|Scientific Name:||Mesoplodon stejnegeri|
|Species Authority:||True, 1885|
|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 no information on global abundance or trends in abundance for this species. It is not believed to be uncommon but it is potentially vulnerable to low-level threats and a 30% global reduction over three generations cannot be ruled out (criterion A).
|Range Description:||Stejneger's beaked whales are found in continental slope and oceanic waters of the North Pacific Basin, from southern California, north to the Bering Sea, and south to the Sea of Japan (presumably including at least the southern Okhotsk Sea – Mead 1989; MacLeod et al. 2006). This appears to be primarily a cold temperate and sub-arctic species, and this is probably the only species of the genus common in Alaskan waters. It is most commonly stranded in Alaska, especially along the Aleutian Islands. Also, there have been a large number of strandings (at least 34) from along the Sea of Japan coast of Japan, and many fewer along the Pacific coast. The large peak in strandings in this area in winter and spring suggests that the species may migrate north in summer (Mead 1989; Yamada 1997).|
Native:Canada (British Columbia); Japan; Russian Federation; United States (Alaska, California, Washington)
|FAO Marine Fishing Areas:||
Pacific – eastern central; Pacific – northeast; Pacific – northwest
|Range Map:||Click here to open the map viewer and explore range.|
|Population:||There are no estimates of abundance, but the species does not seem to be rare, especially off the Aleutian Islands and in the Sea of Japan. It has been hypothesized that there may be a resident subpopulation in the Sea of Japan and southern Okhotsk Sea (Yamada 1997, Kakuda and Yamada 2001).|
|Habitat and Ecology:||Stejneger's beaked whale ranges in subarctic waters, mostly beyond the edge of the continental shelf, in slope and oceanic waters (Houston 1990; Loughlin and Perez 1985). They are presumably deep divers, feeding in the mesopelagic and bathypelagic zones, mainly on squids of the families Gonatidae and Cranchiidae. Examination of stomach contents supports this idea (e.g., Yamada et al. 1995).|
Stejneger's beaked whales were hunted in a Japanese fishery, along with Cuvier’s beaked whales. They are not presently the main targets of any hunt.
In the past, some individuals were taken in the Japanese salmon driftnet fishery in the Sea of Japan and in driftnets off the west coast of North America. Entanglement in fishing gear, especially gillnets in deep water, is probably the most significant threat.
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).
As a cold water species, Stejneger’s beaked whale may be vulnerable to the effects of climate change as ocean warming may result in a contraction of the species range as it tracks the occurrence of its preferred water temperatures (Learmonth et al. 2006). The effect of such changes in range size on this species is unknown.
Evidence from stranded individuals of several similar species 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.
|Conservation Actions:||The species is listed in Appendix II of CITES. Research is needed to determine the impacts of potential threatening processes on this species.|
Balcomb, K. C. and Claridge, D. E. 2001. A mass stranding of cetaceans caused by naval sonar in the Bahamas. Bahamas Journal of Science 8(2): 2-12.
Cox, T. M., Ragen, T. J., Read, A. J., Vos, E., Baird, R. W., Balcomb, K., Barlow, J., Caldwell, J., Cranford, T., Crum, L., D'Amico, A., D'Spain, A., Fernández, J., Finneran, J., Gentry, R., Gerth, W., Gulland, F., Hildebrand, J., Houser, D., Hullar, T., Jepson, P. D., Ketten, D., Macleod, C. D., Miller, P., Moore, S., Mountain, D., Palka, D., Ponganis, P., Rommel, S., Rowles, T., Taylor, B., Tyack, P., Wartzok, D., Gisiner, R., Mead, J. and Benner, L. 2006. Understanding the impacts of anthropogenic sound on beaked whales. Journal of Cetacean Research and Management 7(3): 177-187.
Fernández, A., Edwards, J. F., Rodriguez, F., Espinosa, A., De Los Monteros, Herraez, P., Castro, P., Jaber, J. R., Martin, V. and Arebelo, M. 2005. "Gas and fat embolic syndrome" involving a mass stranding of beaked whales (family Ziphiidae) exposed to anthropogenic sonar signals. Veterinary Pathology 42: 446-457.
Gomercic, H., Gomercic, M. D., Gomericic, T., Lucic, H., Dalebout, M., Galov, A., Skrtic, D., Curkovic, S., Vukovic, S. and Huber, D. 2006. Biological aspects of Cuvier's beaked whale (Ziphius cavirostris) recorded in the Croatian part of the Adriatic Sea. European Journal of Wildlife Research 52(3): 182-187.
Houston, J. 1990. Status of Stejneger's beaked whale, Mesoplodon stejenegeri, in Canada. Canadian Field-Naturalist 104: 131-134.
Jepson, P. D., Arebelo, M., Deaville, R., Patterson, I. A. P., Castro, P., Baker, J. R., Degollada, E., Ross, H. M., Herraez, P., Pocknell, A. M., Rodriguez, F., Howie, F. E., Espinosa, A., Reid, R. J., Jaber, J. R., Martin, V., Cunningham, A. A. and Fernandez, A. 2003. Gas-bubble lesions in stranded cetaceans. Nature 425: 575-576.
Kakuda, T. and Yamada, T. K. 2001. Genetic variability of Stejneger's beaked whale (Mesoplodon stejnegeri) in the Sea of Japan based on mtDNA sequences. 14th Biennial Conference on the Biology of Marine Mammals. Vancouver, British Columbia, Canada.
Learmonth, J.A., Macleod, C.D., Santos, M.B., Pierce, G.J., Crick, H.Q.P. and Robinson, R.A. 2006. Potential effects of climate change on marine mammals. Oceanography and Marine Biology: An Annual Review 44: 431-464.
Loughlin, T. R. and Perez, M. A. 1985. Mesoplodon stejengeri. Mammalian Species 250: 1-6.
Macleod, C. D., Perrin, W. F., Pitman, R. L., Barlow, J., Balance, L., D'amico, A., Gerrodette, T., Joyce, G., Mullin, K. D., Palka, D. L. and Waring, G. T. 2006. Known and inferred distributions of beaked whale species (Ziphiidae: Cetacea). Journal of Cetacean Research and Management 7(3): 271-286.
Malakoff, D. 2002. Suit ties whale deaths to research cruise. Science 298: 722-723.
Mead, J. G. 1989. Beaked whales of the genus Mesoplodon. In: S. H. Ridgway and R. Harrison (eds), Handbook of marine mammals, Vol. 4: River dolphins and the larger toothed whales, pp. 349-430. Academic Press.
Scott, M. D., Hohn, A. A., Westgate, A. J., Nicolas, J. R., Whitaker, B. R. and Campbell, W. B. 2001. A note on the release and tracking of a rehabilitated pygmy sperm whale (Kogia breviceps). Journal of Cetacean Research and Management 3(1): 87-94.
Wang, J. Y. and Yang, S. C. 2006. Unusual cetacean stranding events of Taiwan in 2004 and 2005. Journal of Cetacean Research and Management 8: 283-292.
Yamada, T. 1998. Stejneger's beaked whale, Mesoplodon stejnegeri, True 1885. In: Japan Fisheries Agency (ed.), Redbook Data on Aquatic Flora and Fauna, Part III. Aquatic Mammals, pp. 53-59. Japan Fisheries Resource Conservation Association.
Yamada, T. K. 1997. Strandings of Cetacea to the coasts of the Sea of Japan - with special reference to Mesoplodon stejnegeri. IBI Reports 7: 9-19.
Yamada, T. K., Kubodera, T., Nakamura, Y., Amano, M., Suzuki, M. and Shindo, J. 1995. Stomach contents of a stranded Mesoplodon stejnegeri (Ziphiidae). Nihonkai Cetology 5: 31-36.
|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. Mesoplodon stejnegeri. The IUCN Red List of Threatened Species. Version 2015.2. <www.iucnredlist.org>. Downloaded on 03 September 2015.|
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