Dolphins, Whales and Porpoises: 2002-2010 Conservation - IUCN
Dolphins, Whales and Porpoises: 2002-2010 Conservation - IUCN
Dolphins, Whales and Porpoises: 2002-2010 Conservation - IUCN
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time), they had not yet attained 80% of those levels. Importantly,<br />
the large illegal kills by Soviet factory ships in the<br />
Southern Hemisphere from the 1950s to the early 1970s<br />
would have delayed recovery of southern stocks.<br />
4.3 Gray whale<br />
Gray whale, Eschrichtius robustus<br />
The gray whale was extirpated from the North Atlantic<br />
within the last 300–400 years, so the only extant representatives<br />
of the family Eschrichtiidae are the gray whales<br />
in the North Pacific. The western Pacific stock, which may<br />
number no more than about 100 individuals, was reclassified<br />
in the 2000 <strong>IUCN</strong> Red List from Endangered to<br />
Critically Endangered (under the 1996 categories <strong>and</strong><br />
criteria). Its principal summer feeding area is off Sakhalin<br />
Isl<strong>and</strong> in the Russian sector of the Okhotsk Sea, where a<br />
major oil <strong>and</strong> gas field is being developed by a multinational<br />
energy consortium (Weller et al. <strong>2002</strong>). The annual migration<br />
takes these whales into coastal waters of Japan,<br />
Korea, <strong>and</strong> China, where they are vulnerable to ship collisions<br />
<strong>and</strong> entanglement in fishing gear. Moreover, a female<br />
from this population was found on a Japanese beach in<br />
1996 bearing several harpoons of the kind used in the Dall’s<br />
porpoise hunt off Japan (Brownell <strong>and</strong> Kasuya 1999; Baker<br />
et al. <strong>2002</strong>). This incident demonstrates that the western<br />
Pacific population is at risk from illegal hunting.<br />
The eastern stock of more than 21,000 has been growing<br />
steadily in spite of an annual hunt in Russia governed by an<br />
IWC quota (Buckl<strong>and</strong> <strong>and</strong> Breiwick <strong>2002</strong>). In recent years,<br />
however, this population has experienced an unprecedented<br />
amount of mortality on its migration route <strong>and</strong> in the winter<br />
breeding areas, <strong>and</strong> exhibited a decline in calf production<br />
(Le Boeuf et al. 2000). There is concern that these trends,<br />
should they persist, could lead to a significant decline in<br />
abundance of the eastern Pacific stock.<br />
4.4 Pygmy right whale<br />
Pygmy right whale, Caperea marginata<br />
The pygmy right whale is thought to have a circumpolar<br />
distribution in temperate <strong>and</strong> subantarctic waters of the<br />
Southern Ocean. It is one of the least known cetacean<br />
species, although recently completed anatomical studies<br />
(Kemper <strong>and</strong> Leppard 1999) <strong>and</strong> observations at sea (e.g.,<br />
Matsuoka et al. 1996) have begun to reveal basic information.<br />
There are no known conservation problems (Kemper<br />
<strong>2002</strong>).<br />
37<br />
4.5 Marine dolphins<br />
Commerson’s dolphin,<br />
Cephalorhynchus commersonii<br />
Commerson’s dolphins occur as two disjunct populations.<br />
The larger is centered in coastal <strong>and</strong> inshore waters of the<br />
western South Atlantic, including Patagonia, the Strait of<br />
Magellan, Tierra del Fuego, <strong>and</strong> the Falkl<strong>and</strong> Isl<strong>and</strong>s (Las<br />
Malvinas). Some individuals move south through Drake<br />
Passage as far as the South Shetl<strong>and</strong> Isl<strong>and</strong>s. The other<br />
population inhabits coastal waters around the Kerguelen<br />
Isl<strong>and</strong>s in the southern Indian Ocean (Goodall 1994).<br />
The species’ near-shore distribution makes it vulnerable<br />
to incidental capture in gillnets <strong>and</strong> other fishing gear used<br />
in coastal waters. Commerson’s dolphins are killed at least<br />
occasionally in mid-water trawl nets on the Argentine shelf<br />
(Crespo et al. 1997). The South American population has<br />
also been subjected to harpooning (mainly for crab bait) <strong>and</strong><br />
some live-capture for oceanaria (Lescrauwaet <strong>and</strong> Gibbons<br />
1994). No good estimates are available on the magnitude of<br />
the catches, but recent surveys indicate that the species is<br />
still relatively abundant on the Patagonian shelf <strong>and</strong> in the<br />
Strait of Magellan (Lescrauwaet et al. 2000; Crespo, unpublished<br />
data).<br />
Chilean dolphin, Cephalorhynchus<br />
eutropia<br />
The Chilean dolphin is endemic to coastal waters of Chile,<br />
from near Valparaíso (33°S) south to Navarino Isl<strong>and</strong> near<br />
Cape Horn (55°15’S). It is relatively common in the channels<br />
of Chile’s convoluted coastline south from Chiloé<br />
Isl<strong>and</strong>. The crab bait fishery in southern Chile (cf.<br />
Lescrauwaet <strong>and</strong> Gibbons 1994) <strong>and</strong> a variety of other<br />
fisheries (particularly coastal gillnet fisheries) have been<br />
viewed as potentially serious threats. Some shooting <strong>and</strong><br />
harpooning also occurs, with the dolphins used for bait or<br />
human consumption. Unfortunately, there is no systematic<br />
monitoring of either mortality or abundance, so the species’<br />
status is uncertain. In addition to the mortality caused by<br />
entanglement <strong>and</strong> hunting, Chilean dolphins may now be<br />
excluded by salmon aquaculture operations from some of<br />
the bays <strong>and</strong> fiords that they traditionally inhabited (Claude<br />
et al. 2000).<br />
Heaviside’s dolphin,<br />
Cephalorhynchus heavisidii<br />
Heaviside’s dolphins have an extremely limited range<br />
(Figure 16). They occur only in coastal waters off the west<br />
coast of southern Africa, from near the Angola-Namibia<br />
border (at about 17°S) south to Cape Point, South Africa<br />
(near Cape Town). They are said to be the most commonly<br />
sighted dolphins in Namibian waters. There is no clear