Further observations on the migrations and stock discreteness of bowhead whales in Baffin Bay

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1 SC/55/BRG3 Further observations on the migrations and stock discreteness of bowhead whales in Baffin Bay M. P. Heide-Jørgensen 1*, K. L. Laidre 2, L. Dueck 3 and L. D. Maiers 3 1 Greenland Institute of Natural Resources, Box 570, DK-3900 Nuuk, Greenland 2 School of Aquatic and Fishery Sciences, University of Washington, Seattle, WA 98195, USA 3 Department of Fisheries and Oceans, 501 University Crescent, Winnipeg, Manitoba, Canada * current address: National Marine Mammal Laboratory, 7600 Sand Point Way, WA 98115, USA Correspondance to: Mads Peter Heide-Jørgensen, c/o National Marine Mammal Laboratory, Alaska Fisheries Science Center, 7600 Sand Point Way, WA 98115, USA, madspeter.heide-joergensen@noaa.gov Abstract Eleven bowhead whales (Balaena mysticetus) were instrumented with satellite transmitters in northwest Disko Bay, West Greenland, in May Two systems were used for instrumenting whales; transmitters were either cast in epoxy or mounted in steel cans, or transmitters were imbedded in torpedo-shaped floats with 1.5 m tethered lines. Both transmitter packages were attached to titanium spears or harpoon heads which anchored the tags in the whale blubber. Transmitters mounted in steel cans had a high initial failure rate, but those that were successful provided the longest deployment durations (7 months). The float tags had a low initial failure rate and all provided large numbers of positions initially after deployment. Float tags however lasted for shorter periods (2-33 days) and came off the whales due to unknown reasons. Results demonstrated whales preferred to remain within the northern part of Disko Bay in May. All whales departed from Disko Bay and headed northwest towards Lancaster Sound in the latter part of May, corroborating results from previous studies. One exceptionally long lasting tag (197 day duration) monitored movements of an individual into late November. In August this individual moved north along the coast of Baffin Island and reached southwest Admiralty Inlet. In mid-september, the whale moved to Barrow Strait and remained in a localized area for 3 weeks. The whale departed from Lancaster Sound on 7 October and quickly headed south along Baffin Island, with infrequent stops, until it reached the southeast corner of Baffin Island on 31 October. By 17 November it was located in Hudson Strait, approximately 1/3 of the way to Hudson Bay. This study confirms that bowhead whales move between West Greenland and the Canadian high Arctic, and consequently, belong to the same stock. The movements of one long-term deployment raise critical questions about the assumed stock discreteness of bowhead whales in Foxe Basin and in Hudson Strait and Davis Strait.

2 Introduction The population of bowhead whales, Balaena mysticetus, in Baffin Bay and Davis Strait once numbered at least 12,000 individuals (Woodby and Botkin 1993), yet suffered severe exploitation by commercial whalers prior to It is now believed that the Baffin Bay bowheads number between 250 and 350 whales (Finley 1990; Zeh et al. 1993) based on photographic capture-recapture estimated conducted in Isabella Bay in the eastern Canadian High Arctic. Despite severe historic depletion there are currently several signs of recovery of bowheads in West Greenland. Scattered observations of bowhead whales have been reported from West Greenland during the past 20 yrs, suggesting that they still occupy their historic range (Born and Heide-Jørgensen 1983; Kapel 1985; Reeves and Heide- Jørgensen 1996; Heide-Jørgensen and Acquarone 2002). A recent aerial survey in West Greenland in spring 1998 produced an estimate of 233 bowheads (SE=165) including correction for availability bias (Heide-Jørgensen and Acquarone 2002). Knowledge of migration routes and concentration areas in Canada and Greenland is based on observations from whalers in the s and Inuit hunters (e.g. Reeves et al. 1983; Ross 1993; NWMB 2000). The general perception is that bowhead whales spend the winter distributed from the northeast coast of Labrador to the east coast of Baffin Island across Baffin Bay to West Greenland. In the spring, the whales are found at the ice edge of Davis Strait and Hudson Strait, in localized areas in West Greenland, and along the east coast of Baffin Island. Satellite tracking studies of bowheads instrumented in Disko Bay have revealed that whales cross Baffin Bay from Disko Bay (at approximately 72 o N) reaching Lancaster Sound at the end of May (Heide-Jørgensen et al. 2003). During the summer, bowhead whales are widely distributed and enter many fjords and bays of the Canadian High Arctic. The fall migration begins in September and continues through October, when whales either move south along the east coast of Baffin Island or cross over to the West Greenland coast, appearing there in September and October (Reeves et al. 1983). Studies of the migratory behaviour of bowhead whales in Baffin Bay are of interest for stock delineation, especially in the light of renewed hunting in Canada (Finley 2001). The evidence confirming the relationship between bowhead aggregations in eastern Canada and western Greenland is a photographic re-identification of a whale (Heide-Jørgensen and Finley 1991) and, more recently, satellite tracking of two bowheads in 2001 (Heide-Jørgensen et al. 2003). Bowhead whales inhabit areas with extensive and heavy ice cover and it is unknown how they are be affected by habitat variability. Recent studies of changes of the extent of ice coverage in Baffin Bay indicate an overall increase in ice coverage since 1950 (Stern and Heide-Jørgensen in press). This increase will ultimately lead to reduced availability of open water areas for bowheads in Baffin Bay and perhaps to changes in timing and extent of plankton production that is critical to bowhead feeding (Hansen et al. 2003). Information on the plasticity of the migratory patterns of bowhead whales provides insight on their vulnerability to changes in available habitats. Determination of bowhead migrations also provides direct evidence on stock discreteness of different bowhead aggregations. The purpose of this study was to improve satellite tracking techniques for bowhead whales and to both extend previous tracking durations from Disko Bay and increase sample sizes.

3 Methods Daily searches for whales were conducted from four small boats between 4 and 13 May 2002 near the town of Qeqertarsuaq, Disko Island. Whales were spotted upon surfacing, and when they were underwater, the four boats spread out to search for the next surfacing location. When the whale was re-sighted, the process was repeated again until the whale was surfacing in a predictable manner, which usually took less than half an hour. When a whale was first approached (within 4-5 m), a skin biopsy was taken for genetic studies using a crossbow. Two different configurations for satellite-linked radio transmitters were deployed (transmitters were SPOT2 tags, Wildlife Computers, Redmond, Washington). One configuration mounted transmitters in a stainless steel can (referred to as can tags ) with a 33cm titanium spear (diameter 8 mm) equipped with 3 foldable leaf-like barbs and a sharp pointed tip (Fig. 1a). The transmitters in the can tags had two lithium thianyl batteries. Another configuration imbedded the transmitter and lithium C-cell battery in a torpedo shaped float (referred to as float tags, 28 x 8 cm), which was tethered behind the whale with a 1.5 m stainless steel wire attached to an anchor (Fig. 1b). Two different types of anchoring systems were used for the float tags; a titanium spear (similar to the one used for the can tags) or a sharpened piece of stainless steel configured into a harpoon head, imitating the design used by Inuit hunters (Fig. 1c). Both tags were deployed with an 8 m fiberglass pole from a small boat approximately 4-5 m from the whale. The can tags were mounted on the tip of the pole secured by a nylon line in case of misses. The float tags had their anchoring system at the tip of the pole yet the floats were mounted in a plastic tubing in the middle of the pole, designed to release the float under slight drag from the stainless steel tether connecting it to the anchoring system. The titanium spear or the harpoon head was pushed through the skin of the whale and into the blubber using the pole. When the tag was anchored in the whale, the nylon line was cut by a sharp edge on the pole. It was important to position the satellite tag high on the whale s back in order to be sure the tag was above the water to increase chances of satellite reception of transmissions. When delivering a tag with the pole, a simultaneous biopsy was taken (with a 10 mm hollow cylinder, 28 mm in length with internal barbs). Tags were only deployed when the whale was positioned alongside the boat 4-5 m away, and when the whale remained at the surface long enough to place the tag in a good position. The float tags had an expected longevity of 100,000 transmissions and were programmed to provide an unrestricted number of transmissions. The can tags had an expected longevity of 20,000 transmissions and were programmed only to provide transmissions every other day. Locations were collected using the Argos System (see Harris et al. 1990). Location qualities were provided by Service Argos and coded based on predicted accuracy. Location codes were LC B, A, and 0-3 in order of increasing accuracy of position. All location qualities were used to calculate an average daily position for each whale over the entire tracking period. The average positions were also used to calculate distance and speed over each 24-hour period and provide mean distances and speeds for selected periods during the movements of the whales. DNA was extracted from the skin samples using DNeasy tissue extraction kits (Qiagen). The sex of each of the animals sampled was then determined using a PCR (polymerase chain reaction) based method that amplifies a portion of the X-chromosome and a portion of the Y-chromosome (if present) (Bérubé and Palsbøll 1996). Animals were scored as female if there was only a single amplification product corresponding to the X-chromosome fragment and male if there were two products, one from the X-chromosome and one from the Y-chromosome.

4 Results Instrumentations Between 4 through 13 May 2002, bowhead whales were observed on a daily basis in northwest Disko Bay. Eleven bowheads were tagged with transmitters during this period; all between m long (Table 1). Six were tagged with float tags and 5 were tagged with can tags. All six float tags provided locations for 2-33 days, yet only two of the five can tags lasted more than one day (i.e. beyond the deployment day). There was no difference in the performance of the harpoon head and titanium spear attachment - both lasting 15 days on average. The float tags continued to provide positions for an extended period after they came off the whales. The date of float tag attachment failure was determined by examining the number and quality of ARGOS positions each day. There was a substantial increase in the frequency of good quality positions when the tags were no longer attached to whales and were floating constantly at the surface. The two can tags that provided positions beyond the deployment day lasted 9 and 197 days. The tag with the maximum deployment longevity was a can tag providing positions from 4 May through 17 November (ID 20160). Skin biopsies were collected from 10 whales (4 males and 6 females), including six whales that were tagged (Table 1). No whales were smaller than 12 m ranging up to 18 m in length. Movements and Area use Whale locations were concentrated primarily in the northwestern part of Disko bay. The 95% Kernel probability density range in this area based on daily average locations received from all whales between 4-21 May was estimated to be approximately 1,500 km 2 in 2002 and 4800 km 2 if locations from both 2001 (cf. Heide-Jørgensen et al. 2003) and 2002 are combined (Fig. 3). Localized movements in this area were observed from daily positions, where whales made small-scale movements back and forth within the estimated range. Whales remained in Disko Bay after tagging until as late as 21 May. Six of the eleven whales were tracked during their departure from Disko Bay (Fig. 4). All six whales departed from Disko Bay northwest towards Lancaster Sound, travelling northwest across Baffin Bay. Contact was lost with all but one whale (20160) during this period (Fig. 3). The tag that lasted beyond June provided the first documentation of movements of bowheads after they arrive off the Bylot Island/Lancaster Sound area. Two focal areas were identified, where the whale made localized movements between long distance travel periods. The whale reached the northern part of Baffin Bay in June and remained in a localized area northeast of Bylot Island or farther south (95% Kernel range approximated 26,000 km 2 ), similar to the area use documented from bowhead whales tracked in 2001 (Heide-Jørgensen et al. 2003). In July, the whale moved south towards the east coast of Baffin Island and then turned north in August, quickly moving north along the coast of Baffin Island. The whale reached Admiralty Inlet in the latter half of August and remained stationary through the end of August in the southwestern part of the Inlet. The whale then moved north to Barrow Strait in mid September, and made localized movements through 3 October (95% Kernel range approximated 2400 km 2 ). The whale moved east and left Lancaster Sound after the 7 October where it headed south along Baffin Island. During this time, the whale moved quickly and there were not extended periods in any region until the whale reached the southeastern corner of Baffin Island on 31 October. By 17 November, the whale had moved to Hudson Strait, about 1/3 of the way to Hudson Bay. At this time, contact was lost with the individual. Using average daily positions the whale that

5 was tracked through 17 November travelled a distance of at least 5,888 km at an average daily speed of 38 km, but with considerable variability depending on where the whale was located (Fig. 5). Discussion Performance of tags This study was the first to attach tethered float tags to cetaceans and the results are mixed. The float tags had a low initial failure rate and gave many more daily positions than can tags, which provided more detail about the local movements of the whales (Table 1). None of the float tags failed completely immediately after deployment, which was the case for some can tags. The float tags did, however, come off the whales relatively soon, after 2 to 33 days. This may be due to the anchoring system or some effect of the tethering system. Several can tags performed poorly by either failing completely or failing after few days. The fact that three can tags did not provide positions beyond the day of the instrumentations suggests that these tags come off the whales immediately after deployment. Two can tags performed well, one provided data for nine days and another gave positions for 197 days. The single can tag that performed well provided positions for 197 days and clearly exceeded the duration of all torpedo tags and other can-like tags that have previously been deployed on bowhead whales (Mate et al. 2000; Heide-Jørgensen et al. 2003). Failure of can tags is most likely related to poor implantation of the tag in the blubber, improper placement of the tag on the back of the whale (positioned too low for transmissions), or failure of the satellite transmitter part itself. It is reasonable to expect that the success of this tag was due to a particularly fortunate location and anchoring of the tag on the whale. Tests of the two anchoring systems (spear with barbs and harpoon head) on a large piece of skin and blubber from a bowhead whale showed that both systems were almost impossible to pull out of the skin by hand. The titanium spear seemed to provide a secure anchoring system, as when the spear was pushed into the blubber, the barbs bent and dug into the blubber when being pulled (Heide- Jørgensen unpubl. data). It is therefore surprising that most tags failed so shortly after deployment and lends caution to conclusions based on this kind of in vitro experiments with tag attachment. When bowhead whales were tagged in Foxe Basin using this same titanium spear system, an entire 33 cm spear could twice be pulled out of the same bowhead whale right after being pushed all the way into the blubber (M.V. Jensen, unpublished personal observations). Anchoring tags in the blubber seems to be the main obstacle for improved success rate and longevity of bowhead whale instrumentations. The float tags clearly gave many more positions of good quality than the can tags and they were therefore more useful when depicting the potential area usage of the whales. However, even the float tags did not provide sufficient details for fine scale descriptions of the exact localities of the whales on their feeding ground in Disko Bay. Even this type of tag had an optimal position on the whales, and success was limited by both diving behaviour and the availability of satellites. Occurrence in Disko Bay Eschricht and Reinhardt (1861) collected information on the time of departure (latest observations in spring) of bowhead whales from Qeqertarsuaq from 1780 to Their mean date for the last observations of whales in the area was 1 June, with a range from April 26 to June 25. The whales that were tracked in this study left Disko Bay between 10 and 21 May. Information collected from local hunters before and after the field season confirmed that bowheads were present in the area at

6 least from mid April through May 20. Apparently the bowhead whales in Disko Bay are still maintaining their historical patterns of distribution and movements, in spite of the severe reduction in numbers. Presumably bowhead whales in Disko Bay feed on large copepods (genus Calanus) and euphausiids (Brown 1868, Lowry 1993) found in large abundances in Disko Bay. In spring, the largest concentrations of copepods are found in the upper 50 m of the water column (Madsen et al. 2001). The biomass of copepods is known to reach a peak in early June where values of more than 100mg C m -3 have been measured (Madsen et al. 2001). In the upper 50 m of the water column, 90% of this biomass estimate was composed of three Calanus species, (C. finmarchicus, C. glacialis and C. hyperboreus). Based on departure dates from 2001 and this study, the bowhead whales leave the Disko Bay area prior to the peak availability of their preferred food species. Baffin Bay This study confirms previous satellite tracking work demonstrating bowhead whales depart from Disko Bay in late May and rapidly cross the heavy pack-ice in central Baffin Bay (Heide- Jørgensen et al. 2003). Most likely, the whales move north off the West Greenland coast until they find a suitable lead in the pack ice to travel across. These leads are known to intersect Baffin Bay from northwest to southeast (Environment Canada ). If whales find a northwest going lead, they may be able to cross from Disko Bay to Lancaster Sound in a short time span. Once whales cross the Baffin Bay pack ice they will find open water in the North Water polynya. From there they will have to await the break up of fast ice in Lancaster Sound before they can move towards their summering grounds, which were also reported by Davis and Koski (1980). Implications for stock identification This study provides further evidence that bowhead whales wintering in Disko Bay move toward northeastern Baffin Island in late May and that whale on both sides of Baffin Bay are connected (cf. Heide-Jørgensen et al. 2003). This study also demonstrates bowhead whales move far west into northern Canada, where one whale went as far as 95 o W spending the late summer and autumn in Lancaster Sound and tributaries. The same whale moved along the east coast of Baffin Island south to Hudson Strait where it was located in mid November. The whale passed along the east coast of Baffin Island in early summer and again in the autumn. At none of these occasions did it show any affinity to Isabella Bay, which has been identified as a major congregation site for Baffin Bay bowhead whales (Finley 1990). Population estimates derived from surveys in Isabella Bay are thus likely to underestimate the actual number of bowhead whales in Baffin Bay. The fact that the whale moved west into Hudson Strait in mid-november suggests this area may be a wintering ground for Baffin Bay bowhead whales, as also proposed by Southwell (1898) and Brown (1868) based on whaling records from the area. Few aerial surveys have been conducted over Hudson Strait in winter with the exception of a survey in March 1981, where twenty-seven bowheads were sighted (Reeves and Mitchell 1990). Wintering bowheads have also been found at other localities in western Baffin Bay: i.e. the North Water, at the Cape Dyer and Cape Kater polynyas and in Cumberland Sound. Whales in these areas are found in much lower numbers and clearly the major part of the population must winter somewhere else. Bowhead whales that winter in Hudson Strait should then move northeast towards Disko Bay in spring along the ice edge in Davis Strait.

7 The identification of Hudson Strait as a common wintering ground furthermore raises the question about the relationship between bowhead whales in Foxe Basin/northern Hudson Bay and the bowhead whales that are found in Baffin Bay and the Canadian High Arctic. The distances covered by the whales that were tracked in this study certainly do not exclude any connections between these bowhead congregations. The distance to Foxe Basin from Hudson Strait is a few days travel for bowhead whales. Bowhead whales are found throughout Hudson Strait and northern Hudson Bay in winter and it seems likely that Foxe Basin bowhead whales winter in the movable pack ice in Hudson Strait. In summer bowheads are observed far south in Prince Regent Inlet, in Gulf of Boothia and south to Fury and Hecla Strait. Consequently, movements from northern Foxe Basin through Fury and Hecla Strait to Gulf of Boothia seem likely. Considering the wide-ranging capabilities of bowhead whales and the occurrence during winter in Hudson Strait and in summer in Prince Regent Inlet and adjacent waters it seems highly likely that exchange between bowhead whales from Foxe Basin and Baffin Bay occur regularly, if not annually then on a scale of decades or certainly on a scale of centuries. The whale that moved to 95 o W in Barrow Strait was located at a position half-way between West Greenland and the Mackenzie Delta in the Beaufort Sea in September, where the Bering Sea stock of bowhead whales spent the summer. The Northwest passage that connects Baffin Bay with the Beaufort Sea is usually obstructed by closed pack ice, but will in light ice years be open for ship traffic. It is not known if bowheads are indeed capable of traversing the closed pack in the narrow straits of the Northwest Passage, but they will definitely be capable of moving through the passage in light ice years, as already suggested by Vibe (1967). Whether that actually happens depends on the behavioural traits of bowhead whales however the travel distance and sea ice conditions are definitely not a hindrance. Considering that the Baffin Bay bowhead whales seem to range widely and show high plasticity of their movement patterns exchange with Beaufort Sea bowhead whales is a likely scenario in time scales of centuries especially under warmer climatic conditions with less condensed pack-ice. Acknowledgements We wish to thank Kale Mølgård, Abel Brandt, Kaleeraq Heilmann, Søren Karl Broberg and Frederik Broberg for their excellent help during the search, pursuit, and tagging of the bowhead whales. Tags were developed by Wildlife Computers and modified by Mikkel Villum Jensen. The field work benefited from the assistance of Ygor Geyer, Mikkel Villum Jensen, Anders Villum Jensen and Kristian Krogh. The board of the Arktisk Station, University of Copenhagen, is acknowledged for providing the facilities at Arktisk Station including the research vessel Porsild. This study was funded by the Greenland Institute of Natural Resources, the Carlsbergfondet, and the Department of Fisheries and Oceans, Canada. Craig George kindly provided the bowhead whale blubber from Alaska for tag imbedding trials. References Bérubé, M. and P. Palsbøll Identification of sex in cetaceans by multiplexing with three ZFX and ZFY specific primers. Molecular Ecology 5: Born, E.W. and M.-P. Heide-Jørgensen Observations of the bowhead whale (Balaena mysticetus) in central West Greenland in March-May Rep. Int. Whal. Commn. 33: Brown, R Notes on the history and geographical relations of the Cetacea frequenting Davis Strait and Baffin s Bay. Proceedings Zoological Society of London 1868:

8 Davis, R.A. and W.R. Koski Recent observations of the bowhead whale in the eastern Canadian High Arctic. Rep. Int. Whal. Commn 30: Environment Canada Arctic Winter Ice Analysis and SAR Imagery. Available from Canadian Ice Service, Ottawa. Eschricht, D.F. and J. Reinhardt Om Nordhvalen (Balaena mysticetus L.) navnlig med Hensyn til dens Udbredning i Fortiden og Nutiden og til dens ydre og indre Saerkjender. K. Danske Videnskabernes Selskabs Skrifter. Series 5, naturvidenskabelig og mathematisk Afdeling 5: Finley, K.J Isabella Bay, Baffin Island: An important historical and present-day concentration area for the endangered bowhead whale (Balaena mysticetus) of the Eastern Canadian Arctic. Arctic 43: Finley, K.J Natural history and conservation of the Greenland whale, or bowhead, in the Northwest Atlantic. Arctic 54: Hansen, A.S., T.G. Nielsen, H. Levinsen, S.D. Madsen, T.F. Thingstad and B. W. Hansen Impact of changing ice cover on pelagic productivity and food web structure in Disko Bay, West Greenland: a dynamic model approach. Deep-Sea Research I 50: Harris, R.B., Fancy, S.G., Douglas, D.C., Garner, G.W., Amstrup, S.C., McCabe, T.R., and Pank, L.F Tracking wildlife by satellite: Current systems and performance. United States Department of the Interior, Fish and Wildlife Service, Fish and Wildlife Technical Report 30: 52 pp. Heide-Jørgensen, M.P. and K.J.Finley Photographic reidentification of a bowhead whale in Davis Strait. Arctic 44: Heide-Jørgensen, M.P. and M. Acquarone Size and trends of the bowhead, beluga and narwhal stocks wintering off West Greenland. NAMMCO Scientific Publications No. 5: Heide-Jørgensen, M.P., K. Laidre, Ø. Wiig, M.V. Jensen, L. Dueck, L.D. Maiers, H.C. Schmidt and R.C. Hobbs From Greenland to Canada in ten days: tracks of bowhead whales, Balaena mysticetus, across Baffin Bay. Arctic 56(1): Kapel, F.O A note on the net-entanglement of a bowhead whale (Balaena mysticetus) in Northwest Greenland, November Rep. int. Whal. Commn 35: Lowry, L Foods and feeding ecology. In: Burns,J.J., Montague, J.J., and Cowles, C.J. eds. The bowhead whale. Society for Marine Mammalogy, Special Publication No. 2. Lawrence, Kansas: Allen Press Madsen, S.D., T.G. Nielsen and B.W. Hansen Annual population development and production by Calanus finmarchicus, C. glacialis and C. hyperboreus in Disko Bay, western Greenland. Marine Biology 139: Mate, B.R., G.K. Krutzikowsky and M. Winsor Satellite-monitored movements of radio-tagged bowhead whales in the Beaufort and Chukchi seas during the late-summer feeding season and fall migration. Can. J. Zool. 78: NWMB (Nunavut Wildlife Management Board) Final report of the Inuit bowhead knowledge study. Iqaluit, Nunavut: NWMB. Reeves, R.R. and E. Mitchell Bowhead whales in Hudson Bay, Hudson Strait, and Foxe Basin: A review. Canadian Naturalist 117: Reeves, R.R. and M.P. Heide-Jørgensen Recent status of bowhead whales, Balaena mysticetus, in the wintering grounds off West Greenland. Polar Research 15 (2): Reeves, R., E. Mitchell, A. Mansfield, and M. McLaughlin Distribution and migration of the bowhead whale, Balaena mysticetus, in the Eastern North American Arctic. Arctic 36: 5-64.

9 Ross, W.G Commercial whaling in the North Atlantic sector. In: Burns,J.J., Montague, J.J., and Cowles, C.J. eds. The bowhead whale. Society for Marine Mammalogy, Special Publication No. 2. Lawrence, Kansas: Allen Press Southwell, T The migration of the right whale (Balaena mysticetus). Natural Science 12: Stern, H.L. and M.P. Heide-Jørgensen. In press. Variability of sea ice in Baffin Bay and Davis Strait. Polar Research Vibe, C Arctic animals in relation to climatic fluctuations. Meddr Grønland 170: 227 pp. Woodby, D.A. and D.B. Botkin Stock sizes prior to commercial whaling In: Burns,J.J., Montague, J.J., and Cowles, C.J. eds. The bowhead whale. Society for Marine Mammalogy, Special Publication No. 2. Lawrence, Kansas: Allen Press Zeh, J.E., Clark, C.W., George, J.C., Withrow, D., Carroll, G.M. and W.R. Koski Current population size and dynamics. In: Burns,J.J., Montague, J.J., and Cowles, C.J. eds. The bowhead whale. Society for Marine Mammalogy, Special Publication No. 2. Lawrence, Kansas: Allen Press

10 Table 1. List of whales instrumented with satellite transmitters and collections of biopsies in May Position on whale is indicated by R and L (left or right), F, M or B (forward of midline, midline, or behind midline) and H or L (high or low). Date Tagging position IDNO Position on whale RMH 7932 RFH RFM RML 7933 LFH RFH RMH RMH RBH RMH RMH Transmitter and attachment can, 33cm titanium spear float, harpoon head float, harpoon head can, 33cm titanium spear float, 33cm titanium spear float, 33cm titanium spear can, 33cm titanium spear, 5 cm outside skin can, 33cm titanium spear float, harpoon head float, harpoon head can, 33 cm titanium spear Sex M M F F F F Whale length Good quality positions (LC-0-3 Poor quality positions (LC-A and B) Tag longevity (days) 12 m m m m >12m >12m >12m m m >12m m 0 4 1

11 Fig. 1a. Satellite transmitter in stainless steel can. Fig. 1b. Satellite transmitter in torpedo float configuration. Fig. 1c. Harpoon head used to attaching float tags to bowhead whales.

12 Fig. 2. Potential range of bowhead whales in Disko Bay in May Only positions obtained the departure from Disko Bay are included. Data from 10 bowheads were used for estimating the range.

13 Fig. 3. Tracks of six bowhead whales that were tagged in Disko Bay in May 2002 that moved across Baffin Bay based only on positions of good quality. Contact was lost with 5 of the 6 whales in June, with the exception of ID The area used in Disko Bay was 4800 km 2 (95% Kernel) and it was calculated using both the 2001 and 2002 trackings of bowhead whales (for data from 2001 see Heide- Jørgensen et al. 2003).

14 Fig. 4. Track of a bowhead whale (ID 20160) that was satellite tagged in Disko Bay on 7 May and tracked through 17 November Daily average positions are shown to make up the trackline.

15 km date Fig. 5. Distances travelled by one bowhead whale (20160) tagged in Disko Bay in May and travelling across Baffin Bay in mid May, into Lancaster Sound in August, to Barrow Strait in September and south along the east coast of Baffin Island in October to Hudson Strait in November. The total travel distance was at least 5888 km.