20.01.2013 Views

Dolphins, Whales and Porpoises: 2002-2010 Conservation - IUCN

Dolphins, Whales and Porpoises: 2002-2010 Conservation - IUCN

Dolphins, Whales and Porpoises: 2002-2010 Conservation - IUCN

SHOW MORE
SHOW LESS

You also want an ePaper? Increase the reach of your titles

YUMPU automatically turns print PDFs into web optimized ePapers that Google loves.

Long-beaked common dolphin,<br />

Delphinus capensis<br />

The long-beaked common dolphin occurs in continental<br />

near-shore tropical <strong>and</strong> warm temperate waters of at least<br />

the Pacific, Atlantic, <strong>and</strong> western Indian oceans (including<br />

Madagascar). In the northern Indian Ocean <strong>and</strong> southeastern<br />

Asia, an even longer-beaked variety replaces D.<br />

capensis, <strong>and</strong> some authors consider it a valid species, D.<br />

tropicalis (van Bree <strong>and</strong> Gallagher 1978; Rice 1998).<br />

Recent morphological evidence indicates that differences<br />

between the two forms are probably clinal, <strong>and</strong> therefore not<br />

species-level (Jefferson <strong>and</strong> Van Waerebeek, <strong>2002</strong>). Although<br />

its known distribution is more restricted than that of<br />

the short-beaked common dolphin, <strong>and</strong> its aggregate abundance<br />

probably much lower, the long-beaked species is not<br />

known to face any major immediate threats to its survival. In<br />

several areas, however, most notably West Africa <strong>and</strong> the<br />

east <strong>and</strong> west coasts of South America, the documentation<br />

of abundance <strong>and</strong> catches is insufficient for proper status<br />

evaluation. There is growing concern about the large<br />

numbers of long-beaked common dolphins killed off Peru<br />

<strong>and</strong> used for human food or shark bait (K. Van Waerebeek,<br />

pers. comm.).<br />

Pygmy killer whale, Feresa attenuata<br />

The pygmy killer whale is widely distributed in tropical <strong>and</strong><br />

subtropical waters worldwide (Figure 17). It appears to be<br />

naturally uncommon, <strong>and</strong> group sizes are generally no<br />

larger than around 30 to 50 individuals. Wade <strong>and</strong><br />

Gerrodette (1993) estimated that there were about 40,000 of<br />

these whales in the eastern tropical Pacific. Because of their<br />

relatively low abundance, even small takes in localized<br />

areas could be significant. However, there is no basis for<br />

serious concern about this species at present.<br />

Short-finned pilot whale,<br />

Globicephala macrorhynchus<br />

This species occurs in tropical <strong>and</strong> warm-temperate<br />

waters worldwide, <strong>and</strong> its distribution extends into<br />

cold-temperate waters in the North Pacific (Bernard<br />

<strong>and</strong> Reilly 1999). Stocks are ill-defined except off<br />

Japan, where two morphologically distinct, allopatric<br />

forms have been identified. The species is<br />

abundant globally, but at least one of the two forms<br />

hunted off Japan is depleted. The northern form,<br />

whose population is estimated at only 4000–5000, is<br />

subject to small-type whaling with an annual national<br />

quota of 50. The southern form, with an<br />

estimated population of about 14,000 in coastal<br />

waters (Miyashita 1993), is subject to small-type<br />

whaling, h<strong>and</strong>-harpoon whaling, <strong>and</strong> drive whaling,<br />

<strong>and</strong> there is an annual national quota of 450.<br />

39<br />

Short-finned pilot whales are hunted by artisanal fishermen<br />

in the Lesser Antilles, especially St. Vincent <strong>and</strong> St.<br />

Lucia, where the combined catch was in the hundreds annually<br />

until at least the mid-1970s. Reliable catch data are<br />

not available for the Caribbean hunts. The species is also<br />

hunted in Indonesia <strong>and</strong> Sri Lanka, but again with no regular<br />

reporting of catch levels. Many short-finned pilot whales are<br />

taken incidentally in fishing gear throughout their range.<br />

Population assessments are needed in areas where directed<br />

hunting takes place or where a large bycatch is known or<br />

suspected. A resident population of pilot whales in the<br />

Canary Isl<strong>and</strong>s is exposed to intensive, <strong>and</strong> thus potentially<br />

disruptive, whale-watching <strong>and</strong> fast-ferry traffic. There are<br />

about 150,000 short-finned pilot whales in the eastern tropical<br />

Pacific (Wade <strong>and</strong> Gerrodette 1993) <strong>and</strong> about a thous<strong>and</strong><br />

in shelf waters off the North American west coast<br />

(Carretta et al. 2001).<br />

Long-finned pilot whale, Globicephala<br />

melas<br />

This species is abundant <strong>and</strong> widely distributed in temperate<br />

to subpolar marine waters. Two subspecies are recognized:<br />

one in the cold temperate <strong>and</strong> subarctic North Atlantic, the<br />

other in temperate to subantarctic waters of the Southern<br />

Hemisphere to as far south as about 68ºS (Bernard <strong>and</strong> Reilly<br />

1999). In the North Atlantic, the species occurs in deep offshore<br />

waters, including those inside the western Mediterranean<br />

Sea, North Sea, <strong>and</strong> Gulf of St. Lawrence. Long-finned<br />

pilot whales tend to follow their prey (squid <strong>and</strong> mackerel)<br />

inshore <strong>and</strong> into continental shelf waters during the summer<br />

<strong>and</strong> autumn.<br />

The southern subspecies has not been exploited on a significant<br />

scale; about 200,000 are estimated to occur in waters<br />

Figure 17. Profile of a pair of pygmy killer whales swimming near<br />

Manado Tua, north-western Sulawesi, Indonesia, August 1998. These<br />

small whales are relatively common in south-eastern Indonesian<br />

waters <strong>and</strong> can sometimes be confused with juvenile Risso’s dolphins.<br />

Photo: Benjamin Kahn.

Hooray! Your file is uploaded and ready to be published.

Saved successfully!

Ooh no, something went wrong!