Reyes, Mead and Van Waerebeek, 1991
English: Peruvian beaked whale, lesser beaked whale, pygmy beaked
German: Peruanischer Schnabelwal
Spanish: Ballena picuda peruana
French: Mésoplodon du Pérou
Mesoplodon peruvianus © Wurtz-Artescienza (see links).
M. peruvianus is the smallest of all Mesoplodon species.
It has a small, triangular dorsal fin and a short, narrow beak.
The head is also narrow and the melon not as bulbous as in some
other species. There are two teeth on the middle of the lower jaw
(gape) in males and the mouthline has a slight to moderate arch.
Peruvian beaked whales are dark grey in colour, which fades to light
grey on the undersides. Maximum known body length is 3.7 - 3.9 m
(Reyes et al. 1991, Urbán-Ramírez and Aurioles-Gamboa
1992). According to Pitman (2009) adult males have a broad white
swathe across the body that forms a conspicuous chevron when viewed
from above, however no such individuals sighted at sea have been
validated as M. peruvianus by a specimen or molecular genetic analysis.
The Peruvian beaked whale was first described in 1991, based on
captured and stranded specimens collected in 1976-1989 from the
coast of Peru, between Playa Paraiso (11°12'S) and San Juan
de Marcona (15°19'S) (Reyes et al., 1991). Recent findings of
Sanino et al. (2007) extend the southernmost known distribution
in the Eastern Pacific to 29°17'S, or 14º of latitude (1,550km)
farther south than the most austral, published record in Peru.
Distribution of Mesoplodon peruvianus
(Taylor et al. 2008; © IUCN; enlarge
map). Peruvian beaked whales are found in the eastern Pacific,
from northern Mexico to central Chile and off New Zealand (Pitman,
2002; Jefferson et al. 2008; Sanino et al., 2007).
Several dozen sightings of Mesoplodon species
"A" , tentatively identified as probable M. peruvianus
by Pitman and Lynn (2001), from the eastern tropical/warm temperate
Pacific, including the Gulf of California extend from about 10°S
to 28°N, have led several authors to suggest that the species
may be an eastern Pacific endemic (Urbán-Ramírez and
Aurioles-Gamboa 1992, MacLeod et al. 2006; Pitman, 2009). The Chilean
and New Zealand (at 42º31'S) specimens (Baker and Van Helden,
1999), sightings near Choros, and the species' common occurrence
in Peru's cool coastal waters (Sanino et al. 2007) question the
hypothesis by Urbán-Ramírez and Aurioles-Gamboa (1992)
who proposed the Eastern Tropical Pacific (ETP) as the core distribution
area of M. peruvianus, believing that the records on the
Peruvian coast are 'close to the limit of their southern range (15°S).
3. Population size
Ferguson and Barlow (2001) estimate a total abundance of 32,678
beaked whales in the genus Mesoplodon in the eastern Pacific
(corrected for missed animals). The majority of these they argued
were M. peruvianus and M.
4. Biology and Behaviour
Sanino et al. (2007) report on three sightings (5 individuals)
off north-central Chile in waters 20-70m deep, suggesting at least
occasional nearshore presence of lesser beaked whales in neritic
habitat, an unusual ecological trait for ziphiids, considered to
be almost exclusively oceanic. It is unclear whether the sighting
of a neonate in February, suggesting calving in summer may be the
key to this inshore occurrence. Sightings attributed to M. peruvianus
consisted of small groups of 1-3 individuals (n=5), consistent with
typical ziphiid behaviour.
The neritic distribution (see above) would explain why lesser beaked
whales are so often captured in Peru's artisanal drift gillnet fishery
for sharks (Reyes et al., 1991).
Sanino et al. (2007) report on a specimen off north-central Chile
showing bullet injuries in the skull presumably originating from
a high-powered handgun, which is the first circumstantial evidence
of such a case. Entanglement in fishing gear, especially gillnets
in deep water (e.g., for billfish and tuna), is probably another
significant threat in the ETP (Taylor et al. 2008). Furthermore,
cetaceans inhabiting waters surrounding the coastal islands off
north-central Chile are facing threats that include direct catches
and unregulated whale-watching operations (Sanino et al. 2007).
Documented range states: Peru, Chile, Mexico, New Zealand (based
on: Reyes et al. 1991; Urbán-Ramírez and Aurioles-Gamboa,
1992; Baker and van Helden, 1999; Sanino et al. 2007). Inferred
range states: Colombia; Costa Rica; Ecuador; El Salvador; Guatemala;
Honduras; Mexico; Nicaragua; Panama (Taylor et al. 2008).
The species is categorised as "Data Deficient" by the
IUCN. M. peruvianus is not listed by CMS but is listed in Appendix
II of CITES.
8. Sources and further information
Mesoplodon - Beaked whales: Introduction and Sources"
© Boris Culik (2010) Odontocetes.
The toothed whales: "Mesoplodon peruvianus". UNEP/CMS
Secretariat, Bonn, Germany. http://www.cms.int/reports/small_cetaceans/index.htm
© Illustrations by Maurizio Würtz, Artescienza. ©
Maps by IUCN.