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No Danger in Sight? An Observation of Sperm Whales (Physeter macrocephalus) in Marguerite Formation off Muscat, Sultanate of Oman

Authors:
  • The MareCet Research Organization
Aquatic Mammals 2016, 42(2), 162-167, DOI 10.1578/AM.42.2.2016.162
Short Note
No Danger in Sight? An Observation of Sperm Whales
(Physeter macrocephalus) in Marguerite Formation
off Muscat, Sultanate of Oman
Louisa S. Ponnampalam1, 2, 3
1Environment Society of Oman, Suite 22, 1st Floor, Building 1197, Ajit Khimji Building, 2519 Darsait, Oman
2Institute of Ocean and Earth Sciences, University Malaya, 50603 Kuala Lumpur, Malaysia
3The MareCet Research Organization, 40460 Shah Alam, Malaysia
E-mail: louisa.ponnampalam@gmail.com
Whales have developed anti-predator strategies of Isla San Pedro Martir in the Gulf of California,
varying sophistication (Lima & Dill, 1990; Ford & Mexico, was made in April 2013. This was sup-
Reeves, 2008). An aspect of the complex behav-ported by photographs and also was reported
ioural ecology of sperm whales (Physeter macro-online (see https://www.expeditions.com/daily-
cephalus) includes the “marguerite” formation, expedition-reports/155632/baja-california).
first described by Nishiwaki (1962) and observed Herein, I report on the first confirmed sighting of
by whalers off Peru (Caldwell et al., 1966). The sperm whales from Oman engaging in marguerite
marguerite formation involves a group of whales and parallel formations, one that is in the absence
positioning themselves in a circle at the surface in of any visible predators.
a manner akin to the spokes of a wheel, with their
The sperm whale is one of 18 species of ceta-
heads together on the inside of the formation and
ceans known to occur in the deeper waters of
their tails radiating outwards (Nishiwaki, 1962;
the Sultanate of Oman (Alling, 1986; Gallagher,
Whitehead, 2002) or in reverse with their heads
1991; Baldwin, 1998; Ballance & Pitman, 1998;
facing outwards (Arnbom et al., 1987). A litera-
Ponnampalam, 2009; Minton et al., 2010). In the
ture review of this behaviour revealed that almost
Arabian Sea, the species was a target of Yankee
every documented observation of sperm whales
whaling fleets between 1850 and 1870 (Wray &
in marguerite and parallel flank-to-flank forma-
Martin, 1983; Smith et al., 2012) and illegal Soviet
tions was associated with the presence of cetacean
whaling fleets between 1963 and 1967 (Mikhalev,
predators, such as killer whales (Orcinus orca),
2000). Sperm whales were the most frequently
short-finned pilot whales (Globicephala macro-
sighted cetacean species during a survey in the
rhynchus), and false killer whales (Pseudorca
western tropical Indian Ocean in 1995, which
crassidens) (Smultea et al., 2008), and/or attacks
included the coast of Muscat, Oman (Ballance &
by these predatory species (Arnbom et al., 1987;
Pitman 1998). Boat-based surveys of cetaceans
Palacios & Mate, 1996; Weller et al., 1996; Pitman
along various parts of Oman’s coastline between
et al., 2001; Hucke-Gaete et al., 2004; Dunn &
2000 and 2006 yielded much lower encounter rates
Claridge, 2013).
of sperm whales (< 10 sightings) (Ponnampalam,
Sironi et al. (2008) reported two incidents of
2009; Minton et al., 2010).
southern right whales (Eubalaena australis) in On 31 May 2006, during line transect boat sur-
Argentina gathering in marguerite formation when veys for cetaceans south of Muscat, my team and
the groups came under attack by killer whales in I were contacted (0944 h) by a dolphin-watching
1972 and 1975. A video posted online showed a tour operator who had encountered a large group
group of sperm whales off southern Sri Lanka of sperm whales offshore (23° 39.725' N, 58°
clustering together in marguerite formation as they 41.574' E) of the village of Sidab, approximately
came under attack by a pod of killer whales in April 11.0 km east of Muscat and 5.7 km northeast of
2013 (Heinrichs, 2013; Gemmell et al., 2015) in where our research team was located. Our team
what appears to be the first documented account immediately proceeded towards the sighting loca-
of such for the Northern Indian Ocean region tion and, upon arrival (0957 h), found the group of
(Gemmell et al., 2015). A similar observation of sperm whales (possibly females and young adults,
an unsuccessful orca attack on sperm whales near judging from body sizes) mixed with bottlenose
163Muscat Sperm Whales
(Tursiops sp.) and Risso’s dolphins (Grampus We did not observe any agonistic behaviour
griseus), along with two dolphin-watching tour or startled reactions from the sperm whales. A
boats. Water depth was 499 m, weather conditions mother-calf sperm whale pair was seen during the
were calm and sunny, and the Beaufort sea state first hour of the sighting, surfacing several times
was 1 to 2. The estimated group sizes of the sperm at the periphery of the main group, with the calf
whales, bottlenose dolphins, and Risso’s dolphins remaining close to its mother (< 1 m distance) at
were 35, 75, and 200, respectively. The bottlenose all times. Approximately 25 min into the sighting,
and Risso’s dolphins were dispersed over approxi-the sperm whales dived, only to resurface 250 m
mately 0.25 km2, an area larger than the area the away less than 10 min later. Seventeen individ-
sperm whales were occupying. Approximately ual sperm whales formed a marguerite formation
10% of the Risso’s dolphins and 20% of the bot-upon surfacing, with the remainder of the group
tlenose dolphins appeared to be swimming near loosely scattered around them nearby. Two indi-
and among the sperm whales, with the remainder viduals were in the center of the formation, ori-
of both species 400 to 500 m away. No other ceta-ented vertically in the water column with their
cean species were observed. melons protruding from the surface (Figure 1).
At the start of the encounter, the sperm whales As our 10-m research vessel moved slowly
appeared to be logging; approximately 12 indi-towards the sperm whales, we saw a large cepha-
viduals were in a haphazard marguerite formation lopod tentacle sinking in the water that was not
with their heads facing inwards and tails radiating chased after by any of the dolphins or sperm
outwards. The other sperm whales were distrib-whales. By this time (1042 h), the tour boats had
uted singly, in pairs, or trios around the subgroup left the scene. The sperm whales did not appear
of 12 whales in formation. During this time, the to react to the presence of our vessel, which fol-
Risso’s and bottlenose dolphin groups as a whole lowed at idle speed. At one point while the sperm
did not appear to be traveling in any specific direc-whales were still in marguerite formation, the
tion, and those near the sperm whales appeared to engines of the vessel were turned off, and the
be milling. A small number of Risso’s dolphins vessel slowly drifted to within 30 m of the sub-
were observed engaging in tail-up/head-standing group in formation. I entered the water briefly
behaviour (see Minton et al., 2010; Bearzi et al., (~5 min) to observe the sperm whales under
2011) and waving their flukes in a slow side-to- water, staying approximately 7 m away. I heard
side motion above the sea surface. Individual clicks (coda) that I attributed to the sperm whales.
bottlenose dolphins that were swimming further Ten minutes later, the sperm whales dived again,
away from the sperm whales were observed to resurfacing 16 min later approximately 400 m
occasionally leap. away in a marguerite formation but without
Figure 1. The sperm whales (Physeter macrocephalus) in marguerite formation, where two individuals in the center are
oriented vertically in the water with their bulbous heads protruding from the surface
164 Ponnampalam
any vertically oriented individuals in the center
(Figure 2). The research vessel moved towards
the sperm whales and stopped approximately
250 m away from the group. At this time, only
a few Risso’s and bottlenose dolphins remained
near the sperm whales and appeared to be mill-
ing, while the remainder of both species’ groups
were highly dispersed (> 0.25 km2) in the general
vicinity and became difficult to track. The tail-up/
head-standing behaviour seen previously in some
Risso’s dolphins had ceased.
The sperm whales logged in marguerite for-
mation for approximately 28 min after their last
surfacing before the formation started changing
shape. The sperm whales then sank below the
water’s surface for 1 min before resurfacing in
two haphazard rows, their bodies parallel to each
other (< 2 m apart) and facing in the same direc-
tion. In slow motion, the sperm whales aligned
themselves in a straight row parallel to each other
within 90 s and logged at the surface for another
3 min (Figure 3). Subsequently, the sperm whales
dove with their flukes up, one by one in a “domino
effect” manner—that is, the animal on the farthest
left of the parallel formation dove first, followed
by the next animal to the right, and then the next,
and so on, until all the whales had dived at 1307 h.
The last dive was completed 4 km northeast from
where the animals were first sighted over 3 h ear-
lier. The Risso’s and bottlenose dolphins that were
still present in the area appeared to cluster and con-
tinued milling. Our team remained in the vicinity
(23° 41.376' N, 58° 43.096' E) for another 45 min,
but the sperm whales were not sighted again.
Most observations of marguerite and paral-
lel formations in sperm whales were linked to
predator presence or attacks (Caldwell et al., 1966;
Arnbom et al., 1987; Visser, 1999; Pitman et al.,
2001; Hucke-Gaete et al., 2004; Dunn & Claridge,
2013) and whaling (Nishiwaki, 1962; Caldwell
et al., 1966). However, during this encounter, these
defense-oriented formations did not appear to be
in response to a particular threat. Surveys of ceta-
cean distribution in Omani waters since 2000 have
yielded many more sightings of sperm whales
than killer whales (Ponnampalam, 2009; Minton
et al., 2010), consistent with the general notion
that killer whales are less common in lower lati-
tudes (Dahlheim & Heyning, 1999). Additionally,
surveys in Oman have not yielded any records of
false killer whale groups mixed with sperm whales
(Baldwin, 1998; Ponnampalam, 2009; Minton
et al., 2010).
Previous surveys in Oman have recorded several
mixed species groups of bottlenose and Risso’s
dolphins (Minton et al., 2010) and bottlenose dol-
phins and sperm whales (Ponnampalam, 2009).
Still, the sighting reported herein represents only
the second record of a mixed species group con-
taining bottlenose and Risso’s dolphins with sperm
whales, the first of which was observed in 1996
(Baldwin, 1998). While there are reports of ago-
nistic behaviours towards sperm whales by Risso’s
dolphins (Pereira, 2008; Smultea et al., 2014) in
which the latter species is possibly displaying
kleptoparasitism (i.e., forcing the sperm whales
to regurgitate their food so that the dolphins can
feed on it [Palacios & Mate, 1996]), the Risso’s
dolphins seen with the sperm whales reported
herein did not display any aggression towards the
sperm whales at the surface. However, it is pos-
sible that such aggression might have occurred and
Figure 2. Sperm whales in marguerite formation, with their heads pointing inwards towards the center and tails radiating
outwards
165
then subsided prior to the arrival of our research
team (see Bacon & Johnson, 2012). Other signs
of distress or excitement associated with observa-
tions of the marguerite formation, such as defeca-
tion (Clarke, 1956; Caldwell et al., 1966; Palacios
& Mate, 1996; Pereira, 2008; Hooper, 2015) and
agitated behaviour (Nishiwaki, 1962; Palacios &
Mate, 1996; Pitman et al., 2001; Pereira, 2008;
Dunn & Claridge, 2013; Smultea et al., 2014;
Gemmell et al., 2015), were not seen during this
encounter.
Sperm whales observed in marguerite forma-
tion off Sri Lanka prior to the incident reported
by Gemmell et al. (2015) seemed to be socialis-
ing (Gordon, 1987). Similarly, there have been
frequent reports and observations of sperm
whales off northwestern and eastern Sri Lanka
logging in parallel formation in the absence of
other species and threats, leading the observers
to believe that the sperm whales were engag-
ing in social behaviour (A. D. Ilangakoon, pers.
comm., 9 September 2014). Sperm whales stud-
ied around the Galápagos Islands were reported
to have “social times” in which the whales spent
1 to 8 h clustering in a compact mass at the sur-
face and were less active (Whitehead, 1987).
Figure 3. The sperm whale group (a) closing ranks and (b) in parallel formation towards the end of the sighting
Muscat Sperm Whales
166 Ponnampalam
A sighting of parallel logging sperm whales off
Muscat in 2012 captured on video and posted
online (https://vimeo.com/61702468) showed that
the animals could have been engaging in similar
behaviour after a bout of feeding. Sperm whales
also have been reported to be skittish (Whitehead,
2003) and may display mild reactions to aircraft
and vessel presence (Pitman et al., 2001; Smultea
et al., 2008). The presence of other species such
as bottlenose dolphins might also cause sperm
whales to dive when approached (R. L. Pitman,
pers. comm., 12 December 2013). While there
appeared to be no obvious threat detected during
the encounter off Muscat, diving and congregat-
ing in marguerite and parallel formations may
have been responses to the presence of the boats
or the underwater behaviour of the Risso’s and
bottlenose dolphins not visible to our research
team. Separately, in southern Sri Lanka, there was
an account of a large group of false killer whales
that were hunting when first encountered. Twenty-
five minutes into observing the false killer whales,
a subgroup of 13 animals suddenly went into a
marguerite formation for a few minutes before
synchronously diving with their flukes up. The
animals repeated this behaviour once, resurfaced
minutes later, and resumed hunting. The observers
who witnessed this sighting reported no apparent
predator threat or other danger at the time, and the
observed behaviour remains unexplained (A. D.
Ilangakoon, pers. comm., 9 September 2014).
Much remains unknown about sperm whales in
Omani waters, although the observations reported
herein provide an insight into the species’ behav-
iour in the Sea of Oman region and could form the
basis of future efforts in sperm whale ethological
research. The behaviours reported herein appear
to be a rarity for Oman and even for the northern
Indian Ocean region (except in Sri Lanka where
parallel formations are reportedly seen regularly).
The apparent scarcity in such observations, how-
ever, may also be due to less survey effort in off-
shore areas where sperm whales are found more
frequently (see Ballance & Pitman, 1998) or to
less killer whale presence in the lower latitudes
(Dahlheim & Heyning, 1999; Forney & Wade,
2006).
Acknowledgments
We would like to thank the Oman Ministry of
Environment and Climate Affairs for relevant
permits to conduct cetacean research and the
Environment Society of Oman (www.eso.org.om)
for its support of cetacean research in Oman. Thank
you to Shell Marketing Oman for its in-kind sup-
port that made surveys possible. Thank you also
to Rebecca Lovegrove, Victoria Hill, and Rebekah
Oxley who volunteered their time and efforts on
the boat during the survey. Appreciation goes to
Dr. Robert Pitman, Anoukchika Ilangakoon, and
Tim Collins for reviewing and improving an ear-
lier version of this manuscript.
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This thorough revision of the classic first edition brings this authoritative book right up-to-date. Articles describe every species in detail, based on the very latest taxonomy, and a host of biological, ecological and sociological aspects relating to marine mammals. The latest information on the biology, ecology, anatomy, behavior and interactions with man is provided by a cast of expert authors - all presented in such detail and clarity to support both marine mammal specialists and the serious naturalist. Fully referenced throughout and with a fresh selection of the best color photographs available, the long-awaited 2nd edition remains at the forefront as the go-to reference on marine mammals. * More than 20% NEW MATERIAL includes articles on Climate Change, Pacific White-sided Dolphins, Sociobiology, Habitat Use, Feeding Morphology and more * Over 260 articles on the individual species with topics ranging from anatomy and behavior, to conservation, exploitation and the impact of global climate change on marine mammals * New color illustrations show every species and document topical articles FROM THE FIRST EDITION "This book is so good... a bargain, full of riches...packed with fascinating up to date information. I recommend it unreservedly it to individuals, students, and researchers, as well as libraries". - Richard M. Laws, MARINE MAMMALS SCIENCE "...establishes a solid and satisfying foundation for current study and future exploration" - Ronald J. Shusterman, SCIENCE.