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Subantarctic Islands
(and continental
shelf areas to 500m
depth)
Map ID number:
1
Location: Island groupings
to the south and southeast
of terrestrial New Zealand
including Snares, Bounty,
Antipodes, Auckland, and
Campbell islands
Approximate area: 104,113km 2
Table 1. Seabirds and marine
mammals that breed on the
subantarctic islands
Description of area:
The five subantarctic island groups are scattered
across the Campbell Plateau and other
submerged shelves of the southern New
Zealand continental region. The plateau is a
major feature that sits just north of the Subantarctic
Front, at the northern boundary of
the Antarctic Circumpolar Current that circles
the Southern Hemisphere and connects all the
large ocean basins. Despite there being plenty
of phytoplankton nutrients, such as nitrates,
the region has relatively low levels of phytoplankton
biomass and primary production
(Bradford-Grieve et al. 2003, Peat 2003).
Biological attributes:
The subantarctic islands are highly pristine
and lack disturbance. Each island has a
unique faunal assemblage because of their
wide geographic spread and diverse and productive
marine environment. Some islands
have no introduced pests (e.g. The Snares,
and Adams Island in the Auckland Islands
group), and on others the pest mammals have
been removed (e.g. from Enderby Island and
Campbell Island). All islands provide excellent
seabird nesting and marine mammal
breeding locations that are close to major
feeding areas. The Auckland and Campbell
islands are a winter breeding ground for a
remnant population of southern right whales
(Eubalaena australis). The continental shelf
is a productive area for inshore and shelf
feeders, such as the yellow-eyed penguin
(Megadyptes antipodes) and New Zealand
sea lion (Phocarctos hookeri).
The islands are also good locations for albatrosses
to access remote productive feeding
areas in the subantartic. Forty seabird species
(11% of the world total) breed in the
New Zealand subantarctic and over 120 species
have been observed at the islands or in
the surrounding oceans. These include 10
(42%) of the world’s 24 albatross species that
breed in the New Zealand subantarctic (5 are
endemic to the region), making the area a
centre of biological diversity for albatrosses.
Furthermore, 21 (30%) of the world’s petrels,
shearwaters, fulmars, and prions are observed
in the subantarctic islands. Four penguin species
breed (Snares crested (Eudyptes robustus)
and erect-crested (Eudyptes sclateri) are
endemic) and there are three endemic shag
species (Campbell Island, Auckland Island,
Antipodes Auckland Bounty Campbell Snares
Islands Islands Islands Island Islands
Albatross 4 4 1 6 2
Flightless duck 0 1 0 1 0
Penguin 2 2 1 3 1
Petrel 12 10 2 9 8
Tern/gull 3 4 1 4 2
Seal 2 2 1 3 0
Whale 0 1 0 1 0
and Bounty Island shags). Table 1 indicates
the number of seabird and marine mammal
species that breed on each of the subantarctic
islands.
Criteria applied:
Species richness; endemism; unusual degree/
proportion of biomass (e.g. millions of seabirds
occupy the Snares).
Status and management:
All islands are nature reserves and collectively
are a World Heritage Site, and the
Auckland Islands are surrounded by a marine
mammal sanctuary and marine reserve. Several
endemic species are considered to face
a high threat of extinction under the IUCN
and/or Department of Conservation threat
classification schemes. For example, two
penguin species (yellow-eyed penguin and
erect-crested penguin) are currently listed as
endangered under the IUCN classification. 4
Most albatross are classified as at least “vulnerable”
because of large population declines
and small breeding areas. More widespread
species have also shown greater than 90%
declines in population in the New Zealand
region, such as the rockhopper penguin (Eudyptes
chrysocome), grey-headed albatross
(Thalassarche chrysotoma), and southern
elephant seal (Mirounga leonine).
State of information:
The breeding information for most species
of birds and mammals in the subantarctic
region is very good. Population assessments
are, however, of variable quality and reliability,
depending upon the species. Knowledge
of species relationships is good. Information
on foraging is limited, therefore niche
separations are not as well understood.
There is detailed information available for
some species, such as the New Zealand
sea lion. Extensive information is available
from satellite telemetry of Buller’s albatross
(Thalassarche bulleri), Gibson’s albatross
(Diomedea gibsoni), and Antipodean albatross
(Diomedea anipodensis) and to a lesser
extent some other albatross species.
References and further reading:
Childerhouse and Gales (1998, 2001),
Childerhouse et al. (2001), Cunningham and
Moors (1994), Department of Conservation
(1997,1999a), Gales (1998), Gales and
Fletcher (1999), Hitchmough (2002),
IUCN (2002), Miskelly et al. (2001), Peat
(2003), Parliamentary Commissioner for the
Environment (1999), Robertson and Nunn
(1998), Stahl and Sagar (2000), Taylor and
Taylor (1989), Tickell (2000), Waugh et al.
(1999).
4
The erect-crested penguin is also listed as
endangered under the Department of
Conservation’s threat classification system.
BIODIVERSITY – NEW ZEALAND’S MARINE ECOREGION ■ 21