SC/60/BRG32
Surveys of bowhead whales (Balaena mysticetus) in the
Northeast Atlantic in 2006 and 2008
Øystein Wiig1, Lutz Bachmann1, Jørgen Berge2, Vincent M. Janik3, Kit M. Kovacs4, René
Swift3, and Christian Lydersen4
1
Natural History Museum, University of Oslo, P.O. Box 1172 Blindern, N-0318 Oslo, Norway
The University Centre in Svalbard, 9171 Longyearbyen, Norway
3
Sea Mammal Research Unit, Gatty Marine Lab, School of Biology, University of St Andrews, Fife KY16 8LB,
United Kingdom
4
Norwegian Polar Institute, Polar Environmental Centre, 9296 Tromsø, Norway
2
ABSTRACT
We report results from two surveys for bowhead whales in the Northeast Atlantic along the ice edge between
Svalbard and Greenland in April 2006 and March 2008. In 2006 we observed about 20 bowhead whales at eight
locations between 80° N and 81° N. In 2008 we did not observe any animals but did record acoustic signals from
bowhead whales on two occasions between 77° N and 78° N. There has been an apparent increase in
observations of bowhead whales in the area between East Greenland and Franz Josef Land in recent years.
Currently, it is not known whether these sightings are animals that are stragglers from other areas or survivors of
the Spitsbergen stock.
INTRODUCTION
The Spitsbergen stock of bowhead whales is believed to number in the tens (Christensen et al. 1992)
and is considered Critically Endangered by the IUCN (Cetacean Specialist Group 2006). Here, we report results
from two surveys for bowhead whales in the Northeast Atlantic along the ice edge between Svalbard and
Greenland in April 2006 and March 2008.
MATERIAL AND METHODS
From 17 to 28 April 2006, we searched north and northwest of Svalbard for bowhead whales (Fig. 1)
from the research vessel Lance (Norwegian Polar Institute). The survey started and ended from Longyearbyen,
Svalbard. The edge of the drifting pack ice was relatively distinct and located in an approximate north/south
direction at approximately 0° longitude with open water east of this up to about 82oN. The observation
conditions were good during most of the survey effort. Fog reduced visibility during two survey days. The total
distance of the survey lines in 2006 was ~2000 km.
We repeated survey efforts in 2008, from 9 March to 3 April. During this second effort we searched the
ice edge between about 80°N and 73°N (Fig. 2). This expedition was a 3-part combined cruise; one team worked
full-time tagging polar bears using a helicopter, while a second team focused on the bowhead surveys except for
a few days, during which time hooded seals were tagged in this species whelping ground in the southern part of
the survey area. We were also removed from survey effort from 18 to 20 March, which were dedicated to
transport from a northern area to the hooded seal whelping ground in the south. The total distance of the onsurvey line was ~ 5000 km.
Throughout the survey, we continuously monitored the sea acoustically and in addition at least two
persons equipped with binoculars were actively searching for whales from the bridge of the vessel (~10 m above
seal level) at all times (see Wiig et al. 2007). We towed two custom made hydrophones 280 m and 380m
respectively behind the vessel. The first hydrophone consisted of a PC5TUBE piezoelectric ceramic by Morgan
Electro Ceramics and a Magrec HP/02 amplifier enclosed in a Pirelli Resin Kit. The second hydrophone
consisted of a Benthos AQ4 hydrophone and a Magrec HP/01 amplifier suspended in a 1-inch diameter
polyurethane tube filled with Isopar M hydrophone oil. The frequency response of both systems was
approximately 100 Hz to 15 kHz ± 3 dB. Both hydrophones were attached to the same Kevlar-strengthened
towing cable. At speed of 10 knots, this array tows at ~ 5-6 m below the surface (Gillespie 1997). If ice
conditions did not permit towing of the acoustic gear, or when Lance was cruising at very low speeds, Dowty
SSQ906A(D) or Plessey SSQ906 sonobuoys were deployed for acoustic monitoring (hydrophone depth set to 40
m). During the 2006 survey the visibility was generally good. During the 2008 survey the visibility north of 78°
N was generally low due to fog, limiting the search area. Throughout the survey, plankton sampling was
performed at regular intervals (Fig. 3) by two consecutive replicate standard WP-2 plankton net hauls (area=0.25
2
m2, mesh size=180 μm) at each station. The nets were towed vertically from 200 m to the surface with a mini
CTD logger attached to the net measuring the depth-specific temperature and salinity at each station.
RESULTS
In 2006 we had eight observation events that included 17-20 bowhead whales (Table 1, Fig. 1). All
whales were detected visually from the vessel’s bridge and all observations were made in a relatively small area
of the Fram Strait over the continental slope at depths between 1,030 and 2,785 meters. Age and sex of the
animals were not determined, but those whales we got close to with small boats for biopsy darting were at least
15 m long. We had no success in recording acoustic signals of any kind from the observed bowheads, or any
other species of cetacean during the survey. In 2008 we did no observations of bowhead whales. However, we
recorded sound within the bowhead frequency range on two occasions. At 30 March we recorded a short call at
77.15° N 5.40° W and 1 April we recorded two longer calls at 78.67 ° N 0.88° W. Plankton sampling revealed
that the blooming period had not started during the study. The only zooplankton collected in our nets was
copepods and these were found at very low densities.
Visual and acoustic detections of killer whales and narwhals occurred during our surveys for bowheads.
DISCUSSION
Habitat selection by bowhead whales is believed to change with season. During spring and summer,
bowheads reside in continental-slope waters (Moore et al. 2000). This is consistent with our sightings in 2006,
which were made on the continental slopes of Svalbard, and with our recordings in 2008, which were on the
continental slope of Greenland. In the Fram Strait area, between Svalbard and Greenland, warm Atlantic Water
of the West Spitsbergen Current meets cold Arctic Water of the East Greenland Current (Schauer et al. 2004).
When the annually formed winter sea ice melts in this region during the spring, phytoplankton begins to grow
vigorously (Smith et al. 1987) making an abundant food source for copepods (Hirsche and Niehoff 1996).
Bowhead whales feed on calanoid copepods and euphausiids (Lowry 1993). In 2006 other copepod specialists,
namely little auks (Alle alle), were also present in significant numbers in the areas where bowheads were sighted.
We assume the whales were feeding on copepods. In 2008, few seabirds were observed during the survey.
Combined with our meagre results from the plankton sampling we conclude that adequate food resources for
bowhead whales were not available during the time of the survey within the area searched.
We expected to hear singing or other calls from bowhead whales at this time during March and April
(Würsig and Clark 1993) but had no success in 2006 (Wiig et al. 2007) and limited success in 2008. However,
the recordings did suggest the presence of bowheads in the Fram Strait in 2008, when they were not physically
observed. Further studies are needed to investigate the acoustic behavior of bowhead whales in the Northeast
Atlantic.
The distribution of bowheads in the Fram Strait is well documented for the 17th and 18th century
(Reeves 1980, Sanger 1991, Hacquebord 1999). There was a “bay” of ice free water in the area between
Svalbard and Greenland that was maintained by the warm Atlantic Water of the West Spitsbergen Current. The
location of the northern extension of this bay varied considerably inter-annually, but in some years reached as far
north as 80°N in late April. It was thought that the bowhead whales moved from the south into this ice bay in
April. A huge number of whales were caught in this area, which whalers referred to as Whaler’s Bay or the
Northern Whaling Ground. The spring ice conditions in 2006 differed dramatically from those in historical
whaling reports; there was open water as far north as 82°N in April. For the surveyed area, we conclude that
during April 2006 bowhead whales within the western range of the Spitsbergen stock were concentrated in the
area 80-81oN, 0-2oE. Obviously, the occurrence of copepods that congregate to feed on the algal bloom along the
ice edge, as well as the sea current systems that keep this part of the Fram Strait more or less consistently open,
make the area a favorable habitat for bowhead whales during the early spring. In 2008, the ice conditions were
heavier than in 2006, presumably due at least in part to constant northerly winds. The northern ice edge was at
about 80° N. In this second survey effort, we searched the same general area about 3-4 weeks earlier than in
2006 in hopes of detecting whales acoustically closer to their peak breeding periods. However, the plankton
bloom had not yet started, which might have resulted in lower densities of whales within the area.. However, our
recordings suggest that there were some bowhead whales present in the region.
Records of bowhead whales have been sporadic but persistent for some time in the Svalbard area
(Reeves 1980) and in the eastern part of the Barents Sea, particularly in the Franz Josef Land area (Wiig 1991,
Moore and Reeves 1993, de Korte and Belikov 1994). In addition, reports of bowhead sightings have been
received annually the last few years from Spitsbergen fjords during summer (Norwegian Polar Institute
unpublished data). There is also an apparent increase in the number of occasional observations of bowheads in
Northeast Greenland during the last decades (Gilg and Born 2005). Currently, it is not known whether the
observed bowhead whales in the Svalbard area are stragglers from the Northwest Atlantic or survivors of the
Spitsbergen stock.
3
REFERENCES
Cetacean Specialist Group. 2006. Balaena mysticetus (Spitsbergen stock) in IUCN 2006 IUCN Red List of
Threatened Species. <www.iucnredlist.org>.
Christensen, I., Haug, T., and Øien, N. 1992. Seasonal distribution, exploitation and present abundance of stocks
of large baleen whales (Mysticeti) and sperm whales (Physeter macrocephalus) in Norwegian and
adjacent waters. International Council for Exploration of the Seas, J. Mar. Sci. 49:341-355.
De Korte, J., and Belikov, S.E.. 1994. Observations of Greenland whales (Balaena mysticetus), Zemlya FrantsaIosifa. Polar Rec. 30:135-136.
Gillespie, D. 1997. An acoustic survey for sperm whales in the Southern Ocean Sanctuary conducted from the
RV Aurora Australis. Rep. int. Whal. Commn. 47:897-907.
Gilg, O., and Born, E.W. 2005. Recent sightings of the bowhead whale (Balaena mysticetus) in Northeast
Greenland and the Greenland Sea. Polar Biol. 28:796-801.
Hacquebord, L. 1999. The hunting of Greenland right whale in Svalbard, its interaction with climate and its
impact on the marine ecosystem. Polar Res. 18:375–382.
Hirche, H.-J., and Niehoff, D.B. 1996. Reproduction of the Arctic copepod Calanus hyperboreus in the
Greenland Sea – field and laboratory observations. Polar Biol. 16:209-219.
Lowry, L.F. 1993. Foods and feeding ecology. Pages 201-238 in J. J. Burns, J. J. Montague and C. J. Cowles,
eds. The bowhead whale. Special Publication Number 2, Society of Marine Mammalogists, Allen Press,
Lawrence, Kansas.
Moore, S.E., DeMaster, S.E., and Dayton, P.K. 2000. Cetacean habitat selection in the Alaskan Arctic during
summer and autumn. Arctic 53:432-447.
Moore, S.E. and Reeves, R.R. 1993. Distribution and movement. Pages 313-386 in J. J. Burns, J. J. Montague
and C. J. Cowles, eds. The bowhead whale. Special Publication Number 2, Society of Marine
Mammalogists, Allen Press, Lawrence, Kansas.
Reeves, R.R. 1980. Spitsbergen bowhead stock: A short review. Marine Fisheries Review 42:65-69.
Sanger, C.W. 1991. Environmental factors affecting 17 th-19th century whaling in the Greenland Sea. Polar Rec.
27:77-86.
Schauer, U., Fahrback, E., Osterhus, S., and Rohardt, G. 2004. Arctic warming through the Fram Strait: Oceanic
heat transport from 3 years of measurements. J. Geoph. Res. 109:1-14.
Smith, W.O., Baumann, M.E.M., Wilson, D.L., and Aletsee, L. 1987. Phytoplankton biomass and productivity in
the marginal ice zone of the Fram Strait during summer 1984. J. Geoph. Res. 92:6777-6786.
Wiig, Ø. 1991. Seven bowhead whales (Balaena mysticetus L.) observed at Franz Josef Land in 1990. Mar.
Mamm. Sci. 7:316-319.
Wiig, Ø., Bachmann, L., Janik, V.M., Kovacs, K.M., and Lydersen, C. 2007. Spitsbergen bowhead whales
revisited. Mar. Mamm. Sci. 23: 688-693.
Würsig, B. and Clark, C. 1993. Behavior. Pages 157-199 in J. J. Burns, J. J. Montague and C. J. Cowles, eds.
The bowhead whale. Special Publication Number 2, Society of Marine Mammalogists, Allen Press,
Lawrence, Kansas.
Table 1. Observations of bowhead whales in the Fram Strait between Svalbard and Greenland in April 2006.
Observation
Date
1
2
3
4
5
6
7
8
17.04.2006
18.04.2006
25.04.2006
26.04.2006
26.04.2006
26.04.2006
28.04.2006
28.04.2006
Time
(GMT)
19:00
15:00
21:00
05:00
09:00
11:00
13:55
15:00
Lat
Lon
80.273 N
80.578 N
81.031 N
81.041 N
81.116 N
81.312 N
81.183 N
81.350 N
00.675 E
02.094 E
01.148 E
01.175 E
01.600 E
02.302 E
01.763 E
01.530 E
Number of
whales
1
7+
1
1
1
3
1
3
Water depth
(m)
2785
2070
2170
1745
1450
1030
1270
1315
4
Fig. 1. Survey track-line and sightings of bowhead whales in the Fram Strait between Svalbard and Greenland in
April 2006 (from Wiig et al. 2007). All tracks except the one going from Svalbard to the west at 80°N are along
the ice edge. The ice was distributed west and north of the track-line and changed during the survey. Sightings of
whales; 1: 17 Apr - 1 whale, 2: 18 Apr - 7+ whales, 3: 25 Apr 1 whale, 4: 26 Apr - 1 whale, 5: 26 Apr - 1 whale,
6: 26 Apr - 3 whales, 7: 28 Apr - 1 whale, 8: 28 Apr - 3 whales.
Fig. 2. Track line of RV Lance from 8 March to 5 April 2008.
5
Fig. 3. Sample sites for zooplankton during 8 March to 5 April 2008. * indicate stations on southbound survey
and ■ indicate stations at northbound survey.