CMS: Mesoplodont whales

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Genus Mesoplodon - Beaked whales:
Introduction and Sources

Mesoplodont whales are relatively small, ranging in size between 3.9 and 6.2 m. Their body is spindle-shaped, with a small, triangular dorsal fin located about two thirds between the beak and the tail. The flippers are small and narrow and fit into pigmented depressions in the body. The unnotched flukes are usually straight across the trailing edge or even slightly convex. A single pair of external throat groves may aid in suction feeding. The head is small and tapered and the melon is also small, blending into the beak without a crease. The blowhole is semicircular with the ends pointed forward. Most species show sexual dimorphism, as only adult males have functional teeth (tusks) and show excessive and conspicuous body scarring resulting from the usage of these teeth by other males in intraspecific fights (Pitman, 2009).

The distribution of many Mesoplodon species is known almost entirely from records of stranded individuals. This situation is due to the difficulty in making specific identifications of these animals at sea and the relative rarity of sighting them at all (Mead, 1989). Until today, M. bowdoini, M. perrini, M traversii, M. ginkgodens and M. hectori have almost never been identified alive in the wild (Pitman, 2009).

Furthermore, the distributional conclusions that are drawn from stranded animals are tentative due to the likelihood that these animals were diseased and strayed from their normal range. It is only when there is a large sample of strandings that have come from the same area that relatively firm distributional conclusions can be drawn. Care must also be taken in the weight which one gives to negative distributional data. In some cases there may be animals frequenting the waters and stranding upon the shores but there has not been enough cetological research in the area to bring the strandings to the attention of scientists (Mead, 1989).

Unfortunately, correct identification of mesoplodont specimens also seems to be fraught with difficulties. Dalebout et al. (1998) report that to assist in the species-level identification of stranded and hunted beaked whales, they compiled a database of 'reference' sequences from the mitochondrial DNA control region, for 15 of the 20 described ziphiid species. Reference samples for eight species were obtained from stranded animals in New Zealand and South Australia. Sequences for a further seven species were obtained from a previously published report. This database was used to identify 20 'test' samples obtained from incompletely documented strandings around New Zealand. Their analyses showed that four of these specimens (20% !) had initially been misidentified.

Much of the research on mesoplodont whales is fairly recent: M. peruvianus was first described in 1991, M. perrini in 2002 and M. bahamondi, described in 1995, turned out to be the same species described by John Gray in 1874 , as M. traversii (Gray, 1874) then forgotten by science since 1875 upon being registered equivocally as a mere synonym of M. layardii. There are surely more surprises to be expected.

Population sizes
According to Pitman (2002) so few mesoplodonts have been reliably identified at sea that it is impossible to accurately determine the population status of any species, although, based on stranding data, at least some species may not be as rare as the sightings records suggest. M. grayi, M. layardii and M. densirostris seem to be widespread and fairly common, whereas e.g. M. bowdoini, M. perrini, M. traversii and M. hectori are rather rare (Pitman 2009).

The best available abundance estimate of beaked whales for the western North Atlantic stock is 3,196, whereas the estimate for the northern USA Atlantic is 2,600 and for the southern USA Atlantic 596 (data from 1998, in Waring et al. 2001).

Most published estimates of abundance or density are based on visual line-transect studies that found narrower effective strip widths and lower trackline detection probabilities for beaked whales than for most other cetaceans. Published density estimates range from 0.4-44 whales per 1,000 km² for small beaked whales and up to 68 whales per 1,000 km² for large beaked whales (Barlow et al. 2006).

Habitat
According to Pitman (2002) mesoplodont whales normally inhabit deep ocean waters (>2000m deep) or continental slopes (200-2000 m) and only rarely stray over the continental shelf. Whereas M. densirostris is found in all tropical and warm temperate oceans, most species are restricted to one or two broad ocean areas. The distribution of M. perrini could be considered localized (C.D.MacLeod, pers. comm. to author, 2003).

Migration
M. layardii may undertake some limited migration to lower latitudes during winter (Pitman, 2002) and M. bidens may undergo migration in the eastern Atlantic (MacLeod et al. unpublished).

Food
Mead (1989) reports that all beaked whales feed primarily on deep-water mesopelagic squid, although some fish may also be taken (Pitman, 2002; MacLeod et al. 2003). Most prey are probably caught at depths exceeding 200m via suction, as the dentition is much reduced and the mouth and tongue are highly adapted for this feeding method (Pitman, 2002). Diving durations of 20-45min have been reported, after which groups of animals surface together and stay within one body length of each other (Pitman, 2002).

Stomach samples of three beaked whale genera Hyperoodon, Mesoplodon and Ziphius primarily contained cephalopod and fish remains, although some also contained crustaceans. Mesoplodon spp. were found to contain the most fish, with some species containing nothing but fish remains, while the southern bottlenose whale (Hyperoodon planifrons) and Cuvier's beaked whale (Ziphius cavirostris) rarely, if ever, contained fish. Of cephalopods identified, Histiotheutid, Gonatid, Cranchiid and Onychoteuthid species usually contributed most to prey numbers and biomass. There was a wide range of species and families of cephalopods recorded from stomach contents, with no obvious preference for bioluminescent prey species, vertical migrating prey species or prey species with specific body conditions. Whales of the genus Mesoplodon generally contained smaller prey, such as cephalopods under 500g in weight, compared with other beaked whales. Hyperoodon and Ziphius frequently contained much larger cephalopods with many important species having a mean weight of over 1000g. This suggests that Mesoplodon occupies a separate dietary niche from Hyperoodon and Ziphius, which may be an example of niche separation. In contrast, Hyperoodon and Ziphius appear to occupy very similar dietary niches but have geographically segregated distributions, with Hyperoodon occupying cold-temperate to polar waters and Ziphius occupying warm-temperate to tropical waters (MacLeod et al. 2003).

Threats
Although there has never been a directed fishery, some animals are occasionally taken by opportunistic whalers, or die in drift nets and lost fishing gear, as well as in longline fisheries (Pitman, 2002; 2009). Off the north-east US coast, 46 fishery-related mortalities were observed in the pelagic drift gillnet fishery between 1989 and 1998: 24 Sowerby's, 4 True's and 17 unidentified beaked whales (Waring et al. 2001).

Currently, the biggest threat to mesoplodonts may be anthropogenic noise sources associated with airgun arrays (seismic exploration) and military mid-frequency sonar (2-10 kHz). Necropsies of mass-stranded beaked whales exposed to these sound sources lead to the hypothesis that mortality may be caused by gas-bubble disease induced by behavioural responses to acoustic exposure (Cox et al. 2006). The authors conclude further that current monitoring and mitigation methods for beaked whales are ineffective for detecting and protecting them from adverse sound exposure. However, Moretti et al. (2006) tested passive acoustic detection of beaked whales (M. densirostris) using distributed bottom-mounted hydrophones in the Bahamas, a first promising step in that direction.

Evidence from stranded individuals of several similar species indicates that they have swallowed discarded plastic items, which may lead to starvation and eventually death (Taylor et al. 2008).

Individual species accounts
see "contents"

Sources cited in species accounts

· Aguayo A, Bernal R, Olavarria C, Vallejos (1998) Cetacean observations carried out between Valparaiso and Easter Island, Chile, in the winters of 1993, 1994 and 1995. Rev Biol Mar Ocean. 33: 101-123.
· Anderson R C, Shaan A, Waheed Z (1999) Records of cetacean 'strandings' from the Maldives. J S Asian Nat His 4: 187-202.
· Baird RW, Webster DL, Schorr GS, McSweeney DJ, Barlow J (2008) Diel variation in beaked whale diving behavior. Mar Mamm Sci 24: 630-642.
· Baird RW, Webster DL, McSweeney DJ, Ligon AD, Schorr GS, Barlow J (2006) Diving behaviour of Cuvier's (Ziphius cavirostris) and Blainville's (Mesoplodon densirostris) beaked whales in Hawaii. Can J Zool 84: 1120-1128
· Baker AN, Van Helden AL (1999) New records of beaked whales, genus Mesoplodon, from New Zealand (Cetacea: Ziphiidae). J Royal Soc N Z 29: 235-244.
· BAKER AN (2001) Status, relationships, and distribution of Mesoplodon bowdoini Andrews, 1908 (Cetacea: Ziphiidae). Mar Mamm Sci 17: 473-493.
· Baker CS, Lukoschek V, Lavery S, Dalebout ML, Yong-un M, Endo T, Funahashi N (2006) Incomplete reporting of whale, dolphin and porpoise 'bycatch' revealed by molecular monitoring of Korean markets Anim Conserv 9: 474-482
· Baker CS, Funahashi N, Steel D (2008) Market surveys of whale meat in Japan, 2007 - 2008, with reference to the number of fin whales for sale. Int Whaling Comm SC/60/BC2
· Barlow J, Ferguson MC, Perrin WF, Balance L, Gerrodette T, Joyace G, Macleod CD, Mullin K, Palka DL, Waring G (2006) Abundance and densities of beaked and bottlenose whales (family Ziphiidae). J Cetacean Res Manage 7: 263-270
· Cárdenas JC, Yañez JL, Reyes JC, Van Waerebeek K (1991) Nuevos registros de cetáceos para el archipielago de Juan Fernández, Chile. Boletín Museo Nacional de Historia Natural de Chile 42: 113-120.
· Carlstroem J, Denkinger J, Feddersen P, Oeien N (1997) Record of a new northern range of Sowerby's beaked whale (Mesoplodon bidens). Polar Biol 17: 459-461.
· Carwardine M (1995) Whales, Dolphins and Porpoises. Dorling Kindersley, London, UK, 257 pp.
· Carwardine M, Hoyt E, Fordyce RE, Gill P (2000) Wale, Delphine und Tümmler. Könemann-Verlag, Köln, Germany, 288 pp.
· Casinos A, Filella S (1995) Mesoplodon densirostris - Blainville-Zweizahnwal. In: Handbuch der Säugetiere Europas. Meeressäuger. Teil IB: Wale und Delphine 2 (Robineau D, Duguy R and Klima M, eds.) Aula-Verlag, Wiesbaden. pp. 575-582.
· Cook MLH, Varela RA, Goldstein JD, McCulloch SD, Bossart GD, Finneran JJ, Houser D, Mann DA (2006) Beaked whale auditory evoked potential hearing measurements. J Comp Physiol A 192: 489-495
· Cox TM, Ragen TJ, Read AJ, Vos E and others (2006) Understanding the impacts of anthropogenic sound on beaked whales. J Cetacean Res Manag 7:177-187
· Dalebout ML, Van Helden A, Van Waerebeek K, Baker CS (1998) Molecular genetic identification of southern hemisphere beaked whales (Cetacea: Ziphiidae). Mol Ecol 7: 687-694.
· Dalebout ML, Mead JG, Van Waerebeek K, Reyes JC, Baker CS (2000) Molecular genetic discovery of a new beaked whale (Ziphiidae). IWC Scientific Committee Document SC/52/SM11.
· Dalebout ML, Mead JG, Baker CS, Baker AN, Van Helden AL (2002) A new species of beaked whale Mesoplodon perrini sp. n. (Cetacea: Ziphiidae) discovered through phylogenetic analyses of mitochondrial DNA sequences. Mar Mamm Sci 18: 1-32.
· Dalebout ML Russell KG, Little MJ, Ensor, P (2004) Observations of live Gray's beaked whales (Mesoplodon grayi) in Mahurangi Harbour, North Island, New Zealand, with a summary of at-sea sightings. J R Soc NZ 34: 347-356.
· De Buffrénil V (1995a) Mesoplodon mirus - True-Zweizahnwal. In: Handbuch der Säugetiere Europas. Meeressäuger. Teil IB: Wale und Delphine 2 (Robineau D, Duguy R and Klima M, eds.) Aula-Verlag, Wiesbaden. pp. 561-574.
· De Buffrénil V (1995b) Mesoplodon bidens - Sowerby-Zweizahnwal. In: Handbuch der Säugetiere Europas. Meeressäuger. Teil IB: Wale und Delphine 2 (Robineau D, Duguy R and Klima M, eds.) Aula-Verlag, Wiesbaden. pp. 545-560.
· Dolar MLL, Leatherwood SJ, Wood CJ, Alava MNR, Hill CL (1994) Directed Fisheries for Cetaceans in the Philippines. Rep Int Whal Comm 44: 439-449.
. Ferguson MC, Barlow J (2001) Spatial distribution and density of cetaceans in the eastern Pacific Ocean based on summer/fall research vessel surveys in 1986-96. SW Fish Sci Cent Admin Rep LJ-01-04: 61 pp
· Forney KA, Kobayashi DR (2007) Updated Estimates of Mortality and Injury of Cetaceans in the Hawaii-Based Longline Fishery, 1994-2005. NOAA Technical Memorandum NMFS SWFSC. no. 412, 35 pp
· Gannon DP, Craddock JE, Read AJ (1998) Food habits of beaked whales (Mesoplodon bidens and Ziphius cavirostris) from the northeastern U.S. In: Abstracts of the World Marine Mammal Science Conference. Monaco, 20-24th January 1998, pp 49.
· Honma Y, Ushiki T, Takeda M, Naito E, Dewa K, Yamanouchi H (1999) Identification by histological and microsatellite analyses of a stranded beaked whale as that struck previously by a jetfoil operating in the Sea of Japan. Fish Sci 65: 547-552
· Hooker SK, Baird RW (1999) Observations of Sowerby's beaked whales, Mesoplodon bidens, in the Gully, Nova Scotia. Can Field Nat 113: 273-277.
· Houston J (1990a) Status of True's beaked whale, Mesoplodon mirus, in Canada. Can Field Nat 104: 135-137.
· Houston J (1990b) Status of Hubbs' beaked whale, Mesoplodon carlhubbsi, in Canada. Can Field Nat 104: 121-124.
· Houston J (1990c) Status of Blainville's beaked whale, Mesoplodon densirostris, in Canada. Can Field Nat 104: 117-120.
· 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, 320 pp.
· Jefferson TA, Webber MA Pitman RL (2008) Marine mammals of the world. Elsevier, Amsterdam, 573 pp.
· Kinze CC, Tougaard S, Baagoe HJ (1998) Danish whale records (strandings and incidental catches) for the period 1992-1997. Flora og Fauna 104 (3-4) 41-53.
· Lien J, Barry F, Breecke K, Zuschlag U (1990) Multiple strandings of Sowerby's beaked whales, Mesoplodon bidens, in Newfoundland (Canada). Can Field Nat 104: 414-420.
· Lien J, Barry F (1990) Status of Sowerby's beaked whale, Mesoplodon bidens, in Canada. Can Field Nat 104: 125-130.
· Liu H, Gan JL, Jia XP (2009) Distribution characteristic and risk assessment of PCBs in blubber of Mesoplodon ginkgodens from Honghai Bay, Guangdong China. J Fish Sci China 16: 381-387
· Loughlin TR, Perez MA (1985) Mesoplodon stejnegeri. Mammalian Species 250. The American Society of Mammalogists: 1-6.
· Lucas ZN, Hooker S (2000) Cetacean strandings on Sable Island, Nova Scotia, 1970-1998. Can Field Nat 114: 45-61.
· Martin V, Carrillo M, Andre M, Hernandez Garcia V (2001). Records of cetaceans stranded on the Canary Islands coast from 1992 to 1994. Copenhagen Denmark ICES. 5 pp.
· Mcalpine DF, Rae M (1999) First confirmed reports of beaked whales, cf. Mesoplodon bidens and M. densirostris (Ziphiidae), from New Brunswick. Can Field Nat 113: 293-295.
· Macleod CD (2000) Review of the distribution of Mesoplodon species (order Cetacea, family Ziphiidae) in the North Atlantic. Mamm Rev 30: 1-8.
· Macleod CD, Santos MB, Pierce GJ (2003) Review of data on diets of beaked whales: Evidence of niche separation and geographic segregation. J Mar Biol Ass UK 83: 651-665.
· MacLeod CD, Herman JS (2004) Development of tusks and associated structures in Mesoplodon bidens (Cetaceae, Mammalia). Mammalia 68(2-3): 175-184.
· MacLeod CD, Perrin WF, Pitman R, Barlow J, Balance L, D'Amico A, Gerrodette T, Joyce G, Mullin KD, Palka DL, Waring GT (2006a). Known and inferred distributions of beaked whale species (Cetacea: Ziphiidae). J Cetacean Res Manage 7: 271-286
· MacLeod CD, Santos MB, López A, Pierce GJ (2006b) Relative prey size consumption in toothed whales: implications for prey selection and level of specialisation. Mar Ecol Prog Ser 326: 295-307
· MacLeod CD, Zuur AF (2005) Habitat utilization by Blainville's beaked whales off Great Abaco, northern Bahamas, in relation to seabed topography. Mar Biol 147: 1-11
· McSweeney DJ, Baird RW, Mahaffy SD (2007) Site Fidelity, Associations, and Movements of Cuvier's (Ziphius cavirostris) and Blainville's (Mesoplodon densirostris) Beaked Whales off the Island of Hawai'i. Mar Mamm Sci 23: 666-687.
· Mead JG (1989) Beaked whales of the genus Mesoplodon. In: Handbook of Marine Mammals (Ridgway SH, Harrison SR eds.) Vol. 4: River Dolphins and the Larger Toothed Whales. Academic Press, London, pp. 349-430.
· Mead JG Walker WA Houck WJ (1982) Biological observations on Mesoplodon carlubbsi (Cetacea: Ziphiidae), Smith Contr Zool 344, 25 pp.
· Moore, JC (1963) Recognizing certain species of beaked whales of the Pacific Ocean. The American Midland Naturalist 70(2): 396-428.
· Moore MJ, Rubinstein B, Norman SA, Lipscomb T (2004) A note on the most northerly record of Gervais' beaked whale from the western North Atlantic Ocean. J Cetacean Res Manage 6: 279-281.
· Moretti D, Morrissey R, DiMarzio N, Ward J (2006) Verified passive acoustic detection of beaked whales (Mesoplodon densirostris) using distributed bottom-mounted hydrophones in the tongue of the ocean, Bahamas. J Acoust Soc Am 119: 3374
· Nishiwaki M, Kamiya T (1958) A beaked whale Mesoplodon stranded at Oiso beach, Japan. Sci. Rep. Whales Res. Inst., Tokyo 13: 53-83.
· Norman SA, Mead, JG (2001) Mesoplodon europaeus. Mammalian Species 688: 1-5.
· Ostrom PH, Lien J, Macko SA (1993) Evaluation of the diet of Sowerby's beaked whale, Mesoplodon bidens, based on isotopic comparisons among northwestern Atlantic cetaceans. Can J Zoo 71: 858-861.
· Palacios DM (1996) On the specimen of the ginkgo-toothed beaked whale, Mesoplodon ginkgodens, from the Galapagos Islands. Mar Mamm Sci 12: 444-446.
· 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.
· Pinedo MC, Lammardo MP, Barreto AS (2001) Review of Ziphius cavirostris, Mesoplodon grayi and Lagenodelphis hosei (Cetacea: Ziphiidae and Delphinidae) in Brazilian waters, with new records from southern Brazil. Atlantica 23: 67-76
· Pinedo MC, Barreto AS, Lammardo MP, Andrade ALV, Geracitano L (2002) Northernmost records of the spectacled porpoise, Layard's beaked whale, Commerson's dolphin, and Peale's dolphin in the southwestern Atlantic Ocean. Aquat Mamm 28: 32-37.
· Pitman RL, Aguayo-L A, Urban-R J (1987) Observations of an unidentified beaked whale (Mesoplodon sp.) in the eastern tropical Pacific. Mar Mamm Sci 3: 345-352.
· Pitman RL, Lynn MS (2001) Biological observations of an unidentified mesoplodont whale in the eastern tropical Pacific and probable identity: Mesoplodon peruvianus. Mar Mamm Sci 17: 648-657.
· Pitman RL (2002) Mesoplodont whales. In: Encyclopedia of marine mammals (Perrin WF, Würsig B, Thewissen JGM, eds.) Academic Press, San Diego, 738-742.
· Pitman RL (2009) Mesoplodont whales. In: Encyclopedia of marine mammals 2nd Ed. (Perrin WF, Würsig B, Thewissen JGM, eds.) Academic Press, Amsterdam, 721-726.
· Reidenberg JS, Laitman JT (2009) Cetacean prenatal development. In: "Encyclopedia of marine mammals, 2nd Ed." Perrin WF, Würsig B, Thewissen JGM (Eds.) Elsevier, Amsterdam, 1316 pp.
· Reiner, F. 1980. First record of a Antillean beaked whale, Mesoplodon europaeus Gervais 1855, from República popular da Guiné Bissau. Memorias do Museu do mar. Ser.Zool. 1(8):1-8.
· Reiner F, Goncalves JM, Santos RS (1993) Two new records of Ziphiidae (Cetacea) for the Azores with an updated checklist of cetacean species. Arq Cien Nat 11: 113-118.
· Reyes JC, Mead JG, Van Waerebeek K (1991) A new species of beaked whale Mesoplodon peruvianus sp.n. (Cetacea: Ziphiidae) from Peru. Marine Mammal Science 7(1): 1-24.
· Reyes JC, Van Waerebeek K, Cárdenas JC, Yañez JL (1995) Mesoplodon bahamondi sp.n. (Cetacea, Ziphiidae), a new living beaked whale from the Juan Fernández Archipelago, Chile. Boletin Museo Nacional de Historia Natural de Chile 45: 31-44.
· Rice DW (1998) Marine mammals of the world: systematics and distribution. Society for Marine Mammalogy, Special Publication Number 4 (Wartzok D, ed.), Lawrence, KS. USA.
· Ritter F, Brederlau B (1999) Behavioural observations of dense beaked whales (Mesoplodon densirostris) off La Gomera, Canary Islands (1995-1997). Aquat Mamm 25: 55-61.
· Robineau D (1995) Mesoplodon europaeus - Gervais-Zweizahnwal. In: Handbuch der Säugetiere Europas. Meeressäuger. Teil IB: Wale und Delphine 2 (Robineau D, Duguy R and Klima M, eds.) Aula-Verlag, Wiesbaden. pp. 583-594.
· Robineau, D. and Vély, M. 1993. Stranding of a specimen of Gervais' beaked whale (Mesoplodon europaeus) on the coast of West Africa (Mauritania). Marine Mammal Science 9(4): 438-440.
. Sanino GP, Yáñez JL, Van Waerebeek K (2007) A first confirmed specimen record in Chile, and sightings attributed to the lesser beaked whale Mesoplodon peruvianus Reyes, Mead and Van Waerebeek, 1991. Bol Mus Nac Hist Nat, Chile 56: 89-96.
· Santos MB, Pierce GJ, Ross HM, Reid RJ, Wilson B (1994) Diets of small cetaceans from the Scottish coast. Copenhagen Denmark Ices 16 pp.
· Santos MB, Pierce GJ, Wijnsma G, Ross HM, Reid, RJ (2001) Diets of small cetaceans stranded in Scotland 1993-1995. Copenhagen Denmark Ices 8 pp.
· Santos MB, Martin V, Arbelo M, Fernandez A, Pierce GJ (2007) Insights Into the Diet of Beaked Whales from the Atypical Mass Stranding in the Canary Islands in September 2002. J Mar Biol Assoc UK 87: 243-251
. Scott MD, Hohn A , Westgate AJ, Nicolas JR, Whitaker BR, Campbell WB (2001) A note on the release and tracking of a rehabilitated pygmy sperm whale (Kogia breviceps). J Cet Res Man 3: 87-94.
· Secchi ER, Zarzur S (1999) Plastic debris ingested by a Blainville's beaked whale, Mesoplodon densirostris, washed ashore in Brazil. Aquat Mamm 25: 21-24.
· Sekiguchi K, Klages NTW, Best PB (1996) The diet of strap-toothed whales (Mesoplodon layardii). J Zool (London) 239(3): 453-463.
· Smeenk C (1995) Cetacea stranded on the Dutch coast in 1990, 1991 and 1992. Lutra 38: 90-104.
· Soto JMR, Vega SS (1997) First record of Gray's beaked whale, Mesoplodon grayi Haast, 1876 (Cetacea, Ziphiidae) from Brazil, with reference to osteology and a review of the ziphiids citations in Brazilian waters. Biociencias 5: 69-89.
· Taylor BL, Baird R, Barlow J, Dawson SM, Ford J, Mead JG, Notarbartolo di Sciara G, Wade P, Pitman RL (2008) Mesoplodon spec. In: IUCN 2009. IUCN Red List of Threatened Species. Version 2009.1
· Tove M (1995) Live sighting of Mesoplodon cf. M. mirus, true's beaked whale. Mar Mamm Sci 11: 80-85.
· Tyack PL, Johnson M, Soto NA, Sturlese A, Madsen PT (2006) Extreme diving of beaked whales. J Exp Biol 209: 4238-4253
· True, F.W. (1913) Description of Mesoplodon mirum, a beaked whale recently discovered on the coast of North Carolina. Proc. US National Museum 45: 651-657.
· Urbán-Ramírez J, Aurioles-Gamboa D (1991) First record of the pygmy beaked whale Mesoplodon peruvianus in the North Pacific. Mar Mam sci 8: 420-425
· Van Helden AL, Baker AN, Dalebout ML, Reyes JC, Van Waerebeek K, Baker CS (2002) Resurrection of Mesoplodon traversii (Gray, 1874), senior synonym of M. bahamondi Reyes, Van Waerebeek, Cárdenas and Yañez, 1995 (Cetacea: Ziphiidae). Mar Mamm Sci 18: 609-621.
· Van Waerebeek K, Leaper R, Baker AN, Papastavrou V, Thiele D (2004) Odontocetes of the Southern Ocean Sanctuary. IWC Scientific Committee Document SC/56/SOS1, Sorrento, Italy, June 2004. 35pp.
· Walker WA, Hanson MB (1999) Biological observations on Stejneger's beaked whale, Mesoplodon stejnegeri, from strandings on Adak Island, Alaska. Mar Mamm Sci 15: 1314-1329.
· Wang JY, Yang SC (2006) Unusual cetacean stranding events of Taiwan in 2004 and 2005. J Cetacean Res Manag 8: 283-292.
· Wang PL, Tong SH, Yuan HM (2006) Stranding of Blainville's Beaked Whale (Mesoplodon densirostris) Along the Coast of Huian, Fujian Province, China. Fish. Sci./Shuichan Kexue 25: 524-527
· Ward HK (2001) Beaked whales. http://www.cetacea.org/whales.htm
· Waring GT, Quintal JM, Schwartz SL (eds.; 2001) U.S. Atlantic and Gulf of Mexico Marine Mammal Stock Assessments - 2001. NOAA Technical Memorandum NMFS-NE-168.