Land-based observations of cetaceans and a review of recent strandings at subantarctic Macquarie Island

Abstract

The occurrence of cetaceans around subantarctic Macquarie Island is poorly known. The current study provides the first quantitative assessment of the occurrence of various cetacean species in inshore waters during 391 systematic, one-hour observation periods over 59 weeks, in 2002 and 2003. Nine species of cetacean were identified during these surveys. Killer whales, long-finned pilot whales and sperm whales were all detected with some frequency. All other species were detected on single occasions. Eight previously unpublished stranding records are also summarised. These results support the notion that most cetacean species are relatively uncommon in the inshore waters of Macquarie Island. Routine archiving of cetacean sightings obtained during shipping activities in surrounding waters is encouraged as this will further contribute to our understanding of the region’s marine megafauna.

Full text

Land-based observations of cetaceans and a review of recent
strandings at subantarctic Macquarie Island
Rohan H. Clarke
A,D
, Rosemary Gales
B
and Martin Schulz
C
A
School of Biological Sciences, Monash University, Clayton, Vic. 3800, Australia.
B
Biodiversity Monitoring Section, Department of Primary Industries, Parks, Water and Environment,
Box 44, Hobart, Tas. 7001, Australia.
C
34 Wilford Street, Corrimal, NSW 2518, Australia.
D
Corresponding author. Email: rohan.clarke@monash.edu
Abstract. The occurrence of cetaceans around subantarctic Macquarie Island is poorly known. The current study provides
the first quantitative assessment of the occurrence of various cetacean species in inshore waters during 391 systematic, one-
hour observation periods over 59 weeks, in 2002 and 2003. Nine species of cetacean were identified during these surveys.
Killer whales, long-finned pilot whales and sperm whales were all detected with some frequency. All other species were
detected on single occasions. Eight previously unpublished stranding records are also summarised. These results support the
notion that most cetacean species are relatively uncommon in the inshore waters of Macquarie Island. Routine archiving of
cetacean sightings obtained during shipping activities in surrounding waters is encouraged as this will further contribute to
our understanding of the region’s marine megafauna.
Additional keywords: beaked whale, killer whale, long-finned pilot whale, seasonal patterns, spectacled porpoise,
strandings, underestimate.
Received 26 February 2016, accepted 25 October 2016, published online 3 January 2017
Introduction
Macquarie Island (54400S, 158490E) is the most southerly of the
subantarctic islands in the Pacific sector of the Southern Ocean
and is situated just to the north of the Antarctic Convergence in the
Polar Frontal Zone. Macquarie Island is Australian territory, and
the island and surrounding waters to a distance of 3 nautical miles
are administered by the state of Tasmania. The island lacks a well
developed continental shelf, with the minimum distance to the
1000-m isobath being only 1.3 nautical miles off the shoreline.
The monthly mean sea temperatures around Macquarie Island
range from 4.3C in July to 6.8C in January (Environment
Australia 2001). Prior to this study, records of cetacean species
occurring in the region were largely based on beachcast
individuals. These strandings are infrequent, with a total of 32
strandings documented since the mid-1950s, comprising 12
species, in addition to approximately six unidentified beaked
whales and five unidentified baleen whales, some of which
involve old skeletal remains (Copson 1994; Department of
Primary Industries, Parks, Water and Environment (DPIPWE)
cetacean stranding database). There have been relatively few
contemporary sightings of cetacean species in waters around the
island, consistent with a reported absence of large whales shortly
after the island’s initial discovery in 1810 (Raine 1824; Copson
1994; Environment Australia 2001). The one notable exception to
this is the high number of killer whale (Orcinus orca) sightings,
predominantly in the spring and summer months (Copson 1994;
Morrice and van den Hoff 1999).
The objectives of the present study were to systematically
survey for cetaceans within inshore waters surrounding
Macquarie Island using daily land-based seawatches over an
entire annual cycle and, in doing so, to provide some insight
into the seasonal occurrence of cetaceans in these waters.
Additionally, we also sought to provide an update to the list of
stranded cetaceans since those reported by Copson (1994).
Methods
In total, 391 hour-long seawatches for cetaceans were conducted
in conjunction with searches for seabirds (reported in Clarke and
Schulz 2005) from various headlands around the island during a
59-week period from 25 October 2002 to 5 December 2003
(Fig. 1). On average, 29.2 h of surveys were conducted across
25 days each month (range: 11–29 days, complete months only;
a monthly breakdown is provided in Clarke and Schulz 2005).
RHC and MS were responsible for all surveys. The timing and
location of seawatches were dictated by primary work schedules,
with each observation period undertaken by a single experienced
observer positioned on an elevated headland (>15 m above sea
level), scanning continuously with a 20telescope for cetaceans,
up to ~3 km offshore. RHC (n= 140 h of survey in the present
study) has logged more than 400 days at sea conducting seabird
Journal compilation  Australian Mammal Society 2017www.publish.csiro.au/journals/am
CSIRO PUBLISHING
Australian Mammalogy Research Note
http://dx.doi.org/10.1071/AM16007

and marine mammal surveys since 1995, and MS (n= 237 h of
survey) has logged more than 200 days at sea since 1990.
Observations were undertaken in all weather conditions, except
when visibility was less than 500 m due to sea fog or persistent
rain, sleet or snow, or when gale/storm-force onshore winds made
viewing through the scope difficult. Seawatches were divided into
three categories of viewing conditions following Parker (1978):
(a) good viewing conditions (Beaufort Scale 0–4) with winds of
<15 kn, calm to slight seas and visibility greater than 1 km, which
comprised 17% of viewing times (n= 65); (b) moderate viewing
conditions (Beaufort Scale 5–6) with wind speeds between 15 and
25 kn with choppy seas, which comprised 52% (n= 197) of
viewing times; and (c) poor viewing conditions comprising either
a Beaufort Scale 7 or above with wind speeds over 25 kn and
rough seas with spray affecting visibility or visibility less than
1 km due to fog or low offshore clouds, which in total comprised
115 seawatches (31% of total seawatches). Good and moderate
viewing conditions (Beaufort 5 or less) enabled the location of
cetaceans 2–3 km offshore, while in poor viewing conditions
cetaceans could be seen only when close to the shore. All
observations were logged directly to a datasheet.
Results
Cetaceans were observed during 26% (102 of 391) of seawatches
throughout the 59-week period, with the majority of detections
158°48'0''E
158°56'33''E
Green Gorge
See inset
North Head
Hurd Point
00.5
02.5 510
<10 hours
10 – 25 hours
25 – 50 hours
50 + hours
km
N
km
1
54°29'42''S
159°60'0''E
158°48'0''E
54°45'0''S 54°36'0''S
54°45'0''S 54°36'0''S
159°60'0''E
Fig. 1. Macquarie Island, showing cetacean observer effort (in hours) for each observation point.
The main map delineates 100-m and 300-m contours. The inset map delineates North Head with
50-m and 100-m contours.
BAustralian Mammalogy R. H. Clarke et al.

(52% of total sightings) occurring under moderate viewing
conditions. A summary of all cetacean sightings obtained during
seawatches is presented in Table 1. The killer whale was the most
frequently observed species (83 sightings; 22% of seawatches).
The species was observed in all months of the year but most
often in December (61% of December seawatches), September
(43% of September seawatches) and June (33% of June
seawatches), and least often in October and November (13% of
October and November seawatches). The winter period between
May and August accounted for 30% of the total seawatches in
which this species was recorded. All sightings of killer whales
occurred within ~1 km of the shore. Adult females accompanied
by calves were observed in February, June, July, September,
October and November. One distinctively marked male
(triangular notch on the posterior edge of the dorsal fin) was
observed on four occasions between 9 May and 5 July 2003 and a
second male (rounded collapsed tip to the dorsal fin) was seen
on two occasions in September. Several killer whale feeding
events were observed, with single or multiple individuals
foraging on mostly unknown prey. When close inshore, killer
whales were observed to prey upon southern elephant seal
(Mirounga leonina), royal penguin (Eudyptes schlegeli), gentoo
penguin (Pygoscelis papua) and king penguin (Aptenodytes
patagonicus). These events, especially when they involved
elephant seals, were usually signified by congregations of
seabirds largely comprising giant-petrels (Macronectes spp.).
The second most frequently observed cetacean was the long-
finned pilot whale (Globicephala melas), which was observed
during 22 seawatches. Most sightings were in February (n= 6),
March (n= 5) and September (n= 4), with a small number of
sightings in May, June, July, August and December. The largest
group observed was of ~200 individuals in December 2002.
The mean estimated group size observed was 32 (s.e. = 2.4),
ranging from 10 to 60 individuals (all seawatches combined,
excluding the group of 200 individuals). All sightings were of
individuals >1 km offshore, with some pods, particularly in the
winter months, attracting numbers of cape petrels (Daption
capense). Juveniles accompanying adults were observed in
February, May, July and August.
The only great whale that was observed regularly was the
sperm whale (Physeter macrocephalus). It was seen during 11
seawatches, with sightings in January (n= 3), February, April
(n= 3), May, June, July and October. All observations were of
individuals >1 km offshore, with most being of single animals.
The only pod observed was of four individuals on 31 January
2003, with an incidental observation of a pod of five in late
December 2002. A single southern right whale (Eubalaena
australis) was observed once in August 2003. Other large baleen
whales were observed on four occasions in 2003 (Table 1).
Incidental observations of two species of baleen whales not
detected during the seawatches were made during the study
period: a subadult humpback whale (Megaptera novaeangliae)
surfaced near zodiacs in November 2002 and a single minke
whale (Balaenoptera sp.) was observed in December 2002
(Table 1).
No beaked whales were observed during the seawatches.
However, on 22 October 2002 an incidental observation of
Arnoux’s beaked whale (Berardius arnuxii) was made just 150 m
off the shoreline. Identification was based on its large size
(8–10 m total length), prominent forehead melon, dark leaden
grey colouration on the back and head with no white patches or
scarring evident and a prominent dorsal fin. A second incidental
sighting of an unidentified beaked whale was made on 29
December 2002 when the animal was ~1 km offshore on the east
coast.
Small dolphins and porpoises were rarely located during the
seawatches, being sighted just three times in total (Table 1). A pod
of at least 80 southern right-whale dolphins (Lissodelphis
peronii), including juveniles, was observed heading south >2km
offshore in February 2003 in association with a pod of ~40 pilot
whales. A pod of ~5 spectacled porpoise (Phocoena dioptrica)
was observed in September 2003. The third sighting involved
two dolphins less than 2 m long that were briefly observed during
heavy seas in January 2003. These animals may have been
hourglass dolphins (Lagenorhynchus cruciger), as they were
small (estimated total length <2 m), with blackish and distinctly
falcate dorsal fins.
Since Copson (1994) there have been eight further cetacean
strandings reported from Macquarie Island. These comprised
single representatives of southern right whale, humpback whale,
sperm whale, Arnoux’s beaked whale, strap-toothed beaked
whale (Mesoplodon layardii), hourglass dolphin and spectacled
porpoise. An unidentified beaked whale was also reported
stranded (Table 1).
Discussion
This study supports the contention that most cetacean species are
relatively uncommon in the inshore waters around Macquarie
Island (Copson 1994). Although nine species were observed from
shore between October 2002 and December 2003, six of these
species involved one-off sightings during this relatively intense
period of surveillance. Stranding records are similarly sparse,
with just seven documented strandings of individual cetaceans
since the publication of Copson (1994) through until September
2016. This is a relatively low reporting rate given that the island
has been permanently occupied throughout this period and
biologists, who are highly likely to report such events, are a
significant component of the island workforce.
It is possible that sightings from shore in the current study are
an underestimate of cetacean occurrence as less than favourable
weather and sea conditions may prevent the detection of some
cetaceans. The shoreline of Macquarie Island also does not
appear to be conducive to cetacean strandings, as all strandings to
date have been represented by single animals and no cow–calf
or mass strandings have been documented (Copson 1994;
Bannister et al.1996; DPIPWE cetacean stranding database).
Under-recording is likely to be further exacerbated for species
such as beaked whales and the spectacled porpoise, as they are
typically difficult to detect due to small group size, lack of a visible
blow and the short periods spent at the surface.
Just three species were shown to be relatively common; killer
whale, long-finned pilot whale and sperm whale. For the killer
whale the paucity of sightings in October and November and the
high frequency of sightings in June and September differs from
the previously reported pattern where most sightings were
reported between October and December, with few sightings
between March and September (Copson 1994; Morrice and van
Cetaceans, Macquarie Island Australian Mammalogy C

Table 1. Summary of all cetacean observations made during active seawatches between October 2002 and December 2003 from various headlands
of Macquarie Island, Southern Ocean
Records documented in Copson (1994) and all subsequent strandings (to September 2016) obtained from the Atlas of Living Australia and the DPIPWE
cetacean stranding database are also included
Common name Latin name Seawatches 2002–03 (this study) Records from Copson (1994) Additional records of strandings
Southern right whale Eubalaena australis One 300 m offshore, August 2003. Two animals, September 1976 and
one, June 1978. One animal
stranded, March 1977.
One stranded, August 2002
(DPIPWE cetacean stranding
database).
Minke whale sp. Balaenoptera sp. Incidental sighting of one,
December 2002, off South West
Point.
A pod of unspecified size observed
in Buckles Bay, November
1989.
Humpback whale Megaptera
novaeangliae
Incidental sighting of one,
November 2002, off Green
Gorge.
One stranded, November 2011
(DPIPWE cetacean stranding
database).
Sperm whale Physeter
macrocephalus
Single individuals on 11 occasions
during: December 2002;
January, February, April–July
and October 2003. One sighting
of a pod of four, January 2003.
Incidental pod of five,
December 2002. All
observations >1 km offshore.
Four sightings between 1968 and
1990: one pod of five January
1978, two adults 1 km out from
Sandy Bay heading north,
February 1985, one 1 km out
from Green Gorge, January
1987, and one off Secluded Bay,
December 1989. Partial remains
found ashore in Hasselborough
Bay, June 1989.
One animal stranded, June 2000
(DPIPWE cetacean stranding
database).
Baleen whale sp. Four sightings of single baleen
whales, January, February, May
and August 2003 and a pod of
three in May 2003. On the basis
of visible features, these
sightings were attributed to
either the fin whale
(Balaenoptera physalis) or sei
whale (B. borealis).
A pod of 2–4 large baleen whales in
Buckles Bay heading south,
October 1988. One baleen
whale off North Head heading
south, December 1988. One
baleen whale off Mt Martin,
January 1989 heading south.
One very large whale ~300 m
offshore from Gadget Gully,
August 1989. Old skeletal
remains of baleen whales were
also located at Langdon Point
dated back to at least 1974 and in
Sandell Bay, February 1986.
Arnoux’s beaked
whale
Berardius arnuxii Incidental sighting of one, October
2002, ~150 m off beach in
Buckles Bay.
One stranded, January 2000
(DPIPWE cetacean stranding
database).
Andrew’s beaked
whale
Mesoplodon bowdoini Specimen collected from
Hasselborough Bay, May 1966
(DPIPWE cetacean stranding
database).
Blainville’s beaked
whale
Mesoplodon
densirostris
Specimen collected from
Hasselborough Bay, July 1965
(Atlas of Living Australian
Database; Bannister et al.1996).
Strap-toothed beaked
whale
Mesoplodon layardii Parts of a skull and vertebrae found
on west coast, January 1986.
Four strandings recorded for the
island (DPIPWE cetacean
stranding database).
Cuvier’s beaked whale Ziphius cavirostris Part of a skull found in Sandell
Bay, 1975.
Three strandings recorded for the
island (DPIPWE cetacean
stranding database).
Beaked whale sp. An incidental sighting of an
unidentified beaked whale
travelling south ~1 km from
shore, December 2002.
A stranded beaked whale
tentatively identified as a
southern bottle-nosed whale,
November 1970. Possible
Arnoux’s beaked whale and
ziphid strandings are also
referenced in Copson (1994).
An unidentified beaked whale
stranded, July 2008 (DPIPWE
cetacean stranding database).
DAustralian Mammalogy R. H. Clarke et al.

den Hoff 1999). Pitman and Ensor (2003) have suggested that the
killer whales visiting Macquarie Island are of the Type A ecotype,
which move from Antarctic waters to lower latitude areas such as
New Zealand in the winter months (Kasamatsu and Joyce 1995).
Previously recognised seasonal patterns in abundance are similar
to those reported around Marion Island and have been attributed
to the timing of the annual breeding cycle of southern elephant
seals, with pregnant females hauling out in September and most
pups being born in November (Condy et al.1978). The larger
summer researcher workforce (typically October to March) and
the much shorter daylengths through winter may have led to some
seasonal bias in past records of killer whales at Macquarie Island.
By contrast, here we undertook near daily hour-long scans for
cetaceans for a ~13-month period to reveal year-round presence
by the species and a relatively high frequency of sightings in the
winter months. Observations of group size, the occurrence of
calves and prey types add to our growing understanding of killer
whale ecology in the waters surrounding Macquarie Island.
Pilot whales were the second most common cetacean species
recorded in this study. We believe all sightings are referable to
the long-finned pilot whale as the short-finned pilot whale
(G. macrorhynchus) is typically a more tropical species. For
example there are just two stranding records of the latter species
in waters around Tasmania ~1500 km to the north (cf. >81
strandings of long-finned pilot whales) (DPIPWE cetacean
stranding database). This also accords with previous records at
Macquarie Island where all three documented pilot whale
strandings involved long-finned pilot whales (Copson 1994).
The proximity of the shoreline to deep (>1000 m) waters
surrounding Macquarie Island may explain the diversity of
beaked whales recorded to date. Several beaked whale species
have been recorded washed ashore on Macquarie Island,
including Arnoux’s beaked whale, Andrew’s beaked whale
(Mesoplodon bowdoini), Blainville’s beaked whale
(M. densirostris), strap-toothed whale and Cuvier’s beaked
whale (Ziphius cavirostris) (Copson 1994; Bannister et al.1996;
DPIPWE cetacean stranding database). Additionally, six
unidentified beaked whales have been recorded, including an
unconfirmed Arnoux’s beaked whale and a possible southern
bottle-nosed whale (Hyperoodon planifrons) (Copson 1994;
DPIPWE cetacean stranding database) (Table 1). Two sightings
of apparently healthy beaked whales in inshore waters during this
Table 1. (continued )
Common name Latin name Seawatches 2002–03 (this study) Records from Copson (1994) Additional records of strandings
Long-finned pilot
whale
Globicephala melas Second most frequently observed
cetacean, with 22 sightings.
Mean group size 32 (range
10–60 individuals, excluding a
pod of 200, December 2002. All
sightings >1 km offshore.
Two sightings of long-finned pilot
whale between 1968 and 1990: a
pod of 10 in Buckles Bay, June
1977 and a pod of ~15 off
Buckles Bay, March 1984.
Strandings of single animals
June 1968, April 1976 and
November 1984.
Southern right-whale
dolphin
Lissodelphis peronii One pod of 80 animals including
juveniles, February 2003, >2km
offshore.
Hourglass dolphin Lagenorhynchus
cruciger
See ‘Dolphin sp.’. One stranded, March 2012
(DPIPWE cetacean stranding
database).
Killer whale Orcinus orca Most frequently observed
cetacean, with 83 sightings
involving 251 animals,
accounting for 22% of total
seawatches. Mean group size of
3.0 (s.e. = 0.4, range = 1–10).
Most frequently observed
cetacean, with 120 sightings
involving ~400 animals
between 1968 and 1990.
Detected year-round with peak
occurrence in the spring/
summer period. Most common
pod size 2–5 (65% of sightings),
with sightings involving
between 1 and ~20 animals.
Single carcasses found ashore,
June 1968, September 1973,
April 1976 and March 1986.
Spectacled porpoise Phocoena dioptrica One pod of ~5 animals, September
2003, off Hurd Point.
Damaged skull found in Aerial
Cove, July 1957 (also Fordyce
et al.1984).
One stranded, July 2003 (this
study).
Dolphin sp. One sighting of two animals (<2m
long) observed in heavy seas,
January 2003. Possibly
hourglass dolphins due to small
size and distinct blackish falcate
dorsal fins.
Three dolphins sighted from
ANARE resupply ship 15–20
nautical miles north-west of
North Head, November 1989.
Cetaceans, Macquarie Island Australian Mammalogy E

study add further weight to the notion that the proximity of
suitable deep-water habitats adjacent to the island has some
influence on reporting rates for what are otherwise rarely reported
species (e.g. Bannister et al.1996).
Given the paucity of recorded cetaceans and the propensity for
one-off sightings of different species during the course of this
study, a more detailed understanding of the cetacean diversity in
waters surrounding Macquarie Island would be valuable. This is
especially so for pelagic waters beyond the normal viewing range
of the shore-based observer. In this context, it is recommended
that observations and associated images of all cetaceans made
from supply ships, tourist vessels and demersal fishing trawlers
in waters surrounding Macquarie Island be sent to and stored
in a centralised database to provide a clearer understanding of
cetaceans frequenting these waters.
Acknowledgements
We thank John Lynn for supporting the study and providing time for MS
within the works program to enable daily surveys; Peter Cusick for providing
the support to enable MS to overwinter; Simon Goldsworthy for providing
the support to enable RHC to oversummer on the island; Parks and Wildlife
Service, DPIPWE Princess Melikoff Marine Mammal Conservation Program
staff, particularly Rachael Alderman and Kris Carlyon; Paul Ensor for
confirming the identity of the stranded spectacled porpoise; and Australian
Antarctic Division staff for documenting and verifying incidental cetacean
strandings and sightings over the years.
References
Bannister, J. L., Kemper, C. M., and Warneke, R. M. (1996). ‘The Action Plan
for Australian Cetaceans.’(Australian Nature Conservation Agency:
Canberra.)
Clarke, R. H., and Schulz, M. (2005). Land-based observations of seabirds
off sub-antarctic Macquarie Island during 2002 and 2003. Marine
Ornithology 33,7–17.
Condy, P. R., van Aarde, R. J., and Bester, M. N. (1978). The seasonal
occurrence of and behaviour of killer whales Orcinus orca, at Marion
Island. Journal of Zoology 184, 449–464. doi:10.1111/j.1469-7998.1978.
tb03301.x
Copson, G. R. (1994). Cetacean sightings and strandings at subantarctic
Macquarie Island, 1968 to 1990. ANARE Research Notes No. 91.
Antarctic Division, Kingston, Tasmania.
Environment Australia (2001). Macquarie Island Marine Park Management
Plan, 2001. Environment Australia, Canberra.
Fordyce, R. E., Matlin, R. H., and Dixon, J. M. (1984). Second record of
spectacled porpoise from subantarctic south-west Pacific. Report of the
International Whaling Commission 30, 445–450.
Kasamatsu, F., and Joyce, G. G. (1995). Current status of Odontocetes in
the Antarctic. Antarctic Science 7, 365–379. doi:10.1017/S095410209
5000514
Morrice, M. G., and van den Hoff, J. (1999). Preliminary investigations of
killer whales (Orcinus orca) from inshore waters around sub-Antarctic
Macquarie Island. Poster presentation for the 13th Biennial Conference
on Marine Mammals, Hawaii.
Parker, D. A. A. (1978). Observations of whales on ANARE voyages
between Australia and Antarctica. Australian Wildlife Research 5,
25–39. doi:10.1071/WR9780025
Pitman, R. L., and Ensor, P. (2003). Three forms of killer whale (Orcinus
orca) in Antarctic waters. The Journal of Cetacean Research and
Management 5, 131–139.
Raine, T. (1824). Notice in regard to Macquarie Island. Edinburgh Philosophy
Journal 11,46–50.
FAustralian Mammalogy R. H. Clarke et al.
www.publish.csiro.au/journals/am