Mesoplodon grayi, von Haast, 1876

Russell A. Mittermeier & Don E. Wilson, 2014, Ziphiidae, Handbook of the Mammals of the World – Volume 4 Sea Mammals, Barcelona: Lynx Edicions, pp. 326-357 : 355

15.

Gray’s Beaked Whale

Mesoplodon grayi

French: Baleine-a-bec de Gray / German: Gray-Zweizahnwal / Spanish: Zifio de Gray

Other common names: Scamperdown Whale, Southern Beaked Whale

Taxonomy. Mesoplodon gray: Von Haast, 1876 ,

New Zealand, “the Chatham Islands...from specimens stranded...on the Waitangi beach of the main island of that group.”

This species is monotypic.

Distribution. Ranges from temperate waters of the S Atlantic, Indian, and S Pacific oceans to waters of Antarctica. A single specimen stranded on the Dutch coast is thought to have been a vagrant individual.

Descriptive notes. Total length 450-500 cm; weight ¢.900 kg (unconfirmed). Body of Gray's Beaked Whale is spindle-shaped, with greatest girth around its midpoint. Flukes are wide in relation to body length, and tailstock is compressed laterally. Dorsal fin is small and set approximately two-thirds the distance betweentip of the beak and end of the tail. Colorationis typically dark brown, dark gray, or black and paler on the ventral surface. Tip of rostrum is often colored white, especially in adult males. Rostrum and lower jaw form a long distinct beak, and there are two grooves on the throat. Adult males have a single tusk on each side of the lower jaw; tusks are positioned about halfway along the jaw line. Tusks are approximately triangular but may become heavily worn over time.

Habitat. Waters greater than 200 m deep. In common with other species of Mesoplodon , Gray's Beaked Whale may be more common in areas of complex seabed topography, but this still has to be confirmed.

Food and Feeding. While it is often assumed that Gray's Beaked Whales consume deep-water cephalopods, analyses of stomach contents suggest that they may primarily consume deep-water fish species. In common with other species of beaked whales, Gray's Beaked Whales likely forage at depths greater than 500 m for much of their lives.

Breeding. Almost nothing is known about the reproductive biology of Gray’s Beaked Whale. Females give birth to a single offspring after gestation that is likely twelve months. Offspring likely remain dependent on their mothers for at least one year.

Activity patterns. There is no information available for this species.

Movements, Home range and Social organization. There is no specific information available for this species, but sightings of Gray's Beaked Whales at sea tend to be of relatively small groups of five or fewer individuals. Nothing is known about the typical composition of these groups.

Status and Conservation. CITES Appendix II. Classified as Data Deficient on The [UCN Red List. There are no estimates of global population size of Gray's Beaked Whale. It may be one of the more abundant species of Mesoplodon and may be relatively common in some areas, such as waters to the south of New Zealand. Like other species of beaked whales, Gray’s Beaked Whale is potentially affected by ingestion of plastic debris and noise pollution, and individuals can be caught as bycatch in driftnet fisheries. As a species restricted to cooler waters, it may also be vulnerable to effects of climate change. Nevertheless, nothing is known about the form or extent ofthese potential impacts.

Bibliography. Macleod, Perrin et al. (2006), MacLeod, Santos & Pierce (2003), Mead (1989b), Rice (1998).

Figures

On following pages: 18. Sowery's Beaked Whale (Mesoplodon bidens); 19. Blainville’s Beaked Whale (Mesoplodon densirostris); 20. Andrews's Beaked Whale (Mesoplodon bowdoini); 21. Spade-toothed Whale (Mesoplodon traversil); 22. Gervais's Beaked Whale (Mesoplodon europaeus).

Distribution. Ranges from temperate waters of the S Atlantic, Indian, and S Pacific oceans to waters of Antarctica. A single specimen stranded on the Dutch coast is thought to have been a vagrant individual.