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Polar Biol
DOI 10.1007/s00300-007-0338-3
123
SHORT NOTE
Observations of a wild polar bear ( ) successfully
shing Arctic charr ( ) and Fourhorn sculpin
( )
M. G. Dyck · S. Romberg
Received: 1 February 2007 / Revised: 29 June 2007 / Accepted: 2 July 2007
Springer-Verlag 2007
Abstract Polar bears, Ursus maritimus, throughout their
range, are nutritionally dependent on ringed (Phoca hisp-
ida) and bearded seals (Erignathus barbatus), which are
predominantly caught on the sea ice. Other marine prey
species are caught and consumed, but less frequently. As
the annual sea ice retreats, polar bears throughout their
range are forced ashore, where they mostly live oV their
stored adipose tissue. However, while land-bound they
have been observed catching birds and terrestrial mammals.
Although polar bears evolved from brown bears (U. arc-
tos), direct observations of polar bears diving for and catch-
ing Wsh have not been reported. Here, we document
observations of a young male polar bear catching Arctic
charr (Salvelinus alpinus) and Fourhorn sculpin (Myoxo-
cephalus quadricornis) by diving in Creswell Bay,
Nunavut. We recorded six search bouts, where six Wsh were
caught during dives, which were preceded by a snorkel.
The average dive and snorkel length was (mean §SD)
13 §5 and 6 §2 s, respectively.
Keywords Polar bear · Ursus maritimus · Fishing
behaviour · Arctic charr · Fourhorn sculpin · Nunavut
Introduction
Polar bears (Ursus maritimus) need the sea-ice platform
to hunt their prey, primarily ringed (Phoca hispida)
and bearded seals (Erignathus barbatus) (Stirling and
Archibald 1977; Smith 1980; Hammill and Smith 1991;
Derocher et al. 2002). During summer when the sea-ice
disappears, bears can spend up to several months on shore
where they mostly live oV their stored fat reserves (Watts
and Hansen 1987; Ramsay and Stirling 1988). While on
land, they also have been known to consume several alter-
native food sources. Food items that are opportunistically
consumed during the ice-free period range from various
bird species, eggs, and conspeciWcs to vegetation (e.g.,
berries, grass) and garbage (e.g., Russell 1975; Lunn and
Stirling 1985; Derocher et al. 1993; Donaldson et al. 1995;
Dyck 2001; Dyck and Daley 2002; Stempniewicz 2006).
The signiWcance of these dietary components to the overall
energy budget of polar bears was considered to be minor
(Lunn and Stirling 1985; Ramsay and Hobson 1991;
Hobson and Stirling 1997).
In this paper, we report on observations of a subadult
male polar bear and its exhibited behaviour during attempts
to catch Wsh. These observations are unique in that they
diVer from reported brown bear (U. arctos) Wshing behav-
iour, and that these observations are the Wrst of its kind in
over 200 years.
Materials and methods
The timing and location to potentially observe polar bear
Wshing behaviour was suggested to us by local traditional
knowledge from Resolute Bay, Nunavut. The Union River
(72°44 08N and 94°19 11W), Sommerset Island, Nunavut
M. G. Dyck
Environmental Technology Program, Nunavut Arctic College,
Box 600, Iqaluit, NU, Canada, X0A 0H0
S. Romberg
Department of Fisheries and Oceans Canada,
Central and Arctic Region, Eastern Arctic Area,
P.O. Box 358, Iqaluit, NU, Canada, X0A 0H0
M. G. Dyck (&)
Department of Environment, Wildlife Research Section,
Government of Nunavut, Box 209, Iglulik,
NU, Canada, X0A 0L0
e-mail: mdyck@gov.nu.ca
Polar Biol
123
is one of several locations where Inuit have been observing
this type of polar bear behaviour for many years. We con-
centrated our observation period between 17 and 30 August
2006 because Arctic charr (Salvelinus alpinus) occur at
high densities at the estuary during fall, getting ready to
migrate up-stream after a summer of feeding in Creswell
Bay, and returning to Stanwell Fletcher Lake for spawning
and wintering (de March et al. 1977).
We used spotting scopes and digital camcorders, usually
at distances of 300–800 m, and between 0700 and
1300 hours to record polar bear behaviour. All observations
of predatory behaviour on Wshes were conducted downwind
of the bear to avoid scent detection.
To determine the catch eVort, we counted the number of
Wsh caught per unit of time. Whenever possible, we
attempted to determine the species of Wsh, either directly by
viewing through the spotting scopes, or by examining the
left-over Wsh carcasses. Moreover, we determined the
amount of Arctic charr biomass consumed based on aver-
age Wsh weights taken during our study (n= 20 for each
gender; mean round weight for charr = 3,417 g).
For every Wshing attempt at the estuary, we quantiWed
the “snorkeling” and “diving” times because this behaviour
was directly associated with predatory behaviour on Wsh.
We deWned a snorkel as swimming with dorsum exposed,
eyes and nose under water, and only the ears above the
waterline. A dive was deWned as being completely sub-
merged below the water surface. We timed a snorkel from
the moment when the nose and eyes were submerged to the
moment when either both were brought above the water
surface, or the bear dove. A dive was timed from the
moment the bear was completely below the water surface
until it re-surfaced. We also timed search bouts in seconds
where timing began after a bear was Wnished feeding on a
carcass and entered the water, and where timing ended
when the bear caught another Wsh, independent of whether
it was dropped into the water or brought to shore for con-
sumption. As soon as the bear vacated the estuary area we
surveyed the shorelines where the bear was Wshing for Wsh
carcasses to ensure we did not miss any Wsh.
All times were measured in seconds with a digital stop-
watch. No statistical tests could be conducted because all
observations were conducted on the same animal. The
research activities were carried out under permits from the
Government of Nunavut and the Department of Fisheries
and Oceans, Canada.
Results
We observed three adult males, one subadult male, one sub-
adult female, and two adult bears of unknown gender
within 1 km of the Union River estuary throughout our
observation period. Only the subadult male was observed
preying on Wshes, whereas the other bears were occasion-
ally observed either scavenging on several narwhal
(Monodon monoceros) and charr carcasses, and/or feeding
on kelp (Laminaria spp.) and Arctic cotton grass (Eriopho-
rum scheuchzeri Hoppe).
We detected the bear around 0900 hours on 28 and 29
August in the water, swimming and wading in the estuary.
We were able to record six search bouts: bouts one to
three on 28 August, and bouts four to six on 29 August.
The average search bout lasted 419 s per Wsh, with an
average of 17 dives (Table 1). The dive lengths ranged from
3 to 29 s (mean §SD: 13 §5s;
n= 66). The mean length
of a snorkel lasted 6 §2 s (range 1–10 s, n= 66). All Wsh
were caught during a dive, where a snorkel preceded the
dive.
Four Wsh (2 charr and 2 sculpin) were caught and con-
sumed on 28 August. Five Wsh (1 charr, 4 sculpin) were
caught on 29 August. Of these, the charr and one sculpin
were completely consumed, two sculpin were partially con-
sumed, and one sculpin was dropped in the water and
escaped. Only the lower jaw remained from one partially
eaten sculpin carcass, whereas most of the body was left
from the second sculpin (remaining round weight 380 g,
fork length 400 mm).
Discussion
This is the Wrst study to our knowledge that recorded polar
bear predatory behaviour on Wshes. Russell (1975) found
traces of Wshes in polar bear scats from James Bay and
southwest Hudson Bay, but it was unclear whether bears
scavenged or actively caught the Wshes. Anecdotal accounts
reported of 32 white bears Wshing salmon at Eagle River,
Labrador, during July of 1778 (Smith et al. 1975), but other
observations have not been published.
Table 1 Observed search bout length, number and type of Wsh caught,
and number of dives per search bout for a subadult male polar bear
preying on Wshes at Union River, Nunavut
Search
bout
Search bout
length (s)
Fish caught Number
of dives
1 149 One Arctic charr Not recorded
2 764 One Fourhorn sculpin 36
3 247 One Arctic charr 12
4 298 One Fourhorn sculpin
(dropped)
15
5 79 One Fourhorn sculpin 3
6 975 One Arctic charr Not recorded
Mean §SD 419 §364 17 §14
Polar Biol
123
It is likely that some polar bears supplement their diet
with charr and sculpin while fasting because streams and
rivers inhabited by these Wsh species occur in many areas
where polar bears are forced on land during the ice-free
period. Inuit people camping or hunting in areas occupied
by polar bears have reported observations of Wshing bears.
Until now, however, successful Wshing by polar bears has
not been reported for over 200 years.
The observed polar bear behaviour is quite diVerent from
what has been reported for Wshing brown bears. Brown
bears catch salmon usually at shallow streams (depth
< 0.5 m; Quinn and Kinnison 1999; Gende et al. 2001) by
running, plunging, or standing (Klinka and Reimchen
2002). Although this polar bear snorkeled and dove to prey
on Wshes, it is very likely that polar bears also catch Wsh
similar to brown bears if the river geomorphology allows it.
Immature polar bears are usually more inexperienced
and ineVective at catching prey than older bears (Stirling
and Latour 1978). However, young bears seem to learn
from older bears how to catch prey eVectively (Stirling
1974). We also believe this to be true for predatory behav-
iour on Wshes. Arctic charr are fast swimmers (several body
lengths per second; Adams et al. 1995), and are confronted
with strong water currents at the Union River estuary. Scul-
pin are benthic Wsh, and use rocks for shelter. The observed
polar bear had to dive in order to locate and catch charr and
sculpin. Additionally, it employed a speciWc skill set (i.e.,
combined snorkel and dive) and underwater agility (e.g.,
move rocks) to capture fast-swimming Wsh like charr, and
inconspicuous Wsh like sculpin. Whether the bear learned
these behaviours from his mother or other conspeciWcs
remains speculation.
Although we observed predatory behaviour toward
Wshes by only one subadult polar bear, we believe that this
behaviour may occur more often across much of the polar
bears’ range. Because of the low human presence in the
areas, over which polar bears range, we suggest that the
best way to collect this speciWc bear behaviour is to record
Inuit Qaujimajatuqangiit (Inuit traditional knowledge)
from people living on the land.
It is well-documented that salmon (Oncorhynchus spp.)
play important ecological roles, which include providing
high energy food sources for brown bears during fall to
accumulate necessary energy reserves needed for hiberna-
tion and cub production (Farley and Robbins 1995; Hilder-
brand et al. 1999, 2000). Until more conclusive food trials
with polar bears have been conducted, the energetic contri-
bution of charr (or other Wshes) to the summer energy bud-
get of polar bears remains speculative.
Acknowledgments Many thanks to the residents of Resolute Bay
and S. Akeeagok for sharing their knowledge about where polar bears
catch Wsh in Nunavut. We also appreciate support contributed by Polar
Continental Shelf Project (PCSP), Nunavut Arctic College, North-
winds, Leica Germany, and R. Romberg. Comments by K. Rhode and
3 anonymous reviewers were helpful to improve the quality of the
manuscript. This is PCSP ÉPCP contribution publication # 019-07.
This paper is dedicated to Atsuli, who was MGD’s loyal companion.
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