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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are taken by driving in some years. Reported catches in the<br />
years from 1995 to 1998 were 157, 152, 350, <strong>and</strong> 438,<br />
respectively (Bloch <strong>and</strong> Olsen 1998, 1999; Bloch et al.<br />
1997, 2000). Smaller numbers are taken occasionally in<br />
southern Greenl<strong>and</strong>. Relatively small numbers are also<br />
killed in fishing gear throughout much of the species’ range<br />
(e.g., Palka et al. 1997; Couperus 1997). Mortality in<br />
mid-water trawls is a particular concern (Couperus 1997).<br />
No population assessment is associated with the Faroese<br />
hunting of white-sided dolphins, nor is there evidence that<br />
this aspect of the drive fishery has a long history, such as<br />
that of the pilot whale component. In the absence of any<br />
proper assessment of stock identity <strong>and</strong> abundance, it is<br />
impossible to judge whether this can be regarded as a sustainable<br />
hunt.<br />
White-beaked dolphin,<br />
Lagenorhynchus albirostris<br />
White-beaked dolphins are endemic to the northern North<br />
Atlantic, where they occur mainly on the continental shelf<br />
<strong>and</strong> in semi-enclosed waters, notably the Gulf of St.<br />
Lawrence <strong>and</strong> North Sea (Northridge et al. 1997; Kinze et<br />
al. 1997; Reeves et al. 1999a). Eastern <strong>and</strong> western populations<br />
are phenotypically distinct (Mikkelsen <strong>and</strong> Lund<br />
1994). Estimates of abundance for a number of areas<br />
indicate that there are at least tens of thous<strong>and</strong>s of these<br />
dolphins, with particularly large numbers in the Barents,<br />
Norwegian, <strong>and</strong> North seas (Øien 1996; Hammond et al.<br />
<strong>2002</strong>). White-beaked dolphins are hunted for food in<br />
Newfoundl<strong>and</strong> <strong>and</strong> Labrador, but no records are kept of<br />
numbers killed, <strong>and</strong> there has been little effort to assess<br />
stocks (but see Alling <strong>and</strong> Whitehead 1987).<br />
Peale’s dolphin, Lagenorhynchus<br />
australis<br />
This dolphin is endemic to coastal <strong>and</strong> shelf waters of the<br />
southern cone of South America, from central Chile to<br />
northern Argentina (Goodall et al. 1997a, 1997b; Brownell<br />
et al. 1999b). It also occurs around the Falkl<strong>and</strong> Isl<strong>and</strong>s <strong>and</strong><br />
on Burdwood Bank. In some areas it is closely associated<br />
with kelp beds. Although common within its core distribution,<br />
Peale’s dolphin is confined to near-shore waters <strong>and</strong><br />
has a limited total range. There are no published estimates of<br />
abundance.<br />
The dolphins in Beagle Channel, the Magallanes, <strong>and</strong><br />
southern Tierra del Fuego have been harpooned for crab bait<br />
since the 1970s. The scale of this killing was great enough to<br />
cause reduced abundance by the late 1980s. Although recent<br />
evidence suggests that the scale of this exploitation has<br />
declined <strong>and</strong> that some recovery may be occurring<br />
(Lescrauwaet <strong>and</strong> Gibbons 1994; Goodall et al. 1997b),<br />
there is an ongoing need for better information on population<br />
structure <strong>and</strong> the extent to which these dolphins may<br />
41<br />
still be used as crab bait. Peale’s dolphins are subject to<br />
entanglement in gillnets set near shore, but the scale of<br />
incidental mortality is not considered large in any area of<br />
their range. There is also concern that the proliferation of<br />
salmon-culture facilities in southern Chile, especially along<br />
the indented coastline of Chiloé Isl<strong>and</strong>, is having a negative<br />
effect on Peale’s dolphins – similar to that reported for<br />
Pacific white-sided dolphins <strong>and</strong> killer whales in British<br />
Columbia, Canada (Morton 2000; Morton <strong>and</strong> Symonds<br />
<strong>2002</strong>).<br />
Hourglass dolphin, Lagenorhynchus<br />
cruciger<br />
The hourglass dolphin has an oceanic circumpolar distribution<br />
in the Southern Hemisphere (IWC 1997a; Goodall<br />
1997; Goodall et al. 1997c; Brownell <strong>and</strong> Donahue 1999).<br />
There are an estimated 144,000 dolphins south of the<br />
Antarctic Convergence in summer (Kasamatsu <strong>and</strong> Joyce<br />
1995). The species has never been subjected to significant<br />
exploitation. A few animals are known to have died in set<br />
nets off New Zeal<strong>and</strong> <strong>and</strong> in driftnets elsewhere in the South<br />
Pacific (Goodall et al. 1997c). Almost nothing is known<br />
about the ecology <strong>and</strong> behavior of hourglass dolphins.<br />
Pacific white-sided dolphin,<br />
Lagenorhynchus obliquidens<br />
This species is abundant <strong>and</strong> widely distributed across the<br />
northern rim of the North Pacific, from Baja California in<br />
the east to Japan <strong>and</strong> Taiwan in the west (IWC 1997a;<br />
Brownell et al. 1999a). Phylogeographic partitioning has<br />
been documented through mtDNA <strong>and</strong> morphometric<br />
studies (Lux et al. 1997), <strong>and</strong> differences are exhibited as<br />
latitudinal as well as longitudinal strata. For example, animals<br />
off Baja California, Mexico, differ significantly from<br />
those farther north <strong>and</strong> offshore, <strong>and</strong> animals in British<br />
Columbia <strong>and</strong> Alaska are significantly different from those<br />
in all other areas sampled thus far.<br />
Although there are probably at least hundreds of<br />
thous<strong>and</strong>s of these dolphins in the offshore waters where the<br />
multinational squid driftnet fishery operated until 1992,<br />
incidental mortality in that fishery may have been high<br />
enough to cause depletion (Yatsu et al. 1994; IWC 1997a).<br />
Moderate numbers of white-sided dolphins are sometimes<br />
killed deliberately in the harpoon <strong>and</strong> drive fisheries in<br />
Japan <strong>and</strong> accidentally in gillnets <strong>and</strong> other fishing gear<br />
throughout the species’ range. There are an estimated<br />
26,000 Pacific white-sided dolphins off the coasts of<br />
California, Oregon, <strong>and</strong> Washington (Carretta et al. 2001).<br />
A long-term study at an inshore site in British Columbia<br />
suggests an association between the local occurrence of<br />
Pacific white-sided dolphins <strong>and</strong> large-scale oceanographic<br />
events (e.g., El Niño). The same study indicates a decline in<br />
abundance of this species <strong>and</strong> other cetaceans from 1994 to