ABSTRACT

INTRODUCTION
One of the main sources of sighting data for assessing the population status of whale species in the Antarctic is the JARPA (Japanese Whale Research Program under Special Permit in the Antarctic), which was conducted between 1987/88 and 2004/05, and its second phase JARPAII. As for whale distribution analyses, the sighting data collected during JARPA have been used for blue whales (Branch et al ., 2004) and other large whale species (Kishino et al ., 1991; Kasamatsu et al ., 2000; Matsuoka et al ., 2003b, 2011, Murase et al. , 2002, 2014). The main objective of this paper is to study the geographical distribution pattern for the main whale species sighted in Antarctic Areas IIIE, IV, V and VIW by JARPA and JARPAII sighting surveys. One of the features of JARPA and JARPAII is that, unlike the IDCR (International Decade for Cetacean Research)-SOWER (Southern Ocean Whale and Ecosystem Research) programmes (Matsuoka et al. , 2003a, Murase et al. , 2005), surveys have been repeated in the same area and in the same months every second season over a long period. Current distribution maps are more detailed by each Area compared to those of the IDCR/SOWER maps which had covered the area only three times for each set of circumpolar data on whales. Therefore the JARPAII surveys facilitate the extent of detailed local distribution of whales.
MATERIAL AND METHODS
Sighting data used in this analysis In this paper, we used all JARPA and JARPAII (1987/88-2008/09) systematic sighting survey data (effort and primary sightings) collected by sighting and sampling vessels (SSV) and dedicated sighting vessels (SV). An outline of the sighting survey is as follows:
Sighting procedure
The sighting procedure of JARPA II (2005/06-2008/09) was not largely changed during the JARPA surveys with some minor changes to the sighting procedure, which were reviewed by Nishiwaki et al. (2014). The research vessels were equipped with barrels, where three top men conducted sighting observation. On the upper bridge, a captain, a gunner, a helmsman and a researcher also conducted the sighting. The sighting activity continued if weather permitted during the daytime from 30 minutes after sunrise to 30 minutes before sunset.
Survey modes
Searching was conducted under closing and passing modes. (Hakamada et al. , 2006, 2014a). These modes were under normal weather conditions defined as having minke visibility of 2 n.miles or more and wind speed under 20 knots in the northern strata (under 25 knot in the southern strata) (Nshiwaki et al . 2014).
Confirmation of the sightings
When a school of a cetacean species appearing to be minke whales or another large cetacean was sighted in the research area, the ship closed on the school immediately in order to identify the species, estimate the school size and get other biological information (number of calves, estimated body length etc.). To improve the estimation of the distance to the school and the angle from the bow, training was conducted in the early portion of each cruise by each vessel. Distance was estimated by referring to the scale of the binoculars, and angle was also estimated referring to the angle board. Surface temperatures were recorded in each whale sighting.
Density Index of whales
The Density Index of Whales (DIW) was calculated by each Lat.1°× Long.1°grid squares using the primary searching effort (n.miles) and the number of whales sighted in each square by each species.
RESULTS AND DISCUSSIONS
Primary searching efforts
A total of 353,134 n.miles was surveyed in south of 60°S in Areas IIIE, IV, V and VIW between 1989/90 and 2008/09 seasons. Figures 1a and 1b show the research area and distribution of the primary searching effort (n,miles), respectively. The research area was covered completely during the surveys.
Distribution pattern of whales
Tables 1a and 1b show the summary of the primary sightings in the JARPA and JARPAII (1987/88-2008/09) for baleen whales and toothed whales, respectively. Table 2 shows the summary of the number of calves, observed mean school size and Density Index of Whales (DIW: number of the primary sightings of individuals / 100 n.miles) in the research area. Figures 2a to 2d show the maps of the DIW of blue, fin, sei, Antarctic minke, dwarf minke, humpback, southern right, sperm, southern bottlenose, unidentified beaked ( Ziphiidae ) and killer whales by each Lat.1°× Long.1°grid squares. Figure 3 shows the monthly change in the density index of these species, except for a small number of sighting species of sei, dwarf minke and unidentified beaked whales.
Blue whale
Blue whale was ranked 8th in the DIW among the 10 species sighted in the research area (Table 2). They were widely distributed in the research area not only in the northern stratum but also the southern stratum. High density values of this species were observed in Areas IIIE (between 45°E and 65°E) (Figure 2a). They were rarely found within the Prydz Bay. They were sighted within the Ross Sea between 70°S and 77°S. A total of 286 schools (495 individuals) were sighted with 11 calves south of 60°S (Table 2). Observed mean school size was 1.73 (individuals). The DIW of this species was 0.140 during the whole season and were almost stable from December to March (Table 2 and Figure 3). Two subspecies of blue whales exist in the Southern Hemisphere: the Antarctic (or true) blue whale ( Balaenoptera musculus intermedia) and the pygmy blue whale ( B. m. brevicauda ) (Machintosh, 1966, Ichihara, 1966, Rice, 1998). A complete review of spatial and seasonal distribution, densities and movements of blue whales is provided by Branch et al . (2007a, 2007b). This study indicated that there is little evidence that pygmy blue whales migrate into high latitudes of the Antarctic. Less than 1% of the records south of 52°S were of this subspecies. There is no current evidence of a population structure in Antarctic blue whales. The latest abundance of this species (south of 60°S, 35°E-145°W) was 1,223 whales (CV=0.345) in 2007/08 + 2008/09 seasons and the abundance trend was 8.2 % (95%CI: 3.9%, 12.5%) between 1995/96 and 2008/09 for combined Areas IIIE+ IV+V+VIW based on JARPAII data (Matsuoka and Hakamada, 2014). There is a need for the continued monitoring of the abundance and abundance trends of this species, especially because they provide an excellent opportunity to improve our understanding of the dynamics of baleen whale populations recovering from low levels.
Fin whale
Fin whale was ranked 5 th in the DIW among the 10 species sighted in the research area. A total of 1,268 schools (5,209 individuals) were sighted with 20 calves (Table 2). Observed mean school size was 4.11 (individuals). Distribution of this species was more frequently encountered in Areas V and VIW than Areas IIIE and IV in both northern and southern strata. High density areas were observed in Areas IIIE (between 55°E and 65°E), VW (between 140°E and 160°E) and VE (between 163°E and 170°W) (Figure 2a). The DIW of this species was 1.475 during the whole season and was increasing from December to March (Figure 3). In the summer feeding grounds in the Antarctic, fin whales can be found year-round, but a higher density is found from November to May (Kasamatsu et al. , 1996; Mackintosh, 1966). Whales can be found as far south as 65-70°S, but the majority of the population seems to be north of 60°S (Miyashita et al ., 1995). Catches occurred throughout the Antarctic, but the majority of whales (~73%) were taken in the IWC Management Areas II and III. Sighting data suggests that spatial distribution varies across ocean basins (Kasamatsu et al. , 1996).
Sei whale
Sei whales were the most rare species sighted in the research area. A total of 36 schools (59 individuals) were sighted with no calves south of 60°S in the Antarctic (Table 2). Observed mean school size was 1.64 (individuals). Distribution of this species was limited more in Areas V and VIW than Areas IIIE and IV in both northern stratums (Figure 2a). The DIW of this species was 0.017 during the whole season. In the summer, sei whales do not venture into higher latitude waters near the Antarctic continent as much as some other baleen whales (Horwood, 1987; Miyashita et al. , 1995). The majority of the population can be found between 40'S and 60°S, usually north of the Antarctic Convergence. Juveniles are found further north than mature individuals. Occurrence in low latitude wintering grounds has been recorded from March to December, but abundance peaks from June/July to August/September (Horwood, 1987). In late spring and summer, abundance peaks in November between 30°S and 50°S. As the season progresses, relatively more whales are observed south of 40°S and abundance between 50°S and 60°S increases consistently until March (Horwood, 1987). Present results of this paper support these studies.
Antarctic minke whale
This species was most frequently sighted throughout the surveys. A total of 25,507 schools (69,076 individuals) were sighted with no calves south of 60°S in the Antarctic (Table 2). Observed mean school size was 2.71 (individuals). High density areas were observed around the entire ice-edge, especially the Ross Sea and Prydz Bay (Figure 2b). The DIW of this species was higher than other species (19.561) during the whole season and was increasing from December to February and decreasing to March (Figure 3). In the austral summer, the majority of Antarctic minke whales congregate in the Southern Ocean, with greatest densities close to and within the pack ice, and lower densities with increasing distance from the ice (Kasamatsu et al. 2000, Hakamada 2014a), including some north of 60°S. Antarctic minke whales are noticeably well adapted to living within the ice (Ainley et al ., 2007), but the exact proportion of Antarctic minke whales found within the pack ice, and in polynyas, is currently a source of great debate. It is possible that a large proportion of the population is found within the pack ice, out of reach of ship-based sighting surveys (Murase et al. , 2005, 2014; Shimada and Kato, 2007).
Dwarf minke whale
The distribution area of this species was limited in the research area. There are two separated areas between 120°E and 147°E, and between 165°E and 170°W, respectively in the northern stratum (mainly between 60°S and 63°S), where the south of Australia and New Zealand (Figure 2b). The dwarf minke whale has a white band on the flipper that distinguishes it from the Antarctic minke whale, but was only fairly recently identified as separate from Antarctic minke whales (Best, 1985). Based on available information, only a small percentage of minke whales in the Antarctic (south of 60°S) are dwarf minke whales. For example, in the IDCR/SOWER surveys from 1993/94–1997/98, only 0.2% of the identified sightings were dwarf minke whales (2 out of 906). No formal analysis has been conducted but it is probable that less than 1% of the minke whales south of 60°S are dwarf minke whales (Branch & Butterworth, 2001).
Humpback whale
Humpback whale was ranked 3rd among the 10 species sighted in the research area. A total of 10,036 schools (18,770 individuals) were sighted with 137 calves (Table 2). Observed mean school size was 1.87 (individuals). They were widely distributed in the research area in both northern and southern stratum. They were rarely found within the Prydz Bay and the Ross Sea and there were no sightings south of 73°S. High density values of this species were observed between 85°E and 110°E (Figure 2b). The DIW of this species was 5.315 during the whole season and was increasing from December to February and decreasing to March (Figure 3). Sightings data from both the IDCR/SOWER circumpolar cruises suggested that whales were encountered more frequently at 20-40°E, 80°E-100°E and 150°E-180°E (Branch, 2011). A current map of this species suggested that humpback whales are encountered more frequently at 80°E-100°E than 20-40°E and 50°E-180°E because of its high productivity area (see Discussions). In that area between 80°E and 100°E, large scale distribution changes were observed (Matsuoka et al. , 2011, Murase et al. , 2014, Hakamada et al. 2014b). It was considered that oceanographic conditions have changed this area as an effect of the Regime Shift in the Global Sea-Surface temperatures in relation to El Nino-Southern Oscillation Events (Watanabe et al. , 2014, Naganobu et al. , 2014). It will be further investigated in the future. Southern right whale A total of 235 schools (298 individuals) were sighted with 6 calves (Table 2). The distribution area of this species was limited in the research area between 80°E and 135°E south of Western Australia (Figure 2c). The DIW of this species was 0.084 during the whole season and was increasing from December to March (Figure 3). After breeding in winter in relatively warm waters, near continental or island coastlines, southern right whales migrate in summer to feed in colder waters, but generally not as far south as other baleen whales. They appear to occur near the subtropical convergence in summer (January to March) at around 40°-50°S (Ohsumi & Kasamatsu, 1985), but there are records of animals much further south (e.g. around 60°S-65°S south of Australia (Bannister et al ., 1999, 2008). The present map of this species supported these studies. The population estimate for the coastal area of Western Australia was 2,400 in 2006 (Bannister, 2008). A current estimate in Area IV south of 60°S is 1,557 individuals (95% CI, 871-2,783) in the 2007/08 season based on JARPAII data. The abundance trend was not significant for this species because they were mainly distributed in the area north of 60°S.
Sperm whale
Sperm whale was ranked 6th among the 10 species sighted in the research area. A total of 3,810 schools (3,926 individuals) were sighted without any calves (Table 2). Solitary schools (large male) were 96.5%, and the observed mean school size was 1.03. They were widely distributed in the research area. High density values of sperm whales were observed in Area IV (between 70°E and 100°E) and Area V (between 170°E and 170°W, in mouth of the Ross Sea (Figure 2c). They tended to be concentrated on the Antarctic continental slope, the southern Kerguelen Plateau, and around the mouth of the Ross Sea, where the most frequent depth was between 1,000m and 4,000m. They were rarely found within the Prydz Bay and the Ross Sea (Figure 2c). There were no sightings south of 74°S in the Ross Sea. The DIW of this species was 1.112 during the whole season and was decreasing from December to March (Figure 3).
Southern bottlenose whales
Southern bottlenose whale was ranked 7th among the 10 species sighted in the research area. A total of 1,666 schools (3,045 individuals) were sighted with 3 calves (Table 1). They were widely distributed in the research area and were rarely sighted within the Prydz Bay and the Ross Sea. High density values of this whale were observed between 85°E and 130°E (Figure 2c). Observed mean school size was 1.83 individuals. The DIW of this species was 0.862 during the whole season and was decreasing from December to March (Figure 3).
Unidentified beaked whales
Unidentified beaked whales was ranked 4th among the 10 species sighted in the research area. A total of 3,175 schools (5,457 individuals) were sighted with 3 calves (Table 1). These sightings were recorded as unidentified species but confirmed as beaked whales. These "unidentified beaked whales" included possibly southern bottlenose whales ( Hyperoodon planifrons ), Arnoux's beaked whales ( Berardius arnuxii ), strap-toothed whales ( Mesoplodon layardii ) and Grey's beaked whales ( M. grayi ). The distribution pattern of unidentified beaked whales was consistent with that of southern bottlenose whales (Figure 2d). If they were identified on the species level, they recorded their species codes. But these records were not used in this paper because the number of records was very small.
Killer whale
Killer whale was ranked 2nd among the 10 species sighted in the research area. A total of 1,472 schools (20,569 individuals) were sighted with 59 calves (Table 2). Observed mean school size was 13.97 individuals. The DIW of this species was 5.825 during the whole season (Table 2). They were widely distributed in the research area and sighted more in the southern stratum than the northern stratum. High density areas were observed within the Prydz Bay and the Ross Sea (Figure 2d).
High productivity in the meander of the southern boundary of ACC
From the viewpoint of large scale whale distributions, Area IV was more highly concentrated between 80° E and 110° E (south of 60° S) than in other parts of the research area. This area was characterized by a large meander (rise to 61° S and slow-moving down to 63° S) of the southern boundary of the ACC which seemed to be formed by a large scale up-welling with nutritious bottom waters resulting from the bottom shape of the southern Kerguelen Plateau (Watanabe et al., 2006, 2014, Naganobu et al. , 2014). The BROKE, Australian Antarctic survey, indicated the possibility of the occurrence of a large-scale upwelling between 80°E and 100° E (Bindoff et. al , 2000). In the JARPA 1999/2000 cruise, a high density of Euphausiids was reported between 100 °E and 120° E (Murase et al. , 2002). Humpback, southern right, large male sperm and southern bottlenose whales used this longitudinal section between 80° E and 100° E as their key feeding area from December to March. It is further necessary to investigate the relationship between oceanographic conditions and whale distribution shifts such as the effect of the Regime Shift on the Global Sea-Surface temperatures in relation to El Nino-Southern Oscillation Events (Matsuoka et al. , 2003b, Watanabe et al. 2014, Naganobu et al. , 2006, 2014). It will be further investigated in the future.
Large data set for Antarctic ecosystem studies
In this paper, low and middle latitude survey data and other species data including Arnoux's beaked whale, long-finned pilot whale, hourglass dolphin and spectacled porpoise was not used. These large sets of data from JARPA and JARPAII surveys including the results of this paper will contribute to investigating habitat utilization and contribute to baleen whale management in the Antarctic Ocean and further investigation of Antarctic marine ecosystems. JARPAII continues to provide more useful information regarding the recovery management of whale stocks including blue whales. It is regrettable that the recent two sighting surveys had to be cancelled due to unscrupulous, obstructive actions by an anti-whaling group.
ACKNOWLEDGEMENTS
We would like to thank all the researchers, captains, officers and crew members participating in the JARPA and JARPAII surveys in the Antarctic. Our gratitude also goes to Luis A. Pastene for his help in the preparation of this paper. We also would like to thank Seiji Ohsumi, Hiroshi Hatanaka, Yoshihiro Fujise, Tomio Miyashita, Hidehiro Kato, Shigetoshi Nishiwaki and Tatsuya Isoda for their useful comments on this paper and also Satoshi Suzuki for his help drawing some figures.
REFERENCES
Ainley, D.G, Dugger, K.M., Toniolo, V., & Gaffney, I. 2007. Cetacean occurrence patterns in the Amundsen and southern Bellinghausen Sea sector, Southern Ocean. Marine Mammal Science, 23, 287-305. Bannister, J.L., Pastene, L. A. and Burnell, S. R., 1999. First record of movement of a southern right whale ( Eubalaena Australis ) between warm water breeding grounds and the Antarctic Ocean, south of 60°S. Mar. Mammal Sci. 15 (4): 1337-1342. Bannister, J.L. 2008. Population trend in right whales off southeastern Australia 1993-2007. IWC Paper SC/60/BRG14 , 13pp. Best, P.B. 1985. External characters of southern minke whales and the existence of a diminutive form. Scientific Reports of the Whales Research Institute, 36, 1-33. Bindoff, Nathaniel, L., Rosenburg, Mark A. and Warner, Mark J. 2000. On the circulation and water masses over the Antarctic continental slope and rise between 80E and 150E. Deep-Sea Research II : Tropical Studies in Oceanography, 47: 2299-2326. Branch, T. A., and Butterworth, D., S., 2001. Estimates of abundance south of 60°S for cetacean species sighted frequently on the 1978/79 to 1997/98 IWC/IDCR-SOWER sighting surveys. J. Cetacean. Res. Manage. 3(3):251-270. Branch, T.A., Matsuoka, K. and Miyashita, T., 2004. Evidence for increases in Antarctic blue whales based on bayesian modelling. MARINE MAMMAL SCIENCE 20 (4): 726-754. Branch, T.A. 2007a. Abundance of Antarctic blue whales south of 60°S from three complete circumpolar sets of surveys. Journal of Cetacean Research and Management, 9(3), 87-96. Branch, T.A. et al ., 2007b. Past and present distribution, densities and movements of blue whales Balaenoptera musculus in the Southern Hemisphere and northern Indian Ocean. Mammal Rev ., 37(2), 116-175. Branch, T.A. 2011. Humpback abundance south of 60°S from three completed sets of IDCR/SOWER circumpolar surveys. J. CETACEAN RES. MANAGE. (SPECIAL ISSUE) 3:53-69. Hakamada, T., Matsuoka, K. and Nishiwaki, S. 2006. An updated of Antarctic minke whales abundance estimates based on JARPA data. IWC paper SC/D06/J6 presented to the IWC workshop on JARPA review. (unpublished). 34pp plus addendum. [Available from the Office of this Journal]. Hakamada, T et al. 2014a. Abundance estimates and trends for Antarctic minke whales ( Balaenoptera bongerensis ) in the Antarctic Areas IV and V for the period 1989/90-2008/09. SC/F14/J3. Xxpp. (this meeting) Hakamada, T. and Matsuoka, K. 2014b. Abundance and abundance trend estimates of humpback whales ( Megaptera novaeanglie ) in the JARPA and JARPAII period. SC/F14/J4. Xxpp. (this meeting) Horwood, J. 1987. The Sei Whale: Population Biology, Ecology and Management . London: Croom Helm. Ichihara, T. (Ed).1966. The pygmy blue whale, Balaenoptera musculus brevicauda, a new subspecies from the Antarctic, In: Kenneth S. Norris, Whales, dolphins, and porpoises p. 79-113 . Berkeley, CA: University of California Press. 789 pp. Kasamatsu, F., Joyce G, Ensor P. and Mermoz J. 1996. Current occurrence of baleen whales in Antarctic waters. Rep. Int. Whaling Comm., 46, 293-304. Kasamatsu, F., Matsuoka, K. and Hakamada, T. 2000. Interspecific relationships in density among the whale community in the Antarctic. Polar Biology 23:466-473. Kishino, H., Kato, H., Kasamatsu, F. and Fujise, Y. 1991. Detection heterogeneity and estimation of population characteristics from the field survey data: 1987/88 Japanese feasibility study of the Southern Hemisphere minke whales. Ann. Inst. Statist. Math. 43:435-53. Mackintosh, N. A. 1966. Distribution of southern blue and fin whales. Pages 125-144 in K. S. Norris, editor. Whales, dolphins, and porpoises. University of California Press, Berkeley, CA. Matsuoka, K., Ensor, P., Hakamada, T., Shimada, H. Nishiwaki, S., Kasamatsu, F. and Kato, H. 2003a. Overview of minke whale sightings surveys conducted on IWC/IDCR and SOWER Antarctic cruises from 1978/79 to 2000/01. J. CETACEAN RES. MANAGE. 5:173-201. Matsuoka, K., Watanabe, T., Ichi, T., Shimada, H. and Nishiwaki, S. 2003b. Large whale distributions (south of 60°S, 35°E-130°E) in relation to the southern boundary of the ACC. Antarctic Biology in a Global Context , pp26-30. Edited by A. H. L. Huiske, W.W.C. Gieskes, J. Rozema, R.M.L. Schrno, S.M. van der Vies & W.J. Wolff. Backhuys Publishers, Leiden, The Netherlands. Matsuoka, K., Hakamada,T., Kiwada, H. Murase H. and Nishiwaki, S. 2011. Abundance estimates and trends for humpback whales ( Megaptera novaeanglie ) in the Antarctic Areas IV and V based on JARPA sighting data. J. CETACEAN RES. MANAGE. ( SPECIAL ISSUE ) 3:75-94. Matsuoka, K. and Hakamada, T. 2014. Abundance and trends estimates for blue, fin and southern right whales in the Antarctic Areas IIIE, IV, V and VIW (35°E -145°W), south of 60oS based on JARPA and JARPAII (1989/90-2008/09) sighting data. IWC paper SC/F14/J5 (this meeting). Miyashita, T., Kato, H. and Kasuya, T., 1995. Worldwide Map of Cetacean Distribution based on Japanese Sighting Data (Volume 1).pp43-56. Murase, H., Matsuoka, K., Ichii, T., and Nishiwaki, S. 2002. Relationship between the distribution of euphausiids and baleen whales in the Antarctic (35°E-145°W). Polar Biology, 25, 135-145. Murase, H., Shimada, H., and Kitakado, T. 2005. Alternative estimation of Antarctic minke whale abundance taking account of possible animals in the unsurveyed large polynya using GAM-based spatial analysis: A case study in Area II in 1997/98 IWC/SOWER. IWC Paper, SC/57/IA6, 20pp. Murase, H., Matsuoka, K., Hakamada, T. and Kitakado, T. 2014. Preliminary analysis of changes in spatial distribution of Antarctic minke and humpback whales in Area IV during the period of JARPA and JARPAII from 1989 to 2006. SC/F14/J20 (this meeting). Naganobu, M., Nishiwaki, S., Yasuma, H. Matsukura, R. Takao, Y. Taki, K. Hayashi, Y. Watanabe, Yabuki, T. Yoda, Y. Noiri, Y. Kuga, M. Yoshikawa, K. Kokubun, N. Murase, H. Matsuoka, K. and Ito, K. 2006. Interactions between oceanograohy, krill and baleen whales in the Ross Sea and Adjacent Waters: An overview of Kaiyo Maru- JARPA joint survey in 2004/05. IWC paper SC/D06/ J23. pp33. [Available from the Office of this Journal]. Naganobu, M., Matsuoka, K., Murase, H. and Kutsuwada, K. 2014. Consideration on the Kerguelen-Davis Oscillation Index (KDOI) influencing variability on environmental ecosystem in the Prydz Bay Region, east Antarctic: data exploration. IWC paper SC/F14/ J23. ppxx. [Available from the Office of this Journal]. Nishiwaki, S., et al. , 2014. Review of general methodology and survey procedure under the JARPAII. IVC Paper SC/F14/J2. xxpp. (this meeting). Ohsumi, S., and Kasamatsu, F. 1985. Recent off-shore distribution of the southern right whale in summer. Report of the International Whaling Commission, (Special Issue)(10), 177-185. Rice, D.W. (ed.). 1998. Marine mammals of the world: systematics and distribution . Lawrence, KS: Society for Marine Mammalogy. 231 pp. Shimada, H., and Kato, A. 2007. Population assessment of the Antarctic minke whale within and out ice field using a sighting data by the Ice Breaker and the IWC SOWER vessels in 2004/2005. IWC Paper, SC/59/IA16, 8pp. Watanabe, T., Yabuki, T., Suga, T., Hanawa, K., Matsuoka, K. and Kiwada, H. 2006. Results of oceanographic analyses conducted under JARPA and possible evidence of environmental changes. Paper SC/D06/J15. Watanabe, T., Yabuki, T., Suga, T., Hanawa, K., Matsuoka, K. and Kiwada, H, 2014. Results of oceanographic analyses conducted under JARPA and JARPAII and possible evidence of environmental changes. Paper SC/F14/J21. (this meeting).
Table. 2. Summary of the main species sightings during the JARPA and JARPAII (1987/88-2008/09). Sch.: Number of the primary sightings of schools. Ind.: Number of the primary sightings of individuals. Calf: Number of calves including Individuals. Mss: mean school size (Ind. / Sch.). DIS: Density Index (schools / 100 n.miles). DIW: Density Index (individuals / 100 n.miles).