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Report of the Intersessional Workshop to Review Data andResults from Special Permit Research on Minke Whales in the
Antarctic, Tokyo, 4-8 December 20061
1. INTRODUCTORY ITEMS

1.1 Welcome and introduction
The Workshop met at the Institute of Cetacean Research(ICR), Tokyo, on 4-8 December 2006. The list ofparticipants is given in Annex A. The Chair of the ScientificCommittee (SC), Bjørge, welcomed the participants, inparticular the invited experts that do not normally attend themeetings of the SC. Bjørge also thanked the Government ofJapan and the ICR for the venue and facilities madeavailable for the meeting and he acknowledged the Japanesescientists for their considerable work in preparation for thismeeting.
A Steering Group chaired by Zeh had planned thismeeting over several years and Bjørge conveyed to themeeting Zeh’s regrets that she could not attend and address
the meeting in person. She sent her sincere thanks to allmembers of the Steering Group, and to all those who had
contributed to the preparations for the meeting. The meeting
agreed to ask Bjørge to forward its thanks and appreciation
to Zeh for her work in the Steering Group.
Morishita welcomed the participants on behalf of theGovernment of Japan who was hosting the Workshop. He
particularly thanked those scientists who had travelled far toattend the Workshop. He explained the importance Japan
attached to the forthcoming discussions and looked forward
to a full and fair scientific discussion of the items on the
Agenda.
1.2 Election of Chair and appointment of rapporteurs
Bjørge noted that the SC/58 Convenors Meeting had agreed
that Bannister should Chair the Workshop. Donovan
coordinated production of the report with assistance from
Hedley, Kitakado, Hoelzel, Cooke, Reid, Mori, Aguilar andPastene.
1.3 Meeting procedures and time schedule
Practical arrangements were dealt with by the ICR. The
meeting agreed to a time schedule proposed by the Chair.
1.4 Adoption of Agenda
The Working Group adopted the Agenda shown in Annex B.

1.5 Documents and data available
The documents presented to the Working Group are listed in
Annex C. The Workshop was pleased to note that the datafrom the programme listed in Annex D had been available
for participants under the Committee’s Data Availability
Agreement (DAA).
1

Presented to the meeting as SC/59/Rep1.

1.6 Terms of reference for this review
The Scientific Committee had agreed two years ago to holdan intersessional scientific workshop to assist in its reviewof the results of the Japanese special permit research in the
Antarctic (JARPA) programme, 1987/88-2004/05 andestablished a Steering Group under Zeh to prepare for theWorkshop. The Committee agreed that the objectives of thefull review are to evaluate:(1) how well the initial and revised objectives of theresearch have been met;(2) other contributions to important research needs;(3) the relationship of the research to relevant IWC
resolutions and discussions, including those dealing
with the Antarctic marine ecosystem, environmental
changes and their impact on cetaceans and Committee
reviews of special permit research; and (4) the utility of
the lethal techniques used by JARPA compared to nonlethal techniques.
The Committee had agreed (IWC, 2006a, p.48) that the full
review will consider only scientific issues; ethical issues arebeyond its competence. This agreement was taken into
account in the discussion. The Committee had also agreed atthat time that some discussion of the respective merits oflethal and non-lethal methodology is important and that
Invited Participants would be able to contribute to thatdebate. However, the Committee had also agreed that themain focus of the Workshop would be on Items 1-8 of theAgenda (Annex B); the more contentious issues under Item
9 would mainly be discussed at the subsequent Annual
Meeting (SC/59). In fact, time constraints at the Workshop
meant that Item 9 could not be discussed here.
1.7 Objectives of JARPA as stated in the original
research proposal and subsequently
SC/D06/J1 presented an outline of the JARPA research
objectives. The Government of Japan has conducted JARPA
surveys since the 1987/88 season under the Article VIII of
the International Convention for Regulation of Whaling, as
a long-term project. The last survey of the JARPA wascompleted in the 2004/05 season. As the programme
progressed, the objectives of the project evolved from two in
the original plan to four after the 1995/96 season. The
authors noted that the additional objectives were not analteration of the original plan, but rather its development.
The IWC Scientific Committee held a mid-term Workshop
in 1997 to review JARPA data and results (IWC, 1998a) andduring its 1997 Annual Meeting (IWC, 1998b), the
Scientific Committee discussed the report of the Workshop

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and identified several future tasks to be addressed in the
programme. The authors concluded that reasonable progress
had been made on most of the tasks.
The two original research objectives as defined in the
JARPA project, submitted as SC/39/O4 (Government ofJapan, 1987) to the 1987 Committee meeting (IWC, 1998b),
were:
Objective 1. Estimation of biological parameters to
improve the stock management of the Southern Hemisphereminke whale; andObjective 2. Elucidation of the role of whales in the
Antarctic marine ecosystem.
The addition of a third objective occurred in 1995/96(Government of Japan, 1995):
Objective 3. Elucidation of the effect of environmental
change on cetaceans (a development of Objective 2).
The final addition was made in 1996/97 (Government ofJapan, 1996):
Objective 4. Elucidation of the stock structure ofSouthern Hemisphere minke whales to improve stock
management (already implicit in Objective 1).
The Workshop did not spend time discussing theobjectives of the programme in any detail. Annex E provides
the wording of the original proposal and the changes
included for the 1995/96 season. The Workshop’s
conclusions on the extent to which the objectives have beenor can be met are given under Item 8.
1.8 General outline of the JARPA research
SC/D06/J2 presented a general outline of JARPA, including
sighting and sampling protocols as had been requested at the2006 Annual Meeting. JARPA was conducted every year
from the 1987/88 to 2004/05 seasons. After two seasons offeasibility research, full-scale research began in 1989/90.
The programme was designed to repeat surveys in Antarctic
Areas IV and V alternately in each of the sixteen years of theresearch period. Area IV was divided into five strata andArea V into four strata. Although the whole research period
ranged from the end of November to March, regularresearch in Areas IV and V was concentrated in January andFebruary. A Special Monitoring Zone was established toinvestigate seasonal variation of whale density from the
1992/93 to 1994/95 seasons. From the 1995/96 season, thesurvey area expanded into a part of Areas III and VI to
improve the stock structure study. In order to achieve its four
objectives JARPA comprises a combination of sighting andsampling surveys. In general, a saw tooth (right triangles)
shape track line at intervals of 4° longitude or
IDCR/SOWER style zigzag track line were used in thesouthern strata and a zigzag track line at intervals of 15°
longitude (or flexibly as in IDCR/SOWER) was used in thenorthern strata. In order to obtain biological samples
representing whole population in the research area, arandom sampling method coupled to line transect sighting
surveying was adopted. Two or three sighting/sampling
vessels (SSVs) conducted sighting and sampling survey on
the predetermined track-line with parallel sub-track lines. A
dedicated sighting vessel (SV) was introduced from 1991/92
and the SV preceded the SSVs by a distance of over 12
n.miles, to avoid influence of sampling activity on thesighting survey. One or two Antarctic minke whales were
sampled randomly from each primary sighted school within
3 n.miles of the trackline of each SSV. Individuals to besampled in a school were chosen by a researcher on board
using a series of tables of random sampling numbers. All thewhales sampled were subject to biological sampling andmeasurements on the research base vessel. Someexperiments with respect to sampling method wereconducted to improve the methodology of thesighting/sampling survey. In parallel with the lethal
sampling survey, a variety of non-lethal studies wereconducted e.g. oceanographic surveys, prey surveys, andphoto-identification and biopsy sampling for large baleen
whales. A summary of research procedures and results ineach cruise was also presented in the document.
The Workshop welcomed this report which provided
valuable information for many topics on the Agenda.
1.9 Overview of the 1997 JARPA review andsubsequent discussions
The Workshop considered the report of the 1997 JARPA
review Workshop (IWC, 1998a) and the discussions at thesubsequent Annual Meeting (IWC, 1998b). Relevant issues
are considered in detail under the appropriate Agenda items
below.
2. SIGHTING SURVEYS AND ABUNDANCEESTIMATION

2.1 Background
The proposers noted that the primary reason for conducting
JARPA sightings surveys was their contribution to theimprovement of the management of Southern Hemisphereminke whales. Their pertinence to the RMP and theassociated implementation for Southern Hemisphere minke
whales was seen as a derivative objective. From the
beginning of the programme in 1987, the first objective of
JARPA was to estimate an age-specific mortality coefficientthrough stochastic sampling (later modified to an average
mortality rate), in combination with systematic sampling
surveys. One of the improvements to the original plan
adopted at the start of the full programme (following two
years of feasibility study) was the conduct of line transect
surveys.
In contrast to the IWC IDCR/SOWER surveys whichhave recently completed the third of three circumpolar (CP)surveys in the Southern Ocean (covering up to 60° of
longitude each year for almost 30 years), JARPA surveys
have been conducted in IWC Areas IV and V for 18 years
with more recent extensions to the east and the west of this.
During the mid-term JARPA review meeting in 1997, it wasnoted that JARPA provides more frequent repetition ofsurveys of the same localities than the IDCR/SOWER
programme, which could better facilitate estimation of theextent on inter-year variability in local abundance, and inturn lead to improved trend estimation. In examining the
JARPA sighting survey results at this Workshop, attention
focussed on the suitability of absolute abundance estimatesfor use in biological parameter studies (Item 4) andestimation of trend from these estimates for input to modelsof the marine ecosystem (Item 5), although inevitably there
will be some inter-relation between the two.
2.2 Issue raised in previous IWC meetings
2.2.1 1997 JARPA review
The 1997 JARPA review meeting recommended that more
research was required to develop a reliable method for
adjusting for negative bias in abundance estimates induced
by undersampling of high density areas resulting from the
JARPA survey design (sampling of whales in high density
areas meant that these areas were under-represented in thesampling effort). It considered that once this had beenachieved, the resultant abundance estimates should be usefulboth as absolute and relative abundance indices.

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The Workshop noted that a number of contributions
addressing this issue had been considered by the Committee
since 1997. Further discussions of this are found under the
relevant agenda items.
2.2.2 Humpback whale Workshop
The 2006 Hobart humpback whale Workshop (IWC, 2006b)
recommended that the following seven items be presented to
the Scientific Committee:(1) clearer/enlarged displays of effort and sightings data, inparticular to show details of the southern strata and theice edge;(2) display/analyses of the temporal distribution of
searching effort within-season, particularly with respect
to latitude and the ice edge, in order to allow evaluationof any changes over time and to evaluate whether
following the path of any migration may be of concern;(3) a full description of the policy that determines when thevessels steam/transit without sampling/sighting effort,
how and when this may change over the course of asurvey and displays/analyses of any potential bias that
may result from policy decisions;(4) analyses of sightings cues by inter alia area, time,
season, sighting distance etc.;(5) separate analyses of sighting effort for vessels that carryout sightings only (SV) and vessels that also catch
whales (SSV);(6) separate analyses of school size by SV and SSV, taking
into account time within a season and area, especiallywith respect to latitude and ice edge; and(7) evaluate/display how the fraction/density of whales in
the northern and southern areas covered by the vessels
may have changed over time (taking into accountseasonal differences in timing of effort etc.).
The first four of these were presented to the 2006 Annual
Meeting (IWC, 2007b , pp.188-209). The analyses requested
in Item 4 did not reveal that heterogeneity in sighting cue
needed to be accounted for directly in the analyses. The last
three items were recognised as matters that would be
relevant when considering the analyses presented to thisWorkshop.

2.2.3 OtherAt the 2006 Annual Meeting, three further issues wereraised when examining line transect analyses. The first ofthese was the question of how to deal with apparently
unsurveyed areas within strata (for example due to ice edge
movement), and it was recommended that abundance
estimates be based on the surveyed (ice-free) portion of thestratum. The second concerned the saw-tooth trackline
design employed in some southern strata. It was suggested
that this design might be biased if there was a density
gradient of whales from the ice edge and that as a sensitivity
analysis, abundance for these strata should be estimatedusing data from the north-south transects only and comparedwith estimates which used data from all the transects. The
third issue raised was the question of uneven coverage
probability within some of the southern strata.
Furthermore, the Committee recommended (IWC, 2007a, p.38) that the JARPA survey design, its protocols, how they
have changed over time, and any differences between thedesign and the implementation of it were set out in a single
document and presented to the JARPA review meeting. It
noted that this should clarify the following three specificquestions, which would help determine the appropriate
method to estimate variance.

413(1) How are tracklines adjusted ‘real-time’ on the vessels,
including when the ice edge is encountered
unexpectedly?
(2) How do the vessels interact at the end of the survey day,and how is the amount of night steaming by each vessel
independently decided?
(3) Which vessels were used in the surveys, and were theyused any differently in different years?
Information on how the location of the ice edge changed
during the course of a survey was also requested.

2.3 Data collection methods and results
The Workshop welcomed the provision of SC/D06/J2 that
had been provided in part as a response to the request fromthe Scientific Committee. The authors had concluded thatthe sightings data obtained from JARPA were reliable
enough to use for abundance estimation purpose because (a)in principle, tracklines were set systematically so as tocollect random data and (b) JARPA has surveyed Areas IV
and V alternatively for 18 years with the maximum survey
effort being spent in Areas IV/V during January andFebruary, which was considered to be the peak migration
period of the minke whales. The authors noted that sighting
surveys had been conducted eight times in Areas IV and V,
respectively. During the survey period searching effort was
distributed uniformly in these Areas (the starting position of
the sighting survey was selected randomly).
The Workshop noted that the sighting survey proceduresthat have been used in JARPA were similar to those used in
IWC IDCR/SOWER surveys. The closing procedures (e.g.
to determine school size) were identical to those used inclosing mode for the IDCR/SOWER surveys, except that
additional time was spent on sampling and that closing was
limited to minke whales. The vessels engaged in such
sampling (termed ‘SSVs’) surveyed along parallel
tracklines, but from the 1991/92 season, one vessel (the‘SV’) at any one time was devoted to sighting only, in order
to investigate the effect of sampling activity on abundance
estimates. Since 1995/96, the SV conducted a sighting
survey and an active acoustic survey independently, using
closing and passing mode procedures on tracklines surveyed
independently from those of the SSVs.
One key difference between JARPA and IDCR/SOWER
was noted, namely that IDCR/SOWER has operated inalternate IO (Independent Observer) and closing modes,
whilst JARPA operated in (different types of) closing andpassing modes without IOs. Conventional line transect
analyses of IDCR/SOWER data have assumed g(0)=1 andhave standardised on IO mode, correcting for possible bias
in closing mode, but the Committee is moving towards moreelaborate estimation methods that do not make theseassumptions.
Relevant data obtained in JARPA sighting surveys are:(1) number of angle/distance experiments: 6,426(2) sighting data (number of schools): 48,600(3) survey effort data: primary effort of 293,811 n.miles
covered in 6,188 ship-days(4) weather data (number of observations): 94,840.
Information on other data can be found in Annex D.

2.4 Data analysis methods and results
In considering the issue of abundance estimates from thesurvey, the Workshop noted that any estimates refer to thenumber of animals present in a particular geographical area
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discussion of stock structure and mixing on the feeding
grounds summarised under Item 3) will not be indicative of
biological population abundance, although abundance forone possible stock structure hypothesis (see Item 3) ispresented.
2.4.1 Minke whales
SC/D06/J3 examined the possibility of correcting for theeffect of skip. Four types of skip arose in JARPA surveys:
night steaming (type A); catching up with the schedule ofthe survey (type B); closing and chasing of whales targeted(type C); and bad weather condition (type D). Amongst
these, Hakamada et al. (2006) suggested that the estimate ofminke whale density is only affected by skip types A and C.
In this paper, a modification of the method of Burt andBorchers (1997) was developed to correct bias due to skip
type A which affected only the surveys from 1989/90 to
1992/93 (after which a different survey protocol applied).
Corrected abundance estimates in Area IV obtained from
SSV data were 32,630 (CV=0.142) in 1989/90 and 34,982(CV=0.171) in 1991/92. Those in Area V were 108,457(0.124) in 1990/91 and 84,813 (CV=0.162) in 1992/93. The
corrected abundance estimates were greater than theuncorrected ones. This suggested that skip type A resulted innegatively biased estimates although the level was notsubstantial. Corrected abundance estimates obtained fromthe method developed in the paper tended to be smaller thanthose from the method of Burt and Borchers (1997). A
further correction was made by using Haw’s method (Haw,
1991) to calibrate the difference between survey vessels.
The estimated abundance series were used to estimate
annual increase rates and their CV’s, and results showed thatthe estimates were 21.10% [-4.25%, 2.02%] and 22.16%[-4.83%, 0.44%] in Area IV and V, respectively. Neither
estimate was significantly different from 0, and the authors
concluded that skip type A would not substantially affectestimates of trends in abundance trend for Antarctic minke
whales.
The Workshop noted that this was an issue raised at the2006 Annual Meeting and welcomed this analysis that
represented progress in correcting bias due to skip.
However, some concerns were raised about the approach
employed and it was suggested that it would be difficult toremove this bias completely. The need for further
investigation of the approach using simulation studies toassess correction performance was also suggested. It wasnoted that a slight difference in estimates for annual increase
rate with and without the correction could still lead to thelarge differences over a longer period. Given that theestimates of abundance from 1989/90-1992/93 might reflect
overcorrection of the bias caused by skip, it was noted that
this implied that estimated annual increase rates based onabundance series that incorporate this correction were
probably lower bounds. Thus the results in this paper
contributed to limiting the possible ranges of annual
increase rates.
SC/D06/J4 reviewed the spatial modelling analyses(density surface models (DSM)) that have been conducted
on JARPA survey data. These analyses were originallyproposed as a potential means to correct for the negative
biased induced by skip type ‘A’. Initial results fromsimulation studies which looked at a range of densities andclustering scenarios were promising, with little or no bias
evident from one of the model-based approaches examinedin the simulation study when appropriate levels ofsmoothing were chosen. However, some problems wereencountered when applying this approach to real JARPA
survey data. In particular, the available spatially-referenced
covariates (latitude, longitude and distance from ice edge as
recorded from the vessels when in the southern strata) were
frequently inadequate to describe the distribution ofsightings. Model-fitting was difficult, particularly in the
more topographically complex Area V, and sometimes low
coverage in the edges of the survey region caused
undesirable behaviour in the smooth surface. This was
especially apparent when estimating variance, because thenon-parametric bootstrap was unable to reproduce thespatial coverage in effort achieved by the actual data. The
authors concluded that whilst spatial modelling methods inprinciple can correct for a non-random sampling design, thecurrent application of the methods relies on appropriate
model specification and this has proved difficult with the
JARPA data. Furthermore, they anticipate that some of thespecific problems related to appropriate smoothers andcomplex geographical areas may be alleviated when
methods that deal with these issues directly (Wood et al.,2007) are fully developed.
In discussion, it was suggested that determination of theappropriate scale of the grids was important for such
purposes. If the length of skip type A is larger than the scaleof whole clusters, then effects of large and small densities in
the part of a leg skipped leg might cancel out, and hence theimpact of skip would be negligible. In this sense, local
clustering would not affect skip type A. However, it waspointed out that the effect of local clustering could not beignored in examination of skip type C. Local clustering also
affects the assessment of uncertainty in abundance
estimation even if the effect of the skip is small. It was alsosuggested that the possibility of the post-application of theadaptive sampling (Thompson and Seber, 1996) to closing
mode survey for finding better correction formulae should
be investigated.
In the DSM approach (see SC/D06/J4), the abundance
estimate is derived by summing up the grid-basedabundance estimates predicted by the smoother, which arecorrelated. However, the variance of the abundance estimate
is estimated without taking this covariance into account, andtherefore is negatively biased. Bootstrap methods thatincorporate covariance were suggested as a possible way toaddress this. Over-smoothing also causes underestimation ofvariance. It was noted that a new model allowing for trend
and clustering being developed by Bravington may provide
better variance estimates. It was also suggested that satellite
data may provide more accurate information on the ice-edge
for the DSM.
In summary, the workshop noted potential difficulties
in correcting for skip effects by applying spatialmodels to estimate abundance, and agreed that standard
design-based estimates were best at this stage even if
those need some sorts of correction as put forward in
SC/D06/J3.
SC/D06/J5 introduced a model for the estimation of g(0)under a single-platform sighting survey. The surfacing
probability in a unit time was used as a known parameter. A
detection probability function with covariates such assighting conditions and group size is employed, andestimated by the maximum likelihood method. Simulation
studies showed that the estimator of g(0) was unbiased when
the true detection probability function was assumed
although it was not robust to misspecification of thisfunction. The method was applied to the JARPA survey data
in Area IV, and provided estimates of g(0) that weresignificantly less than 1.

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Workshop agreed that a better approach, similar to thatapplied in SC/D06/J06, is to fit a model which is able toaccount for heteroscedascity in sampling variance andincorporate additional variance. Such a model could also be
more readily adapted to examine other factors, such aschanges in mode effect over time (depending on samplesize).
In further discussion, a number of technical issues withthe analyses presented in SC/D06/J6 were raised. A small
group under Hedley was convened to discuss these issues indetail, to recommend alternative or additional analyses
where appropriate and to consider, possibly in the light ofthese new analyses, the utility of abundance and trend
estimates from JARPA data. Their discussions andrecommendations have been incorporated into the report
below.

J. CETACEAN RES. MANAGE. 10 (SUPPL.), 2008

The Workshop recognised the value of developing
methods to estimate g(0) from single platform surveys suchas JARPA. It thanked the author for his paper but for anumber of reasons it did not believe that the approach given
in SC/D06/J5 was appropriate. For example, the method
assumes that Q (0,0)=1 where Q is the detection probability
function. Furthermore, as the model assumes constantsurfacing rates, which imply essentially Poisson processes
for surfacing pattern, well-established hazard probability
models under the Poisson assumption can be applied
without the complication of the model developed. The
Workshop strongly encouraged the author to consider
previous literature and discussions of the Committee on theissue of g(0). The Workshop also draws attention for theneed for any proposed new techniques to be tested using the
IWC simulated datasets.
SC/D06/J6 presents updated abundance estimates for
Antarctic minke whale based on JARPA sighting data using
IWC ‘standard’ methodology and the inter-mode calibration
method of Haw (1991). All estimates assumed g(0)=1. Inorder to address some of the recommendations andcomments made at the 2006 Annual Meeting (Item 2.2), thefollowing adjustment and sensitivity tests were conducted.
The effects of closing mode and of sampling activities onabundance estimates were investigated using a linear model
approach. The area size was recalculated to reconsider
boundaries of survey strata to address the issue of
unsurveyed areas. In addition, the effect on estimation ofincluding and excluding certain tracklines along the ice edge
was investigated by estimating abundance using option A,
all tracklines (PA), exclusion of tracks that appeared tofollow the ice edge (PB) and finally excluding all but N-S
tracks (PC). The authors concluded that their results showedthat including tracklines along ice edge in the analysis does
not lead to overestimates of abundance. After recalculationof areas, the abundance estimates differed by typically up to
about 10%. The average of PB/PA was not significantly
different from one in each case; the average of Pc/PA issignificantly larger than one in some cases. The authors
concluded that including all completed tracklines would not
greatly impact estimates of abundance while improving
estimates of precision. The estimates of abundance in Areas
IV and V presented were 44,564 (CV=0.291) in 2003/04 and
72,087 (CV=0.146), respectively and those for the putative
I and P stocks proposed in SC/D06/J12 (see discussion
under Item 3) were 118,956 (CV=0.164) in 2003/04 and91,819 (CV=0.147) in 2004/05, respectively, based on thecalibration method of Haw (1991). The estimated annual
rates of increase are discussed under Item 2 and their 95%
CIs in Areas IV and V were 20.42% [-4.02%; 4.59%](1989/90-2003/04) and 21.54% [-4.91; 2.18%] (1990/912004/05), respectively. For the putative I and P stocks thevalues were 7.93% [-0.05%; 11.45%] (1995/96-2003/04)
and 25.88%. No significant increase or decrease inabundance trend was detected.
The Workshop acknowledged the considerable work that
had gone into the analyses of SC/D06/J06, and in particular
was appreciative of progress made in addressing questions
raised by the previous IWC meetings discussed under Item
2.2. One of these issues was the estimation of a correction
factor due to survey mode. SC/D06/J6 considered two
approaches to this question: estimation of ‘Haw-type’
calibration factors that standardise on SV passing mode anduse inverse-variance weighting to adjust estimates in SSV
mode to SV closing mode and in turn SV closing mode to
SV passing mode. One drawback of this two-stage process
is that it fails to account fully for covariances. The

415

DETECTION FUNCTION ESTIMATIONIn SC/D06/J6, different detection functions were estimatedfor each stratum. In some cases, this led to estimating
detection functions using very few sightings (possible due tothe ‘smearing’ technique used). The Workshop
recommended that as a guideline, detection functions
should be estimated using an absolute minimum of 15
sightings. Where fewer sightings occur pooling should beundertaken. The preferred option for this is to pool EastWest strata as sighting conditions and school size
distributions would be expected to be fairly similar.
Although a suggestion that pooling options for analysis ofdata for a small number of specific years could be selectedusing an objective criterion such as Akaike’s Information
Criterion (AIC), the Workshop recognised that this could be
difficult to apply consistently when considering the fullseries of JARPA data.
VARIANCE ESTIMATION FROM THE SSV DATAIn SC/D06/J6, variance in encounter rate was estimatedseparately for each transect covered by the SSVs. (Survey
protocols dictated that the SSVs rotated transects daily).
This estimation method assumes that the three parallel SSV
transects are located independently of each other, and would
be expected to underestimate the true variance (since thevariability between any two parallel transects on the same
day would be expected to be less than any two randomly
selected transects). Whilst recognising that this issue has
only relatively recently been raised within the Committee,
the Workshop nevertheless considered it important andrecommended that the data be re-analysed, treating all threeparallel transect legs as the sampling unit.
ACCOUNTING FOR THE ORDER THAT THE STRATA WERESURVEYED (RELEVANT FOR TREND ESTIMATION)

In the first half of the JARPA surveys, both the northern andsouthern strata had been surveyed in the early part of thesurvey period, but latterly survey effort at this time wasprimarily in the northern strata. This change may cause aproblem particularly when estimating trends in abundanceand considering other processes such as changes in thelocation of the ice edge (and ice type) and whale migration.
This issue is not simple to resolve but as an appropriate firststep the Workshop recommended that a generalised linear
modelling (GLM) approach (similar to that conducted in
SC/D06/J6) be taken whereby appropriately chosen
covariates or factors (such as the middle date that a stratum
was surveyed in a given year) could be included to enable
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recommended that additional variance be estimated as well
as taking due account of estimates of sampling variance foreach stratum (e.g. IWC, 2007d).
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REPORT OF THE INTERSESSIONAL WORKSHOP TO REVIEW DATA AND RESULTS

WHALE REACTION TO SAMPLING ACTIVITIESThe general question of the possible effect of chasing andsampling whales by one vessel on the sightings made byother vessels (and thus abundance estimates) was raised.
This is particularly relevant to the three SSVs travelling inparallel seven miles apart and potentially disturbing
individuals from one line to another. The Workshop was
informed of an experiment conducted in four of the JARPA
surveys to examine how minke whales may respond to suchactivities. In the summary of these experiments provided in
SC/D06/J2, the authors stated that there was no evidence ofobvious whale reaction to sampling activity apart from one
case (out of 69 schools observed) where there wasdiscernible movement away from the sighting vessel when
it approached to 1.5 n.miles. Furthermore, the Workshop
was reminded of the protocols on JARPA to alleviate theeffects of such disturbance to the whales by the sightingssurvey. If the chasing of a whale by one vessel was
considered by the Cruise Leader (stationed on the NishinMaru) to be affecting the sighting activities of a vessel on an
adjacent trackline, then the affected vessel would stop andwait until those activities were over (or no longer considered
to be within the surveyable strip of the affected vessel),before resuming effort. Given this additional information(more fully explained in SC/D06/J2), no further analyses
were specifically recommended at this stage. Nevertheless,it was noted that an empirical way of examining the existingdata to see if these activities might be problematic would be
to check that sightings on the three SSV tracklines werelocated in three (along-trackline) distance bands (in front, in
between, behind) in equal proportions in the presence ofchasing/sampling on an adjacent trackline.
The general question of responsive movement to vessels
was also raised. The Workshop agreed to refer this matter tothe IA sub-committee as it was relevant to estimating minke
whale abundance for both the IDCR/SOWER and JARPA
surveys.
ESTIMATION OF EFFECTIVE STRIP WIDTH AND MEAN SCHOOLSIZE FROM THE SSV DATA

The analyses in SC/D06/J6 had pooled across the three SSV
tracklines for estimation of effective strip width and meanschool size. Although recognising that the rotation of vessels
between these tracklines would help to ‘average out’ any
potential vessel effect, the Workshop recommended thatsensitivities to this pooling be investigated. Furthermore,because of the rotation, not only should a potential vessel
effect be examined but also a potential ‘transect effect’.
These sensitivity tests are considered particularly importantfor effective strip width estimation and less so for theestimation of mean school size.
EXTRAPOLATION INTO UNSURVEYED AREAS

As reported under Item 2.2.3, the Committee hadrecommended at the 2006 Annual Meeting that abundance
estimates be based only on the ice-free areas within asurveyed stratum (so that when converting density estimatesto abundance estimates, areas covered by ice were
excluded). As part of the analyses presented in SC/D06/J6,
this issue was specifically examined. Abundance in theunsurveyed area was in fact estimated using densities
estimated from the northern stratum. The Workshop noted
the process which led to these areas not being surveyed, thatthey did not occur very often and that they occurred only in
Area IV (Table 1). The authors of the paper concluded that
this treatment typically made a difference of up to about
10% of the total estimates and therefore would not
substantially impact on trend estimation. After considerable
discussion, while the Workshop broadly agreed with theauthors’ conclusion, it also recommended that it would bevaluable to bound the problem by examining results forwhich the abundance in the unsurveyed area is treated aszero, as had been recommended at the 2006 Annual
Meeting. During discussion of the report, Childerhouse
noted that in some cases, different treatment of unsurveyed
areas could make up to about 20% difference.

As in any survey, poor weather and other factors canaffect the cruise schedule and may lead to some planned
tracklines in an area not being completed. Occasionally thisoccurred in the JARPA surveys so that, for example, only
the tracklines in the western part of a stratum were covered
and not those in the eastern part. Whilst extrapolation into
unsurveyed areas is not generally desirable, when looking at
trends in abundance it is helpful to do so for comparable
areas. The Workshop recommended that where such(primarily E-W) extrapolations are necessary, the ratio of
density in the unsurveyed area to the surveyed area becalculated from data in other years. The product of this ratio
and the density in the surveyed area in that year would be
used as the estimated density to extrapolate into theunsurveyed area in that year.

ANALYSIS USING THE SAW-TOOTH TRACKLINE DESIGNAt the 2006 Annual Meeting, the Committee hadrecommended that the saw-tooth trackline design employedin some southern strata be examined. In particular, it had
considered that design-unbiased estimates would beobtained from the N-S transects and that as a sensitivity test,
estimates from these transects alone should be comparedwith estimates from all saw-tooth transects (i.e. using those
constructed at an angle to the next planned waypoint aswell). SC/D06/J6 reported the results of this sensitivity
analysis, which somewhat counter-intuitively seemed toindicate that estimates using all transects were allappreciably and in most cases significantly less than for the
N-S transects only (table 4 of that document). Noting
concerns about a reduction in precision using the data fromthe N-S transects alone, the authors of SC/D06/J6 concluded
that it was better to use data from all transects.
Ishikawa (Cruise leader on several JARPA surveys)
commented that JARPA adopted both the saw-tooth design
and IDCR/SOWER design tracklines in the southern strata
and the latter had been introduced in the complex region
where the ice-edge could be changing substantially, such as
in the Ross Sea, adding that all tracklines were implemented
in conformity with the protocols (i.e. trackline construction
was not arbitrary even in ‘difficult’ regions). Nevertheless, it
was evident to the Workshop from examination of the plots

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J. CETACEAN RES. MANAGE. 10 (SUPPL.), 2008of tracklines that the practical logistics of designingtracklines real-time in complex regions where the ice edge
could be changing were so difficult that it was impossible toimplement the saw-tooth design as intended in some years.
There was considerable discussion of this issue, during
which it became apparent that for some ice edge
configurations, particularly the more complex ones
frequently encountered in Area V, it was not necessarily truethat estimates using the N-S transects alone would bedesign-unbiased. The Workshop agreed that all transects
would be useful at least in estimating effective strip widthand mean school size (and their variances). However, it was
unable to resolve the issue of which transects to use forabundance estimation at this Workshop. In order to more
fully understand the results in Table 4 of SC/D06/J6 andtheir implications, the Workshop recommended that thesensitivity analyses of SC/D06/J6 are repeated but withappropriate weighting of the data (e.g. in proportion to thenumber of sightings within a stratum), and/or bybootstrapping (conditional on the total number of sightings).
These new analyses should also be categorised into
‘successful’ implementation of the saw-tooth design and‘unsuccessful’ implementation (i.e. situations where thesaw-tooth pattern is not clearly seen because of complex iceedge configurations). Although recognising that this would
be a substantial piece of work, it was also suggested that thedata be post-stratified (for example into three bins) with
distance from ice-edge, and re-analysed. Noting that it is notnecessary to have results from every year of the JARPA
programme to look at trends, a further possible pragmatic
way forward suggested was to use only those surveys where
the saw-tooth design was subjectively considered to havebeen successfully implemented.
The Workshop recognised the progress that had been
made with respect to obtaining abundance estimates fromthe JARPA surveys but it believed that progress would
probably have required fewer iterations if the Committee
and analysts had adopted a more co-operative approach.
Some of the additional work required has been due to either
a misunderstanding of recommendations made by theCommittee or due to the lack of detail given in theCommittee’s report. It therefore agreed to establish an
Advisory Group (comprising Kitakado (Convenor),
Butterworth, Hedley, Hakamada and Matsuoka) to facilitate
the undertaking of the recommendations given here (and therecommendations made with respect to abundance estimates
and trends given elsewhere under Item 2). This group will
work by email to ensure that the work to be done is fully
specified, review the results and if necessary suggest
modifications with a view to consolidated analyses being
presented, ideally in time for consideration at the 2007
Annual Meeting.
Towards the end of the meeting, Wade reviewed coverageof strata and the sequence of surveys relative to the ice edge
during JARPA. Some of these points had arisen during
discussions in the Workshop and sub-groups but there had
not been time for full consideration. He noted that thelogistics of surveys in the Southern Ocean are difficult,particularly with regard to surveying along the ice edge. The
fact that the surveys take three to four months to becompleted means that considerable changes can occur in thelocation of the ice edge during the survey. In Area IV, there
were trends in (a) the timing of the survey of the ice edge
(i.e. southern) strata, (b) in the extent of sea ice at the timeof coverage of the ice edge strata and (c) in whether a gap
occurred between the northern and southern strata. In
particular, the last three surveys (from 1999/00 to 2004/05)

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were different from the previous five surveys in all thesecategories. In Area V there was also a trend in the sequencein which the strata were surveyed, with a different sequenceoccurring particularly during the last three surveys. The iceedge stratum (SW) was surveyed later (March) during thelast three surveys than during the first five surveys(December-February); furthermore, he noted that coverage
was relatively low during the last two surveys. The SE
stratum (Ross Sea) was surveyed earlier during later
surveys, and the extent of ice was high or medium during
three of the last four surveys whereas it was low in all of thefirst four surveys. Given that minke whale density isrelatively high in the ice edge strata, he considered thatchanges in timing of the coverage of these strata could haveinfluence on the trends in abundance resulting from the
JARPA surveys. Such changes can potentially confoundinterpretation of trends in abundance of any whale species
from JARPA data if that species’ density has some relation
to the ice edge. He also noted that the large changes in theextent of ice at the time of the surveys changes the size ofthe overall survey area considerably, with the survey arealarger in Area IV but smaller in the Ross Sea in the more
recent surveys. This could influence absolute abundance, as
the proportion of minke whales south of 60°S (and therefore
in the study area at the time of the survey) could vary
according to the amount of open ocean available at thattime. He believed that it was important to try to determine
methods to account for such changes in the sequence andtiming of the survey of the southern strata.
The Workshop noted that given the lack of time, it was
not possible to discuss the review in any detail. It wasagreed to append an abbreviated version to the present
report as an authored Annex (Annex F). Wade was
encouraged to present the full version or a modified version
to the Scientific Committee for consideration at the Annual
Meeting, particularly by the IA sub-committee. The
Advisory Group established above to examine abundance
estimates further would also consider these general issues tothe extent possible in its intersessional work.
Finally, it was noted that within the Committee, muchtime has been devoted to discussing potential sources of bias
in estimating abundance and trend from IDCR/SOWER
surveys. Many of the generic issues (i.e. those not related to
specific IDCR/SOWER methodology) could also be sourcesof bias for JARPA estimates, such as changes in thelocations of the ice edge, changes in the proportion ofanimals south of the ice edge and changes in the proportionof animals north of 60°S (Branch, 2006). The magnitude ofsome of these biases could be large and in either direction
with resulting impacts on the estimates.
2.4.2 Other species
SC/D06/J7 reported information on current distribution
abundance for humpback (Megaptera novaeangliae), fin(Balaenoptera physalus) and blue (B. musculus intermedia)
whales in the Antarctic Areas IIIE, IV, V and VIW, south of
60°S. The sighting survey under JARPA was designed as alarge-scale and long-term monitoring exercise using linetransect surveys. As noted above, it was carried out in a
broadly consistent way every year alternating between
Areas IV and V from 1987/88 to 2004/05 austral summer
seasons. Sighting surveys were repeated in the same area inthe same month (mainly January and February) for 18 years.
For the whole period, a total search distance on primaryeffort of 293,811 n.miles was achieved during 6,188 shipdays. The survey protocols were similar to those used
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2.5.1 Minke whales
The extensive discussion of the abundance estimates for
Antarctic minke whales presented under Item 2.4.1 is clearly
relevant to the discussion of the trends presented in
SC/D06/J6. Table 2 provides the estimates of trend andassociated confidence intervals from the JARPA surveys asreported in SC/D06/J6 (tables 8 and 9).

REPORT OF THE INTERSESSIONAL WORKSHOP TO REVIEW DATA AND RESULTS

using the program DISTANCE, taking into account thesuggestions offered in recent Committee meetings. The
largest concentration of humpback whales has occurred
recently to the east of the Kerguelen Plateau between 80°
and 120°E, and the authors commented on apparent
latitudinal and longitudinal expansions of this area overtime. In general, fin whales were said to be more widespreadin Area V than Area IV. However, in recent years they havealso been observed frequently in the western part of Area IV.
Furthermore, high density areas were observed to the westof the Balleny Islands and Kerguelen Plateau. Blue whales
were widely distributed in the research area although noapparent regional aggregation was evident. The eight fullscale surveys in each of Areas IV and V provided estimatesof abundance for these species with reasonable precision
given the relatively large number of sightings. The effect ofsurvey mode on the estimates was examined by the authors.
Sensitivity to alternate selection from tracklines in southern
strata showed that possible biases in estimates were verysmall. The resultant abundance estimates of humpback
whales were 27,783 (CV=0.12) in Area IV in 2003/04 and
9,342 (CV=0.34) in Area V in 2004/05. Abundance
estimates of fin whales were 6,514 (CV=0.27) in 2003/04
for the Indian Ocean stock and 5,241 (CV=0.38) in 2004/05
for Western South Pacific stocks, although it must be
remembered that fin whales are mainly found north of 60°S.
The abundance of blue whales for the whole research area
was estimated as 1,265 (CV=0.33). A total abundance
estimate for fin whales based on the two recent surveys forthe half of Antarctic Areas (35°E 2145°W) south of 60°S
was 12,000 (CV=0.22). The authors proposed a ‘shift inbaleen whale dominance’ from Antarctic minke to
humpback whales in Area IV since the 1997/98 survey.
As
notedabove,
severalsuggestions
andrecommendations had been made at previous IWC meetings
regarding the estimation of abundance as well as its trend(e.g. see Item 2.2.2). The Workshop appreciated that theconsiderable amount of work had been undertaken in therelatively short time available since the 2006 Annual
Meeting. It agreed that a large dataset on distribution andabundance for humpback, fin and blue whales has been
accumulated by sighting surveys conducted under JARPA.
The Workshop noted that some of the points raised in thediscussion of the Antarctic minke whale analyses are also
relevant to the analyses of these other species. In the limited
time available for discussion, some specific points that
require further consideration were made, including the factthat in some cases the effective strip widths in somestrata/years were estimated to be rather small, indeed
smaller than for minke whales in the same strata/years.
Overall, the Workshop agreed that the abundance estimatesprovided in this paper represented useful steps forward inworking towards acceptable estimates of abundance. It also
agreed that the future work can best be facilitated by theAdvisory Group appointed above.
2.5 Estimates of trends in abundance
In considering the issue of trends, the Workshop reiterated
that any estimates refer to trends in the number of animals
present in a particular geographical area at a particular timeof the year and that this (given the discussion of stock
structure and mixing summarised under Item 3) is notnecessarily indicative of trends in populations, althoughabundance for one possible stock structure hypothesis (seeItem 3) is presented.

The Workshop noted that the current confidence intervals
for the estimates of trend are relatively wide. These results
are, therefore, consistent with a substantial decline, asubstantial increase, or approximate stability in minke whale
abundance in these geographic areas over the period of
JARPA. These trend estimates were based on abundance
estimates for which several important re-analyses and reevaluations had been recommended, and these could lead tochanges to the point estimates and variance estimates noted
above. Given the importance of the recommended reanalyses, the Workshop agreed that the estimates of trend aspresented in SC/D06/J6 need to be re-evaluated once revised
analyses have been completed.
2.5.2 Other species
SC/D06/J7 reported estimates of trends in abundance forhumpback, fin and blue whales. For humpback whales, theannual increase rates from 1989/90 to 2004/05 seasons in
Area IV and V were estimated as 12.4% (95% CI=7.5%23.4%) and 9.7% (95% CI=1.5%-18.0%), respectively (i.e.
significantly greater than zero). Abundance estimates forhumpback whales from IDCR/SOWER surveys, which werenoted at the 2006 Hobart workshop as being broadly
comparable to those from JARPA surveys (IWC, 2006b),
also indicated high increase rates for this species in both theAreas. The authors suggested that the apparent habitat
expansion of humpback whales to the south of the Antarctic
Circumpolar Current observed in Area IV might had been
related to high increase rates south of 60°S for humpback
whales. A significant increase for fin whales of 10.2% (95%CI=8.9%-19.3%) was observed for the 1995/96 to 2004/05
period; an estimate of 7.4% (-1.4%-29.0%) was obtained forblue whales from 1989/90 to 2004/05 in Areas IV and V
combined. Catch data showed that in summer fin whales
were once widely distributed from middle latitudes to southof 60°S over a wide longitudinal range; they concentrated in
Area III (between 10°E-60°E), in Area IV (between 80°E110°E), Area V (between 140°E-170°E) and Area VI(between 170°W-150°W). During the Japanese Scouting
Vessel (JSV) period, fin whales were rarely found south of
60°S. However, large numbers of fin whales have been
observed south of 60°S during the JARPA period (1987/882004/05) and the authors noted that this change in the
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commented that the point increase rate for blue whales for
the JARPA survey is similar to that obtained using the
IDCR/SOWER data for the whole Antarctic pooled (7.8%)(Branch and Ensor, 2004). Finally, they noted that thepresent estimates of absolute abundance show that the blue
whale remains well below its pre-exploitation abundance.
The Workshop welcomed the information presented in
SC/D06/J7. It drew attention to the comments made during
the discussion of trends for Antarctic minke whales (Item2.5.1), many of which are also applicable to these otherspecies. Discussion focussed on the trends reported for
humpback whales. The Workshop noted that there have beenreports of recent increases of humpback whale numbers
from studies on the breeding grounds, feeding grounds andmigratory corridors. This was discussed extensively at the2006 Hobart Workshop. Regarding the estimation of trend,
the Workshop recommended further refinement of thelinear model, as discussed for minke whales, byincorporating process error as well as a trend parameter, an
area effect and examination of survey sampling error. Thismodel should also allow estimation of the additionalvariance, which might lead to better estimation of theuncertainty of abundance estimates from feeding groundsurveys.
The Workshop noted that the estimates of increase rate
and associated precision for humpback whales from the
JARPA surveys would change when abundance estimates
were refined in the light of the recommendation above. It
noted further that the precision of these estimates isappreciably less than those from coastal surveys; this is as tobe expected, as spatial movements from year to year would
be greater on feeding grounds than in the migration corridor.
Turning to the fin and blue whale estimates, the Workshop
recommended that refinement of the method for estimating
trend be applied also to fin and blue whales. It emphasisedthat overlap between areas surveyed and distribution of fin
whales be carefully considered. It noted that the wide rangeof the 95% CI for the increase rate for blue whales arosefrom one particular influential abundance estimate, deletionof which would greatly improve the estimated 95% CI.
However, considering the wide confidence intervals, itremained difficult to identify a clear trend for fin and blue
whales from the JARPA surveys.
The Workshop agreed that the details of the improved
analyses be considered by the Advisory Group establishedunder Item 2.4.1.
3. STOCK STRUCTURE (ANTARCTIC MINKEWHALE)

3.1 Background
The Workshop noted that the study on stock structure in the
Antarctic minke whale was conducted under the JARPA
research objective ‘elucidation of the stock structure of theSouthern Hemisphere minke whales to improve stock
management’. Information on stock structure is importantfor (a) the estimation of biological parameters, which should
ideally be carried out on the basis of biologically identified
stocks and (b) the future application of the multi-stock rulesof the Revised Management Procedure (RMP) (IWC, 1994).
When JARPA surveys began in IWC Antarctic Areas IV and
V in 1987/88, the assumption was that these two Areas were
occupied by different genetic stocks. At that time there waslittle scientific evidence supporting such an assumption. At
the time of the 1990 Comprehensive Assessment (IWC,1991) none of the molecular genetic techniques nor any of
the non-genetic techniques that examined past commercial

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data provided any evidence of stock level differences
between minke whales in Areas IV and V. Subsequently,
JARPA samples were used in genetic studies (mtDNA)
which suggested substantial genetic heterogeneity in Areas
IV and V and some stock structure hypotheses were
proposed, which were not consistent with the current
boundaries of Areas IV and V. Results were presented anddiscussed during the JARPA review meeting in 1997. That
meeting recommended that additional analyses be
conducted (in addition to mtDNA) and the possibility ofdifferent stock structure than implied by the traditional
management areas was not discarded. Subsequently, in
1997, the Scientific Committee recommended that several
tasks be completed to improve understanding of stock
structure (IWC, 1998b). In reviewing the results on stock
structure derived from JARPA in 2004, the Committee notedthat only preliminary conclusions can be drawn at that time
and that more concrete conclusions will be able to be madefollowing the completion of additional analyses. It further
supported the suggestion that additional analyses using
alternative groupings and analytical methods should be
conducted (IWC, 2004b). Consequently the JARPA stock
structure study was extended by the use of several biologicalmarkers, both genetic and non-genetic, and a more detailed
grouping of samples.
3.2 Issues raised in 1997 JARPA review
3.2.1 Stock definition
During the 1997 meeting the Committee had agreed that thelack of a working definition of stocks and sub-stocks is a
general problem, not for JARPA alone, and therefore needed
to be addressed by the Committee (IWC, 1998b). The
Committee consequently established a Working Group on
Stock Definition, where this particular topic is discussed
annually. However, the Committee has not yet reachedagreement on the definition of stocks for management
purposes. In discussion at this Workshop, a question was
raised about the consideration of ‘soft’ boundaries, and it
was reported that this had not been dealt with specifically bythat Working Group, but reference was made to the‘TOSSM’ approach (IWC, 2007c).
3.2.2 Statistical analysis of mtDNA data considering theinclusion of school size as a covariate
Analyses considering the inclusion of school sizes as acovariate in the mtDNA survey were carried out by Pastene
and Goto (1999). Results were presented during the 1999
SC Meeting (IWC, 2000a). These authors found no
significant differences in haplotype frequencies among
different categories of school sizes.

3.2.3 Pilot study on nuclear DNA analysis on JARPA
minke samples
Studies on stock identity in JARPA based on nuclear DNA
markers (microsatellites) started in 1998 and preliminary
results were presented to the 1999 Committee meeting (Abeet al., 1999). Currently all samples taken by JARPA havebeen examined with a set of six microsatellites (seeSC/D06/J9).
3.2.4 Effort to obtain biological materials for genetic
analysis from low latitude areas of the Southern
Hemisphere (potential breeding grounds) and comparewith feeding ground data
Results of a survey of biological materials from minke
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REPORT OF THE INTERSESSIONAL WORKSHOP TO REVIEW DATA AND RESULTS(IWC, 1997b); apart from the Brazil region, no othercomprehensive materials of the Antarctic minke whale fromlow latitudes were available. Pastene reported that 61
samples from Brazil had been compared with 119 samples
from combined Areas IV and V in a mtDNA control region
sequencing analysis, and no significant differentiation was
found based on KST (Pastene et al., 2007). Of interest for the
JARPA studies are the materials from low latitudinal areasof the eastern and western side of the Indian Ocean and thewestern side of the South Pacific Ocean. Japanese scientists
have been informed of a collection of 200 baleen platesamples of the Antarctic minke whales taken in Durban,
South African (western part of the Indian Ocean). Thesesamples have been stored in formalin for some decades.
Effort is being made to develop suitable genetic techniques
to examine such samples. Hoelzel noted that it is the acidityof formalin that degrades DNA, and that buffered solutions
preserve DNA better, although useful DNA can sometimes
be extracted even from unbuffered formalin (dependent inpart on the age and permeability of the samples).
3.2.5 External morphology/morphometry analyses
Morphometric analysis to examine stock structure had been
conducted using all Antarctic minke whale samples taken by
the JARPA (see SC/D06/J10 below).

3.3 Data collection methods and results
Samples of Antarctic minke whales for studies of stock
structure were taken along pre-defined track-lines coveringboth offshore and ice-edges regions (see SC/D06/J2). From
1987/88 to 1991/92 a maximum of two whales were taken
randomly from primary sighted school within 3 n.miles of
the track line by SSVs (see SC/D06/J2). From 1992/93 only
one whale was randomly sampled regardless of school size.
The rational for this change was that the sampling thencovers all schools sighted by the SSVs. The objectives of
JARPA relative to stock identification included both genetic
and non-genetic techniques. As a result the following
samples collected as part of JARPA (sample size inparenthesis) are particularly relevant to stock structurestudies:(1) liver, heart, muscle, kidney (6,777 samples each) andskin (6,7782) tissues for genetic analyses;(2) standard body length plus 19 additional bodymeasurements for morphometric analysis (6,777);(3) photographs of dorsal surface, dorsal fin and flippers formorphological studies(6,777); and(4) external and internal parasites occurrence observed(6,777).
Information on other data can be found in Annex D.
While this represents an extremely large andcomprehensive dataset for the feeding grounds, it was notedthat the lack of samples from the breeding grounds
precluded description of this as a completely comprehensive
dataset for stock structure analyses, given the importance ofsuch samples for a full interpretation of stock structure (andsee Item 3.5 below). This applies to studies on stock
structure in any other baleen whale species. Pastenesuggested that the effect size for the Antarctic minke whale
is low, and therefore a large sample size is necessary. While
this may be the case it was also noted that the apparent low
effect size may simply reflect mixing. It was further notedthat a power analysis should be undertaken to determine the2
One skin tissue sample collected from one individual taken but lost
during transportation to the research base vessel.

relationship between sample size and power for theseanalyses. Pastene indicated that a preliminary study had
been undertaken, and agreed that further analyses would be
useful. It was suggested that in addition to genetic studies, itwould be useful to include potential alternative stock
markers such as stable isotopes (e.g. carbon, oxygen,hydrogen and strontium). Aguilar noted that pollutant
markers may have limited power in the Antarctic, as thishabitat is far from the point sources of pollution.
3.4 Data analysis methods and results
3.4.1 Genetics
SC/D06/J09 investigated stock structure of Antarctic minke
whales in the feeding grounds using mtDNA restriction
fragment length polymorphism (RFLP, six restriction
enzymes) and microsatellites (six loci). Samples used wereobtained during JARPA surveys from 1987/88 to 2004/05
austral summer seasons in Areas IIIE, IV, V and VIW.
Samples were grouped into six longitudinal strata used by
JARPA surveys: IIIE (35°-70°E); IVW (70°-100°E) (northand south); IVE (100°-130°E); VW (130°-165°E); VE(165°E-170°W) (north and south) and VIW (170°W145°W). Both genetic approaches showed substantial spatial
genetic heterogeneity among the strata. For both genetic
markers, whales in the most distant geographic strata (IIIE,
IV and VE, VIW, respectively) were differentiatedgenetically. The authors noted that mtDNA was better able
to detect structure in the middle longitudinal strata. Results
were consistent with the hypothesis of at least two stocks,
possibly related to proposed breeding areas in the Indian andwestern South Pacific Oceans, respectively. The pattern of
spatial differentiation found provides little support for IWC
stock boundaries for Areas III, IV, V and VI. The dispersal
pattern of males and females in the feeding grounds was
similar according to the mtDNA analysis, which isconsistent with the previous view on whale longitudinal
movement based on mark-recapture analysis. The
microsatellite heterogeneity tests suggested more structure
in females than males. However no significant differenceswere found when the allele frequencies of males andfemales were compared in each of the strata. The authors
stated that the results of a fine-scale mtDNA analysis
suggested a stock division in the longitudinal sector 150160°E and that the possibility of an area of mixing of stocks
around that longitude cannot be discarded. They noted thatsite fidelity to particular areas of krill concentrations could
explain the spatial segregation of stocks of Antarctic minke
whales in the feeding grounds.
In discussion, Pastene noted that an earlier analysis(Pastene and Goto, 1997) based just on mtDNA and smaller
sample sets had suggested population structure that is nolonger supported. He also indicated that independence withrespect to linkage disequilibrium had been tested. The
Workshop noted that for many relevant analyses, power ismore effectively increased by an increase in the number ofpolymorphic markers used, and Pastene reported that further
microsatellite loci would be included in future. Given thatthe sampling area is in the feeding grounds and may well
represent a mixed assemblage of stocks, it was noted thatclustering methods based on individual genotypes, thatavoid a priori assumptions about population boundaries
may be usefully applied. Further, methods such as MDS(multidimensional scaling) or PCA (principal component
analysis) were recommended, as assignment methods
based on violation of equilibrium assumptions (such as
STRUCTURE) may have too little power.

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With respect to the area of transition, it was suggested thatmethods that address the question of isolation by distance(such as spatial autocorrelation and Mantel tests) would help
resolve the position and nature of this transitional pattern. It
was further suggested that other analyses based on
individual genotypes, such as landscape genetics as assessedin the program ‘alleles in space’ (Miller, 2005) may help
resolve the pattern of structure and mixing (though thiswould likely require 15+ microsatellite loci to provide
sufficient power). Hoelzel related a relevant experience withthe analysis of minke whale population structure in the
North Atlantic whereby analyses based on individual
genotypes (in this case using likelihood assignments
implemented in the program Geneclass) revealed structurethat could not be detected using Wright’s inbreeding
coefficients (such as FST) or exact tests. SC/D06/J9
indicated heterogeneity by year, and it was suggested thatthese anomalous samples be investigated further as this
could conceivably be indicative of breeding stocks that wereat other times obscured by more extensive mixing.
Schweder suggested that the transitional area be studied byfitting a mixing model where the fraction of whales
belonging to one putative population is a function of thelongitude at which it was sampled. This could be a simple
logistic regression model coupled with two-productmultinomial models describing the allele frequencies in thetwo putative stocks either side of the transition area. It could
also be extended beyond two populations, and incorporate
both genetic and morphometric data.
The Workshop stressed the importance of obtaining
samples from the breeding areas, noting the potential
problems with interpreting the results of mixing models
without this. Given lack of knowledge of the location of thebreeding areas, the value of satellite tracking studies wasemphasised. The question of the existence of historical/archive samples for the potential extension of the analyses
geographically, and to enable further comparisons among
years (especially over a longer timeframe) was raised. An
initial enquiry indicated that at least some of these samples
are still available. Goto and Pastene reminded the Workshopthat in 1998 the Committee noted that because thecommercial catch had been mainly near the ice edge, theanalysis of past commercial catches would not be
particularly useful for stock identification (IWC, 1999,p.25).
3.4.2 Morphometrics and morphology
SC/D06/J10 provided a comparison of morphology basedon 10 external measurements from 2,629 male and 1,803
female mature Antarctic minke whales undertaken across
the JARPA research area. Males and females were separated
into two groups at 130°E and 165°E, respectively. Some
concerns were expressed about the fact that not allmeasurements were included in the comparisons, and thatthe sex ratio varied between areas. This was explained bynoting that some measurements were difficult or unstable
when assessed by different researchers, and therefore
excluded. The Workshop agreed that finer scale geographic
analyses would be worth undertaking in future. The broadconsistency of the morphological and genetic data wasnoted, and it was suggested that they be investigated
together.
SC/D06/J11 investigated stock structure in the Antarctic
minke whale in the feeding grounds by examining bodylength of physically mature whales based on samples
collected during JARPA surveys from 1987/88 to 2004/05.
Grouping of the samples was the same as that used in the421

genetic analysis. Significant differences were found for thisbiological parameter among the geographical strata
examined, which rejected the scenario of a single stock in
the research area. Whales in the western strata (IIIE, IVW,
IVE, VW) are significantly larger than those in the eastern
strata (VE, VIW) for both sexes. Results were consistent
with the hypothesis of at least two stocks in the JARPA
research area, possibly related to the proposed breedingareas in the Indian and western South Pacific Oceans.
There was some discussion about the potential that this
could instead reflect the age structure of the respective
populations. To address this, it was noted that most of the
final body length is reached by sexual maturity, and thatmuch of the subsequent growth is with respect to increased
girth. It was also noted that length could reflect differencesin nutrition or other environmental factors.

3.5 Synthesis
SC/D06/J12 provided an overview of the studies on stock
structure in the Antarctic minke whale with the purpose of
establishing a plausible hypothesis for the stock structure ofthis species in the JARPA research area (Areas IIIE-Area
VIW). Studies on stock structure started at the end of the
1970s and results were reviewed by the Committee during
the Comprehensive Assessment in 1990 (IWC, 1991). All
the analyses were conducted using samples and data fromcommercial pelagic whaling in the Antarctic. Most genetic
studies were based on allozymes although some studies
based on mitochondrial and nuclear DNA were conducted.
Most of these analyses involved small sample sizes from
Areas IV and V only. Non-genetic studies reviewed in 1990
involved morphology, catch and sighting distribution
pattern, analysis of Discovery marks and ecologicalmarkers. Results from the different approaches failed to
identify unambiguously any isolated population in the
Antarctic. Ecological markers were identified as apotentially useful approach. Analysis of sightings datasuggested the occurrence of five breeding areas. Studies on
stock structure under JARPA began after the Comprehensive
Assessment. The author believed that samples taken by
JARPA were more useful for studies on stock structure
given the wider geographical coverage of the surveys andbecause minke whales were taken along tracklines in arandom mode design. Initially, the JARPA studies on stock
structure were based on mtDNA and considerable genetic
heterogeneity in Areas IV and V was found. More recently,
the total minke whale samples taken by JARPA in Areas
IIIE, IV, V and VIW have been examined using different
analytical approaches (genetics and non-genetics) using
similar groupings. In general, the results of the different
approaches were inconsistent with the single stock scenario.
The author concluded that the results of the different
approaches were consistent with the occurrence of at least
two stocks in the research area, probably related to thebreeding areas in the eastern Indian Ocean and westernSouth Pacific suggested by previous sightings data. The
author proposed that these be termed the Eastern Indian
Ocean Stock (I-Stock) and Western South Pacific Ocean
Stock (P-Stock). In order to estimate biological parametersin JARPA, he proposed that a boundary between I and P
Stocks should be adopted at the division between Areas VW
and VE (165°E). This is consistent with the results of markrecapture that showed marked movements of whales
between Areas IV and VW. Although the most recent
analyses indicated that whales in Area IIIE belong to the I
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possibility of estimating Maximum Sustainable Yield Rate(MSYR), an important parameter for the RMP, from catch atage data. Other parameters such as recruitment rate, age atsexual maturity and reproductive rates are also potentially
useful for stock management and could contribute toimproving Implementation Simulation Trials for the RMP.
At the JARPA review meeting in 1997, it was agreed that,
although not required for management under the RMP, theinformation presented provided valuable information on
recruitment, natural mortality, decline in age at sexual
maturity and reproductive parameters in Areas IV and V.
However, that meeting had also recognised that there someunsolved problems in the analyses and that further analysis
was necessary, for which some recommendations weremade (see below).

REPORT OF THE INTERSESSIONAL WORKSHOP TO REVIEW DATA AND RESULTS

possibility of additional stock structure in Area III (e.g. theoccurrence of animals from the western Indian Ocean
breeding ground) should be investigated in the future. The
author noted that any stock boundary (or sectors of mixing)
among stocks in the Antarctic should be considered to vary
according to oceanographic conditions, which in turncontrols the distribution of the key prey species of the
Antarctic minke whale, the krill. He finally identified
several future research needs for stock structure studies.
The Workshop welcomed this review, and with respect tostock structure studies, recognised the very considerable
amount of work undertaken since the mid-term review andthe progress that has and can be made given the datacollected. Based on the analyses of the genetic andmorphometric data presented, it agreed that there are at least
two stocks of Antarctic minke whales present in the JARPA
research area. The data do not support the current IWC
management Areas. The data also suggest an area oftransition in the region around 150-165°E across which
there is an as yet undetermined level and range of mixing.
Some of the genetic analyses suggest the possibility offurther subdivision (e.g. for microsatellite DNA data,
pairwise comparisons for females showed heterogeneity
between IIIE and IVWS), and the Workshop identified theneed for further analyses of the existing samples (together
with available historical samples from commercial whaling,
but see comment under Item 3.4.1), related especially to
new statistical analyses, genetic marker development, andadditional non-genetic markers, to further assess the numberof putative stocks. Such analyses should allow a morethorough specification of stock structure and the relativeplausibility of different hypotheses. The Workshop
recognised that samples from the breeding areas (e.g. as
could be obtained through a combination of satellite
tracking and biopsy sampling) would greatly facilitate theseanalyses, and are likely to be required to resolve issues
relevant to stock structure and mixing within the JARPA
research area. Analysis of historical samples (as available)from areas to the east and west of the study area may also be
useful towards resolving stock issues within the JARPA
research area, especially with respect to Areas III and VI.
4. BIOLOGICAL PARAMETER STUDIES

4.1 Background
The original primary objective for JARPA, as specified in
SC/39/O4, was to estimate the age-specific natural mortality
coefficient for Antarctic minke whales (IWC, 1988), sinceknowledge of this parameter was at the time considered tobe the key to determining the replacement yield rate andhence important for the rational management of Antarctic
whale populations. After five seasons, a change in theimmediate focus of the primary objective was reported,from estimating the age-specific natural mortality to theaverage natural mortality rate (IWC, 1993). The ScientificCommittee completed the RMP in 1992. Since the RMP
does not require biological parameters such as the natural
mortality rate, M, Japanese scientists reconsidered whether
or not the first objective be further modified. By the 1997
Workshop to review the results of JARPA to date, thisobjective had evolved to the current ‘estimation of thebiological parameters to improve the stock management of
the Southern Hemisphere minke whale’ (IWC, 1998b).
Hatanaka explained that Japan considered that estimationof M was still useful for understanding the population
dynamics of minke whales, and therefore important for the
management of whale stocks. Furthermore, there is the

4.2 Issues raised in the 1997 JARPA review
In relation to biological parameters, the Committee
recommended a number of tasks (IWC, 1998b, p.103, table2) of which the following relate to biological parameters:(1) segregation study; and(2) recalculation of biological parameters by biologicalstocks (IWC, 1998b, p.103, table 2).

4.2.1 Segregation study
A study on segregation was conducted in the context of the
distribution pattern of minke whales in relation to the packice edge. Results (Fujise et al., 1999) for Area IV werereported to the Scientific Committee (IWC, 2000a, p.168).
The authors used regression analyses to suggest thefollowing segregation pattern:(1) males (especially matures) predominated in the researcharea in all seasons although their proportion tended todecrease with increasing latitude;(2) mature males tended to be found in larger school sizes;
and(3) females (especially matures) tended to be found in thesouthern part of the research area.
4.2.2 Recalculation of biological parameters by biologicalstocksMany biological parameters were estimated on the basis of
proposed (SC/D06/J12) new biological stocks (the putative
I and P stocks with their boundary set at 165°E discussed
under Item 3).

4.3 Data collection and results
Following the cessation of commercial whaling, biological
data and samples have been accumulated under the JARPA
programme from 1987/88 to 2004/05 in Areas IIIE, IV, V
and VIW. A total of 6,779 individuals, including 2 animals
taken but lost in transit, were taken. Each whale was
examined in detail and a variety of samples were collected,
including:(1) body length measurements (6,777);(2) earplugs for age determination (6,777); and(3) testis (3,636) and ovaries (3,151) for sexual maturity
status.
Other available biological samples and data can be found in
the list of JARPA data (Annex D).

Reliability of age determination
The issue of the reliability of the age determination resultsarose in several contexts in the discussion of biologicalparameters. The catch-at-age analyses by Punt andRep 1:Layout 1

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Polacheck (Polacheck and Punt, 2006) showed that there
was an inconsistency in the age determination of younger
animals between the commercial and scientific catches thatcan not yet be explained. Hatanaka and Kato noted that theprocedures had been much improved in the JARPA
programme relative to the data collection from commercial
whaling. They believed that, at least for the JARPA data, theage readings could be treated as reliable. A particular
problem with the commercial data had been the large
number of broken or incomplete earplugs: better handling of
the material meant that this rarely occurred in JARPA, andthat 85% readability had been achieved. The residual
fraction of unreadable earplugs was mainly due to theabsence of a clear pattern of layering in those earplugs.
Childerhouse asked what effect the residual proportion of
unreadable earplugs might have on the estimates of
biological parameters. This had not been assessed
quantitatively, but Butterworth considered that theunreadable earplugs would have to come from an extremely
select component of the population in order to materiallybias parameter estimates.
The Workshop noted that to date there were no readings
from known age animals with which to directly verify
earplug readings. Butterworth noted that for southern blue
fin tuna, otolith readings had been calibrated withradiocarbon signals corresponding to atomic bomb tests ofknown date. Brownell recalled a paper (Bada and Brownell,
1996) where the bomb signal had been examined in a
Bryde’s whale sample in order to determine its year of
capture. The Workshop recommended that the feasibility ofdetecting the bomb radiocarbon signal in earplug laminae belooked into.
The Workshop agreed that the earplug laminae probably
were annual layers that were deposited independently of
feeding, migration and other external factors, analogous
with tooth layers that are laid down in odontocetes even in
populations that do not migrate. However, Aguilar pointed
out that accessory layers often occur which can confuse thereader: because of this, experience and inter-reader
calibration are important. He suggested that there should be
at least three readers, and earplugs or teeth that yieldinconsistent results be omitted from the analyses.
Kato drew attention to the inter-reader calibration study
between himself, Ohsumi and Zenitani (Kato et al., 1991)
which showed good agreement between experienced readers(Kato and Ohsumi) and a CV of age readings of only 6.6%.
Cooke recalled the analyses of Cooke et al. (1997) to the1997 JARPA review which showed notable shifts between
years, for example the Zenitani readings for the first two
years of overlap were significantly lower than the Kato
readings by 1.5 years on average, while in the third year her
readings were an average of 0.5 years higher than the Kato
readings. Kato explained that this occurred during thetraining period, after which the two readers obtained
comparable results.
Walløe and Ohsumi drew attention to the good correlation
between age readings and corpora counts in females shown
in SC/D06/J17 (see Item 4.4.3).
The Workshop recommended that the comparability ofcommercial and JARPA age data be investigated by rereading a subset of the commercial samples in an
appropriately designed blind test.
4.4 Data analysis methods and results
The Workshop noted that many of the results in this section
are presented in terms of the putative I and P stocks (seeSC/D06/J12 and Item 3), by partitioning the data at 165°W

423

by catch location, which represent one stock structure
hypothesis. The Workshop emphasised that there is noagreement yet that these represent valid stock designations,but agreed that it was useful, for the purpose of comparing
results from different data and methods, that the same
partition was used for all analyses.

4.4.1 Natural mortality
SC/D06/J13 derived estimates of the average natural
mortality rate of the 10+ population for the I and P stocks
from JARPA abundance and age sample data, using themethod originally proposed by Tanaka (1990). The estimate
of annual mortality rate was 0.038 (SE=0.036) for the Istock and 0.040 (SE=0.035) for the P-stock. The method
uses both catch age composition and abundance estimatesfrom the surveys, both stratified by stock area (I/P), school
size (solitary vs. schools of size 2+) and sex. The method
estimates the decline in abundance of groups of cohorts overtime: for example the 10+ population in 1990 becomes the12+ population in 1992, and the decline in their numbers
represents natural mortality over 2 years. The authors
considered that these estimates are valuable because they are
direct estimates from large scale surveys. The estimates arelower than the value of M used in the Implementation
Simulations Trials and also that in the assessment by Hitterruns (e.g. IWC, 1991). Use of these estimates will lead tosome results different from those in the past and the authors
expected that will reduce the extent of uncertainty in M.
In discussion, it was noted that the main contribution to
the variance of the estimate is from the variance in theabundance trend, and this limits the precision of the results.
The high standard error implies that the confidence interval
extends from negative values to greater than 0.10. A muchsmaller standard error would be obtained if it could beassumed that the abundance had zero trend, but theWorkshop agreed that this assumption should not be made,especially given that one of the original motivations for
estimating the natural mortality rate was to better determine
the trend in stock size.
Cooke noted that the variance of the age composition wasprobably underestimated, because previous studies (e.g.
Cooke et al., 1997) had shown that there is considerable
overdispersion in the age composition, even after stratifying
by more covariates that had been considered in SC/D06/J13.
However, it was likely that the variance in the abundancetrend would still be the dominant factor.
Cooke further noted that the very low precision of theestimate had been predicted in the review of the initial
JARPA feasibility study proposal in 1987 (IWC, 1989), forexample as calculated in his document (Cooke, 1987). The
authors of SC/D06/J13 responded that the precision was
lower than had been anticipated at the start of the
programme because: (1) the abundance data showed
considerable inter-annual additional variance in addition to
the sampling variance of the abundance estimates, and thiswas taken into account in SC/D06/J13; and (2) the data
showed that even with the JARPA sampling scheme, it was
not possible to sample the younger animals representatively,
because they did not all migrate beyond 60°S; consequent
restriction of the analysis to the 10+ population diminishedthe effective sample size.
The Workshop agreed that the method used to derive theestimates in SC/D06/J13 was broadly valid, and in particular
was free of assumptions about stock-recruitment
relationships, but some members felt that the extremely low
precision meant that the result was that the natural mortality
rate had, for practical purposes, not been determined. In

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particular, even a zero value was not excluded by the
analysis. Butterworth countered that, prior to JARPA, thecommercial whaling age data were suggesting an apparent
mortality rate of around 0.14, but this was confounded witha suspected trend in stock size. At that time, a finding thatthe true mortality rate was less than 0.11 would have been
regarded as very valuable information.
In
SC/D06/J14,
the ADAPT-VPA assessment
methodology originally developed by Butterworth et al.
(1999b) was improved by taking into account various
comments made during recent Scientific Committee
discussions. It was applied here to abundance estimates(from both IDCR/SOWER and JARPA surveys) and catchat-age data (both commercial and scientific) for the putative
I and P-stocks of Antarctic minke whales. The
improvements to the methodology reported at the 2006
Scientific Committee meeting (IWC, 2007a) allowed
account to be taken of various further aspects, primarily: (1)inter-annual differences in the distribution of the population
between different management Areas; (2) a stockrecruitment relationship; and (3) the effects of possible
ageing error. Furthermore sensitivities to various functional
forms for selectivity and natural mortality with age were
explored. The general pattern shown by the results for bothstocks was of a minke whale abundance trend that increased
over the middle decades of the 20th Century to peak at about
1970, and then stabilised or declined somewhat for the next
three decades. The recruitment trend was similar, althoughwith its peak slightly earlier. The annual natural mortality
rate, M, was estimated to be 0.056 with a CV of 0.16 for the
I-stock, and 0.069 with a CV of 0.15 for the P-stock for the‘reference case’ assessments. When only the JARPA
abundance estimates are used for tuning, M is estimated as
0.038 and 0.060 for the I- and P-stocks, respectively. The
estimation of M is fairly robust to the various assumptionsof the model. The CVs of these M estimates for the‘Reference case’ assessments, when compared with those of
typically 0.35 for the Area-specific assessments of(Butterworth et al., 1999b), which were based on fewer data,
indicate an appreciable improvement in the precision ofthese estimates due to the accumulation of data over the
long-term of the JARPA surveys. The fits of the stockrecruitment model generally required a carrying capacity forminke whales that first increased and then stabilised or
declined somewhat during the last century, and suggested
MSYR(1+) values in the 4-6% range. The improved precisionin the estimation of M may contribute to the improvement ofmanagement and assessment of this species on a stockspecific basis, since it can reduce the uncertainty concerning
the value of M and provide an improved prior distribution
for MSYR. The latter in particular, in the context ofproviding a measure of the productivity of which the species
is capable, is essential information for effective RMP
implementation through reduction of the range of plausible
scenarios which need to be considered in Implementation
Simulation Trials.
The Workshop noted that SC/D06/J14 was an integrated
analysis that involved simultaneous estimation of natural
mortality and recruitment rates. It was discussed both under
this Item and under Items 4.4.3 and 4.4.4.
With regard to natural mortality, discussion focussed on
how SC/D06/J14 was able to produce more precise
estimates of M, and hence of other linked parameters, thanSC/D06/J13. That is, which additional assumptions or data
are driving the results. The additional data used were: (1) thecommercial age data; and (2) the IDCR abundance data,
which provided a longer time series of abundance data than

JARPA alone. The additional assumptions included: a stockrecruitment relationship; and alternative options for theselectivity of the commercial age data.
In analyses of catch-at-age data there are three factors thatare confounded in the present context: (1) the natural
mortality rate; (2) the past recruitment trend; and (3) the
selectivity slope. The role of the trend in abundance
provided by the sightings surveys in removing one elementof this confounding had been illustrated in earlier analyses
presented on this issue (e.g. Butterworth et al., 1999a; Mori,
2006) but specification of the selectivity slope remained
influential. Butterworth drew attention to the results of thesensitivity tests reported in SC/D06/J14 that showed inparticular that it would require a very marked downward
trend in selectivity of older animals in the commercial catchto invalidate the finding of an increased recruitment trend
prior to exploitation. Furthermore, the overall pattern inrecruitment (rising from low levels to a peak in 1968,
followed by a quick decline to lower levels and little change
thereafter) did not depend on the introduction of a stockrecruitment relationship into the estimation method, as
previous analyses without such inclusion had provided
similar results.
Some members expressed considerable unease arisingfrom apparent dependence of the finding of increasing
recruitment before 1968 on the inclusion of the commercial
age data, especially in the light of the problems with thecommercial age data (if taken at face value, these implied asudden change in somatic growth when JARPA started). A
sensitivity test in SC/D06/J14 to exclusion of the first half ofthe commercial age data reduced estimated rate of increaseof the I stock from 0.057 to 0.014. Wade considered that if
the change in age distribution from the commercial to the
JARPA period is the factor that is driving the results, itwould place a major question mark over the results.
Butterworth argued that the problems found by Punt andPolacheck with the commercial data applied only to
growing animals, whereas SC/D06/J14 had used thecommercial age data only for ages 16+. Cooke responded
that Punt and Polacheck had only discovered the problem
through the inconsistencies in the age-length distributions
for younger animals. Since length for older animals was nota function of age, the problem would not be detectable inthis way for older animals, even if they were also affected by
it. It was, therefore, not safe to assume that the problem wasrestricted to the younger animals.
Maunder considered that if the aging of the older cohorts
is acceptable, the trend in recruitment ought to be correctly
estimated, but wanted to see what extent of bias or error in
aging could account for the apparent trend. He asked to what
extent the precision of the mortality estimate depended on
the stock recruitment relationship. Butterworth replied thatthe sensitivity to this could be checked by downweighting
its contribution to the likelihood. Maunder also considered it
useful to determine to what extent the precision of the M
estimate in this analysis depended on inclusion of the datafrom the lethal part of the JARPA programme, i.e. the catchat age.
Implications of the ‘reference case’ results of SC/D06/J14
are discussed further under Item 4.4.4.
4.4.2 Growth curves and age at sexual maturity

4.4.2.1 GROWTH CURVES

SC/D06/J17 presented growth curves from JARPA data,
stratified by the putative I and P stocks, sex and cohort(grouped by decade). The results indicated that there had
been no discernible changes in growth rate over the JARPA

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period. Data from the commercial period presented in
SC/D06/J26 (reproduced from Kato, 1987) showed anapparent increase in growth rate from the 1940s through tothe 1970s.
In discussion, it was noted that in the JARPA data, cohorts
prior to 1970 are already at maximum body length, such that
one would not necessarily expect an earlier increase in
growth rate to show itself in the JARPA data. Further
analyses of growth rates had been presented to the 2006
Scientific Committee Annual Meeting in Polacheck andPunt (2006) which showed an apparent sudden drop in
growth rates between the commercial and JARPA periods,
but the authors cautioned against taking these results at facevalue because of unexplained residual features in thecommercial age/length data and the difference in sample
size between the two data sets.
4.4.2.2 AGE AT SEXUAL MATURITY

SC/D06/J15 provided an updated analysis of the trend in age
at sexual maturity, using transition phase (TP) and age
readings from a total of 2,803 individuals collected during
1987/88 to 2004/05 under JARPA. The analyses werestratified by the putative I and P stock areas, and confirmed
the previously noted decline from about 10-12 years in pre1955 cohorts to around 7 years in the late 1960s and early
1970s cohorts, for both stocks. Since the early 1970s, themean age at transition phase for both stocks has remained
constant at 7-8 years or increased slightly from the early
1970s to the early 1990s cohorts.
SC/D06/J16 applied a model-based approach similar tothat of Thomson et al. (1999) to the transition phase dataobtained from JARPA surveys to examine trends in the age
at maturity for the putative I and P stocks of Antarctic minke
whales. The results, which take into account various
potential biases related to examining trend in transition
phase data (i.e. truncation and fringe effects, differences
between readers, and readers learning over time) suggestthat the age at maturity of Antarctic minke whales declined
from about 11 years in the late 1940s to 7 years in the late1960s for both stocks, and that these declining trends are
statistically significant at the 5% level. The analyses alsosuggest that the age at maturity increased slightly from thelate 1960s to the late 1970s and has stabilised thereafter.
These trends are broadly consistent with the results obtained
from VPA (Mori, 2006), which suggest that for both the I
and P stocks, abundance increased from the 1940s to the late1960s and thereafter has been stable or declined somewhat.
This consistency enhances the confidence to be placed inestimates of parameters (such as natural mortality andMSYR) from such VPA analyses that may be of value formanagement purposes. It also serves to demonstrate theutility of age-at-maturity as an index to monitor stock status,and suggests that continued monitoring of this parameter isdesirable both for this purpose and for contributing to theunderstanding of the dynamics of the Antarctic ecosystem.
SC/D06/J17 contained estimates of age at maturity basedon the fraction mature by age (for both sexes) and the age atfirst ovulation for females. The age at 50% sexual maturity
for males was 5.3 years (I stock) or 5.4 years (P stock), andfor females 7.6 years (I stock) or 8.0 years (P stock). The age
at 50% physical maturity was 16.0 years (I stock) or 17.0
years (P stock for males, and 21.2 years (I stock) or 20.6
years (P stock) for females. The mean age at first ovulation
was 7.9 years (I stock) and 8.4 years (P stock). There was asignificant decline in mean age at first ovulations over theperiod for the P stock (0.11yr–1/yr or about 1.5-2yr for the425whole period 1987/88-2004/05), but no significant trend forthe I stock. A summary of the findings of SC/D06/J17 isgiven in Table 3.
The 1997 JARPA review had noted an apparent
discrepancy between the JARPA results and the earlier
results using commercial age data which implied a muchhigher average age at transition phase for the early cohorts
than did the JARPA data (IWC, 1998b). This had not been
investigated further, and in the analyses presented to thisworkshop, only the JARPA data had been used.
The Workshop recalled the previous discussions of theCommittee, including the workshop held in 1983 (IWC,
1984) as to whether the transition phase was an indicator ofsexual maturity, and as to whether trends in the transition
phase readings reflected genuine trends in age at maturity.
The 1997 JARPA review meeting had found that there didseem to be a genuine decline over time, rather than merely
an age-specific effect, because later cohorts showed a lower
age at maturity than earlier cohorts, even when comparing
animals of the same age (captured in different years).
It was noted that even for older animals, there was notalways a transition phase; this did not imply that theseanimals were not mature, but that for some earplugs, thetransition from the irregularly spaced younger layers to thenarrower, evenly spaced older layers did not occur at a welldefined point but was a more gradual transition, and in these
earplugs the readers found it safer not to identify a transition
layer.
There was some discussion as to what event in the life of
the animal the transition phase was measuring. Lockyer(1972) had suggested it may be related to skull growth. Theage at transition phase of 7-8 years in recent decades is
consistent with the age at sexual maturity of females
reported in SC/D06/J17. However, the transition phaseoccurs at a similar mean age in males and females, and theage at 50% maturity for males is much lower.
In discussion of SC/D06/J16, comments were made thatthe analyses had compared the patterns based on retaining
the observed trends in age at transition phase as a real
phenomenon, versus the patterns expected if the change
were a certain kind of artefact. The fact that the latterhypothesis did not fit the data well did not necessarily imply
that the effect was real, although it was agreed that such an
exercise involving an alternative hypothesis was useful.
Butterworth responded that the various kinds of artefact
suggested to date could sometimes explain a decline but it
was hard to see how they could ever cause an increase, as
has been observed in Icelandic fin whales and now in recent
years in Antarctic minke whales.
The consistency claimed by the authors of SC/D06/J16,
between the age at maturity trends and the results of catch atage analyses (SC/D06/J16) is discussed under Item 4.4.4.

4.4.3 Reproductive and sustainable yield rates
SC/D06/J17 examined pregnancy rate data among mature
females. These averaged 93% for the I stock and 85% for the
P stock. There were some fluctuations between years, inparticular low values (below 80%) occurred in 1997-99 forthe I stock and 1990/91 and 1994/95 for the P stock.
Regression of ovulation rate against age showed ovulation
rates close to one per year (0.98 yr–1 for the I stock and 1.01
yr–1 for the P stock). Cohorts prior to 1970 had been omitted
from the regression, to avoid the confounding effect of ahigher age at maturity in earlier cohorts.
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inter-annual changes in population pregnancy rate, or
due to segregation of reproductive classes andfluctuations in the sampling of each. Kato considered that
the JARPA pregnancy rate data indicated a genuinely highpregnancy rate in this species, and that if pregnancy rate isdensity dependent, as some studies have reported for fin
whales, it is probably currently close to its upper limit for
Antarctic minke whales. Clapham noted that this could
imply that the stocks are well below their carrying capacity(K).
The regression plots of ovulation were found hard tointerpret without seeing the scatter around the regression
line. Assuming that actual pregnancies cannot exceed one
per year per individual, the scatter around the line would
places an upper bound on the pregnancy rate consistent withthese data. Only if the scatter is sufficiently small, would theresults be consistent with average pregnancy rates as high as
those observed.
In general, the Workshop agreed that the results
confirmed the high pregnancy rates found in this species in
the previous commercial data, and correspond essentially toa 1-year reproductive cycle. However, pregnancy rates are
not necessarily well correlated with effective recruitment
rate (production of age 1 animals) because of potentiallyhigh losses before full term and in the first year of life.
SC/D06/J14 presented an integrated analysis of catch-atage and abundance data, which provided estimation interalia of the history of annual recruitment (production of aged
1 animals) to the stocks, and of the adult female stock sizes,
and hence also per capita recruitment. The analysis also
estimated the natural mortality rate, and the paper issummarised under Item 4.4.1, where some concerns are
discussed. The paper showed that per capita recruitment
rate (recruits per mature female) was apparently high at
around 0.4 in the 1950s and early 1960s in both stocks, but
declined thereafter to much lower levels (0.1-0.2) by 1980
and has remained low since. The decline started about 1965
in the I stock and about 1970 in the P stock.
The Workshop noted that the analyses had assumed aconstant age at maturity throughout. If account was taken ofa decline in the age at sexual maturity as suggested by
SC/D06/J15 and SC/D06/J16, then the mature female stock
would be lower in the earlier period and hence the estimatedrecruitment per mature female would have been higher.
Butterworth explained that the estimates of Maximum
Sustainable Yield (MSY) rates (4%-6%) were largely driven
by the estimated increasing trend in recruitment in theearlier years. Under the model, the stock needed to have ahigh MSY rate to show such an increase. Hatanaka notedthat the estimates of MSY rate, if they are reliable, would bevery important for management.

4.4.4 Synthesis of information on biological parametersfrom different sources
SC/D06/J26 examined historical changes in the Antarctic
minke whale stocks based on various results obtained from
JARPA including age at sexual maturity, growth curve,
blubber thickness, prey consumption, and ADAPT-VPA
analysis of the stocks as well as research on mercury
accumulation etc. It was assumed that feeding conditions of
the minke whale improved with the removal of large baleen
whales such as the blue whale by commercial whaling,which promoted rapid growth and younger age at sexual
maturity; however, around 1970, conditions graduallyshifted unfavourably, resulting in slower rates of change inthe foregoing parameters. These changes were then arrestedby the 1980s to the 1990s. Observations reflecting theseunfavourable changes, were reductions in blubber thickness
and stomach content weight, which indicated less prey
consumption. There was also a decrease in the accumulationof mercury, perhaps resulting from less prey consumption(see Item 6.3.1). In addition, the authors noted that the
distribution area of humpback and fin whales in the feeding
season expanded southward in the Antarctic from around1990, suggesting further deterioration of feeding conditions
for the Antarctic minke whales. The apparent consistency
between the different trends was also noted in the discussionsections of other papers to the Workshop, e.g. SC/D06/J16.
Discussion focussed on whether the apparent trends invarious minke whale parameters were indeed consistent
with this general picture, also indicated by the results of the
VPA-ADAPT catch at age analysis in the manner suggested.
To assist discussion, results from various studies were
replotted to aid comparison as shown in Annex G. It wasrecognised that the projections back prior to 1950 werebased on very few data from old individuals, and werelargely model-driven. Discussion therefore focussed on the
post-1950 period.
With respect to the apparent trends in minke age maturity,
the transition phase data suggested a decline from around 11
years in pre-1955 cohorts to 7-8 years in post-1980 cohorts.
The ADAPT-VPA analyses suggested that per capita
recruitment was high in the 1950s and 1960s but low post1980. The age-length relationship from the commercial datasuggested higher growth rates in the post 1970-cohorts andlower rates in the pre-1960 cohorts.
The Workshop recognised that these results are inapparent contradiction to the conventional expectation thathigh ages at maturity and low somatic growth rates would
tend to be associated with low per capita recruitment rates,
while low ages at maturity and high somatic growth rates
would tend to be associated with high per capita recruitment
rates. In discussion, a number of alternative suggestions

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(summarised below) were made to explain the apparent
discrepancy, but in the time available it was not possible toevaluate them further, and in particular to compare theconsequences of alternate VPA results to those of the‘reference case’ in SC/D06/14 upon which thesecomparisons were all based.
(1) It was suggested that the paradox may be a temporalphenomenon, in that the response of some of theindices, such as age at maturity, may be subject to timelags. However, Walløe reported that studies of terrestrial
mammals showed that age at maturity expressed bycohort is determined primarily by nutrition very early inlife, and considered it unlikely that this parameter would
be subject to much time lag.
(2) The concern was noted under Item 4.4.1 that the trends
in recruitment estimated by the ADAPT-VPA analysis
may be unreliable, because they seemed to depend on
inclusion of the commercial age data, with which someunresolved problems had recently been identified(Polacheck and Punt, 2006).
(3) The question of whether the pre-1970 decline in age atmaturity indicated by the transition phase analyses wasreal had been discussed extensively at the 1997 JARPA
review and in previous Scientific Committee meetings,
and some members still considered this to be an open
question. However, others considered that the results of
SC/D06/J16 and those of Thomson et al. (1999) had
demonstrated that the declining trend had been real. The
1997 JARPA review had reached a similar conclusion.
(4) The reality or otherwise of the apparent somatic growthrate increase shown by the commercial data had beenquestioned when it was presented to the ScientificCommittee in the 1980s (IWC, 1990), and furthermore
the recently identified problems with the commercial
age and length data identified in (Polacheck and Punt,
2006) placed it in further doubt. Some members
considered that little weight be attached to these data.
(5) Some members considered that even though the pre1970 decline in age at maturity was hard to reconcile
with the ADAPT-VPA results, the slight increasing trend
in age at maturity post-1970 indicated by the transition
phase data may be consistent with other data, such as
declining blubber thickness. However it was surprisingthat, if the earlier decline had really been so large, thelater rise was not more pronounced, as the VPAADAPT assessment suggested that the stocks were now
close to their current carrying capacity. In addition, theage at first ovulation appeared to have declined during
the JARPA period, at least for the P stock (see Item
4.4.2).
There was some discussion about the plausibility of the
ADAPT-VPA results that the carrying capacity K was
estimated to have increased about 5-fold prior to its peak in
the 1960s. However, the issues relating to the high estimatedper capita recruitment rates pre-1960s relative to theirrecent values could also be considered without reference toK.
There was insufficient time to discuss in detail what
analyses might resolve the questions, and the Workshop
recommended that the matter be discussed further in the
Scientific Committee. In the meantime, the following tasks
were identified as providing potentially useful information:(1) the ADAPT-VPA could be run without using thecommercial age data; and427(2) a subset of the commercial age data could be re-read as
discussed under Item 4.3.

In summary, the Workshop concluded that there werediffering views expressed about the level of reliability that
could be assigned to the estimates of historical trends inbiological and population parameters of minke whales prior
to the JARPA period. For the JARPA period, no marked
trends in biological parameters were found. The growth
rates were apparently fairly constant, while the pregnancy
rate remained high with some annual fluctuation. The
transition phase data suggested a possible small increase in
the mean age at maturity over the JARPA period, but the age
at first ovulation showed a decrease, at least for the P stock.
The natural mortality rate estimates from JARPA data alone(SC/D06/J13), were, at around 0.04, within the plausible
range, but the confidence limits (from below zero to above0.10) spanned such a wide range that the parameter is still
effectively unknown. The ADAPT-VPA provided estimatesof natural mortality rates with a CV of about 0.15 but thesedepend on the use of commercial catch-at-age data, about
which, as discussed above, there are some problems.
5. MARINE ECOSYSTEM

5.1 Background
One of the objectives of the JARPA established in 1987 wasthe ‘Elucidation of the role of whales in the Antarctic marine
ecosystem’. In the 1996/97 research plan, this second
objective was restated as ‘Elucidation of the role of whalesin the Antarctic marine ecosystem through whale feeding
ecology’.
The research plan concentrates on the feeding ecology ofminke whales by the analysis of stomach contents andblubber volume. Changes in prey availability and their
possible effects on minke whales are expected to be detectedby monitoring the feeding conditions and consequential fat
storage of minke whales.
In the JARPA review meeting in 1997, the striking
similarity in the results obtained from the three methods for
estimating the daily prey consumption was noted. That
meeting agreed that these estimates could be used withconfidence for the estimation of total prey consumption by
the Antarctic minke whale. It also noted the decrease inblubber thickness since 1970s and it was suggested that,among possible explanations, this might be due to changes
in food availability due to inter-specific or intra-specificcompetition. Such information could contribute to thespecification of a range of krill surplus hypotheses for use infurther Implementation Simulation Trials for the RMP.
Finally, that meeting suggested that elucidating the role ofwhales in the marine ecosystem also requires concurrent
studies on the distribution and abundance of prey species.
5.2 Issues raised in 1997 JARPA review: Meso-scale
survey plan
The JARPA review meeting in 1997 suggested thatelucidating the role of whales in the marine ecosystem
requires concurrent studies on the distribution andabundance of prey species. It was also suggested thatprocess-oriented studies would be useful which integrated
information from physical and biological oceanography
with zooplankton and predator studies.
In response to that suggestion, acoustic surveys for krill
have been conducted since 1998/99 and a cooperative preyspecies survey was conducted concurrently from 25
December 2004 to 27 February 2005 (65 days) in the Ross

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5.3 Data collection methods and results
Data on the feeding ecology of the minke whale wereobtained from the species composition and mass of stomach
contents. Body mass, length, girth and blubber thickness ofeach whale were also measured. The abundance of thewhales obtained from the sighting surveys was used to
extrapolate food consumption to a larger area. The Kaiyo
Maru – JARPA joint survey in the Ross Sea in 2004/05 was
designed as a multi-disciplinary study combining surveys on
cetaceans, krill and oceanography. During the multidisciplinary study, the JARPA vessel conducted the cetaceansighting and sampling surveys while Kaiyo Maru conducted
detailed oceanographic and cetacean prey species surveys.
Oceanographic data were collected using CTD and XCTD;
prey species data were collected using the RMT 8 net (themultiple rectangular mid-water trawl net) and quantitativeecho sounder.
The following main types of data were collected for thisparticular objective, with sample sizes as indicated:(1) stomach content weight: 6,777;(2) stomach content (prey species): 6,777;(3) body weight: 6,491;(4) blubber thickness: 6,777; and(5) diatom adhesion record: 6,777.
Information on other data can be found in Annex D.
5.4 Results
5.4.1 Food habit and krill consumption of Antarctic minke
whales.
In SC/D06/J18, 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 prey species throughout the survey
period. The results indicated that the timing of feeding hadstrong diurnal variation with most feeding occurring atnight. The authors suggested that there had been a decreasein average mass of fresh stomach contents for mature males
and females from 1991-present. In Area V, there was same
trend for mature females. The daily prey consumption of
Antarctic minke whales was estimated using a direct method(diurnal changes of stomach contents mass) and an indirect
method (energy requirement). The results of daily
consumption estimates were similar for the two methods
and ranged from 2.6 to 5.0 % of body weight. The annual
consumption of Antarctic krill from the 1990/2000 season to
the 2004/05 season in Areas IV and V was calculated as
being equivalent to 3-4 % and 21-35 % of the krill biomass,
respectively.
In discussion, the Workshop noted that the daily prey
consumption estimates presented in SC/D06/J18 weresimilar to those from North Atlantic common minke whales(Haug et al., 1995) and to those predicted by Lockyer(1981). The issue of the specific method used to subsample
stomach material, and whether this might bias the resultscompared to larger prey items was considered.
Childerhouse believed that the key biological findings ofthe research did not represent an increase in knowledge,
namely that 99% of the minke whale diet is krill and that theestimated prey consumption rates simply confirmed resultsof previous analyses by Lockyer (1981) and Bushuev(1986).
Some participants expressed their disappointment andconcern at how little analysis had been undertaken given theenormous dataset available. The Workshop recommended
that more sophisticated analyses should be undertaken that
more fully utilise the considerable dataset available. The
following factors at least should be taken into account:(1) determination of the duration of the feeding period isfundamental to estimating total consumption and must
be adequately addressed;(2) examination at smaller spatial scales; and(3) use of GLM or similar approaches to examine trends,
incorporating covariates such as age, size andreproductive status of whales as well as the date andtime of day.
It was also noted that since some whales are not killed
instantaneously, they might vomit during capture. This
could be examined by comparing the stomach contents ofwhales killed instantaneously with those that were not killed
instantly. In response it was noted that although noquantitative analysis had been undertaken, scientists present
had not observed this phenomenon.
SC/D06/J19 examined annual trends in energy storage in
the Antarctic minke whale. The results of stepwise multiple
linear regression analyses showed that blubber thickness has
been decreasing over the JARPA period at 20.0190 cm
year–1. Date, extent of diatom adhesion, sex, body length,
foetus length and longitude were all identified as partiallyindependent predictors of blubber thickness. Possible
explanations for this were discussed in the paper and theauthors suggest that this indicated that food availability for
Antarctic minke whales in the Antarctic has decreased over
the JARPA survey period, presumably caused by either or
combination of intra- and inter-species competition among
baleen whales.
There was considerable discussion of this paper. Although
the authors’ analysis as presented showed a declining trend
in the blubber thickness measurement chosen, somemembers argued that the conclusion of a trend in energy
storage was premature and could not be confirmed until
improved analyses had been conducted. In particular thisinvolves the examination of other factors including age,
latitude, distance from ice-edge and non-linearity in trends.
In addition, even if it is assumed that the trend is real,consideration should be given to whether the particular
blubber thickness measurement chosen was actually a goodproxy for energy storage (for example, lipid content canvary considerably without necessarily affecting the
thickness of blubber). The Workshop recommended that theanalysis be expanded to incorporate, in an integrated
manner, the other extensive information available from the
JARPA dataset that relates to energy storage (e.g. otherblubber measurements, organ weights, etc.).
Tamura pointed out that the reliability of the body
condition indicators of Antarctic minke whales was also
analysed using indicators such as girth, body mass and othermeasurements of blubber thickness by Konishi (2006), that
paper was not presented to the Workshop.
There was considerable discussion over the authors’ viewthat a likely explanation for the results was that it reflected
declining body condition of Antarctic minke whales as aresult of ‘competition’. The differing views expressed canbe summarised as follows:Rep 1:Layout 1

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(1) the idea of interspecific competition between minke andhumpback whales is overly simplistic in the context of
the rest of the Antarctic marine ecosystem (simply
because two species feed on the same species of prey
does not mean that there is competition per se unlessthere is evidence that species are food limited) and is notsupported by the data presented; or(2) as both minke and humpback whales are feeding on krill
in the same area, then competition is happening de facto– what is of importance, however, is to identify theextent of this competition relative to the other factors
influencing the dynamics of the populations.
SC/D06/J20 presented the results of a comparison between
the length-frequency distribution of krill in the stomach
contents of Antarctic minke whales and from net sampling
using a multiple rectangular mid-water trawl(RMT(1+8)M). Whales fed mostly on Antarctic krill inoffshore areas and ice krill (E. crystarollophias) on thecontinental shelf of the Ross Sea. For both species, there
was almost complete overlap in the length-frequency
distribution from stomach contents and RMT net samples(although it was noted that RMT nets do not provide anunbiased sample). In the western slope area, the stomach
content weights of the minke whale were the highest (noempty stomachs were found), indicating that the continental
slope of the Ross Sea is an important feeding ground for the
Antarctic minke whales.
SC/D06/J21 reported the results of krill biomass
estimation using a quantitative echo sounder onboard
Kyoshin Maru 2 (KS2) since 1998/99 season in JARPA. The
survey covered the region 35°E-145°W using an EK500(Simrad, Norway) echosounder. Acoustic backscatterings
were identified as krill when the difference between themean volume backscattering strength (DMVBS) of 120 and
38kHz fell between 2 and 16dB. Similar biomass estimates
were obtained in Area IV in the 1999/2000 (34.2 million t)
and 2001/2002 (34.1 million t) seasons. In Area V, biomassin the 2000/2001 (20.7 million t) and in the 2002/2003 (22.6
million t) seasons were similar but biomass in 1998/1999(29.7 million t) was higher than the other two years. In
2004/2005, Kaiyo Maru (KM) conducted a standardised
krill biomass estimation survey applying methods adopted
by CCAMLR, using both RMT net sampling and acoustic
surveys. The other vessel, KS2, conducted only an acoustic
survey as in previous JARPA cruises. The results of biomass
estimates for Antarctic krill from the two vessels werecomparable (KM 5.36 (95% CI=7.45) gm–2; KS2 2.64 (95%CI=2.35) gm–2).
SC/D06/J22 attempted to assess the magnitude of theinterspecific competition among three baleen whale species,
Antarctic minke, humpback and fin whales, for their majorprey, Antarctic krill. Whale abundance (see SC/D06/J6 andSC/D06/J7) and daily krill consumption rate of Antarctic
minke whales (SC/D06/J18) and krill biomass(SC/D06/J21) were used. Daily food consumption of
humpback and fin whales (assumed as mature males) andaverage body masses of those species reported in Trites andPauly (1998) were used. The authors reported that the threebaleen whales consumed 10-21% and 31% of krill standing
stock in Area IV and V, respectively. In Area IV, humpback
whales (7-12%) consumed krill twice to three times as much
as Antarctic minke whales (4%). In contrast, 21-25% of krill
biomass was consumed by Antarctic minke whales in Area
V. The authors suggested that in order to accurately assess
the feeding impact of humpback and fin whales on krill,
long term biological data sets for those two species are429

critically important. The mechanism of the interactions
among baleen whales for krill should be tested using aminimum realistic ecosystem model such as Mori and
Butterworth (2006).
Some participants expressed particular concern that theseanalyses ignored the many other important krill predator
populations, as well as ignoring the substantial uncertainties
around krill biomass estimates, environmental controls on
krill population dynamics and a number of other, what
they considered to be, prerequisites to demonstratecompetition.
SC/D06/J23 also used data from the joint survey of theR/V Kaiyo Maru and JARPA and examined interactions
between oceanography, distribution of krill and baleen
whales in the Ross Sea and its adjacent waters in 2004/05.
The results indicated close relationships between
oceanography, krill and baleen whales. The oceanography ofthe surface layer was summarised as an oceanographic
environmental index that integrated mean temperature from0 to 200m in depth (ITEM-200). Distribution of ITEM-200
was used as background information for comparing with
distribution patterns of each species. Antarctic krill weremainly found in the Antarctic Surface Water (ASW) area
(ITEM-200 = 0 to 21oC) and extended into the Shelf Water(SW) area (less than 21oC). Ice krill were widespread in
SW but not ASW. Humpback whales were mainly found in
the Antarctic Circumpolar Current (ACC) waters with highdensity around 0oC near the Southern Boundary of ACC andslightly extended in ASW. Antarctic minke whales weremainly found in ASW and SW with high densities around
21oC in the continental shelf slope frontal zone. Theinteraction between distributions of krill and baleen whales
with ITEM-200 provide quantitative information to identify
the boundary of distribution of Antarctic krill and ice krill
for biomass estimation using acoustic data in the surveys. A
conceptual model of the relationships between
oceanography relating water mass and circulation pattern ofthe oceanic surface layer with ITEM-200, will be able todescribe adequately the distribution and abundance of krill
and baleen whales.
The Workshop welcomed the multi-disciplinary approachpresented in this analysis, noting that it provided a clear
indication that there was oceanic habitat segregation of
Antarctic minke, humpback, blue and fin whales in the Ross
Sea part of the JARPA research area.
SC/D06/J24 reported on the results of the study of
distribution patterns and biomass of Antarctic and ice krill in
the Ross Sea in 2004/5 using Kaiyo Maru-JARPA joint
survey data. Ice krill were found on the continental shelfregion (<1,000m water depth). In contrast, Antarctic krill
were found mainly in the oceanic waters (depth >1,000m)
although they were also found on the continental shelfwhere the integrated mean water temperatures between 0200m were higher than 21°C. The distribution of Antarctic
minke whales was related to the distribution of Antarctic
krill. School sizes of Antarctic minke whales were large
where the densities of Antarctic krill were high. The
distribution of Antarctic minke whales in the Ross Sea could
also be related to the distribution patterns of Antarctic krill.
The biomasses of Antarctic and ice krill in this study were
estimated as 1.46 (CV=0.32) and 0.82 (CV=0.18) million t,
respectively. The authors suggested that Antarctic minke
whales could be considered as a biological sampler tomonitor krill, which plays key role in the Antarctic
ecosystem. They concluded that multi-disciplinary studies
such as the Kaiyo Maru-JARPA survey can reveal theecological relationships between krill and baleen whales.

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SC/D06/J25 reported the results of examination of
influential environmental factors on distribution patterns of
Antarctic minke whales at a small scale. At the JARPA
review meeting in 1997, it was suggested that small scale (ofthe order of ten to one hundred kilometres) study of physicaland biological oceanography with zooplankton andpredators should be conducted to elucidate the role ofwhales in the marine ecosystem (one of the main objectivesof JARPA). This study was conducted in response to thatsuggestion. Influential environmental factors on distribution
patterns of Antarctic minke whales at small scale (30 n.miles
segments) in the Ross Sea in 2004/05 were examined basedon the Kaiyo Maru-JARPA joint survey data using thegeneralised additive model (GAM) approach. Three abiotic
factors, distance from physical boundary (combination ofcoast, ice edge and shelf ice lines), integrated temperatureand salinity mean from surface to 200m (ITEM-200 and
ISAM-200) as well as latitude and longitude were used ascovariates in the study. The distribution of krill was
described by ITEM-200 and ISAM-200 as well as latitude
and longitude. Mean krill density increased at salinity values
higher than 34.5. The results indicated that krill
distribution could be related to the presence of Modified
Circumpolar Deep Water (MCDW). Distributions of
Antarctic minke whale schools were explained by krill
density and ISAM-200 as well as latitude and longitude. In
contrast to krill, the distributions of Antarctic minke whales
increased at salinity values lower than 34.4. The presence ofAntarctic minke whales could be related to Antarctic
Surface Water (ASW). The peak number of schools of
Antarctic minke whales was observed around the 1g m–2 ofkrill density and it levelled off toward both lower and higher
densities of krill. The authors hypothesised that at the scaleof this study, Antarctic minke whales might not be directly
searching for krill aggregations but following the retreating
sea ice (low salinity water) where the occurrence ofmoderate densities of krill could be found with highprobability. It is promising that distribution patterns ofbaleen whales in relation to environmental factors can be
related if good data sets from multi-disciplinary studies areavailable. However, the authors stressed that the modelling
used in this study was preliminary and much improvement
is necessary
The Workshop agreed that this approach could provide
important information required for model-based estimationof cetacean distribution and density in unsurveyed areas.
5.5 Synthesis
SC/D06/26 examined historical changes in the Antarctic
minke whale stocks based on various results from JARPA
including age at sexual maturity, growth curve, blubber
thickness, prey consumption, ADAPT-VPA analysis andpollutant (mercury) accumulation. It proposed the following
hypothesis of changes in the Antarctic ecosystem in the 20th
Century: minke whale feeding conditions improved with theremoval of large baleen whales such as the blue whale bycommercial whaling, which promoted rapid growth andyounger age at sexual maturity; however, around 1970,
conditions gradually became unfavourable, resulting inslower rates of change in these parameters. These changes
were then arrested by the 1980s-90s. SC/D06/26 further
suggested that, reflecting these unfavourable changes,
blubber thickness and stomach content weight were reduced(indicating less prey consumption). There was also adecrease in the accumulation of mercury which was also

attributed by the authors to less prey consumption.
Furthermore, the distribution of humpback and fin whales in
the feeding season had expanded southward in the Antarctic
from around 1990, suggesting further deterioration of
feeding conditions for Antarctic minke whales.
The Workshop noted that in the presentation of
SC/D06/J26, a general hypothesis of inter-specificcompetition had been used to provide a framework for the
analysis.
In considering the synthesis of the different components
of JARPA presented in SC/D06/J26, some memberssuggested that this was simplistic and ignored many othercomponents of the Antarctic marine ecosystem. They thus
believed that it was not particularly informative regarding
what may have occurred.
Some members (Clapham, Gales and Childerhouse) notedthat demonstration of interspecific competition was not a
simple matter, and listed prerequisites derived from other
ecological studies together with comments on how JARPA
had addressed them: (1) that the species in question must be
shown to be resource-limited (JARPA has not provided dataon total krill abundance and on total consumption by all krill
predators); (2) that there must be substantial overlap in
spatio-temporal distribution of the two species (JARPA has
shown this is some areas, but found evidence for segregationin others); (3) other variables must be categorically excluded
as causes of failure to recover (JARPA has not collected thedata to address this); and (4) that both species must occupy
essentially similar ecological niches. With regard to thelatter, they noted that the only directed study of thisinvolving Antarctic minke whales (Friedlaender et al., 2006)
has shown strong evidence for avoidance of competition
through niche separation. They also commented that theterm competition is consistently used loosely in JARPA, andwas not defined; furthermore it was surprising that the
JARPA papers made no reference to the large body ofliterature on competition from terrestrial and marine studies.
They concluded that conducting any investigation ofinterspecific competition without reference to this body ofwork almost guarantees that interpretation of results, andindeed of the study design itself, would be inadequate or
wrong.
Other members (Tamura, Fujise, Konishi, Murase,
Ishikawa, Mori and Hatanaka) commented that the study
described in (Friedlaender et al., 2006) was conducted in
April/June. This is much later than the peak feeding seasonof these species and thus inferring that this also applies tothe peak feeding season required great caution. Further, thestudy was conducted in Area I. The estimated annual rate ofincrease (ROI) in abundance for humpback whales in Area I
is 4% while it is 15% in Area IV (part of the JARPA surveyarea) (Branch, 2007). Given the differences in area-specific
ROIs, it is important to take into account the status of the
populations in a given area when evaluating the extent towhich competition for limited resources is occurring. The
results of the recent JARPA surveys suggested that the
spatial distribution of Antarctic minke and humpback
whales appreciably overlapped (Ishikawa, 2003; Ishikawa etal., 2004; Ishikawa et al., 2002). These direct observations
strongly suggest the possibility of competition between
Antarctic minke and humpback whales for krill at the same
spatio-temporal scale.
During the Workshop, several recommendations for morecomprehensive analysis of the time series summarised in
SC/D06/J26 had been suggested. For example, theWorkshop agreed that a more complete analysis of energy
storage over time is required to evaluate the hypothesis of a

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long-term decline (see recommendations above). The
Workshop also recalled the recommendation for further
analysis of the stomach content mass data before any trend
analysis could be undertaken.
Some members considered that the multiple strands ofevidence, notwithstanding the recommendations for
improved/reanalysis, were generally indicative andprovided support for the hypothesis of interspecificcompetition. However, other members considered that,when considering the current state of the analyses and being
aware of the considerable uncertainties involved, there was
not necessarily consistency in the support provided for the
hypothesis of inter-specific competition outlined in
SC/D06/J26.
The Workshop agreed that it would be valuable to havethe opportunity to review the trends summarised in
SC/D06/J26 when the recommended analysis had been
conducted, in order to formulate alternative hypotheses that
set the observed changes in the context of a broader suite ofindicators from the Southern Ocean.
Finally, the Workshop agreed that the JARPA dataset
provides a valuable resource to allow investigation of some
aspects of the role of whales within the marine ecosystem.
With appropriate analyses, this has the potential to make animportant contribution to the Scientific Committee’s workin this regard, as well as the work of other relevant bodies
such as CCAMLR. In order to facilitate the comprehensive
analyses that this dataset warrants, the Workshop strongly
recommended that an advisory group is established to work
co-operatively to guide such analyses.
6. ENVIRONMENTAL CHANGE INCLUDINGPOLLUTION

6.1 BackgroundAs already noted, the 1995/96 research plan added thefollowing objective ‘Elucidation of the effect ofenvironmental changes on cetaceans’. This objective wasadded in response to resolutions adopted by the Commission
on research on the environment and whale stocks (IWC,
1995b) and on the promotion of research on theconservation of large baleen whales (IWC, 1995a). Thisobjective is also related to the resolution on research on theenvironment and whale stocks (IWC, 1996).
In the Scientific Committee, environmental changes are
addressed under the following topics (IWC, 1995c): (1)global warming; (2) ozone depletion; (3) pollution; (4)direct (intentional and incidental mortality) effects offisheries and indirect (ecological ramifications) effects offisheries; (5) noise; and (6) other human activities (e.g.
tourism, coastal developments). The Committee had notedthat it was not feasible to address all these topics
simultaneously; this would be a longer-term iterative project(IWC, 1995c). Given this, it was agreed that initially two
specialised workshops should be held, one relating tochemical pollutants and cetaceans, and the other on potential
ecological effects on cetaceans of climate change and ozone
depletion. The former Workshop was held from 27-29
March 1995 in Bergen (Reijnders et al., 1999b), and thelatter Workshop was held from 25-30 March 1996 in Hawaii(IWC, 1997a). These meetings emphasised that studies
related to such topics should be conducted in the Antarctic.
At the JARPA review meeting in 1997, reference wasmade to the recommendations of the Bergen Workshop; it
was considered that the pollutant studies under JARPA were431

pertinent to recommendations 1, 4 and 5 of the Bergen
Workshop.

6.2 Data collection methods and results
There is a close relationship between the data collected forstudies on the marine ecosystem and those required forstudies on environmental change. In addition to these, data
have been collected on marine debris and body burdens ofpollutants, including organochlorines and heavy metals.
Tissues samples, including liver, muscle, kidney andblubber have been collected for these analyses. Marine
debris data have been based on visual observations, but
recently the use of nets has been introduced to estimate
prevalence of smaller items of marine debris. Air and sea
water samples have been collected to monitor pollutant
levels in the environment. The main relevant data collectedduring JARPA are:(1) blubber tissues for organochlorine analysis: 113;(2) liver tissues for heavy metal analysis: 1,072;(3) stomach content of Antarctic minke whales for heavy
metal analysis: 100;(4) air samples for organochlorine analysis: 4; and(5) sea water samples for organochlorine analysis: 4.
Oceanographic data have been collected from the JARPA
research area. Vertical oceanographic structure wasobserved by using XBT (eXpendable Bathy Thermograph),
CTD (Conductivity-Temperature-Depth profiler) and themore recent XCTD (eXpendable CTD). XBT was mainly
used in the first stage of JARPA (1987/88-1996/97) and
XCTD was used from the late 1990s. Relevant datacollected during JARPA are as follows:(1) XBT surveys: 916;
(2) XCTD surveys: 915;
(3) CTD surveys: 499; and(4) EPCS surveys: 1,307.
Information on other data can be found in Annex D.

6.3 Data analysis methods and results
6.3.1 Pollution
SC/D06/J27 examined concentrations of Mn, Fe, Ni, Cu,
Zn, Cd, Hg and Pb determined in Antarctic krill collectedfrom Areas III, IV, V and VI, as well as their temporal andspatial variations during the period 1989/90 to 1998/90.
Differences associated with body size were found for someelements and size groups. Although some temporal variation
was observed in some trace elements, concentrations of
toxic elements (Hg and Cd) did not show any significant
variation through the study period. Changes within season
were only found for Cd. As compared to other regions,concentrations were low except for Cd, which showed
relatively high values.
SC/D06/J28 examined concentrations of trace elements inthe liver of 1,056 minke whales taken from Areas IIIE, IV,
V and VIW during the period 1988/89 to 2004/2005 andtheir variations in the liver of Antarctic minke whales.
Levels of all elements except Fe were overall low andsignificantly lower than those in cetaceans from theNorthern Hemisphere, which the authors took as anindication that whale health was not affected. Age- and sexrelated differences were observed for some elements. A
decrease in Hg levels in the juvenile class (1-15 years old)
was proposed to occur through the study period and theauthors attributed this to a decrease in food intake rates since
the mid-1980s.

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There was some discussion on this hypothesis and several
members considered that the apparent decrease might beeither an artefact or due to other biological factors notnecessarily related to food intake. Further work is required
to address this.
SC/D06/J29 described yearly changes on organochlorine
pollutants. Concentrations of DDTs, PCBs, HCHs, HCB andchlordanes were determined on the blubber of minke
whales. The research focused on adult males only to avoid
interference of age- and sex-related variations. The levels of
PCBs and DDTs in blubber of Antarctic minke whales were
one order of magnitude lower than those of other whales in
the mid and low latitude areas of the Northern Hemisphere,
and the authors suggest that such levels would not have an
adverse effect on whale health. Some variation wasobserved between Areas. All organochlorine blubber levels
in Area V and HCHs and HCB levels in Area IV decreased
with time. The decrease was particularly marked for HCHs.
The authors suggested that this might be an indication of
decreased food availability throughout the period.
In discussion, several members noted that sinceorganochlorines are more difficult to mobilise than lipids, adecrease in fatness caused by lowered food availability
would probably produce an increase of organochlorine
blubber concentrations with time rather than a decrease.
6.3.2 Oceanography
SC/D06/J30 examined oceanographic data obtained by
JARPA and provided some information on possible
environmental changes in recent years in JARPA areas. The
time series of oceanographic data obtained by JARPA
surveys has allowed for the study of temporal changes inenvironmental conditions. It is important to link JARPA
oceanographic observations with the monitoring by other insitu observation projects (Argo, IPY, etc.) and satellite
observations. In order to contribute to research of theSouthern Ocean, it is also important to make the JARPA
oceanographic data available internationally. Developmentof all aspects of Southern Ocean research adds to theunderstanding and improved management of all marine
resources in the area.
7. OTHER RESULTS

7.1 Stock structure of humpback whales
SC/D06/J31 used biopsy samples from 411 humpback
whales obtained during JARPA and the IDCR/SOWER
cruises to describe their genetic population structure in partsof the Antarctic feeding grounds. Samples were obtained
from the IWC management Areas III (n=81), IV (n=172), V(n=97) and VI (n=61), and were examined for (i) sex
determination; (ii) the sequence variation of the first 334bp
nucleotides of the mtDNA control region; and (iii) genetic
variation at the genotypes of six microsatellite loci.
Duplicated samples were excluded from the analysis. The
level of genetic diversity in the Antarctic was high for bothgenomes: the nucleotide diversity at the mtDNA wasestimated at 0.0263 and the mean expected heterozygosity at
the nuclear loci at 0.7820 for the total samples. In general,
results based on both mtDNA and microsatellites weresimilar and they suggest population structure among
humpback whales in the Antarctic feeding grounds. These
genetic results are consistent with the previous view basedon non-genetic data that Areas III, IV, V and VI are occupied
by different populations. The most plausible pattern ofstructure in the Southern Hemisphere therefore is multiple
breeding and feeding grounds with some degree of site

fidelity. Marked differences were found between whales inAreas IV and V for both mtDNA and microsatellites, and thesame pattern was found for both sexes. Results of the otherpair-wise comparisons among Areas showed more
subdivisions in females than in males. A possible
explanation for this is that the difference is due to the lower
sample sizes for males in these comparisons. The possibilityof intermingling of populations in bordering sectors cannot
as yet be discarded and a comprehensive analysis thatinvolves genetic data from low and high latitudes isrecommended.
The Workshop welcomed this paper. Hoelzel noted thatsome genetic data suggested the possibility of male-biased
dispersal, but that further analyses would be required toassess this (including assignment tests). Pastene noted thatin the case of Areas IV and V, the Areas with the largest
sample sizes, the pattern of genetic differentiation was thesame for females and males for both mtDNA andmicrosatellites, based on the analyses undertaken to date.
The Workshop was reminded that at the 2006 meeting, the
Scientific Committee endorsed the Hobart workshop
recommendation that every effort be made for scientists toshare data from low and high latitude and carry out DNA
analyses under the IWC Data Availability Access protocol(IWC, 2007a). Such co-operative analyses would allow fora more comprehensive study of stock structure of humpback
whales of Breeding Stocks D, E and F (see IWC, 2007a).
7.2 Other
SC/D06/J08 presented a brief review of genetic studies onsouthern dwarf minke whale. Prior to the JARPA surveys,
dwarf minke whales were believed to be only found between
7-41°S. However, the distribution of the JARPA catches inAreas IV and V was mainly between 55-62°S (one animal
was caught at 65°S), showing that the dwarf minke whale
can be found, very rarely, much further south than thatindicated by the previous data. A total of 16 dwarf minke
whales was sampled by JARPA and these animals were
examined genetically with the purpose to investigate theirrelationship to the southern ‘ordinary’minke whale and tominke whales in the Northern Hemisphere. Early studies
showed that the level of mtDNA differences between thesouthern minke whale ‘forms’ was large and similar to thatfound between the ‘ordinary’ minke whales and Northern
Hemisphere minke whales. Phylogenetic analyses showedthat the dwarf minke whale was more closely related to
Northern Hemisphere minke whales than it was to thesouthern ‘ordinary’ minke whale. In 1993, the ScientificCommittee recommended the inclusion of the dwarf minke
whale in the Schedule, so that catch limits for Antarctic
minke whales recognise the distinction between the two‘forms’. The genetic analysis undertaken with JARPA
samples greatly assisted the taxonomic review of minke
whales conducted by Rice (1998) who confirmed theexistence of two species, the larger (‘ordinary’) Antarctic
minke whale confined to the Southern Hemisphere, and thesmaller, common minke whale distributed in bothhemispheres. The distribution of dwarf minke whales andAntarctic minke whales overlap partially in the feeding
grounds; the former is considered by some authors as a subspecies of the common minke whale. More recent studies
have revealed genetic structure in dwarf minke whales in theSouthern Hemisphere (Pastene et al., 2007).
The Workshop recognised the important contribution of
the genetic analyses of dwarf minke whale samples from
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basins. Genetic results had contributed to the taxonomic
review of minke whales conducted by Rice (1998) that
confirmed the existence of two species of minke whales, theAntarctic minke whale and the common minke whale.
Hoelzel suggested that the apparent paraphyly of dwarf
minke whales should be investigated further, and suggested
that if further supported, it may have implications for thetaxonomic classification of dwarf minke whales, including
the possibility of parallel evolution in different ocean basins.
Pastene responded that discussion on classification of thecommon minke whale (including the dwarf minke whale)should await the completion of ongoing morphometric andmorphological studies, as well analyses based on nuclear
DNA. Finally it was noted that only one of the dwarf minke
whales sampled by JARPA was sampled in more southerly
latitudes.
SC/D06/J32 presented an overview of other JARPA
results. JARPA systematically collected a comprehensive
data/sample set over a long time period in order to conduct
studies related to the four objectives of the programme.
Samples collected by both the lethal and non-lethal
components of JARPA have also been used in several
studies with different objectives than the four objectives ofthe programme. The paper presented an overview of thesestudies. They have contributed to knowledge of whales
primarily in three areas: reproductive physiology of
Antarctic minke whale, taxonomy and phylogenetic
relationships among large whales and distribution andmovement of baleen whales.
In discussion, the Workshop recognised the contributionof JARPA research to other aspects of whale biology,
genetics, movement and distribution. Daníelsdóttir notedthat several co-operative studies have been conductedsuccessfully between ICR scientists and international
scientists. She also noted that DNA data from minke whales
sampled from JARPA were included in the Japanese DNA
register for large whales and that this represented apotentially useful scientific tool, aside from its use inmanagement. Matsuoka commented that in addition, in situ
observation projects (Argo, IPY, etc.) and satellite
observations are being conducted.
8. OVERVIEW OF RESULTS IN THE CONTEXT OF
THE STATED OBJECTIVES OF THE JARPAPROGRAMME AND OF STOCK MANAGEMENT
Although the Terms of Reference (TOR) specified thisoverview to include how well the initial and revised
objectives of the research had been met, it was inevitablethat the discussions at the Workshop would give rise tosuggestions for further and/or refined analyses. Thus it was
unclear whether or not the conclusions of the Committee
under this component of the TOR should or should not await
consideration of the results of further analyses.

8.1 Contribution to minke whale management
The Workshop noted that the Southern Ocean Sanctuary
established in 1994 covers most of the Antarctic waters
south of 40°S and all of the waters to the south of 60°S;
within the Sanctuary, commercial whaling is prohibited
although the Government of Japan has an objection withrespect to Antarctic minke whales. If catch limits were to be
set at some time in the future, the present approach the
Scientific Committee has agreed to use for providing advice
to the Commission on commercial whaling catch limits isthat specified by the RMP. When it last considered this issue
in 1997, the Committee agreed to the statement below.

433

The results from the JARPA programme, while not required for
management under the RMP, have the potential to improve
management of minke whales in the Southern Hemisphere in thefollowing ways: (1) reductions in the current set of plausible
scenarios considered in Implementation Simulation Trials; and (2)identification of new scenarios to which future Implementation
Simulation Trials will have to be developed (e.g. the temporalcomponent of stock structure). The results of analyses of JARPA data
could be used in this way perhaps to increase the allowed catch ofminke whales in the Southern Hemisphere, without increasing
depletion risk above the level indicated by the existing
Implementation Simulation Trials of the RMP for these minke
whales.

The present Workshop concurred with that view.
In its discussions of possible contributions tomanagement, the 1997 Workshop also referred to: (1)questions about long-term changes in abundance of minke
whales in Areas IV and V; (2) elucidation of the role ofminke whales in the Antarctic ecosystem (including thepossible ‘krill surplus’ model); (3) elucidation of the effectof environmental change on cetaceans and variation ofminke whale biological parameters; and (4) elucidation ofstock structure to improve management. Progress andconclusions on these are considered below.

8.1.1 Stock structure
The issue of stock structure is fundamental to the analysesof the data collected under JARPA, the interpretation of theresults and a view of whether it has reached its stated aims
and objectives. As noted in 1997, the Scientific Committee
at that time had no clear definition of a ‘stock’ in a
management context. Despite the ongoing work of theWorking Group on Stock Definition, the Committee is still
not in a position to provide such a definition, although it
recognises that any definition has to be linked to the
management implications of such a definition, particularly
with respect to feeding areas. This is being investigated aspart of the Committee’s Testing of Spatial Structure Models(TOSSM) project. In an RMP context, the approach has
been to use the available data to establish ‘plausible’
hypotheses and to examine the management implications ofthese in the context of Implementation Simulation Trials.
Given this background, it is not surprising that theWorkshop cannot conclude that this issue has been resolvedfor Antarctic minke whales in the JARPA research area at
the present time; however, it recognises that considerable
progress has been made in addressing the issue of stock
structure since the 1997 review. For example, the Workshop
agreed that there are at least two stocks of Antarctic minke
whales present in the JARPA research area and that the datasuggest an area of transition in the region around 150-165°E
within which there is an as yet undetermined level and rangeof mixing. The Workshop has made a number of suggestions
and recommendations for future work (see Item 3). The
results of this additional work will have major implications
for determining the level to which the programme will meetits other objectives. It is also clear that this work is essential
to any future Implementation Review under the RMP.
8.1.2 Stock abundance and trends
Information on stock structure is also important for theinterpretation of abundance and trend information obtained
during surveys on feeding grounds. As stressed earlier in thereport, such surveys provide information on numbers ofanimals (and trends in those numbers) within a geographicalarea. Information on abundance and trends in abundance isrelevant to aspects of all of the objectives of JARPA
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8.2 Elucidation of the role of whales in the marine
ecosystem
At the 1997 Workshop, it had been noted that the data on
body condition and biological parameters should result in abetter understanding of the status of Antarctic minke whalesin the research area and be useful to test hypotheses related
to aspects of the ‘krill surplus’ model. The importance ofunderstanding the feeding ecology of Antarctic minke
whales has been recognised by the Committee and formed
an important part of its SOWER 2000 programme (IWC,
2000b). The importance of but the inherent difficulties inecosystem modelling are also recognised by the Committee(IWC, 2004a; 2007a). The Committee has long been unable
to reach agreement on interspecific competition among
baleen whales in the Antarctic, particularly with respect tothe so-called ‘krill surplus’ model. The Committee
welcomed the oceanographic and krill-related work
undertaken since the 1997 Workshop. The Workshop also
agreed that considerable relevant data had been collected by
the JARPA programme on matters related to body condition
and feeding. However, it is clear from the discussion under
Item 5 that the simple nature of several of the analyses
presented at the present Workshop means that relatively
little progress has been made in addressing this objective,
even allowing for the complexities of the subject. Issues
related to the ‘krill surplus’ model remain as controversial as
ever. The Workshop strongly recommended theestablishment of an advisory group (Item 5.5) to ensure thatthe extensive dataset is used to its full potential and progress
is made. It also agreed that it is essential that information onother krill predators as well as information on krill dynamics
is incorporated into analyses of the role of whales in theecosystem and notes that planned discussions in the
IWC/CCAMLR joint workshop would assist in this.

REPORT OF THE INTERSESSIONAL WORKSHOP TO REVIEW DATA AND RESULTS

Antarctic ecosystem. At the 1997 Workshop it had been
agreed that more research was needed to develop a reliable
method to use the JARPA data to obtain estimates ofabsolute abundance and trends.
There are general unresolved issues related to estimating
abundance and trends in these waters that apply not only to
the JARPA data but also to the IDCR/SOWER data that
require further work by the Committee. Given that, it is not
surprising that the Workshop has not developed agreed
estimates of abundance and trend for Antarctic minke
whales in the JARPA research area at the present time;
however, it recognises that considerable progress has been
made in addressing the issues related to abundance andtrends and provided the recommendations given under Item
2 are followed, the Committee should soon be able to agree
estimates. The Workshop draws attention to its comments on
the confidence intervals surrounding the preliminary
estimates of trends presented that suggest that even therevised estimates may only be able to detect very majorchanges in the abundance of animals using the JARPA area
over long time periods. The implications of this latter
finding for addressing the other objectives (e.g. biologicalparameter estimation) require further investigation. The
abundance estimates will be valuable for any future
Implementation Review under the RMP.

8.1.3 Estimation of biological (life history) parameters to
improve the stock management of the Southern
Hemisphere minke whale
As noted above, issues of stock structure are directly
relevant to the question of biological parameter estimation.
The 1997 review had noted that the information from
JARPA had set the stage for answering many questions
about long term changes in minke whales in the JARPA
research area and had recommended that biologicalparameters be analysed by stocks. Some advance towards
that had been made at the present Workshop in that estimates
had been presented for one possible hypothesis based on thestock structure analyses undertaken thus far, in accordancewith a Committee recommendation made in 2006. However,further work will be required as progress is made withrespect to stock structure and mixing in accordance with therecommendations made under Item 3. Given thatbackground and notwithstanding further comments below,
the Workshop cannot conclude that this objective has been
fully met at present; however, the Workshop acknowledgedthat considerable effort had been put into attempting toobtain agreed estimates of biological parameters (andchanges in these over time) for one stock structure
hypothesis. In discussion of the analyses presented at thisWorkshop, the Workshop agreed that no marked trends inlife history parameters were found for the JARPA period.
However, problems were identified with the age data for thecommercial period and for this reason, there were differing
views on the reliability of estimates of historical trends inlife history and population parameters prior to the JARPA
period. It was also noted that the confidence intervals
around the estimates of natural mortality estimated from the
JARPA data alone spanned such a wide range that theparameter remains effectively unknown at present (narrower
confidence intervals were estimated for the ADAPT-VPA
analysis but this relies on commercial age data). The
Workshop agreed that every effort should be made to try toresolve the issue of the commercial age data as this has
important implications as to how well the objectives of the
programme can be met.

8.3 Environmental change
At the 1997 Workshop, it was noted that the pollutant
analyses undertaken by the JARPA programme should take
into account the recommendations made at the 1995 IWC
Workshop on Chemical Pollutants and Cetaceans (Reijnders
et al., 1999a). The Workshop welcomed the presentation of
the pollutant analyses at this Workshop, although there wassome disagreement over the implications of the results
drawn by the authors (see Item 6.3.1). The Workshop also
welcomed the oceanographic work presented, noting that inaddition to its potential to assist in the ecosystem work, italso has the potential to contribute to other environmental
monitoring programmes in the Antarctic.
8.4 Scientific contributions of JARPAThe JARPA project has generated extensive data that areavailable to IWC scientists through the data sharing
agreement. The programme has also resulted in a number ofpublications in the IWC Journals and in other international
peer-reviewed journals. Except for cruise reports andcommentaries there have been 22 articles in Rep. int. Whal.
Commn and J. Cetacean Res Manage., and 58 articles inEnglish language journals. Of the latter, the majority is in
the fields of physiology, reproduction and chemistry,
while six articles are concerned with management. In
addition a total of 182 scientific documents based on JARPA
data have been presented to the IWC Scientific Committee
meetings.

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The Workshop agreed that there was insufficient time toaddress these items and refers them to the Committee.
10. OTHER MATTERS

There were no other matters discussed.

11. ADOPTION OF REPORTThe report was adopted on 8 December 2006. The Chair
thanked all of the participants for their co-operation andhard work and in particular the rapporteurs under Donovan.
He also thanked the Government of Japan and the staff of
ICR for the excellent facilities provided. The meeting
expressed appreciation to the Chair for his usual firm but
fair handling of the Workshop.
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Annex A
AUSTRALIA
N. Gales
GERMANY
J. Cooke
GRENADA
F. Hester

ICELAND
G. Vikingsson
JAPAN
T. Bando
Y. Fujise
D. Goodman
M. GotoT. Hakamada
H. Hatanaka
J. Hyugaji
H. Ishikawa
Y. Ishizuka
H. KatoT. Kitakado
T. Matsuishi
K. Matsuoka
T. Miyashita
M. Mori
J. Morishita

List of Participants
H. Moronuki
H. Murase
M. Naganobu
R. Nakamura
S. Ohsumi
L.A. Pastene
R. Suzuki
T. Tamura
E. Tanaka
S. Tanaka
T. Watanabe
G. Yasunaga
R. Zenitani

T. Eguchi
P. WadeINVITED PARTICIPANTS
A. Aguilar
J. Bannister
D. Butterworth
A. Daníelsdóttir
T. Haug
S. Hedley
R. Hoelzel
Y. Ivashchenko
T. Kasuya
H. Kishino
M. Maunder
K. Reid
T. Schweder

NEW ZEALAND
S. Childerhouse
NORWAY
L. Walløe

SCIENTIFIC COMMITTEE
CHAIR
A. Bjørge

REPUBLIC OF KOREA
Y.R. An

IWC SECRETARIAT
G. Donovan

ST. LUCIA
J. Rambally

INTERPRETERS
S. Baba
R. Kawagishi
M. OtaUSA
R. Brownell
P. Clapham

Annex B
Agenda

1.
1.
1.
1.
1.
1.
1.
1.
1.
1.
2.
1.
1.
1.
1.
1.

Introductory items
1.1 Welcome and introduction
1.2 Election of Chair and appointment of rapporteurs
1.3 Meeting procedures and time schedule
1.4 Adoption of Agenda
1.5 Documents and data available
1.6 Terms of reference for this review
1.7 Objectives of JARPA as stated in the original
research proposal and subsequently
1.8 General outline of the JARPA research
1.9 Overview of the 1997 JARPA review andsubsequent discussions
Sightings surveys and abundance estimation
2.1 Background
2.2 Issues raised in previous IWC meetings
2.1 2.2.1 1997 JARPA review
2.1 2.2.2 Humpback whale Workshop
2.1 2.2.3 Other

1.
1.
1.
1.
1.
1.
1.

2.3
2.4
2.1
2.1
2.5
2.1
2.1

3.
1.
1.
1.
1.

Stock structure (Antarctic minke whale)
3.1 Background
3.2 Issues raised in 1997 JARPA review
2.1 3.2.1 Stock definition
2.1 3.2.2 Statistical analysis of mtDNA dataconsidering the inclusion of school size
as a covariate
2.1 3.2.3 Pilot study on nuclear DNA analysis on
JARPA minke samples
2.1 3.2.4 Effort to obtain biological materials forgenetic analysis from low latitude areas

1.
1.

Data collection methods and results
Data analysis methods and results
2.4.1 Minke whales
2.4.2 Other species
Estimates of trends in abundance
2.5.1 Minke whales
2.5.2 Other species

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of the Southern Hemisphere (potential
breeding grounds) and compare withfeeding ground data
3.2.5 External morphology/morphometry
analyses
Data collection methods and results
Data analysis methods and results
3.4.1 Genetics
3.4.2 Morphometrics and morphology
Synthesis

1.

2.1

1.
1.
1.
1.
1.

3.3
3.4
2.1
2.1
3.5

4.
1.
1.
1.
1.

Biological parameter studies
4.1 Background
4.2 Issues raised in 1997 JARPA review
2.1 4.2.1 Segregation study
2.1 4.2.2 Recalculation of biological parameters
by biological stocks
4.3 Data collection and results
4.4 Data analysis methods and results
2.1 4.4.1 Natural mortality
2.1 4.4.2 Growth curves and age at sexual maturity
2.1 4.4.2 4.4.2.1 Growth curves
2.1 4.4.2 4.4.2.2 Age at sexual maturity
2.1 4.4.3 Reproductive and sustainable yield rates
2.1 4.4.4 Synthesis of information on biologicalparameters from different sources

1.
1.
1.
1.
1.
1.
1.
1.
5.
1.
1.

1.

Marine ecosystem
5.1 Background
5.2 Issue raised in 1997 JARPA review: Meso-scale
survey plan
5.3 Data collection methods and results
5.4 Data analysis methods and results
2.1 5.4.1 Food habit and krill consumption of
Antarctic minke whale
5.5 Synthesis

6.
1.

Environmental change including pollution
6.1 Background

1.
1.
1.

1.
1.
1.
1.

6.2
6.3
2.1
2.1

7.
1.
1.

Other results
7.1 Stock structure of humpback whales
7.2 Other

8.

Overview of results in the context of the statedobjectives of the JARPA programme and of stock
management
8.1 Contributions to minke whale management
2.1 8.1.1 Stock structure
2.1 8.1.2 Stock abundance and trends
2.1 8.1.3 Estimation of biological (life history)
parameters to improve the stock
management of the Southern Hemisphereminke whale
8.2 Elucidation of the role of whales in the marine
ecosystem
8.3 Environmental change

1.
1.
1.
1.

1.
1.
9.
1.
1.
1.
1.
1.

10.

Data collection methods and results
Data analysis methods and results
6.3.1 Pollution
6.3.2 Oceanography

Overview of results in the context of IWC resolutions
and discussions
9.1 Utility of lethal versus non-lethal researchtechniques
9.2 Other mandates regarding SC reviews of special
permit research
9.3 With respect to resolutions on the Antarctic
marine ecosystem
9.4 With respect to resolutions on pollution
9.5 With respect to resolutions on environmental
change and cetacean response
Other matters

11. Adoption of report

Annex C

List of Documents
SC/D06/J
1. Hatanaka, H., Fujise, Y., Pastene, L.A. And
Ohsumi, S. Review of JARPA research objectives andupdate of the work related to JARPA tasks derived from the1997 SC meetings.
2. Nishiwaki, S., Ishikawa, H. And Fujise, Y. Review ofgeneral methodology and survey procedure under the
JARPA.
3. Hakamada, T., Goto, M. And Ishikawa, H.
Examination of the effect of skip on abundance estimates for
Antarctic minke whales.
4. Burt, M.L. And Paxton, C.G.M. Review of density
surface modeling applied to JARPA survey data.
5. Matsuishi, T., Ikeda, H. And Nishiwaki, S.
Estimation of g(0) based on the sighting survey data of
JARPA incorporating additional information.

6. Hakamada, T., Matsuoka, K. And Nishiwaki, S. An
update of Antarctic minke whales abundance estimate basedon JARPA data.
7. 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°E145°W).
8. Pastene, L.A. A brief review of the genetic studies on
dwarf minke whale based on JARPA samples.
9. Pastene, L.A., Goto M. And Kanda, N. Genetic
analysis on stock structure in the Antarctic minke whales
from the JARPA research area based on mitochondrial DNA
and microsatellite.
10. Hakamada, T. A study on stock structure in the
Antarctic minke whale from the JARPA research area basedon morphometric analysis.

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11. Bando, T., Zenitani, R. And Fujise, Y. A study on
stock structure in the Antarctic minke whales from the
JARPA research area based on analysis of body length ofphysically matured whales.
12. Pastene, L.A. What do we know about the stock
structure of the Antarctic minke whale? A summary ofstudies and hypotheses.
13. Tanaka, E., Zenitani, R. and Fujise, Y. An estimateof natural mortality coefficient in Antarctic minke whales
using JARPA data.
14. Mori, M., Kitakado, T. and Butterworth, D.S.
Progress on application of ADAPT-VPA to minke whales inAreas IV and V given updated information from
IDCR/SOWER and JARPA surveys.
15. Zenitani, R. and Kato, H. Temporal trend of age atsexual maturity of Antarctic minke whales based ontransition phase in earplugs obtained under JARPA surveys
from 1987/88 to 2004/05.
16. Mori, M., Butterworth, D.S., Zenitani, R. andKato, H. Model-based transition phase analyses for the
Antarctic minke whales in the JARPA research area.
17. Bando, T., Zenitani, R., Fujise, Y. and Kato, H.
Biological parameters of Antarctic minke whale based onmaterials collected by the JARPA survey in 1987/88 to
2004/05.
18. Tamura, T. and Konishi, K. Food habit and prey
consumption of Antarctic minke whale Balaenoptera
bonaerensis in the JARPA research area.
19. Konishi, K., Tamura, T. and Walløe, L. Yearly
trend of energy storage in the Antarctic minke whale
Balaenoptera bonaerensis in the JARPA research area.
20. Tamura, T., Konishi, K., Nishiwaki, S., Taki, K.,
Hayashi, T. and Naganobu, M. Comparison between
stomach contents of Antarctic minke whale and krill
sampled by RMT net in the Ross Sea and adjacent waters.
21. Murase, H., Kiwada, H., Matsuoka, K. andNishiwaki, S. Results of the cetacean prey survey using
echo sounder in JARPA from 1998/99 to 2004/2005.
22. Murase, H., Tamura, T., Matsuoka, K., andHakamada, T. First attempt of 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.

439

23. Naganobu, M., Nishiwaki, S., Yasuma, H.,
Matsukura, R., Takao, Y., Taki, K., Hayashi, T.,
Watanabe, Y., Yabuki, T., Yoda, Y., Noiri, Y., Kuga, M.,
Yoshikawa, K., Kokubun, N., Murase, H., Matsuoka,
K. and Ito, K. Interactions between oceanography, krill andbaleen whales in the Ross Sea and Adjacent Waters: An
overview of Kaiyo Maru-JARPA joint survey in 2004/05.
24. Murase, H., Tamura, T., Nishiwaki, S., Yasuma,
H., Matsuoka, K., Yabuki, T. and Naganobu, M.
Biomass estimation of Euphausia superba and E.
crystallorophias in the Ross Sea in 2004/05 using Kaiyo
Maru-JARPA joint survey data.
25. Murase, H., Kitakado, T., Matsuoka, K.,
Nishiwaki, S. and Naganobu, M. Relating the distribution
patterns of Antarctic minke whales with abiotic and biotic
environmental factors in the Ross Sea in 2004/05 using
Kaiyo Maru-JARPA joint survey data.
26. Fujise, Y., Hatanaka, H. and Ohsumi, S. Changes
occurred on Antarctic minke whale stocks in the Antarctic
and their ecological implications.
27. Yasunaga, G., Fujise, Y. and Honda, K. Traceelement accumulations of Antarctic krill, Euphausia
superba, in Areas-III, IV, V and VI from Antarctic Ocean
during 1989-1999.
28. Yasunaga, G., Fujise, Y., Zenitani, R., Honda, K.
and Kato, H. Yearly trend of trace element accumulation inliver of Antarctic minke whales, Balaenoptera bonaerensis.
29. Yasunaga, G., Fujise, Y., Zenitani, R., Tanabe, S.
and Kato, H. Spatial and temporal variation inorganochlorine contaminants in the Antarctic minke whales,
Balaenoptera bonaerensis.
30. Watanabe, T., Yabuki, T., Suga, T., Hanawa, K.,
Matsuoka, K. and Kiwada, H. Results of oceanographic
analyses conducted under JARPA and possible evidence ofenvironmental changes.
31. Pastene, L.A., Goto, M., Nishiwaki, S., Yoshida,
H. and Kanda, N. Genetic characteristics and population
structure of humpback whales in the Antarctic feeding
grounds as revealed by mitochondrial DNA control region
sequencing and microsatellite analyses.
32. Pastene, L.A., Ishikawa, H., Goto, M. andNishiwaki, S. Overview of the studies on large whales not
related with the main objectives of the JARPA

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Annex D

List of JARPA Data Sets
List of JARPA data sets, sighting data, biological data for Antarctic minke whales, genetic data for other large whales andenvironmental data collected by the JARPA in the period 1987/88-2004/05.

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In addition, there is the dataset from the RV/Kaiyo Maru
Antarctic Ross sea survey in 2004/05):(1) Navigation data

441(6) Chemical environment data
(7) Primary production data
(8) Acoustic survey(2) (b) (i)i Acoustic export/track(2) (b) (ii) Checked(2) (a) ekset/1999-2000 krill/daily backup(2) (b) - 2001 Tangaroa(2) (b) - Backup(2) (b) - Daily backup(2) (b) SA map CSV(2) Field note(2) (a) Noon position(2) (b) Climate and sea(2) (c) Iceberg(3) Climate and sea satellite information(2) (a) Climate(2) (b) Sea ice(9) Biological data(2) (a) Fish
(2) (b) Krill(2) (c) Salpa(2) (d) Squid(4) Survey point field book(5) Physical environment data(2) (a) Data Excel CSV(2) (b) Raw data/ADCP(2) (b) (i)ii CTD/Parm(2) (b) (ii)i Report(2) (b) (iii) EPCS
(2) (b) (iv) XBT(2) (b) (v) XCTD

(10) RMT(2) (a) Sample photos(2) (b) Total field note(11) Sighting data

Annex E

Objectives of JARPA

ORIGINAL OBJECTIVES OF JARPA (IWC, 1988,
p.139)

Objective 1. Estimation of biological parameters to
improve the stock management of the Southern
Hemisphere minke whale
According to the original proposal, the main reason for the
failure of the SC to recommend an agreed catch limit for the
Antarctic minke whale stock in 1980s had been that its
members were not able to reach agreement on the value ofnatural mortality coefficient and its age-specific patterns.
The proposal stated that its primary purpose was to estimate
the age-specific natural mortality coefficient throughstochastic sampling, which was carried out in combination
with systematic sighting surveys. The programme was also
designed to try to estimate reproductive parameters and theirchanges based on the same samples as well as stochasticchanges in stock size.
Objective 2. Elucidation of the role of whales in the
Antarctic marine ecosystem.
The reason for the establishment of Objective 2 was basedon the consideration that the most important need tounderstand the Antarctic ecosystem was the collection ofdata on the prey-predator relationship among krill, fish,squid and whales. The global scientific interest in theRep 1:Layout 1

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Antarctic ecosystem had been growing, as reflected in thecreation of the Convention on the Conservation of Antarctic
Marine Living Resources (CCAMLR).
The plan of original research programme was reviewed
during the 1987 Annual Meeting (IWC, 1988) and the planfor the feasibility study was reviewed at a Special Meetingin December 1987 (IWC, 1989). After the completion of thefeasibility study, the Japan retained the same two objectives
but noted it would amend the original plan to: include
monitoring of recruitment among the main subjects of thestudy; shorten the interval between sampling years; andconduct surveys using line transect methods.
Results from the permit studies are reviewed each year
and comments can be found in the Scientific Committee
reports. A major mid-term review was held in 1997 (IWC,
1998).
ADDITIONS/CHANGES TO THE OBJECTIVESAn additional objective was added for the 1995/96 season.

Objective 3. Elucidation of the effect of environmental
change on cetaceans
Japan added this objective in response to two Commission
Resolutions in 1994: 1994-13 Resolution on research on
environmental change and whale stocks (IWC, 1995b); and1994-12 Resolution on promotion of research related toconservation of large whale stocks in the Southern Ocean(IWC, 1995a). Some work on this new objective had been
carried out under the original objective 2.

A further (and final) objective was added for the 1996/97
season.
Objective 4. Elucidation of the stock structure of theSouthern Hemisphere minke whales to improve stock
management.
Japan added this objective (the topic was already included in
the original Objective 1), as a consequence of the increased
importance of this topic to the proper estimation of
biological parameters and for the implementation of the
RMP to the Antarctic minke whales.

REFERENCES
International Whaling Commission. 1988. Report of the ScientificCommittee, Annex R. The Japanese scientific permit proposal forSouthern Hemisphere minke whales: background and comments.
Rep. int. Whal. Commn 38:139-49.
International Whaling Commission. 1989. Report of the Special
Meeting of the Scientific Committee to consider the Japanese
research permit (feasibility study). Rep. int. Whal. Commn 39:15966.
International Whaling Commission. 1995a. Chairman’s Report of the
Forty-Sixth Annual Meeting, Appendix 13, IWC Resolution 1994-12.
Resolution on promotion of research related to conservation of large
baleen whales in the Southern Oceans. Rep. int. Whal. Commn 45:48.
International Whaling Commission. 1995b. Chairman’s Report of the
Forty-Sixth Annual Meeting, Appendix 14, IWC Resolution 1994-13.
Resolution on research on the environment and whale stocks. Rep.
int. Whal. Commn 45:49.
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.

Annex F

A review of the coverage of strata and the sequence of surveys
relative to the ice edge during JARPAPaul R. Wade
Note: A longer version of this Annex was developed
towards the end of the Workshop. There was insufficient
time to discuss this (or this Annex) during the Workshop (seeItem 2.3 of the report).
INTRODUCTION

Matsuoka et al. (2006) provides detailed maps showing
achieved trackline effort (same for all species) during the
JARPA surveys in Areas IV and V. The logistics are complex
since the surveys attempted to cover the complete area from
600S to the ice edge by a Sighting Vessel (SV) and by
Sighting and Sampling Vessels (SSV) working in close
association. Effort was divided between a southern stratum(ice edge to 45 n.miles north of the ice edge) and a northern
stratum (from the southern stratum north to 600S). The iceedge was usually retreating south during the time period of

the surveys (typically December to March) whichsometimes meant that the location of the ice edge hadchanged between the time a northern stratum was surveyed
and the time the southern stratum below it was surveyed.
The density of minke whales is thought to have someassociation with the ice edge, so good coverage of the iceedge strata is important to the abundance estimatescalculated from JARPA data. For example, in SC/D06/J6,
approximately 40-50% of the abundance estimates forminke whales calculated in Areas IV and V over the periodof JARPA comes from the southern strata (e.g. Tables 1-h
and 1-i), even though the southern strata were typicallymuch smaller than the northern strata.
This review is based on figs 1-30 in Appendix 4 of
Matsuoka et al. (2006). Some evaluations were madesubjectively from the figures, and the evaluation should be
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Page 443(4) Strata order (Order strata were surveyed)This lists the order in which the survey strata were surveyed
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survey data. However, this subjective evaluation was all thatwas possible in the time available at the workshop. The
evaluations are given in Table 1 and independent checking
can be undertaken intersessionally.
A summary of my interpretation of these results is
included in the main report under Item 2.3.
EXPLANATION OF COLUMNS IN THE TABLE(1) IESC (Ice edge strata coverage)
SC/D06/J2 (fig. 2) shows the ‘ideal’ method of trackline
design for the ice edge strata: one transect due north fromthe ice edge for 45 n.miles followed by a transect at an angle
designed to intersect the ice edge again 4° longitude further
to the east or the west. However, the maps in Matsuoka et al.
(2006) show that these ideal tracklines could not always be
accomplished in practice. I have subjectively evaluated (forSV and SSV separately) whether: the tracklines provided
complete coverage from the ice edge to the northernboundary of the stratum; there were significant gaps incoverage from east to west; and the sawtooth pattern was
accomplished as planned. The evaluation is expressed ashigh (H), medium (M), or low (L), where the goal was toevaluate whether coverage appeared to be >75% (H), 5075% (M), or <50% (L), with additional consideration given
to as to whether a sawtooth pattern extending from the iceedge to the northern boundary was successfully
accomplished.
(2) NSC (Northern strata coverage)
Coverage was evaluated subjectively from inspection to behigh (>75%), medium (50-75%), or low (<50%).

(3) IE main (Main months in which ice edge stratum
was covered)This lists the ‘main’ months that the ice edge strata werecovered where ‘main’ is taken as a month that appeared tohave more than 20% of the survey coverage, so effort in amonth that appeared to be less than that was not recorded
here. It provides some information on temporal changes incoverage of survey strata from north to south. For Area V,
the Ross Sea is also given in parentheses.

443(5) Ave order (Average order of survey of the southern
strata)This takes the order (1 to 5 for Area IV or 1 to 4 for Area V)
given in the previous column and simply calculates what I
have termed the ‘average order’ in which the southern strata(SE and SW) were surveyed. As an example, if the survey
order in Area IV was SE-NE-SW-PB-NW, then the averageorder would be calculated as:(1 [since SE was surveyed first] + 3 [since SW was surveyed
third]) ÷ 2 (two southern strata were surveyed) = 2
I have calculated this to try to make it easier to see patterns
in the timing of the survey of the ice edge.

(6) IESW and IESW (Ice extent in the western andeastern strata)
There is considerable variability in the extent of ice that
occurred along the continent in different surveys that may
reflect inter-annual variability in ice conditions and/or thetiming of the survey. This column lists my subjective viewof the amount of ice as either: H (high) for a year in whichmuch of the extent of ice extended more than 2° latitude
from the continent; L (low) for a year in which considerable
stretches of the continent appeared ice-free; or M (medium)for a year in which the ice extent was less than 2° latitude
but there were no large ice free stretches along the continent.
However, for the Ross Sea (the SE stratum in Area V): H isfor a year in which it had little ice-free area; L is for a year
in which most of the width of the stratum was ice-free andthe ice-free area extended south to at least 76°S; and M isintermediate.

(7) Comments
In some years a gap was left between the southern andnorthern strata which was left unsurveyed. This appeared tohappen particularly in years in which the northern stratum
was surveyed first, such that when the ice edge stratum wasRep 1:Layout 1

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surveyed later, the ice edge had retreated and was further
south, and therefore the northern boundary of the southern
stratum (extending 45 n.miles north of the ice edge) still fell
far short of the southern boundary of the northern stratum.
This column also includes information on whether data were
missing, if there were east to west gaps in survey coverage
within a stratum, and other changes in survey conditions orcoverage.

REFERENCE
Matsuoka, T., Hakamada, T., Kiwada, H., Murase, H. and Nishiwaki, S.
2006. Updated distribution and abundance estimates of humpback
whales in the Antarctic Areas IV and V (70E-170W). Paper
SC/58/SH21 presented to the IWC Scientific Committee, May 2006,
St. Kitts and Nevis, West Indies (unpublished). 41pp. [Paper available
at the Office of this Journal].

Annex G

Apparent trends in various minke whale parameters obtained
from a variety of studies

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