Peponocephala electra (Gray,
English: Melon-headed whale
Spanish: Calderón pequeño
Peponocephala electra © Wurtz-Artescienza (see
The melon-headed whale is mostly dark grey, with a faint darker
grey cape that narrows at the head. A faint light band extends from
the blowhole to the apex of the melon. A distinct dark eye patch,
broadening as it extends from the eye to the melon, is often present.
The lips are often white, and white or light grey areas are common
in the throat region and urogenital region. At sea, the melon-headed
whale is difficult to distinguish from the pigmy killer whale (Feresa
attenuata), but it has a more pointed head and sharply pointed
pectoral fins. The largest female was 2.78 m long and the largest
male 2,64 m, weighing 228 kg (Perryman, 2009).
Melon-headed whales have a pantropical distribution. They range
north to the Gulf of Mexico, Senegal, Arabian Sea, Bay of Bengal,
South China Sea, Taiwan, southern Honshu, Hawaiian Islands, and
Baja California Sur; and south to Espiritu Santo in Brazil, Timor
Sea, northern New South Wales, and Peru (Rice, 1998).
Distribution of Peponocephala electra: tropical
and subtropical offshore waters around the '
world (Taylor et al. 2008; © IUCN; enlarge
Specimens from southern Japan, Cornwall in England,
Cape Province in South Africa, and Maryland, USA are probably from
the extremes of the normal distribution for this species and likely
came from populations in adjacent warm currents (Perryman et al.
1994; Rice, 1998).
3. Population size
The most recent abundance estimate for melon-headed whales is for
the northern Gulf of Mexico. Data from line-transect surveys were
pooled from 2003 to 2004, and yielded and estimate of 2,283 (CV=0.76)
animals (Mullin 2007). This value is not statistically different
from the 1996-2001 estimate of 3,451 (CV=0.55) for the same region
(Waring et al. 2008). In the US EEZ around Hawaii, the 2002 estimate
is 2,947 animals (CV = 111%) (Barlow 2006).
In the Philippine region, Dolar et al. (2006) reported 921 (CV=0,83)
in the eastern Zulu Sea, as opposed to an earlier estimate of 1,200
(Dolar, 1999). They estimated 1,383 in Tañon Strait between
Cebu and Negros Islands (Dolar et al. 2006).
For the eastern tropical Pacific the most recent population estimate
is 45,000 (CV = 0.47) individuals (Wade and Gerrodette, 1993). They
are frequently seen in waters around the Hawaiian Islands, in the
Tuamotus-Marquesas Islands, along the east coast of Australia, and
in the oceanic, equatorial Pacific. The lack of reports on this
species from many other areas may reflect a preference for offshore
habitats where survey effort is generally lowest (Perryman et al.
1994 and refs. therein).
For the Indian Ocean, there are only a few accounts: Kiszka et al.
(2007) reported observing 5 melon-headed whales off Mayotte, Comoros
Arquipelago in 2004-2005 during 284 hours at sea. Anderson (2005)
observed cetaceans in Maldivian waters between 1990 and 2002 and
found melon-headed whales to be particularly common in the south
of the Maldivesbut rare in the centre and north.
During a dedicated survey of the cetacean population of the Marquesas
Islands in French Polynesia, covering 2,255 km in 1998-99, 14 melon-headed
whales were identified at sea. During a total effective effort of
6,482 km conducted off the Society Islands (French Polynesia) between
1996-1999, melon-headed whales were also observed, but less frequently
(Gannier, 2000, 2002).
4. Biology and Behaviour
Habitat: Most sightings are from the continental shelf seaward
and around oceanic islands. They are rarely found in temperate waters
(Carwardine, 1995). In the eastern tropical Pacific, the distribution
of reported sightings suggests that the oceanic habitat of this
species is primarily in the upwelling modified and equatorial waters
(Perryman et al. 1994). When they are observed near the coast, it
is generally in areas where deep oceanic waters occur nearby (Perryman,
Behaviour: The animals make low, shallow leaps out of the
water when travelling fast, often creating a lot of spray as they
surface and making it difficult to see any detail. Slow swimmers
may lift the head right out of water on surfacing. They are usually
wary of boats, but many observations are in areas where tuna boats
regularly chase dolphins, so their behaviour may differ elsewhere.
They are known to bow-ride for short periods, and breaching has
occasionally been recorded. Sometimes they spyhop (Carwardine, 1995;
Perryman et al. 1994).
Schooling: Melon-headed whales are highly social and more
likely to be seen in large pods than the pygmy killer whale. They
occur usually in pods of 100 to 500 (with a known maximum of 2,000
individuals). Animals in a pod are often tightly packed and make
frequent course changes (Jefferson et al. 1993).
P. electra may associate with Fraser's dolphins (Lagenodelphis
hosei) and sometimes other cetaceans such as spinner dolphins
longirostris) and spotted dolphins (Stenella
frontalis) Carwardine, 1995). In Hawaiian waters a group
of 30 melon-headed whales was seen interacting with a group of 15
short-finned pilot whales (Globicephala
macrorhynchus). The interactions involved behaviours that
suggest the encounter was unrelated to feeding symbioses, but it
may have involved an inquisitive and/or protective response by the
pilot whales (Migura and Meadows, 2002). Off the island of Rota
in the Northern Mariana Islands, a group of about 500-700 melon-headed
whales was observed at the surface and extensively underwater for
several hours. An unidentified number of rough-toothed dolphins
bredanensis) were also part of this sighting. Bottom depths
ranged from about 77 to 1,100 m over the course of the sighting
(Jefferson et al. 2006).
Mass strandings of melon-headed whales have been reported from
Moreton Island and Crowdy Heads, Australia; Malekoula Island; Vanuatu;
the Seychelles; Aoshima, Japan; Piracanga Beach, Brazil; the Kwajalein
Atoll; and Tambor, Costa Rica. It has been noted that in several
mass strandings of this species, the ratio of females to males was
about 2:1. This may reflect behavioural segregation (Perryman et
al. 1994 and refs. therein).
Reproduction: Females reach sexual maturity at about 11.5
years and males at 15 years (Perryman, 2009). There is some evidence
to indicate a calving peak in July and August, but this is inconclusive
(Jefferson et al. 1993). In the southern hemisphere, calving may
peak between August and December (Klima, 1994).
Food: Melon-headed whales are known to feed on squid and
small fish (Jefferson et al. 1993; Perryman et al. 1994; Clarke
and Young, 1998).
No migrations are known (Carwardine, 1995), although the fact that
the species follows warm currents may lead it through coastal waters
of a variety of countries.
Direct catch: This species has been taken occasionally in
the subsistence fishery for small cetaceans near the island of St
Vincent in the Caribbean and in the Japanese dolphin drive fishery.
They continue to be taken in a long-lived and well-established harpoon
fishery for sperm whales and various small cetaceans at Lamalera,
Indonesia. Small-boat fisherman also occasionally harpoon or net
this species near Sri Lanka and in the Philippines (Jefferson et
al. 1993; Perryman et al. 1994). Dolar et al. (1994) investigated
the fisheries for marine mammals in central and southern Visayas,
northern Mindanao and Palawan, Philippines, and reported that hunters
at several sites took melon-headed whales for bait or human consumption.
They are taken by hand harpoons or, increasingly, by togglehead
harpoon shafts shot from modified, rubber-powered spear guns. Around
800 cetaceans of various species are taken annually by hunters at
the seven sites, mostly during the inter-monsoon period of February-May.
These catches may be ongoing, although their extent is unknown (Perryman,
Incidental catch: Mortality from incidental captures in
the purse-seine fishery for yellowfin tuna in the eastern Pacific
will probably continue at a very low level (Perryman et al. 1994;
Perryman, 2009). For US Gulf of Mexico waters, there has been no
reported fishing-related mortality of melon-headed whales during
1998-2006 (Waring et al. 2008).
Pollution: Concentrations of polychlorinated biphenyls (PCBs),
DDTs, and hexachlorbenzole (HCB) in melon-headed whales stranded
on Japanese coasts were lower after the year 2000 than in specimens
stranded in 1982, whereas polybrominated diphenyl ethers (PBDE)
and CHL levels showed a temporal increase during the past 20years,
suggesting that the peak of their usage and contamination occurred
recently (Kajiwara et al. 2008). Specimens stranded on these shores
also showed substantial concentrations of mercury and cadmium (Endo
et al. 2008).
Noise pollution: In 2004, 150 - 200 melon-headed whales
occupied the shallow waters of Hanalei Bay, Kauai, Hawaii for over
28 hours. The usually pelagic animals stayed in the shallow, confined
bay and returned to deeper water only with human assistance. This
event was coincident with military training exercises in the Hawaiian
Islands, suggesting that military sonar might have been the cause
(Southall et al. 2006; Taylor et al. 2008).
Range states (Taylor et al. 2008):
American Samoa; Anguilla; Antigua and Barbuda; Aruba; Australia;
Bahamas; Bangladesh; Barbados; Belize; Benin; Bermuda; Brazil; Brunei
Darussalam; Cambodia; Cameroon; Cayman Islands; Cocos (Keeling)
Islands; Colombia; Congo; Congo, The Democratic Republic of the;
Cook Islands; Costa Rica; Côte d'Ivoire; Cuba; Djibouti; Dominica;
Dominican Republic; Ecuador; El Salvador; Equatorial Guinea; Fiji;
French Guiana; French Polynesia; Gabon; Gambia; Ghana; Grenada;
Guadeloupe; Guam; Guatemala; Guinea; Guinea-Bissau; Guyana; Haiti;
Honduras; India; Indonesia; Iran, Islamic Republic of; Jamaica;
Japan; Kenya; Kiribati; Liberia; Madagascar; Malaysia; Maldives;
Marshall Islands; Martinique; Mauritania; Mayotte; Mexico; Micronesia,
Federated States of; Mozambique; Myanmar; Namibia; Nauru; Netherlands
Antilles; New Caledonia; Nicaragua; Nigeria; Niue; Northern Mariana
Islands; Oman; Pakistan; Palau; Panama; Papua New Guinea; Peru;
Philippines; Pitcairn; Puerto Rico; Saint Kitts and Nevis; Saint
Lucia; Saint Vincent and the Grenadines; Samoa; Senegal; Sierra
Leone; Singapore; Solomon Islands; Somalia; South Africa; Sri Lanka;
Suriname; Taiwan, Province of China; Tanzania, United Republic of;
Thailand; Timor-Leste; Togo; Tonga; Trinidad and Tobago; United
States of America; Vanuatu; Venezuela; Viet Nam; Virgin Islands,
British; Virgin Islands, U.S.; Wallis and Futuna; Western Sahara;
Classified as "Least Concern" by the IUCN (Taylor et al.
2008). Not listed by CMS. The species is listed in Appendix II of
This is a poorly known oceanic species which probably follows oceanographic
features such as currents and upwellings near coasts. This behaviour
might bring it into coastal waters of a variety of range states
in tropical and subtropical waters. Data on abundance, behaviour
at sea and by-catch rates are very sparse.
For South American stocks, see further comments and recommendations
in Hucke-Gaete (2000) in Appendix
1, and regarding Southeast Asian populations, please see Perrin
et al. (1996) in Appendix
· Anderson RC (2005) Observations of cetaceans in the Maldives,
1990-2002. J Cetacean Res Manage 7: 119-135
· Barlow J (2006) Cetacean abundance in Hawaiian waters estimated
from a summer/fall survey in 2002. Mar Mamm Sci 22: 446-464
· Carwardine M (1995) Whales, dolphins and porpoises. Dorling
Kindersley, London, UK, 257 pp.
· Clarke M, Young R (1998) Description and analysis of cephalopod
beaks from stomachs of six species of odontocete cetaceans stranded
on Hawaiian shores. J Mar Biol Assoc U K 78: 623-641.
· Dolar ML (1999) Abundance, distribution and feeding ecology
of small cetaceans in the Eastern Sulu Sea and Tañon Strait,
Philippines. PhD thesis, U Cal San Diego, USA.
· Dolar M L L, Leatherwood S J, Wood C J, Alava M N R, Hill
C L (1994) Directed fisheries for cetaceans in the Philippines.
Rep Int Whal Commn 44: 439-449.
· Dolar MLL, Perrin WF, Taylor BL, Kooyman GL, Alava MNR
(2006) Abundance and distributional ecology of cetaceans in the
central Philippines. J Cetacean Res Manage 8:93-111.
· Endo T, Hisamichi Y, Kimura O, Haraguchi K, Baker CS (2008)
Contamination levels of mercury and cadmium in melon-headed whales
(Peponocephala electra) from a mass stranding on the Japanese
coast. Sci Total Environ 401: 73-80
· Gannier A (2000) Distribution of cetaceans off the Society
Islands (French Polynesia) as obtained from dedicated surveys. Aquat
Mamm 26: 111-126
· Gannier A (2002) Cetaceans of the Marquesas Islands (French
Polynesia): distribution and relative abundance as obtained from
a small boat dedicated survey. Aquat Mamm 28: 198-210
· Hucke-Gaete R ed. (2000) Review on the conservation status
of small cetaceans in southern South America. UNEP/CMS Secretariat,
Bonn, Germany, 24 pp.
· Jefferson TA, Leatherwood S, Webber MA (1993) FAO Species
identification guide. Marine mammals of the world. UNEP/FAO, Rome,
· Jefferson TA, Fertl D, Michael M, Fagin TD (2006) An unusual
encounter with a mixed school of melon-headed whales (Peponocephala
electra) and rough-toothed dolphins (Steno bredanensis)
at Rota, Northern Mariana Islands. Micronesica 38: 239-244.
· Kajiwara N, Kamikawa S, Amano M, Hayano A, Yamada TK, Miyazaki
N, Tanabe S (2008) Polybrominated diphenyl ethers (PBDEs) and organochlorines
in melon-headed whales, Peponocephala electra, mass stranded
along the Japanese coasts: Maternal transfer and temporal trend.
Environ Pollut 156 : 106-114.
· Kiszka J, Ersts PJ, Ridoux V (2007) Cetacean diversity
around the Mozambique Channel Island of Mayotte (Comoros archipelago).
J Cetacean Res Manage 9: 105-109
· Klima M (1994) Peponocephala electra - Melonen-kopf
oder Breitschnabeldelphin. In: Handbuch der Säugetiere Europas
(Niethammer J, Krapp F, eds.) Band 6 Meeressäuger. Teil 1A:
Wale und Delphine 1. Aula-Verlag, Wiesbaden, Germany, pp. 482-488.
· Migura KA, Meadows DW (2002) Short-finned pilot whales
(Globicephala macrorhynchus) interact with melon-headed whales
(Peponocephala electra) in Hawaii. Aquat Mamm 28: 294-297
· Mullin KD (2007) Abundance of cetaceans in the oceanic
Gulf of Mexico based on 2003-2004 ship surveys. 26 pp. Available
from: NMFS, Southeast Fisheries Science Center, P.O. Drawer 1207,
Pascagoula, MS 39568.
· Perrin WF, Dolar MLL, Alava MNR (1996) Report of the Workshop
on the Biology and Conservation of Small Cetaceans and Dugongs of
Southeast Asia. East Asia Seas Action Plan. UNEP(W)/EAS WG. 1/2,
Bangkok, Thailand, 101 pp.
· Perryman WL (2009) Melon-headed whale - Peponocephala
electra. In: Encyclopedia of marine mammals (Perrin WF, Würsig
B, Thewissen JGM, eds.) Academic Press, Amsterdam, 719-721.
· Perryman WL, Au DWK, Leatherwood S, Jefferson TA (1994)
Melon-headed whale - Peponocephala electra. In: Handbook
of marine mammals (Ridgway SH, Harrison SR, eds.) Vol. 5: The first
book of dolphins. Academic Press, London, pp. 363-386.
· Rice DW (1998) Marine mammals of the world: systematics
and distribution. Society for Marine Mammalogy, Special Publication
4, Lawrence, KS. USA.
· Southall BL, Braun R, Gulland FM, Heard AD, Baird RW (2006)
Hawaiian Melon-headed Whale (Peponocephala electra) mass
stranding Event of July 3-4, 2004. NOAA Tech Memo NMFS OPR. no.
31, 78 pp
· Taylor BL, Baird R, Barlow J, Dawson SM, Ford J, Mead JG,
Notarbartolo di Sciara G, Wade P, Pitman RL (2008) Peponocephala
electra. In: IUCN 2009. IUCN Red List of Threatened Species.
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and distribution in the eastern tropical Pacific. Rep Int Whal Commn
· Waring GT, Josephson E, Fairfield-Walsh CP, Maze-Foley
K, editors (2008) U.S. Atlantic and Gulf of Mexico Marine Mammal
Stock Assessments -- 2008. NOAA Tech Memo NMFS NE 210; 440 p
© Boris Culik (2010) Odontocetes.
The toothed whales: "Peponocephala electra". UNEP/CMS
Secretariat, Bonn, Germany. http://www.cms.int/reports/small_cetaceans/index.htm
© Illustrations by Maurizio Würtz, Artescienza. ©
Maps by IUCN.