Mesoplodon europaeus (Gervais, 1855)

English: Gervais' beaked whale
German: Gervais-Zweizahnwal
Spanish: Zifio de Gervais, ballena picuda de Gervais
French: Mésoplodon de Gervais, baleine à bec de Gervais

Family Ziphiidae

Mesoplodon europaeus © Wurtz-Artescienza (see links).

1. Description

Gervais' beaked whales are generally dark grey, with pale grey on the undersides. The triangular teeth of the male are found one third behind the tip of the beak on the lower jaw (Norman and Mead, 2001; Jefferson et al. 2008). M. europaeus measures 3.7 - 5.2 m and reaches a body mass of at least 1,200 kg (Reidenberg and Laitman, 2009).

2. Distribution

Gervais' beaked whale occurs mainly in the North Atlantic from Cape Cod to Ireland and the English Channel south to southern Brasil, Guinea Bissau and as far south as Angola (Norman and Mead, 2001; Jefferson et al., 2008, Macleod, 2000).

Distribution of Mesoplodon europaeus (Jefferson et al. 2008; Taylor et al. 2008; © IUCN;
enlarge map). Gervais' beaked whale prefers warm temperate and tropical waters mostly
in the North Atlantic but also somewhat south of the equator.

While the distribution is inferred mainly from 54 strandings (Mead, 1989), newer records seem to indicate a larger distribution in the temperate waters of the North Atlantic, not only near Florida and on the eastern coast of central America, but also in the Gulf Stream, the Canary Islands and in currents north of the equator. According to Robineau (1995) European seas seem to mark the end of the distributional area, but stranded specimens are reported from the Canary Islands (Martin et al., 2001), the Azores (Reiner et al. 1993), Guinea Bissau (Reiner, 1980) and Mauritania (Robineau and Vely, 1993) which confirms the wider distributional range. Moore et al. (2004) report on a stranded specimen in Cape Cod Bay, which in the western North Atlantic seems to mark the northernmost limit of the distribution.

3. Population size

Unknown.

4. Biology and Behaviour

Mead (1989) suggests that Gervais' beaked whale prefers deep waters, which is deduced from lack of sightings nearshore. However, there are few observations at sea to test this hypothesis. Strandings suggest that the species prefers tropical and subtropical waters. There are only a few sightings in the wild (Jefferson et al. 2008).

According to Jefferson (1993) Gervais' beaked whale seems to feed on squid. However, Santos et al. (2007) report that a stranded animal from the Canary Islands had eaten both fish and cephalopod prey. The most numerous prey remains belonged to viperfish (Chauliodus sp.). These results are consistent with the limited published data on diet in Mesoplodon species which suggest a relatively higher proportion of fish in their diet whereas Ziphius caviristris specialises on cephalopods.

5. Migration

Unknown.

6. Threats

There is a record of one specimen having been taken in a pound net off New Jersey and others may have been taken in Caribbean small cetacean fisheries (Jefferson et al., 1993).

From 1992 to 1998 a total of 49 beaked whales stranded along the US Atlantic coast between Florida and Massachusetts (NMFS unpublished data). This included 28 Gervais' beaked whales, which was therefore the most frequently affected species (Waring et al. 2001). Furthermore, several unusual mass strandings of beaked whales, including also Gervais' beaked whales, were associated with naval activities: Mid to late 1980's on the Canary Islands (Waring et al. 2001), and again in September 2002 during a naval NATO manoeuvre involving low frequency sonar around the Canaries (Vidal, pers. comm.).

Cook et al. (2006) confirm, that M. europaeus is most sensitive to high frequency signals between 40 and 80 kHz, but produced smaller evoked potentials to 5 kHz, the lowest frequency tested. The beaked whale hearing range and sensitivity are similar to other odontocetes that have been measured.

Evidence from stranded individuals of several species, including M. europaeus, indicates that they have swallowed discarded plastic items, which may eventually lead to death (e.g. Scott et al. 2001 ).

7. Remarks

Known and inferred Range states (Taylor et al. 2008):
Bahamas; Brazil; Cape Verde; Cuba; France; Guinea-Bissau; Ireland; Jamaica; Mauritania; Saint Helena; Spain; Trinidad and Tobago; United Kingdom; United States of America.

Categorised as "Data Deficient" by IUCN. Gervais' beaked whale is not listed by CMS but is listed in Appendix II of CITES.

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8. Sources and further information

see "Genus Mesoplodon - Beaked whales: Introduction and Sources"

© Boris Culik (2010) Odontocetes. The toothed whales: "Mesoplodon europaeus". UNEP/CMS Secretariat, Bonn, Germany. http://www.cms.int/reports/small_cetaceans/index.htm
© Illustrations by Maurizio Würtz, Artescienza. © Maps by IUCN.