Gervais’ beaked whale (Mesoplodon europaeus)
|Also known as:||Antillean beaked whale, Gulf Stream beaked whale|
|French:||Mésoplodon De Gervais|
|Spanish:||Ballena De Pico De Gervais, Zifio De Gervais|
|Size||Adult length: 4 – 5.2 m (2)|
Adult weight: 1000 – 1200 kg (3)
Length at birth: 1.6 -2.2 m (3)
Weight at birth: 50 kg (3)
Gervais’ beaked whale is classified as Data Deficient (DD) on the IUCN Red List 2004 (1), and is listed on Appendix II of CITES (4). All cetaceans (whales and dolphins) are listed on Annex A of EU Council Regulation 338/97; they are therefore treated by the EU as if they are included in CITES Appendix I, so that commercial trade is prohibited.
Gervais’ beaked whale has a prominent, slender beak with only two teeth which, whilst obvious in males, are not visible in females (5). These whales are dark grey to black on the back, fading to light grey or white on the underside. The head is relatively small with a slightly bulging forehead and the dorsal fin is situated towards the tail end of the back (2) (5).
Although the first specimen of this species was found in the English Channel, it has only been found in the Atlantic Ocean since. The range has been deduced from stranding sites, and is possibly inaccurate, but is thought to stretch from New York to Trinidad on the western side of the Atlantic and from Ireland to Guinea Bissau on the eastern side (2).
Inhabits warm to tropical pelagic waters (2).
This species is assumed to be a deep diver (6) that only comes close to the shore to give birth, as many strandings are females with their newborn calves, and sightings of this whale are extremely rare (5). Gervais’ beaked whale is nearly impossible to distinguish from other beaked whales when sighted at sea (2). Females are thought to be larger than males, becoming sexually mature at 4.5 m and giving birth to highly dependent young of just 2.1 m. The species is known to live to at least 27 years in the wild (2).
They are thought to live in couples or small groups, and fighting between males is assumed to occur as stranded males are highly scarred. However, the distinctive tooth marks of the cookie-cutter shark and the orca have been seen on individuals as well. The stomach, which has unexplained multiple chambers, has been found to contain mainly squid, in addition to deep sea shrimp and viper fish (2).
The main threats to Gervais’ beaked whale are accidental entanglement in gillnets and acoustic trauma following military noise pollution underwater (1). In the mid to late 1980s, several mass strandings were thought to be associated with naval activities around the Canary Islands. Later, between 1992 and 1998, 28 Gervais’ beaked whales were stranded along the US coast between Florida and Massachusetts, followed by more mass strandings in September 2002 after NATO tested low frequency sonar (7).
There are no special conservation plans for this species, although trade in this species is limited by CITES around the world and prohibited in Europe.
For further information on this species see Animal Diversity Web:
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- Cetaceans: a group comprising all whales, dolphins and porpoises.
- Pelagic: inhabiting the open oceans.
IUCN Red List (November, 2004)
Animal Diversity Web (November, 2004)
Cetaceans of the World (November, 2004)
CITES (November, 2004)
The Mammals of Texas (November, 2004)
Convention on Migratory Species (November, 2004)
Gervais' Beaked Whale - Mesoplodon europaeus - MarineBio.org (November, 2004)