attachment ii - abstract release

INTERNATIONAL WHALING COMMISSION 60TH ANNUAL MEETING (Santiago, Chile, 2008) ______________________________________________________________________________ SC/60/BRG9

DISTRIBUTION AND ABUNDANCE OF WESTERN GRAY WHALES OFF THE NORTHEAST COAST OF SAKHALIN ISLAND (RUSSIA), 2007 Valeriy A. Vladimirov1, Sergey P. Starodymov1, Alexey G. Afanasyev-Grigoryev2, Judith E. Muir3, Olga Yu. Tyurneva2, Yuri M. Yakovlev2, Valeriy I. Fadeev2, Vladimir V. Vertyankin4 1 - All-Russian Research Institute of Fisheries and Oceanography (VNIRO) - 17, V. Krasnosel’skaya ul., Moscow, 107140, Russia (contact email: [email protected]). 2 - Institute of Marine Biology (IBM) DVO RAN - 17, ul. Palchevskogo, Vladivostok, 690041, Russia (contact emails: [email protected], [email protected], [email protected]). 3 - LGL Limited, environmental research associates, 9768 Second Street, Sidney, BC V8L 3Y8, Canada (contact email: [email protected]). 4 - North-East Department of Fisheries Management (SevVostRybVod), 58, ul. Koroleva, Petropavlovsk-Kamchatskiy, 683049, Russia (contact email: [email protected]).

Abstract Vessel and shore-based surveys of Western gray whales performed in the summer-fall period of 2007 as part of the Northeast Sakhalin Gray Whale Monitoring Program showed that the distribution of gray whales in their feeding areas in both Piltun and the Offshore area significantly changed in comparison to the previous year. The total number of whales identified off Northeast Sakhalin in 2007 increased from 2006 (from 126 to 131 individuals), based on photoidentification data. However the average abundance of Western gray whales observed from shore and vessel surveys in 2007 decreased compared to the previous year with a concurrent increase in numbers of Western gray whales observed off the East coast of Kamchatka. Analysis of benthic data indicated that food availability did not decrease compared to 2006. One hypothesis for these changes in whale distribution and the utilization of both northeast Sakhalin and Kamchatka in 2007 is that the unusually late breakup of the ice cover in the northeast Sakhalin coastal waters resulted in migrating whales selecting other locations to feed. Shore and vessel based distribution and abundance data indicated no avoidance of areas near to the offshore construction or production facilities of the Sakhalin-I or Sakahlin-II projects. KEY WORDS: WESTERN GRAY WHALE, SAKHALIN, PILTUN, DISTRIBUTION, NUMBER, ANTHROPOGENIC IMPACT.

Distribution surveys (vessel-based and shore-based) in the feeding areas of the Western gray whale population in the shelf waters of northeast Sakhalin Island were performed in the summer-fall period of 2007. Vessel-based surveys and observations were carried out regularly from July 4 through October 9 from the “Academician Oparin” and “Professor Bogorov” research vessels. Shore-based surveys were conducted between June 23 and October 17, weather permitting. All surveys were performed by specialists from Russian research institutes in Moscow (VNIRO) and Vladivostok (IBM DVO RAN), with the participation of student biologists from Far Eastern universities.

Vessel-based surveys in the Piltun area were conducted on one transect, approximately 170 km long, running along the coast of the island at a distance of approximately 4.0 km offshore from Urkt Bay in the north to Nyyskiy Bay in the south. In the Offshore area surveys were conducted along 8 transects oriented from east to west at intervals of 6.5 km. Vessel-based surveys were also performed in the waters of the Arkutun-Dagi license area (Sakhalin-1) along 7 east-west transects (Figure 1-a). Surveys in all areas were conducted at a vessel speed of 10-11 knots. Shore-based vehicle-assisted route surveys were performed from 13 observation stations located approximately 8 - 10 km apart (to minimize double counting) at vantage points along the Sakhalin coast (Figure 1-b). This allowed observations of whales within most of the Piltun feeding area from the waters opposite Ekhabi Bay in the north to the waters adjacent to the north part of Chayvo Bay in the south (i.e., approximately 120 km long). Four-wheel-drive all-terrain vehicles were used for transport between shore-based survey points to provide safe transport of survey teams along the shore from one observation post to another. This minimized time intervals between surveys from neighboring stations (in order to reduce possible errors related to movements of the whales along the coast). Reticule binoculars with built-in compasses were used for both the vessel-based and shore-based surveys. Distance to the sighted gray whales was calculated according to Lerczak and Hobbs (1998) with coordinates of observed whales determined on the basis of the data obtained. Western gray whale density was calculated in 1km2 grid cells with average Western gray whale weighted densities estimated for each cell that was sampled during the 2007 survey season. Average density estimates correct for the possible double counting of WGWs from different vessel transects or shore stations by incorporating each survey’s effort in addition to correcting for availability and perception bias. A total of 14 dedicated vessel-based surveys (3 in the Piltun, 5 in the Offshore and 6 in the Arkutun-Dagi area), and 73 shore-based surveys (including 26 complete surveys) were performed in 2007. A total of 287 whales were observed during dedicated surveys (120 animals in the Piltun, 159 in the Offshore and 8 in the Arkutun-Dagi area). 1997 whales (1612 sightings) were recorded during the onshore surveys. The main results of the surveys carried out in 2007 are as follows: 1. Whales used the entire northeast Sakhalin feeding range in 2007 as in prior years: large groups of whales stayed here through the entire summer-fall season in the same two marine feeding areas – the Piltun coastal area and the Offshore area, which is located 35 - 50 km off the island's coast. In the Piltun area, consistent with previous years the majority of whales (99.5%) were observed from shore to be within a 5-kilometer coastal zone between 52о25'N and 53о30'N. Around half the observations (48.2%) were 1 - 2 km from shore; 23.9% of observations were between 2 and 3 km from shore and 16.7% of observations were between 0.5 and 1 km. The majority of observations (99.2%) were in waters no deeper than 20 m (Figure 2), as in previous years with 43.8% of whales observed at depths from 6 to 10 m and 37.3% observed at a depth of 11 to 15 m. In the Offshore area, the gray whales were observed within similar boundaries as 2001 – 2006: an area located between 51°52′N and 52°25′N and between 143°28′E and 143°46′E.

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2. Although the whales stayed within the usual overall boundaries in their East Sakhalin feeding areas during the summer-fall period of 2007, their territorial distribution within these boundaries changed substantially compared to 2006 (Vladimirov et al., 2007a, b). The whale feeding congregations that had previously formed in the northern part of the Piltun area were largely absent in 2007 with the population density decreasing significantly compared to 2006 (Figure 2). The density of whales in the southern part of the coastal area also decreased. In contrast, the density of whales near the mouth of Piltun Bay increased (the area adjacent to Survey Points 8 and 9) where during the peak feeding season (August – September) up to 40 – 50% of the whales present in the Piltun area at the time were grouped within a limited area. In the Offshore feeding area, most observations in 2007 were in the eastern and southsoutheastern portions of this area, which have the deepest waters; these whales were found in waters 40 – 50 m deep, where they had been observed quite rarely in prior years (Figure 2). They were relatively sparsely grouped here, without forming dense congregations. 3. In addition to shifts in gray whale distribution in the Piltun and Offshore feeding areas, changes in the average abundance of Western gray whales compared to 2006 were also observed in 2007. The average abundance of whales in the Piltun area during the summer-fall months of 2007, was 75.8 ± 19.5. This is a 25% decrease in the average abundance compared with the average abundance observed in 2006 of 101.6 ± 20.1. The abundance of Western gray whales on each day when a complete survey had been conducted was estimated on the basis of the density analysis (these calculations for August – September are presented in Table 1). In the Offshore area, assessments of gray whale abundance based on estimated WGW densities for each systematic survey ranged from 0.0 to 31.3 whales, with an average estimated abundance of 13.9 whales (SD 13.37) during 2006, whereas in 2007, gray whale abundance ranged from 14.8 to 29.9 whales, with an average estimated abundance of 22.8 whales (± 5.66). 4. Taking into account that whales may transfer between the Piltun and Offshore feeding areas within a few days, the abundance of whales observed in both areas (shore based and vessel surveys) within a 48 hour period was evaluated to gain some insight into the general abundance of whales observed in the Piltun and Offshore area at any given time. Two surveys meeting these criteria were conducted in 2007. A shore-based survey was conducted in the Piltun area on August 31, and a vessel-based survey was performed in the Offshore area shortly afterward, on September 1. The data obtained (124.4 whales in the Piltun area and 20 in the Offshore area) results in a maximum abundance in both areas combined of 144 whales. In 2006, the overall data from two similar surveys, which were also performed over 2 subsequent days – an onshore survey in the Piltun area (October 6) and a vessel-based survey in the Offshore area (October 7) – gave a similar number of whales – 136 (120.1 in the Piltun area and 16.1 in the Offshore area). Despite an overall lower average abundance in 2007, photo-identification data gathered as part of the Russian comprehensive gray whale monitoring program documented the highest number 3

of individual whales since the beginning of this program in 2002. In 2006, there were 126 whales photographically identified in Northeast Sakhalin waters (Tyurneva et al., 2007). In 2007 photo-identification data indicated that the number of gray whales individually identified in Sakhalin waters was higher than in 2006, totaling 131 individuals. This result compared to the decrease in average seasonal density and abundance of gray whales in the Piltun feeding area (Figure 2) leads to the supposition that last year the number of whales arriving at the Northeast Sakhalin shores did not decrease, but the residence time in the area appeared to be less for some individuals than in 2006. In the course of the season Western gray whales were documented in other feeding habitats within their total summer-fall range in the Russian Far East waters – which, in addition to northeast Sakhalin, include the coastal waters of East Kamchatka (Vertyankin et al., 2007). Photo identification of gray whales conducted by V.Vertyankin off East Kamchatka in 2007 confirmed that during summer there were significantly higher numbers of Western gray whales observed offshore East Kamchatka within their feeding areas (especially in Olga Bay, where the total number of gray whales increased to 30 from 15 in 2006, and also Vestnik Bay, where the maximum numbers of gray whales observed during late spring and summer increased from 2 in 2006 to 7 in 2007). The photo-identification analysis performed at IBM DVO RAN (Vladivostok) indicated that in 2006 there were only 5 whales previously observed off Sakhalin out of the 13 gray whales encountered and photographed in Kamchatka waters during the summer (and only 2 of those 5 Western gray whales visited both areas between July and September). In 2007, 37 individual gray whales were photographed in Kamchatka, including 19 individuals that have also been documented off northeast Sakhalin. Of these 19 individuals, 12 were observed in both Sakhalin and Kamchatka feeding areas during summer-fall 2007 (Figure 3). Similarly, the number of gray whales identified by the IBM DVO RAN group in northeast Sakhalin area that had also been recorded in East Kamchatka increased between 2006 and 2007. While in 2006 such whales had numbered only 3 individuals, in 2007 this number was 14 (including the 12 already mentioned above that had been encountered in both areas). The increased use of Kamchatka for feeding in 2007 is consistent with decreased abundance off northeast Sakhalin during the same period. The importance of East Kamchatka and other areas outside of northeast Sakhalin that have been historically used by Western gray whales may be under-estimated and further regional studies, including satellite-based tracking, will likely provide significant further insight on gray whales' use of Far East feeding habitats. It is noteworthy that gray whales were also observed in 2007 near the northern tip of Sakhalin by the east coast of the Shmidt Peninsula, approximately 60 km north of Odoptu Bay. Within the 1kilometer coastal zone between August 13 – 18, a group of 7 gray whales was seen feeding there for at least 6 days (the dates indicated above were the only time that the researcher spent in this region; it is unknown how long this group actually stayed there). 5. Analysis of biomass distribution in the Piltun Area indicated that the average abundance in key amphipod species increased in 2007 to 32.1±4.8 g/m2 compared with 28.5±3.8 g/m2 in 2006 indicating that an obvious decrease in food availability was not responsible for changes in gray whale habitat use in 2007 (table 2). One hypothesis for the change in gray whale distribution in the Piltun and Offshore feeding areas in 2007 and utilization of areas outside of Sakhalin is that

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unusually long (till late June) ice cover in the coastal area resulted in whales searching elsewhere to forage. 6. The maximum number of mother-calf pairs observed in the Piltun area during shore-based surveys in 2007 was 5 (as it had been in 2005 and 2006). Difficulty in observing mother-calf pairs from shore at distances greater than 2 – 2.5 km because of small body size and low blow height of calves leads to possible underestimation of such pairs. Nonetheless, the constancy of these numbers from shore over recent years indicates that the reproduction rate of the Korean stock gray whales is at least not decreasing. 7. The distribution and photo identification data collected in 2007 does not indicate any obvious negative impact on gray whale distribution in the Piltun area caused by the installation work on the above-sea portion of the "PA-B" platform that was performed during the summer-fall season as part of the Sakhalin II Project. Research conducted within the framework of the monitoring program on Western gray whales offshore northeast Sakhalin will continue, because many aspects of their vital activities remain insufficiently studied. Knowledge of these aspects is necessary to develop science based mitigation and project design to minimize anthropogenic impact on these animals as industrial operations increase in this region. Further work in East Kamchatka will provide additional insight into the importance of the area for Western gray whale foraging.

References Lerczak, J.A. and R.C. Hobbs. 1998. Calculating sighting distances from angular readings during shipboard, aerial, and shore-based marine mammal surveys // Mar. Mamm. Sci., 14 – p. 590-599. Vertyankin V.V., V.A.Vladimirov, O.Yu.Tyurneva, Yu.M.Yakovlev, A.V.Andreev, V.N.Burkanov, 2007. Sightings of gray whales (Eschrichtius robustus) offshore Eastern Kamchatka and in the northern Sea of Okhotsk, 2006 // Int'1 Whaling Com., 59th meeting, doc. SC/59/WP6 – 8 pp. Vladimirov V.A., S.P.Starodymov, A.G.Afanasyev-Grigoryev, A.V.Vladimirov, A.T.Ashchepkov, 2007a. Distribution and abundance of Western gray whales off the northeast coast of Sakhalin Island, Russia, in 2006 // Int'1 Whaling Com., 59th meeting, doc. SC/59/WP5 – 10 pp. Vladimirov V.A., S.P.Starodymov, A.T.Ashchepkov, A.G.Afanasyev-Grigoryev, J.Muir, A.V.Vladimirov, 2007b. Distribution and abundance of gray whales of the Okhotsk-Korean population in northeastern Sakhalin waters in June-October, 2006 (based on the data of onshore and vessel surveys) // Report by VNIRO, Moscow, Russia, for Exxon Neftegas Limited and Sakhalin Energy Investment Company, Yuzhno-Sakhalinsk, Russia – 137 p. [available on the Sakhalin Energy Investment Company website ] Yakovlev, Y.M., O.Yu.Tyurneva and V.V.Vertyankin, 2007. Photographic identification of gray whales (Eschrichtius robustus) of the Okhotsk-Korean population in the northeast shelf of Sakhalin Island and the southeast coast of the Kamchatka Peninsula, Russia, 2006 // Report for Exxon Neftegas Limited, Yuzhno-Sakhalinsk, Russia and Sakhalin Energy Investment Company Limited, Yuzhno-Sakhalinsk, Russia - 119 p. [available on the Sakhalin Energy Investment Company website ].

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Table 1. Gray whale abundance estimated from complete (north and south) shore-based distribution surveys, 2007 Gray whale abundance 77.8 95.8 60.4 92.4 64.6 86.6 70.1 76.9 57.7 124.4 80.7 77.6 46.5 99.6 76.5 49.4 71.7 55.9

Survey date 8/3/2007 8/4/2007 8/16/2007 8/17/2007 8/18/2007 8/24/2007 8/25/2007 8/28/2007 8/30/2007 8/31/2007 9/8/2007 9/9/2007 9/13/2007 9/14/2007 9/17/2007 9/18/2007 9/20/2007 9/30/2007

Table 2. Macrobenthos average biomass distribution (g/m2) in the Piltun area based on the field data from 2006 and 2007 Depth 11–15 m

16–20 m

21–25 m

26–30 m

Entire area

2006

2007

2006

2007

2006

2007

2006

2007

2006

2007

Amphipoda Isopoda

59.8 17.3

74.7 5.5

25.5 10.6

22.8 5.7

19.8 12.4

19.9 4.2

9.4 7.7

16.8 11.3

28.5±3.8 11.6±1.6

32.1±4.8 6.8±3.8

Bivalvia

6.4

32.9

19.6

21.4

32.2

54.5

56.2

34.4

30.1±7.1

35.9±5.6

Cumacea Echinoidea Polychaeta

0.3 4.5 4.1

1.2 2 6.6

0.3 110 4.6

0.8 339.1 11.4

0.4 620 3.2

2.4 319 8.7

9.1 523 9.1

19.5 655 8.2

2.7±1.1 335±65 5.3±1.2

7.3±3.9 334±84 8.7±3.2

Pisces

7.5

0.6

9.1

15.1

17.6

23.1

34.1

39.9

17.7±9.9

27.7±12.1

102.5

123.5

183.8

416.3

709.9

431.8

658.2

775.1 434.3±64.5 448.5±87.1

Totals:

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Fig. 1. Western gray whale surveys off northeast Sakhalin in June-October, 2007. A – vessel-based survey transects 1 – in the Piltun feeding area 2 – in the Offshore feeding area 3 – in the Arkutun-Dagi license area

B – shore-based survey points

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Fig. 2. Distribution of Western gray whales off northeastern Sakhalin, June-October 2006 and 2007. Combined data of shore-based and vessel-based surveys (whale number per square km).

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Fig. 3. Movements of Western gray whales between the Far Eastern regions, 2007 (based on the photo-identification data)

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