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Chatham Islands
Map ID number:
2
Location: 860 km east of
New Zealand’s south island on
the Chatham Rise
Approximate area: 14,334km 2
Description of area:
The Chatham Islands are the most easterly
island group in the New Zealand marine
zone. They sit atop the Chatham Rise, a submarine
plateau that extends eastward from
the South Island. In this zone subantarctic
and subtropical elements intermix. There are
complex currents and eddies associated with
the shelf edges and subterranean features of
the area.
Biological attributes:
The habitat of this area provides island
breeding locations close to productive feeding
areas for seabirds. Many species feed
close to the breeding islands. A mix of
breeding species is found on the Chatham
Islands, with feeding ranges extending to the
subtropical waters in the north, the subantarctic
waters in the south, and to the pelagic
areas and over the submarine volcanic chains
to the east. The islands are known for massstrandings
of whales and oceanic dolphins,
indicating large populations in the surrounding
waters. They are also the type-locality
(the site where the specimen used to describe
the species originated) for two beaked
whales (Mesoplodon grayi and M. traversii).
The ocean around the Chatham Islands is
rich in marine life, supporting valuable fishing
resources for people and animals. There
are internationally significant populations of
seabirds and nationally significant populations
of whales, dolphins, and seals.
There is a high level of endemism in the
seabird fauna of the Chatham Islands. Seven
albatross species breed on the islands. One
of the species (Chatham Island albatross)
is a local endemic, and four are endemic
to the New Zealand region – two of which
have the vast majority of the population on
the Chatham Islands (northern royal and
Pacific albatrosses). The Chatham Islands
blue penguin (Eudyptula minor chathamensis)
is the islands’ only penguin species, and
is a subspecies endemic to the islands. The
Chatham Island oystercatcher (Haematopus
chathamensis) is endemic and classified as
endangered. Thirteen petrel species live in
©2004 DOC, Te Papa Atawhai/C.J.R. Robertson
the Chatham Islands, two of which (taiko or
magenta petrel (Pterodroma magentae) and
Chatham Island petrel (Pterodroma axillaris))
are endemic and endangered. The
islands are home to 2 cormorant species
(Chatham Island and Pitt shags), both of
which are endemic, and 4 tern and gull species,
one of which is endemic. The Chatham
Islands also have a fur seal population that is
recovering from significant human impact to
be one of the major New Zealand groups of
colonies.
Criteria applied:
Endemism; species richness; species diversity;
conservation status/threat classification.
Status and management:
The Chatham Islands have the highest levels
of endemism and greatest number of endangered
seabird species of any New Zealand
area. The endemism and endangered status
of these seabirds is primarily related to modification
of habitat and introduced predators
combined with restricted breeding sites.
About 50% of the bird species (land and
marine) present at the time of European contact
are today either extinct, endangered or
severely reduced in numbers. Approximately
20% of New Zealand’s threatened bird fauna
occur on the Chatham Islands.
The main seabird fauna is confined to outer
islands and islets after human modification
of the two main islands. The three island
groups with albatrosses are in private Maori
ownership while other significant bird sites
are mostly island reserves or part of the main
island reserve. There are no marine mammals
endemic to the islands. On the main
Chatham Island there are predator control
programmes to improve the productivity and
survival of the endangered Chatham Island
oystercatcher and taiko.
State of information:
There is much information available for
endemic and endangered species currently
under extensive conservation management
(e.g. Aikman et al. 2001, Aikman and
Miskelly 2004).
References and further
reading:
Aikman et al. (2001), Aikman
and Miskelly (2004), Bell and
Robertson (1994), Department
of Conservation Canterbury
Conservancy (1996), Department
of Conservation (1996, 1999b),
Holdaway (1994), Taylor (2000).
Chatham Island mollymawk on nest
22 ■ BIODIVERSITY – NEW ZEALAND’S MARINE ECOREGION