarctic Circumpolar Current, may contribute to an understanding of minke whale stockboundaries. It is recommended that data collection on physical oceanography and work to examine therelationships with the patterns of distribution of whale stocks and prey be continued.
Overall, the meeting considered that JARPA had made good progress in addressing its objectives (seesection 5).

15In conclusion, the meeting agreed that:--

JARPA has collected a very large and consistent date base (Annexes D and E)
over a 16-year period, which provides a basis for time series analyses relating
whales to the Antarctic environment and the beginning of an ecosystemapproach to the management of whale resources in the region;
JARPA has contributed to the elucidation of biological parameters of minke
whales, and improved the understanding of the Antarctic marine ecosystem;JARPA has revealed that changes have occurred in the ecosystem since the1970’s, suggesting competition among minke and other large whales; anddata obtained through this monitoring will contribute to the development of
ecosystem models, which are necessary for ecosystem-based management of
whales.

The meeting also agreed that tasks identified in the midterm review meeting in 1997 (see section 5)
had been appropriately addressed and progressed.

9. OTHER
No matters were raised under this Agenda item.

10. REVIEW OF THE REPORT
A first draft of the report was available to the meeting. Several editorial suggestions were offered. It
was agreed that the rapporteurs should complete the final draft of the report for subsequent distribution
among participants via e-mail.

11. CLOSURE
Walloe, on behalf of the foreign participants, thanked the Government of Japan for hosting the meetingand for the hospitality provided. In addition he thanked the Chairman Kato, the rapporteurs Pastene,
Mori, Kanda and Murase, and the interpreters Ohta, Kawagishi and Yamagiwa. Hatanaka thanked the
Chairman for his efficient conduct of the meeting. He also thanked all participants for theirconstructive approach to the review of results from the JARPA program and noted that the outcome ofthis review would be taken into account in the planning of the JARPA II program which will be
submitted to the IWC Scientific Committee at the end of March.

REFERENCES

Butterworth, D. S., Punt, A. E., Geromont, H. F., Kato, H. and Fujise, Y. 1999. Inferences on the
dynamics of Southern Hemisphere minke whales from ADAPT analyses of catch-at-age information. J.
Cetacean Res. Manage. 1(1):11-32.
Haw, M.D. 1991. An investigation into the differences in minke whale school density estimates frompassing mode and closing mode surveys in IDCR Antarctic assessment cruises. Rep. int. Whal. Commn
41:313–30.
International Whaling Commission. 1998. Report of the Intersessional Working Group to Review Data
and Results from Special Permit Research on Minke Whales in the Antarctic, Tokyo, 12-16 May 1997.
Rep. int Whal. Commn. 48:377-412.
International Whaling Commission. 2003. Report of the workshop on North Pacific common minke
whale (Balaenoptera acutorostrata) Implementation Simulation Trials. J. Cetacean Res. Manage. 5(Suppl.): 455-488.
International Whaling Commission. 2004. Report of the Scientific Committee. J. Cetacean Res.
Manage. 6 (Suppl.):1-60.

16

Kasamatsu, F., Nishiwaki, S. and Ishikawa, H. 1995. Breeding areas and southbound migrations ofsouthern minke whales Balaenoptera acutorostrata. Mar. Ecol. Prog. Ser. 119:1-10
Tanaka, S. 1990. Estimation of natural mortality coefficient of whales from the estimates of abundance
and age composition data obtained from research catches. Rep. int Whal. Commn 40:531–6.
Thompson, R.B., Butterworth, D.S. and Kato, H. 1999. Has the age at transition of Southern
Hemisphere minke whales declined over recent decades? Marine Mammal Science 15 (3):661-82.

17Figure 1: Map of the JARPA research area (from JR2).

18

Annex A
List of ParticipantsBando, Takeharu
Butterworth, Douglas
Fujise, Yoshihiro
Goodman, Dan
Hachimine, Akira
Hakamada, Takashi
Hatanaka, Hiroshi
Hester, FrankThe Institute of Cetacean Research, Japan.
University of Cape Town, South Africa.
The Institute of Cetacean Research, Japan.
The Institute of Cetacean Research, Japan
Fisheries Agency, Government of Japan.
The Institute of Cetacean Research, Japan.
The Institute of Cetacean Research, Japan.
Technical Advisor to the Government ofGrenada.
Ishikawa, Hajime
The Institute of Cetacean Research, Japan.
Kanda, Naohisa
The Institute of Cetacean Research, Japan.
Kato, Hidehiro
National Research Institute of Far Seas
Fisheries, Japan.
Kawahara, Shigeyuki
National Research Institute of Far Seas
Fisheries, Japan.
Kiwada, Hiroshi
The Institute of Cetacean Research, Japan.
Kim, Zang Geun
National Fisheries Research and Development Institute, Republic of Korea
Kitakado, Toshihide
Tokyo University of Marine Science and Technology, Japan.
Komatsu, Masayuki
Fisheries Agency, Government of Japan.
Konishi, Kenji
The Institute of Cetacean Research, Japan.
Mae, Akihiro
Fisheries Agency, Government of Japan.
Matsuoka, Koji
The Institute of Cetacean Research, Japan.
Miyashita, Tomio
National Research Institute of Far Seas
Fisheries, Japan.
Mori, Mitsuyo
University of Cape Town, South Africa.
Morishita, Joji
Fisheries Agency, Government of Japan.
Moronuki, Hideki
Fisheries Agency, Government of Japan.
Murase, Hiroto
The Institute of Cetacean Research, Japan.
Nagatomo, Takanori
Fisheries Agency, Government of Japan.
Ohsumi, Seiji
The Institute of Cetacean Research, Japan.
Otani, Seiji
The Institute of Cetacean Research, Japan.
Pastene, Luis
The Institute of Cetacean Research, Japan.
Rambally, Jeannine
Ministry of Agriculture, Forestry, Fisheries and the Environment, St. Lucia.
Rerambyath, Guy Anicet IWC Commissioner for Gabon, Gabon
Suga, Toshio
Tohoku University, Japan.
Tamura, Tsutomu
The Institute of Cetacean Research, Japan.
Tanaka, Eiji
Tokyo University of Marine Science and Technology, Japan.
Tanaka, Syoiti
The Institute of Cetacean Research, Japan.
Tominaga, Haruo
Fisheries Agency, Government of Japan.
Vikingsson, Gisli
Marine Research Institute, Iceland.
Walløe, Lars
University of Oslo, Norway.
Yasunaga, Genta
The Institute of Cetacean Research, Japan.
Zenitani, Ryoko
The Institute of Cetacean Research, Japan.
Observers
Bjørge, Arne

Vice-chair, IWC Scientific Committee.

Interpreters
Kawagishi, Rei
Ota, Midori
Yamakage, Yoko

19

Annex B
Agenda
1.
2.
3.
4.
5.
6.

Election of Chair
Election of rapporteur
Adoption of the agenda
Review of documents
Review of JARPA research objectives
Review of JARPA survey procedure and data collected
6.1 Survey procedure
6.2 Data collected
7. Review of results in the light of JARPA objectives
7.1 Stock structure of Antarctic minke whale
7.1.1
Genetic analyses
7.1.2
Non-genetic analyses
7.1.3
Summary of results
7.2 Biological parameters of Antarctic minke whale
7.2.1
Unbiased estimation of abundance and trends
7.2.2
Estimation of biological parameters
7.2.3
Summary of results
7.3 Role of whales in the Antarctic marine ecosystem
7.3.1
Krill consumption and body condition of Antarctic minke whale
7.3.2
Distribution and abundance trends of Antarctic minke and large (blue, fin andhumpback) whales
7.3.3
Inter-species relationships
7.3.4
Summary of results
7.4 Effects of environmental changes on cetaceans
7.4.1
Pollutant analysis
7.4.2
Environmental changes examined through oceanographic analysis
7.4.3
Summary of results
7.5 Other results
7.5.1
Stock structure of humpback and fin whales
7.5.2
Other
8. Overview of results and identification of future research needs
9. Other
10. Review of the report
11. Closure20Annex C
List of Documents
JA/J05/JR1. Hatanaka, H., Fujise, Y., Pastene, L.A. and Ohsumi, S. Review of JARPA research
objectives and update of the work related to JARPA tasks derived from the 1997 SC meetings.
JA/J05/JR2. Nishiwaki, S., Ishikawa, H. and Fujise, Y. Review of general methodology and survey
procedure under the JARPA.
JA/J05/JR3. Pastene, L.A., Goto M., Kanda, N., Bando, T., Zenitani, R., Hakamada, T., Otani, S. andFujise, Y. A new interpretation of the stock identity in the Antarctic minke whale (Balaenoptera
bonaerensis) based on analyses of genetics and non-genetics markers.
JA/J05/JR4. Hakamada, T., Matsuoka, K. and Nishiwaki, S. An update of Antarctic minke whales
abundance estimate based on JARPA data, including a comparison to IDCR/SOWER estimates.
JA/J05/JR5. Bando, T., Zenitani, R., Fujise, Y. and Kato, H. Biological parameters of Antarctic minke
whale based on materials collected by the JARPA survey in 1987/88 to 2003/04.
JA/J05/JR6. Tanaka, E., Zenitani, R. and Fujise, Y. A point estimate of Natural Mortality Coefficient
using JARPA data.
JA/J05/JR7. Zenitani, R. and Kato, H. Long- term trend of age at sexual maturity of Antarctic minke
whales by counting transition phase in earplugs.
JA/J05/JR8. Tamura, T. and Konishi, K. Feeding habits and prey consumption of Antarctic minke
whales, Balaenoptera bonaerensis in JARPA research area.
JA/J05/JR9. Konishi, K. and Tamura, T. Yearly trend of blubber thickness in the Antarctic minke
whale Balaenoptera bonaerensis in Areas IV and V.
JA/J05/JR10. Matsuoka, K., Hakamada, T. and Nishiwaki, S. Distribution and abundance of humpback,fin and blue whales in the Antarctic Areas IIIE, IV, V and VIW (35°E-145°W).
JA/J05/JR11. Murase, H., Nishiwaki, S., Ishikawa, H., Kiwada, H., Yoshida, T. and Ito, S. Results ofthe cetacean prey survey using echo sounder in JARPA from 1998/99 to 2002/03.
JA/J05/JR12. Murase, H., Tamura, T., Matsuoka, K., Hakamada, T. and Konishi, K. Preliminary
estimation of feeding impact on krill standing stock by three baleen whale species (Antarctic minke,
humpback and fin whales) in Areas IV and V using JARPA data.
JA/J05/JR13. Yasunaga, G., Fujise, Y., Zenitani, R., Honda, K. and Kato, H. Yearly trend of traceelement accumulation in liver of Antarctic minke whales, Balaenoptera bonaerensis.
JA/J05/JR14. Yasunaga, G., Fujise, Y., Zenitani, R., Tanabe, S. and Kato, H. Spatial and temporalvariation in organochlorine contaminants in the Antarctic minke whales, Balaenoptera bonaerensis.
JA/J05/JR15. Watanabe, T., Yabuki, T., Suga, T., Hanawa, K., Matsuoka, K. and Kiwada, H. Resultsof oceanographic analyses conducted under JARPA and possible evidence of environmental changes.
JA/J05/JR16. Pastene, L.A., Goto, M., Kanda, N. and Nishiwaki, S. Genetic analyses on stock
identification in the Antarctic humpback and fin whales based on samples collected under the JARPA.
JA/J05/JR17. Fujise, Y., Hatanaka, H. and Ohsumi, S. Changes occurred on Antarctic minke whale
stocks in the Antarctic and their ecological implications.
JA/J05/JR18. Mori, M. and Butterworth, D.S. Progress on application of ADAPT-VPA to minke
whales in Areas IV and V given updated information from IDCR/SOWER and JARPA surveys.

21

JA/J05/JR19. Johnston, S.J. and Butterworth, D. Assessment of the west and east Australian breeding
populations of southern hemisphere humpback whales using a model that allows for mixing on thefeeding grounds and taking account of the most recent abundance estimates from JARPA.
JA/J05/JR20. Burt, M.L., Hedley, S.L., Marques, F.F.C., Hakamada, T. and Matsuoka, K. Spatialmodeling of JARPA survey data in Area V.
JA/J05/JR21. Kitakado, T., Fujise, Y., Zenitani, R., Hakamada, T. and Kato, H. Estimation of natural
mortality coefficients for Antarctic minke whales through VPA studies.
JA/J05/JR22. Butterworth, D.S. and Mori, M. Implications of the updated ADAPT-VPA assessments
for the dynamics of minke whales in Areas IV and V.
JA/J05/JR23. Mori, M. and Butterworth, D.S. Progress on multi-species modelling in the Antarctic.
For information Papers
For information 1. Report of the Intersessional Working Group to Review Data and Results fromSpecial Permit Research on Minke Whales in the Antarctic, Tokyo, 12-16 May 1997.
(Rep.Int,Whal.Commn. 48: 377-390)
For information 2. Mori, M. and Butterworth, D.S. Consideration of multispecies interaction in the
Antarctic: A preliminary model of the minke whale -blue whale- krill interaction. Ecosystem
Approaches to Fisheries in the Southern Benguela, Afr. J. mar. Sci. 26: 245-259.
For information 3. Murase, H., Matsuoka, K., Ichii, T. and Nishiwaki, S. Relationship between the
distribution of euphausiids and baleen whales in the Antarctic (35ºE-145ºW). Polar Biology 25:135145.
For information 4. Matsuoka, K., Watanabe, T., Ichii, T., Shimada, H. and Nishiwaki, S. 2003. Large
whale distributions (south of 60°S, 35°E-130°E) in relation to the southern boundary of the ACC.
Antarctic Biology in a Global Context, pp 26-30. Edited by A.H.L. Huiske, W.W.C. Gieskes, J.
Rozema, R.M.L. Schrno, S.M. van der Vies and W.J. Wolff. Backhuys Publishers, Leiden, The
Netherlands.
For information 5. Kasamatsu, F., Nishiwaki, S. and Ishikawa, H. Breeding areas and southboundmigration of southern minke whales Balaenoptera acutorostrata. Mar. Ecol. Prog. Ser. 119: 1-10.

22

Annex D
Outline of the JARPA Surveys

23

Annex E
List of Data Sets Produced by JARPA
Total
Sample size
1
2
3
4
5

I SIGHTING DATA
Angle and distance experiment data (no. of experiments)
Photo-ID, other species than minke whale (no. of photographs)
Sighting data (no of schools)
Survey effort data (research days * no. of SV and SSVs)
Weather data (research days * no. of SV and SSVs)

Number of samples (no. of individuals)

II BIOLOGICAL DATA
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55

Age
Baleen plate set mouth cavity
Baleen plates, length of plate series
Blubber thickness (14 points)
Blubber thickness (3 points)
Blubber thickness (5 points)
Body length
Body proportion
Body weight
Brain weight
Catching date
Catching location
Corpora albicantia and lutea (number)
Craniometric data
Discovery-type marks recovery
Endocrinogical studies on reproduction
Epididymis weight
Foetus, body length
Foetus, body proportion
Foetus, body weight
Foetus, number
Foetus, sex
Jacobson's organ shape
Lactation condition
Lipids contents
Mammary gland measurements
Maturity stage
Mitochondrial DNA control region sequences, humpback whale
Mitochondrial DNA control region sequences, fin whale
Mitochondrial DNA control region sequences, minke whale
Mitochondrial DNA RFLP-derived haplotype distribution
Nuclear DNA microsatellite (6 loci)
Organ weights
Parasites, external occurrence record
Parasites, internal occurrence record
Ribs (number)
Selenium analysis
Sex
Skeleton (whole skeleton measurement)
Skull (length and breadth)
Stomach contents (IWS format)
Stomach contents weight, first stomach, excluding liquid
Stomach contents weight, including liquid
Stomach contents weight, second-fourth stomachs, excluding liquid
Tail notch shape
Testis weightTransition phase
Uterine horn (breadth)
Ventral grooves (number)
Biopsy sampling (Humpback, blue, right, fin, sei, sperm, killer whales)*Heavy metals (liver)
Heavy metals (Stomach contents)
Marine debris (Stomach contents)
Organochlorine (blubber)

60
61
62
63

Marine debris (Sighting survey)
Organochlorine compounds (air)Organochlorine compounds (sea water)
Temperature (XBT survey)

♂
3,452
681
767
583
1,579
1,859
3,452
3,452
3,291
1,131
3,453
3,453
19
1
0
3,452
814
755
813
817
3,452
587
3,452
143
0
516
3,195
3,203
587
3,452
3,452
3,451
0
3,453
5
3,345
3,451
3,336
3,336
644
3,452
3,452
3,452
3,452

♀
2,901
593
748
492
1,261
1,606
2,901
2,900
2,773
975
2,901
2,901
2,896
23
3
0
773
720
767
2,894
817
2,900
2,894
493
2,894
2,901
133
0
476
2,643
2,610
493
2,900
2,900
2,900
0
2,901
5
2,812
2,899
2,802
2,802
613
2,900
2,901
2,876
2,900

Total
6,353
1,274
1,515
1,075
2,840
3,465
6,353
6,352
6,064
2,106
6,354
6,354
2,896
42
4
4
3,452
1,662
1,482
1,616
2,894
1,692
6,352
2,894
1,080
2,894
6,350
276
23
992
5,838
5,813
1,080
6,352
6,352
6,351
74
6,354
10
6,157
6,350
6,139
6,139
1,257
6,352
3,452
6,353
2,876
6,352
410

Number of samples (no of individuals)
Total
♂
♀
922
150
1,072
67
33
100
7
2
10
105
0
105
Number of samples
255
9
7
904

III ENVIRONMENTAL DATA
56
57
58
59

5935
879
44531
5820
5820

*: This includes 304 humpbacks, 35 right, 26 fin, 22 blue, 20 minke, one sei, one sperm and one killer whales.

24