|Scientific Name:||Indopacetus pacificus|
|Species Authority:||(Longman, 1926)|
Mesoplodon pacificus (Longman, 1926)
Mesoplodon pacificus Longman, 1926
|Taxonomic Notes:||Some marine mammal scientists believe this species should be in the genus Mesoplodon. In 1996, it was listed under Mesoplodon, but it is now generally considered under Indopacetus (Rice 1998). Until just a few years ago, this species was only known only from two skulls. Sightings of what are now known to be this species in tropical waters were often mistakenly attributed to a whale of the genus Hyperoodon (Dalebout et al. 2003).|
|Red List Category & Criteria:||Data Deficient ver 3.1|
|Assessor/s:||Taylor, B.L., Baird, R., Barlow, J., Dawson, S.M., Ford, J., Mead, J.G., Notarbartolo di Sciara, G., Wade, P. & Pitman, R.L.|
|Reviewer/s:||Hammond, P.S. & Perrin, W.F. (Cetacean Red List Authority)|
There is almost no information on abundance and no information on trends in global abundance for this species. As a relatively uncommon species it is potentially vulnerable to low-level threats and a 30% global reduction over three generations cannot not be ruled out.
|Range Description:||There have been many sightings at widespread locations in the tropical Pacific and Indian Oceans (Dalebout et al. 2003). The distribution is not fully known, but it appears to be limited to the Indo-Pacific region (Culik 2004). The collected specimens are from Australia, Somalia, South Africa, the Maldives, Kenya, the Philippines, Taiwan and Japan. These beaked whales are relatively infrequently seen in the eastern tropical Pacific and may be more common in the western Pacific. They also appear to be more common in the western Indian Ocean, especially around the Maldives archipelago (Anderson et al. 2006).|
Native:Australia; Comoros; Japan; Kenya; Malaysia; Maldives; Mayotte; Mexico; New Caledonia; Philippines; Saudi Arabia; Somalia; South Africa; Sri Lanka; Taiwan, Province of China; United States (Hawaiian Is.)
|FAO Marine Fishing Areas:||
Indian Ocean – eastern; Indian Ocean – western; Pacific – western central
|Range Map:||Click here to open the map viewer and explore range.|
While it is certainly not the rarest of beaked whales, the paucity of recent sightings of Longman’s beaked whales indicate that it is not particularly common either. The only estimates of abundance available are of 1,007 individuals (CV=126%) in the waters around Hawaii (Barlow 2006), and 291 (CV=100%) in the eastern North Pacific (Ferguson and Barlow 2001).
There is no information on trends in the global abundance of this species.
|Habitat and Ecology:||
The sightings of this species come from scattered locations, many in deep, oceanic waters, in the tropical to subtropical Indo-Pacific. Sightings have occurred in areas with surface water temperatures of 21-31°C.
Nothing is known of its feeding habits, except for the stomach contents of a single specimen from Japan (Yamada 2003). These suggested that the species feeds primarily on cephalopods, like other beaked whales.
Direct hunting has never been associated with this species. Pervasive gillnet and longline fisheries throughout the species' range raises concern that some bycatch is likely. Even low levels of bycatch might cause unsustainable impacts on this naturally rare cetacean.
It is unknown if military, seismic or other loud noise-producing human activities resulted in the live stranding of a possible mother/calf pair in NE Taiwan (Wang and Yang 2006; Yang et al. 2008). However, “bubble-like lesions” were reported in at least one of these whales by Yang et al (2008). There is some evidence from Sri Lanka for occasional incidental or directed takes of animals identified as ‘bottlenose whales’ which are likely to be Indopacetus (Dayaratne and Joseph 1993).
Evidence from stranded individuals of several similar species of beaked whales indicates that they have swallowed discarded plastic items, which may eventually lead to death (e.g. Scott et al. 2001); this species may also be at risk.
This species, like other beaked whales, is likely to be vulnerable to loud anthropogenic sounds, such as those generated by navy sonar and seismic exploration (Cox et al. 2006).
Predicted impacts of global climate change on the marine environment may affect this species of whale, although the nature of impacts is unclear (Learmonth et al. 2006).
|Conservation Actions:||The species is listed in Appendix II of CITES. Research is needed to determine the impact of possible threats on this species.|
|Citation:||Taylor, B.L., Baird, R., Barlow, J., Dawson, S.M., Ford, J., Mead, J.G., Notarbartolo di Sciara, G., Wade, P. & Pitman, R.L. 2008. Indopacetus pacificus. In: IUCN 2012. IUCN Red List of Threatened Species. Version 2012.2. <www.iucnredlist.org>. Downloaded on 22 May 2013.|
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