SC/F14/J16

Preliminary analyses on prey consumption by fin whales
based on JARPAII data
TSUTOMU TAMURAThe Institute of Cetacean Research, 4-5, Toyomi-cho, Chuo-ku, Tokyo, 104-0055, Japan
Contact e-mail: tamura@cetacean.jp

ABSTRACTIn this study, the information on the feeding habits of fin whales (Balaenoptera physalus) sampled during the surveys of the second phaseof the Japanese Whale Research under Special Permit in the Antarctic (JARPAII), for the period 2005/06-2010/11 (n= 16) wassummarized. The fin whales fed mostly on Antarctic krill (Euphausia superba) in the research area. The daily prey consumption by fin
whales per capita using three methods ranged between 276kg and 2,136kg. These values were equivalent to 0.50 and 3.84% of the bodyweight. The seasonal prey consumptions for all fin whales in the total research area based on three methods were 0.54-0.78million tons,
3.38-4.51million tons and 2.19-2.93 million tons, respectively. There was coincidence in the frequency of body length of the E. superba
consumed by fin and Antarctic minke whales (B. bonaerensis). It seems that fin and Antarctic minke whales have similar feeding habitswith no prey size selectivity
KEYWORDS: FEEDING; ENERGETICS; FOOD/PREY; MODELLING; SCIENTIFIC PERMITS; ANTARCTIC; ANTARCTICMINKE WHALE; FIN WHALE

INTRODUCTION
Fin (Balaenoptera physalus) and Antarctic minke (B. bonaerensis) whales are the dominant whale species in the
Antarctic, which migrate to this area in austral summer for feeding with other baleen whale species (Kawamura, 1980).
The feeding method of both species is swallowing. The dominant prey species of these whales is the Antarctic krill,
Euphausia superba. E. superba predominates over the Antarctic Oceans, and is not only the prey of baleen whales but
also the prey of most marine mammals, such as seals, sea-birds, fish, squids and benthic animals.
In the Antarctic Ocean, commercial whaling first began with blue whales and humpback whales. The level of catcheson these two species increased rapidly, and the stocks were greatly depleted. Next, whaling moved to fin whales in themid 1930s, and the stocks of this species were again severely depleted. The substantial reduction in abundance of these
species, which are important components of the ecosystem, resulted in a substantial surplus of krill (Krill surplus
hypothesis; e.g. Laws, 1977). The catches of humpback, blue and fin whales were banned in 1963, 1964 and 1976,
respectively. The increasing trend of the humpback and fin whales’ abundance has become apparent in recent years(Matsuoka et al., 2005; Branch, 2006). The composition of baleen whale species in the Antarctic ecosystem is changing.
According to Ruud (1932), the Norwegian whalers understand well 'blue whale krill’ and ‘fin whale krill’ meaning
1year and 2year groups of E. superba, respectively. Peters (1955) noted that blue whales fed mainly on the krill of 20 to30mm in body length, on the other hand, fin whales fed mainly on 30-40mm in body length. He considered that thedifference in body lengths was the sampling period, because blue whales migrate earlier to the Antarctic than fin whales.
There is no information on the feeding ecology of the fin whale since commercial whaling of this species stopped in the
Antarctic some 36 years ago. This study provides new information on the feeding ecology of the fin whale based onwhales sampled during the JARPAII. Specifically this study presents information on prey composition and daily prey
consumption rate. Furthermore the size of the E. superba consumed by fin whales is compared with that consumed by
the Antarctic minke whales. The information on prey consumption of fin whales in this paper can contribute to thedevelopment of ecosystem models in the research area.
MATERIALS AND METHODS
Research area and period
Data used in the present study was collected during the surveys of the JARPAII in the International Whaling
Commission (IWC) Antarctic management Areas III-East (35°-70°E), IV (70°-130°E), V (130°E-170°W including theRoss Sea) and VI-West (170°-145°W), south of 62°S (Fig. 1). The surveys were conducted mainly from December toMarch between the 2005/06 and 2010/11 seasons.

1Sighting and sampling methods
The survey track line was designed along each 10 degree longitudinal width interval in principle. The survey starting
point was randomly selected from the arrangement of the survey track line and longitude standard lines in the survey.
Sighting procedures were the same as in the previous JARPA surveys (Nishiwaki et al. 2006, 2014). The survey was
operated under optimal research conditions (when the wind speed was below 25knots in the south strata and below
20knots in the north strata, and when visibility was more than 2n.miles). SSVs advanced along parallel track lines
7n.miles apart from each other at a standard speed of 11.5knots. The sampling activity was focused to the area south of
62°S as mentioned in the original plan (Government of Japan, 2005). The sampling of fin whales was restricted toanimals with an estimated body length of less than 20m due to technical limitations on the research base vessel (NM),and to avoid any handling accidents.
Sample size and biological research
After capture, the animals were placed aboard a research base vessel where they were examined. A total of 17 fin
whales were sampled by the JARPAII between the 2005/06 and 2010/11 seasons. This study used the data of 16 fin
whales (Male 8; Female 8), because one fin whale was lost before landing on the flensing deck of the research basevessel (Table 1). Body length of the whales was measured to the nearest 10cm from the tip of the upper jaw to thedeepest part of the fluke notch in a straight line. Sex and maturity were recorded for each whale on the basis of routine
observations of reproductive organs during dissection and tissue observations in the laboratory. Body weight wasmeasured using a large weighing machine to the nearest 50kg.
Analytical procedure of the daily prey consumption
The uncertainty in several components involved in estimating the amounts and types of prey consumed by whales was
assisted by a recent review by Leaper and Lavigne (2007) and Tamura et al. (2009). They considered that theappropriate consumption estimates is between the high end of Equation 1 and the low end of Equation 2. The estimateof consumption by Equation 3 was considered by the authors at the upper range of these reasonable values. I also
estimated using Equation 4. Equation 4 which was used by Hunt et al. (2000) in PICES region was applied to the
Antarctic Peninsula marine ecosystem model and simulation by Hoover et al. (2012).
Equation 1: R = 0.42 W0.67 (Innes et al., 1986)
Equation 2: FMR = 2529.2 W0.524 (Boyd, 2002)
Equation 3: FMR = 863.6W0.783 (Sigurjónsson and Víkingsson, 1997)
Equation 4: FMR = 803.9W0.75 (Perez et al, 1990)

(1)
(2)
(3)
(4)

R is the daily prey consumption (expressed by kg) and W is body weight in kg. FMR is the daily prey consumption(expressed in KJ d-1) and W is body weight in kg. It should be noted here that the estimates from Equation 1 depend
only on the body weight data (expressed in kg). The estimates from Equations 2, 3 and 4 require body weight data
(expressed in kg) and energy content of prey (expressed in kJ kg-1). For comparative analysis, it was assumed that theenergy content of prey and assimilation efficiency was 4,473kJ kg-1 (E. superba; this value was measured by bomb
calorimeter (n=1)) and 84% (Lockyer, 1981a), respectively. Therefore, the energy value of prey items of whales wasestimated to be 3,757kJ kg-1. I compared daily prey consumption of fin whales among Equations 2, 3 and 4 in this study.
Estimation of seasonal prey consumption in Areas III east, IV, V and VI west
The seasonal prey consumption by all fin whales in each sub area was estimated using information on abundance, bodyweight and residence days in the feeding ground. The information on abundance of fin whales was described in
Matsuoka and Hakamada (2014). Average body weight of female and male fin whales in the Antarctic was estimated at
59,800 and 51,400kg, respectively (Trites and Pauly, 1998). Therefore the weight of “average sized” fin whales wasestimated to be 55,600kg.
Baleen whales are generally known to migrate between feeding grounds in high latitudinal waters in summer and thebreeding grounds in low latitudinal waters in winter. The ratio of high to low feeding seasons and the proportion of theenergy intake per year during the high feeding season are assumed without actual data. This could bring someuncertainty to the estimations.
For example Lockyer (1981a) indicated that around 83% of the annual energy intake in Southern Hemispherebalaenopterid species is ingested during the high feeding season (HF=120days) and predicted that 17% of annual foodintake for Southern Ocean balaenopterid species was outside the high feeding period. In this case, the ratio of low
feeding season (LF)/high feeding season (HF) intake (r) is 0.10. Leaper and Lavigne (2007) estimated the r to be from
0.34 (Antarctic minke whales) to 0.62 (North Atlantic minke whales) based on other sources.
The relationship between the rate of daily consumption during the high feeding season (RCH) and r is shown infollowing equation.
RCH=365 / (HF (days)* 1+LF (days) * r)

(5)2

Hinga (1979) assumed that baleen whales spend 120 days in the Antarctic feeding area (HF). I estimated RCH based on
the three following cases using Equations 2, 3 and 4.
Case-1: RCH=1.34(6)High feeding days (HF) 120days, Low feeding days (LF) 245days. Low feeding/High feeding intake (r)=0.62.
Case-2: RCH=1.79(7)High feeding days (HF) 120days, Low feeding days (LF) 245days. Low feeding/High feeding intake (r)=0.34.
Case-3: RCH=2.53(8)High feeding days (HF) 120days, Low feeding days (LF) 245days. Low feeding/High feeding intake (r)=0.10.
The assumption of the resident period of fin whales in the Antarctic was 120days, but fin whales feed on various preyduring their non-resident period in the Antarctic (Kawamura, 1980). r=0.01 does not seem appropriate for thisestimation of prey consumption. I chose cases-1 (RCH=1.34; r=0.62) and 2 (RCH=1.79; r=0.34) in this study.
Analyses of the stomach contents
The stomach contents were removed from forestomachs and fundus of each whale, and the contents of forestomachs
were first classified into major prey groups, such as euphausiids, amphipod, copepods, fish and others onboard. The
freshness of the stomach contents was recorded according to the following categories (1=fresh (F), 2=lightly digested(fff), 3=moderately digested (ff), 4=heavily digested (f)). Then, the contents from the forestomach and fundus were
weighed to the nearest 0.1kg. If prey species were found, we sampled a portion and placed it in 10% formalin solution
water for later analyses. Fourteen sub samples of fin whales were collected. Prey species were identified to the lowest
taxonomic level as possible using external morphology (Barnard, 1932; Fischer and Hureau, 1985a, b; Baker et al.,1990). To examine body length composition of E. superba, randomly taken specimens (between 50 and 100) from each
sub sample was measured to the nearest 1mm, from the anterior tip of the rostrum to the posterior end of the telson
described by Makarov and Denys (1981) and Mauchline (1981). To examine body length composition of E. superba
between fin whales and Antarctic minke whales, I selected sub-samples of Antarctic minke whales, which werecollected on the same days that fin whales were sampled (excluding eastern sector; Appendix 1). Finally nine subsamples of fin whales and eight sub-samples of Antarctic minke whales were measured for this analysis.
RESULTS
Prey species composition
A total of four prey species, including one amphipod, one euphausiid and two fishes were identified from the stomachsof the fourteen fin whales (Table 2). The E. superba was the dominant prey species, found in almost 100% of thewhales’ stomachs examined in each area (Table 3). The position of fin whales and Antarctic minke whales sampled inthis paper was shown in Fig. 2. It was confirmed that fin whales and Antarctic minke whales sampled near the position
fed on E. superba in this study (Table 3 and Appendix 1).
Stomach contents weight and RSC
The average and maximum weight and the ratio of stomach contents weight to body weight, expressed as a percentage(RSC) of fresh or lightly digested stomach contents (freshness category F and fff) by different reproductive classes areshown in Table 4. The mean weight and RSC of stomach contents were 324.3±208.3kg (RSC:0.7%) and 665.6±592.7kg(RSC:0.8%) for males and females, respectively. The maximum weight and RSC of stomach contents (freshness
categories F and fff) were 633.7kg (RSC:1.3%) and 1,084.7kg (RSC:2.0%) for males and females, respectively.
Per capita daily and seasonal prey consumption
The daily prey consumption of fin whales in each equation and RCH are shown in Table 5 and Fig. 3. In case 1(RCH=1.34), the daily prey consumption by “average sized” fin whales was between 276kg and 1,599kg. These values
were equivalent to 0.5 and 2.9% of body weight. In case 2 (RCH=1.79), the daily prey consumption by “average sized”
fin whales was between 369kg and 2,136kg. These values were equivalent to 0.7 and 3.8% of body weight.
The stomach contents weight of fin whales sampled and estimated daily prey consumption by Antarctic minke whales(Tamura and Konishi, 2014) is shown in Fig. 3. If RCH was the same value (1.34 or 1.79), among the equations thehighest value (Equation 3) of consumption was 5.8 times larger than the lowest one (Equation 2).
In case 1 (RCH=1.34), the per capita seasonal (120 days) prey consumption of average fin whales was between 33.1tons
and 191.9tons. In case 2 (RCH=1.79), the per capita seasonal prey consumption by average fin whales was between
44.3tons and 256.3tons.

3Seasonal prey consumption for all fin whales in the research area
In Areas III east and IV in the 2007/2008 season, the abundance was estimated to be 956 and 1,654, respectively. In
Area V and VI west in the 2008/2009 season, the abundance was estimated to be 10,056 and 4,925, respectively (Table
6).
The seasonal prey consumptions for all fin whales in the total research area based on three methods were estimated tobe 0.54-0.78 million tons, 3.38-4.51million tons and 2.19-2.93million tons, respectively (Table 6).
Length frequency distribution of Euphausia superba in the stomach
Western (Area IV 70-85E)
The sub-samples of six fin whales in the 2005/06 JARPAII were used for this analysis. The length distribution of E.
superba fed on by fin whales is shown in Fig. 4 This distribution consists of unimodal compositions (modes at 40mm).
The sub-samples of five Antarctic minke whales in the 2005/06 JARPAII were used for this analysis. The length
distribution of E. superba fed on by Antarctic minke whales is shown in Fig. 4. This distribution consists of unimodal
compositions (modes at 40mm). The body length composition of E. superba consumed by fin whales and Antarctic
minke whales almost coincided.
Central (Area IV 114-121E)
The sub-samples of two fin whales in the 2005/06 JARPAII were used for this analysis. The length distribution of E.
superba fed on by fin whales is shown in Fig. 5 This distribution consists of unimodal compositions (modes at 40mm).
The sub-samples of two Antarctic minke whales in the 2005/06 JARPAII were used for this analysis. The length
distribution of E. superba fed on by Antarctic minke whales is shown in Fig. 5. This distribution consists of unimodal
compositions (modes at 45mm). The body length composition of E. superba consumed by fin whales and Antarctic
minke whales almost coincided.
Eastern (Area V 163-166E)
The sub-sample of one fin whale in the 2008/09 JARPAII was used for this analysis. The length distribution of E.
superba fed on by fin whales is shown in Fig. 6 This distribution consists of unimodal compositions (modes at 48mm).
The sub-sample of one Antarctic minke whale in the 2008/09 JARPAII was used for this analysis. The length
distribution of E. superba fed on by Antarctic minke whales is shown in Fig. 6. This distribution consists of unimodal
compositions (modes at 45mm). The body length composition of E. superba consumed by fin whales and Antarctic
minke whales almost coincided.
DISCUSSION
The main prey species of fin whales in our research area was E. superba. The present results were similar to those ofprevious studies (Nishiwaki and Hayashi, 1950; Nishiwaki and Oye, 1951; Mizue and Murata, 1951; Ohno and Fujino,
1952; Nemoto and Nasu, 1958). It was reported that fin whales fed mainly on other krill species such as T. macrura, E.
vallentini, E .frigida, E .lucens, and E .diomedeae etc in middle and lower latitudes (north of 60 degree) in the Antarctic(Kawamura, 1974; Kawamura, 1980). The difference in prey species of fin whales depends on the prey distribution in
the feeding area.
Some stomach contents data (N=5) of fin whales in the Antarctic was reported in Kawamura (1968). In this report, theaverage and maximum stomach contents weight were 404kg and 885kg, respectively. The results in this study weresimilar to the values in the previous report.
The uncertainty in several components involved in estimating the amount and types of prey consumed by whales was
assisted by a recent review by Leaper and Lavigne (2007) and Tamura et al. (2009). The amount of krill consumed by
Antarctic minke whales was estimated using two independent methods, which were from theoretical energy
requirements calculations (method-1) and from diurnal changes of stomach contents (Total of forestomach (1st.
stomach) and fundus (2nd. stomach)) (method-2) (Tamura and Konishi, 2014). The number of fin whales sampled in
the JARPAII was too low to allow for the same kind of analyses. In this study, the prey consumption by fin whales wasestimated using theoretical energy requirements calculations. Leaper and Lavigne (2007) considered that theappropriate consumption estimates are between the high end of Equation 1 and the low end of Equation 2. The estimateof consumption using Equation 3 was considered by the authors at the upper range of these reasonable values. The
assumption of the resident period of fin whales in the Antarctic was 120days (Lockyer, 1981b), but fin whales feed on
various prey during the non-resident period in the Antarctic (Kawamura, 1980). r=0.01 does not seem appropriate forthis estimation of prey consumption. The cases-1 (r=0.62) and 2 (r=0.34) were chosen in this study. Leaper and Lavigne(2007) discussed these equations which involve values of β>0.75 and their conclusion was that they were notsupported either by theory or data. Based on the actual stomach contents data of the previous report and the JARPAII,
the consumption under Equation 2 seems to be underestimated, because consumption estimates by this equation are
similar to that of average stomach contents weight. On the other hand, the consumption under Equation 3 seems to beoverestimated, because in case 1 (RCH=1.34) and 2 (RCH=1.79) in Equation 3, fin whales need to feed twice or three4

times in a day to reach full stomachs. Cases 1 and 2 of Equation 4 seem to be appropriate for prey consumption
estimation of large baleen whale species. These values were equivalent to 2.2 and 2.9% of body weight. The validity ofdifferent models for estimating the total consumption can be investigated with additional data collected by the JARPAII
in the future. It might be possible in the near future to provide estimates within a narrow range.
The body length composition of E. superba consumed by fin whales and Antarctic minke whales almost coincided inthis study. It suggested that fin whales and Antarctic minke whales have similar feeding habits with no prey size
selectivity in our research area and there was some inter specific interaction between them. In the present results, thesize difference of the E. superba consumed by fin and Antarctic minke whales seems to depend on the size of E.
superba distributed. The body length of E. superba fed on by whales in the western sector was smaller than that in theeastern sector. It seems to depend on seasonal and geographical factors.
In the JARPAII, prey species and their body composition coincided for fin whales and Antarctic minke whales. It was
supported that there was some inter specific interaction between fin whales and Antarctic minke whales. More data on
krill species and their body size fed on by humpback and blue whales in the Antarctic are needed before conclusions
can be drawn with regard to the inter specific interaction among them. Many parameters for application in the multispecies ecosystem modelling should be improved in the future. Improving estimates of the daily and seasonal
consumption by fin whales is also important. These results are useful to apply as input data regarding daily consumption
by fin whales in the development of ecosystem models (e.g. Kitakado et al., 2014).
ACKNOWLEDGMENTS
The stomach contents examined in this study were collected by many researchers and crews. I would also like to thankthe captains, crews and researchers who were involved in the JARPAII research cruises for their efforts. My sincere
thanks goes out to Seiji Ohsumi, Hiroshi Hatanaka and Luis A. Pastene of the Institute of Cetacean Research (ICR) for
their valuable suggestions and useful comments on this paper.
REFERENCES
Baker, A.de C., Boden, B.P. and Brinton, E. 1990. A practical guide to the euphausiids of the world. Natural History Museum Publications London.
96pp.
Barnard, K.H. 1932. Amphipoda. Discovery Rep., 5:1-326.
Branch, T.A. 2006. Humpback abundance south of 60°S from three completed sets of IDCR/SOWER circumpolar surveys. IWC Document
SC/AO6/HW6: 14pp. [Available from the Office of this Journal]Boyd, I.L. 2002. Energetics: consequences for fitness. pp.247-77. In: Hoelzel. A.R. (eds). Marine Mammal Biology: An Evolutionary Approach.
Blackwell Science. Oxford. 448pp.
Fischer, W. and Hureau, J.C. (eds). 1985a. FAO species identification sheets for fishery purposes. Southern Ocean (Fishing areas 48, 58 and 88)(CCAMLA Convention Area). Prepared and published with the support of the Commission for the Conservation of Antarctic Marine Living
Resources. Rome, FAO., Vol.1:1-232.
Fischer, W. and Bureau, J.C. (eds). 1985b. FAO species identification sheets for fishery purposes. Southern Ocean (Fishing areas 48, 58 and 88)(CCAMLA Convention Area). Prepared and published with the support of the Commission for the Conservation of Antarctic Marine Living
Resources. Rome, FAO., Vol.2:233-470.
Government of Japan. 2005. Plan for the Second Phase of the Japanese Whale Research Program under Special Permit in the Antarctic (JARPAII) Monitoring of the Antarctic Ecosystem and Development of New Management Objectives for Whale Resources. Paper SC/57/O1 presented to the
IWC Scientific Committee, Jun 2005 (unpublished). 99pp. [Available from the Office of this Journal]
Hinga K.H. 1979. The food requirements of whales in the southern hemisphere. Deep-Sea Research 26A:569-77.
Hoover, C., Pitcher, T. and Pakhomov, E. 2012. The Antarctic Peninsula marine ecosystem model and simulations: 1978-present. Fisheries Centre
Research Reports. 20:108-82.
Hunt, G.L., McKinnell, S.M. and Kato, H. 2000. Predation by marine birds and mammals in the Subarctic North Pacific Ocean. PICES Science
Report. 14:1-165.
Innes, S., Lavigne, D.M., Earle, W.M. and Kovacs, K.M. 1986. Estimating feeding rates of marine mammals from heart mass to body mass ratios.
Mar. Mammal Sci. 2(3):227-9.
Kawamura, A. 1968. The results of stomach contents weight of baleen whales in the Antarctic (a prompt report). Geiken Tsuusin (in Japanese).
201:150-3.
Kawamura, 1974. Food and feeding ecology in the southern sei whale. Sci Rep Whales Res Inst., 26:25-144.
Kawamura, A. 1980. A review of food of Balaenopterid whales. Sci Rep Whales Res Inst., 32:155-97.
Kitakado, T., Murase, H., Tamura, T. and Yonezaki, S. 2014. Ecosystem modelling for species in Area IV in the Antarctic Ocean using JARPA and
JARPAII data and its implication to management of cetacean species. Paper SC/F14/J26 presented to the JARPAII Review Meeting, Tokyo,
February 2014 (unpublished). **pp.
Laws, R.M. 1977. Seals and whales of the Southern Ocean. Phil Trans R Soc Lond, Ser. B279:81-96.
Leaper, R. and Lavigne, D. 2007. How much do large whale eat?. J. Cetacean Res. Manege. 9(3):179-88.

5

Lockyer, C. 1981a. Estimation of the energy costs of growth, maintenance and reproduction in the female minke whale, (Balaenoptera acutorostrata),
from the southern hemisphere. Rep. int. Whal. Commn, 31:337-43.
Lockyer, C. 1981b. Growth and energy budgets of large baleen whales from the Southern Hemisphere. FAO Fish. Ser. [Mammals in the Seas] 3:397487.
Makarov, R.R. and Denys, C.J. 1981. Stages of sexual maturity of Euphausia superba Dana. Biomass Handbook 11:1-13.
Matsuoka, K, Hakamada, T, Kiwada, H, Murase, H. and Nishiwaki, S. 2005. Abundance increases of large baleen whales in the Antarctic based on
the sighting survey during Japanese Whale Research Program (JARPA). Global Environ. Res. 9:105-15.
Matsuoka, K. and Hakamada, T. 2014. Estimates of abundance and abundance trend of the blue, fin and southern right whales in Areas IIIE-VIW,
south of 60ºS, based on JARPA and JARPAII sighting data (1989/90-2008/09). Paper SC/F14/J5 presented to the JARPAII Review Meeting, Tokyo,
February 2014 (unpublished). **p.
Mauchline, J. 1981. Measurement of body length of Euphausia superba Dana. BIOMASS handbook 4:1-9.
Mizue, K. and Murata, T. 1951. Biological investigation on the whales caught by the Japanese Antarctic whaling fleets season 1949-50. Sci. Rep.
Whales Res. Inst., Tokyo. 6:73-131.
Nemoto, T. and Nasu, K. 1958. Thysanoessa macrura as a food of baleen whales in the Antarctic. Sci. Rep. Whales Res. Inst., Tokyo. 13:193-9.
Nishiwaki, M. and Hayashi, K. 1950. Biological survey of fin and blue whales taken in the Antarctic season 1947-48 by the Japanese fleet. Sci. Rep.
Whales Res. Inst., Tokyo. 3:132-90.
Nishiwaki, M. and Oye, T. 1951. The biological investigations on blue and fin whales caught by Japanese Antarctic fleet. Sci. Rep. Whales Res. Inst.,
Tokyo. 5:91-167.
Nishiwaki, S., Ishikawa, H. and Fujise, Y. 2006. Review of general methodology and survey procedure under the JARPA. Paper SC/D06/J2 presented
to the Intercessional Workshop to Review Data and Results from Special Permit Research on Minke Whales in the Antarctic, Tokyo, December
2006 (unpublished). 47pp.
Nishiwaki, S., Ishikawa, H., Goto, M., Tamura, T. and Matsuoka, K. 2014. Review of general methodology and survey procedure under the JARPAII.
Paper SC/F14/J2 presented to the JARPAII Review Meeting, Tokyo, February 2014 (unpublished). 15pp.
Ohno, M. and Fujino, K. 1952. Biological investigations on the whales caught by Japanese Antarctic whaling fleets, season 1950-51. Sci. Rep. Whales
Res. Inst., Tokyo. 7:125-88.
Perez, M.A., McAlister, W.B. and Mooney, E.E. 1990. Estimated feeding rate relationship for marine mammals based on captive animal data. NOAA
Tech. Memo., NMFS F/NWC-184. 30pp.
Peters, H. 1955. Uber das Vorkommen des Walkrebschens Euphausia superba Dana und seine Bedeutung fur die Ernahrung der sudlichen
Bartenwale. Arch. Fishreiwissenschaft 6:288-304.
Ruud, J.D. 1932. On the biology of southern Euphaussidae. Hvalrad. Skr. 2:1-105.
Sigurjónsson, J. and Víkingsson, G.A. 1997. Seasonal abundance of and estimated prey consumption by cetaceans in Icelandic and adjacent waters. J.
Northw. Atl. Fish. Sci. 22:271-87.
Tamura, T., Konishi, K., Isoda, T., Okamoto, R., Bando, T. and Hakamada, T. 2009. Some examinations of uncertainties in the prey consumption
estimates of common minke, sei and Bryde’s whales in the western North Pacific. Paper SC/61/JR2 presented to the IWC Scientific Committee,
June 2009 (unpublished). 24pp. [Available from the Office of this Journal]
Tamura, T. and Konishi, K. 2014. Prey composition and consumption rate of Antarctic minke whales based on JARPA and JARPA II data Paper
SC/F14/J15 presented to the JARPAII Review Meeting, Tokyo, February 2014 (unpublished). 20pp.
Trites, A.W. and Pauly, D. 1998. Estimating mean body masses of marine mammals from maximum body length. Can. J. Zool. 76:886-96.

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Table 1
Sample size of fin whales used in this study
Area

Area III-East

Area IV

Area V

Total

Sex

Male Female

Male Female

Male Female Unknown

Male Female Unknown

Number

1

0

4

6

3

2

1

8

8

Table 2Prey species of fin whales sampled by the JARPAII
species
Main prey
Krill

Euphausia superba

Minor prey
Amphipoda Parathemisto gaudichaudi
PiscesPleuragramma antarcticum
Notolepis coatsi

Table 3Composition of prey found in the stomachs of fin whales sampled by the JARPAII
Species

Area III-E

Area IV

Area V

100.0

100.0

100.0

Amphipods Parathemisto gaudichaudi

0.0< 0.01< 0.01Fish

Pleuragramma antarcticum

0.0

0.0

< 0.01

Notolepis coatsi

0.0< 0.01

0.0

Krill

Euphausia superba

Table 4
Stomach contents weight (kg) and RSC of fin whales

Sex

Number

Weight (Categories F and fff)
Average

Male

4

324.3

S.D.
208.3

(RSC: 0.7%)
Female3665.6(RSC: 0.8%)

7

Maximum
633.7(RSC: 1.3%)

592.7

1,084.7(RSC: 2.0%)

1

Table 5
The daily prey consumption of fin whales in each equation and RCH. B.W. is body weight (kg).

Equation 2

Equation 3

Equation 4

Boyd (2002)

Sigurjonsson and Vikingsson (1997)

Perez et al . (1990)

FMR = 2529.2W 0.524

FMR = 863.6W 0.783

FMR = 803.9W 0.75

B.W. (kg） Co nsumption (k g)B.W. (kg） Con sumption (kg )B.W. (kg） Consu mption (kg)

RCH

1.34

1.79

RCH

1.34

1.79

RCH

1.34

1.79

3,500

65

87

3,500

183

245

3,500

130

174

3,800

68

91

3,800

196

261

3,800

139

185

5,000

78

105

5,000

243

324

5,000

170

228

6,900

93

124

6,900

312

417

6,900

217

290

7,500

97

129

7,500

333

445

7,500

231

309

8,100

101

135

8,100

354

473

8,100

245

327

10,000113

150

10,000417

558

10,000287

383

15,000139

186

15,000573

766

15,000389

519

20,000162

216

20,000718

959

20,000482

644

25,000182

243

25,000855

1,143

25,000570

761

30,000200

267

30,000987

1,318

30,000654

873

30,400201

269

30,400997

1,332

30,400660

882

35,000217

290

35,000

1,113

1,487

35,000734

980

40,000

233

311

40,000

1,236

1,651

40,000811

1,083

45,000247

331

45,000

1,355

1,810

45,000886

1,183

50,000262

349

50,000

1,472

1,966

50,000959

1,281

55,600276

369

55,600

1,599

2,137

55,600

1,038

1,387

60,000288

384

60,000

1,698

2,268

60,000

1,099

1,468

65,000300

401

65,000

1,808

2,415

65,000

1,167

1,559

70,000312

417

70,000

1,916

2,559

70,000

1,234

1,648

75,000323

432

75,000

2,022

2,701

75,000

1,299

1,736

80,000335

447

80,000

2,127

2,841

80,000

1,364

1,822

85,000345

461

85,000

2,230

2,979

85,000

1,427

1,907

90,000356

475

90,000

2,332

3,115

90,000

1,490

1,990

95,000366

489

95,000

2,433

3,250

95,000

1,552

2,073

100,000

376

502

100,000

2,533

3,383

100,000

1,612

2,154

8

Table 6
The seasonal prey consumption for all fin whales in the research area based on three methods
Area

Year

Abundance

Prey consumption (million tons)(inds.)

Equation 2

Equation 3

Equation 4

III East

2007/08956

0.03- 0.04

0.18- 0.25

0.12- 0.16

IV

2007/08

1,654

0.05- 0.07

0.32- 0.42

0.21- 0.28

V

2008/09

10,056

0.33- 0.45

1.93- 2.58

1.25- 1.67

VI West 2008/09

4,925

0.16- 0.22

0.95- 1.26

0.61- 0.82

Total

17,591

0.54-0.78

3.38-4.51

2.19-2.93

9

Area III
East

Area IV

Area V

Area VI
West

Ross Sea(Areas V+VI)

Fig.1.

Research area in the Antarctic

Western

CentralEasternFig.2. The position of fin whales sampled and Antarctic minke whales sampled in this study.
(●: Fin whales, ▲: Antarctic minke whales)

4000

Daily prey consumption (kg)

3500
3000
2500
2000
1500
1000
500
0
0

20000

40000

60000

80000

100000120000Body weight (kg)
Eqn-2*1.34

Eqn-2*1.79

Eqn-3*1.34

Eqn-3*1.79

Eqn-4*1.34

Eqn-4*1.79

Antarctic minke whale

Fin whales

Fig.3. The relationship between body weight and daily prey consumption in each equation and RCH.
(○: Stomach contents weight observed of fin whales, ●: estimates consumption of Antarctic minke whales)
10Fin whales

Antarctic minke whales

15.0

15.0
West
N =412

West
N =331
10.0
%

%

10.0

5.0

5.0

0.0

0.0

10 15

20 25 30 35 40 45 50

55 60

10 15 20 25 30 35 40 45 50 55 60

mm

mm

Fig.4. The length of frequency distributions of Euphausia superba for fin whales (Left: N=6) and Antarctic minke
whales (Right: N=5) sampled on the western side.

Fin whales

Antarctic minke whales

15.0

15.0
Central
N =200Central
N =46
10.0

%

%

10.0

5.0

5.0

0.0

0.0
10 15 20 25 30 35 40 45 50 55 60

10 15 20 25 30 35 40 45 50 55 60

mm

mm

Fig.5. The length of frequency distributions of Euphausia superba for fin whales (Left: N=2) and Antarctic minke
whales (Right: N=2) sampled on the central side.
Fin whales

Antarctic minke whales

30.0

30.0
East
N =100East
N =100
20.0
%

%

20.0

10.0

10.0

0.0

0.0

10

15 20 25

30 35 40

45 50 55

60

10 15

mm

20 25 30 35 40 45 50

55 60

mm

Fig.6. The length of frequency distributions of Euphausia superba for fin whales (Left: N=1) and Antarctic minke
whales (Right: N=1) sampled on the eastern side.

11

Appendix 1. The summary table of data on fin whales and Antarctic minke whales in this study.
Sector: See to Fig. 2 in this paper.
SCW: Total of forestomach and fundus stomach contents weight (kg)Body length of krill: The data on body length of Euphausia superba ingested by whales was used in this study.
*: A part of the body of this whale was torn off and sank into the sea while it was being pulled onboard the NM.
●: I measured the body length of krill in the stomach contents.
N.D.: No data
Fin whale （N=17）
Year

No

Sighting position

Catch date Area Sighting

Catching position

BL(m) BW(t) Sex

SectorTime
2005/06

F001

02/03/2006

IV

10.11

65 50 S71 28 E

65 44 S71 38 E

19.17

2005/06

F002

02/08/2006

IV

6.12

65 55 S77 56 E

65 54 S78

6 E

20.05 53.48

N.D.

2005/06

F003

02/09/2006

IV

6.13

65 52 S78

4 E

65 48 S78

7 E

2005/06F004

02/10/2006

IV

7.42

65 42 S78 26 E

65 37 S78 13 E

2005/06F005

02/13/2006

IV

6.42

65 25 S

81 49 E65 22 S81 60 E

2005/06F006

02/14/2006

IV

7.43

65 10 S81 45 E65 10 S

2005/06

F007

03/07/2006

IV

14.48

64 32 S111 60 E

2005/06

F008

03/09/2006

IV

9.14

65

2 S

114 14 E

2005/06

F009

03/10/2006

IV

6.38

64 57 S114 15 E

M WesternF

Western

19.47 52.05

F

Western

18.73 41.87

M Western

19.14 47.28

M Western

81 59 E

19.15 47.04

F

64 34 S111 51 E

20.22 61.52

F

64 53 S114

18.22 41.06

F

64 48 S114 14 E

18.3

42.27

M

6 E

Western

CentralStomach Body length

SCW

Freshness of E. superba

254.9

2

●

1,084.7

2

●

246.6

2

●

524.5

3

●

633.7

1

●

468.9

3

●

25.9

N.D.

N.D.

29.4

3

●

545.8

4

N.D.

3

●
N.D.

F010

03/13/2006

IV

9.50

65 34 S120 15 E

65 36 S120 30 E

19.35 47.24

F

2006/07

F001

01/03/2007

V

9.51

64

170 38 W

63 53 S

170 44 W

N.D.

N.D.

*

2006/07

F002

01/05/2007

V

8.38

62 34 S174 18 W

62 35 S174 17 W 20.67 51.62

M

183.8

1

N.D.

2006/07

F003

02/02/2007

V

12.36

68 51 S173 42 W

68 46 S173 41 W 21.15 65.02

F

437.0

3

N.D.

2008/09

F001

03/13/2009

V

6.36

65 40 S

165 23 E

65 38 S165

8 E

14.79 22.26

F

0.0

2

●

2009/10F001

02/03/2010

III

5.10

66

0 S

62 18 E66

62 33 E

17.61 34.20

M

90.6

N.D.

N.D.

2010/11F001

01/07/2011

V

7.42

63 23 S

175 42 W

63 28 S

175 40 W 19.05 39.63

M

194.0

3

N.D.

2010/11F002

01/20/2011

V

7.58

66 39 S

165 47 E

66 39 S

165 32 E

M

224.7

2

N.D.

8 S

18.99 43.78

333.9

N.D.

2005/06

4 S

Central

1+2nd

N.D.

Eastern

Antarctic minke whale （ N=8）
Year

No

Sighting position

Catch date Area Sighting

Catching position

BL(m) BW(t) Sex

SectorTime
2005/06 AM453 02/03/2006

IV

6.25

66 18 S71

5 E

2005/06 AM507 02/08/2006
2005/06 AM513 02/10/2006

IV

6.14

66

78

9 E

IV

6.53

65 42 S71

1

78 25 E

65 60 S78

7 E

65 43 S78 30 E

2005/06 AM547 02/13/2006

IV

6.42

65 18 S81 24 E65 16 S81 16 E

2005/06 AM550 02/14/2006

IV

6.27

65 17 S81 52 E65 18 S

2005/06 AM801 03/09/2006

IV

6.33

64 59 S113 21 E

65

2005/06 AM828 03/13/2006

IV

7.59

65 28 S120

2008/09 AM661 03/15/2009

V

8.53

65 12 S

0 S

66 21 S

Stomach Body length

SCW

Freshness of E. superba
1

●

135.4

1

●

75.65

2

●

240.45

1●

M Western

123.2

1

●

N.D.

M

Central

82.45

1

●

6.16

N.D.

M

Central

40.15

1

●

6.34

3.75

M

Eastern

19.24

1

●

N.D.

M Western

8.67

N.D.

M Western

7.62

N.D.

F

Western

9.15

N.D.

F

Western

81 48 E

8.32

N.D.

3 S

113 25 E

8.27

7 E

65 32 S

119 45 E

163 42 E

65 12 S

163 50 E

12

E

1+2nd

9.35

18.15