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= Heard Island and McDonald Islands =
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Introduction
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The Territory of Heard Island and McDonald Islands is an Australian
external territory in the southern Indian Ocean. Discovered in the
mid-19th century, the territory is a group of sub-Antarctic volcanic
islands that lie on the Kerguelen Plateau. It is about 4000 km
south-west of the Australian mainland and 1700 km north of Antarctica.
The territory contains Australia's only active volcanoes and is home
to its highest point outside the Australian Antarctic Territory,
Mawson Peak. The territory is uninhabited and has been described as
one of the most remote places on Earth.
The first confirmed sightings of Heard Island and the McDonald Islands
took place in the 1850s. Heard Island was occupied by sealers until
1882 and saw occasional scientific visits in the late 19th and early
20th centuries. The territory was claimed by the United Kingdom and
was then transferred to Australia in 1947. Between 1947 and 1955, the
Australian National Antarctic Research Expeditions (ANARE) occupied a
research station on the island. Since the closure of the ANARE
research station, the islands have been visited by occasional
scientific and private expeditions. Today, the islands are a nature
reserve and World Heritage Site managed by the Australian Antarctic
Division.
Heard Island is dominated by Big Ben, a stratovolcano that is topped
by the volcanic cone Mawson Peak. About 70 percent of the island is
covered by year-round glaciers, while vegetation occupies just 5
percent. The island is volcanically active, with Mawson Peak regularly
emitting steam and vapour and occasionally releasing flows of lava.
The McDonald Islands, located about 43 km to the west of Heard Island,
are a group of smaller volcanic islands that have seen just two
recorded human landings. Heard Island and the McDonald Islands are
known for their harsh climate, characterised by cold temperatures,
strong winds, and heavy rain and snow.
Heard Island and the McDonald Islands are home to a large number of
eastern rockhopper, gentoo, macaroni, and king penguins. With more
than one million breeding pairs, Heard Island contains about 20
percent of the world's macaroni penguins. The islands also contain
substantial populations of elephant seals and Antarctic fur seals.
They are a breeding site for at least 15 flying seabird species,
including the Heard Island cormorant, a species unique to Heard
Island. Commercial fishing of Patagonian toothfish and mackerel
icefish takes place in the surrounding waters. Heard Island has seen
rapid melting of its glaciers and other environmental changes in
recent decades, largely due to climate change.
History
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The first confirmed sighting of Heard Island took place in 1853 when
the island was spotted by the American captain John Heard aboard
'Oriental'. Other sailors had reported observing land south of the
Kerguelen Islands during the 1830s and 1840s, but whether they in fact
sighted Heard Island is unclear. Researchers have suggested that
earlier sightings of the island may have been kept secret for
commercial reasons, but no evidence has been found on the island of
human inhabitation or visitation prior to the 1850s. Heard named the
island Heard Island and claimed it for the United States, but the
country's government declined to endorse the claim. In 1854 the
British captain William McDonald sighted the McDonald Islands aboard
'Samarang'; he likewise named the islands after himself. A party of
sealers led by the American captain Erasmus Darwin Rogers of the ship
'Corinthian' made the first recorded landing on Heard Island in 1855.
Sealers continued to occupy the island over the following decades,
with more than 40 vessels collectively making over 100 visits to hunt
elephant seals and process their blubber into oil. Between 1855 and
1880, more than 100,000 barrels of oil were produced on the island. At
the peak of production in 1859, there were 24 vessels stationed at
Heard Island. The majority of the sealing companies were American and
were based out of ports in New England, although some of the sealers
were from Cape Verde. The island was also exploited by Australian
sealers, including James William Robinson, who conducted an expedition
on behalf of the Tasmanian merchant William Crowther in 1858. Robinson
wrote a memoir about the expedition, which is now held by the W. L.
Crowther Library. During the sealing period 14 ships were wrecked near
the island. According to one estimate, 30 sealers died on Heard Island
between 1857 and 1881 and 30 died on their way to the island, largely
after being washed overboard. By the 1880s the elephant seal
population on the island had been severely depleted and sealing
activity declined substantially.
Brief scientific expeditions to Heard Island took place in 1874, 1902,
and 1929, with their observations limited to the north-western side of
the island. The first two expeditions were undertaken by the ships
'Challenger' and 'Gauss' in 1874 and 1902 respectively; each remained
at Heard Island for just a few hours. Two scientific parties landed on
the island in 1929 and remained for eight days: one was led by the
Swiss geologist Edgar Aubert de la Rüe, while the other was composed
of members of the British Australian and New Zealand Antarctic
Research Expedition (BANZARE) party. The BANZARE party had planned to
spend just three days on the island, but were forced by poor weather
to remain for an additional five days. Between 1907 and 1930, some
sealing activity resumed on the island and whaling ships made
occasional visits.
Heard Island and the McDonald Islands were claimed by the United
Kingdom in 1908. The British flag was raised on Heard Island in 1910
and 1929, and between 1910 and 1926 the British government issued
licences for sealing and whaling on the island. A British company was
allowed to lease the islands from the British government in 1926,
although by 1930 it was no longer exercising its lease. By the 1930s
the British government felt that Australia's proximity to its
Antarctic possessions would provide a firmer claim to sovereignty,
particularly over sectors of the Antarctic continent, and would reduce
the logistical complexity of administering the territories. After
Britain's transfer of the Australian Antarctic Territory to Australia
in 1933, the Australian government began preparing to also take
possession of Heard Island and the McDonald Islands.
On 11 December 1947 a party of 14 men from the Australian National
Antarctic Research Expeditions (ANARE), led by Stuart Campbell, landed
at Atlas Cove on Heard Island and established a research station. The
goal of the expedition was to establish an observatory on the island,
reinforce Australia's strategic and economic interests in the
territory, and lay the foundations for a permanent ANARE presence on
the Antarctic continent. They raised the Australian flag and conducted
weather observations, performed geological and wildlife surveys, and
mapped the island over the next 14 months. The station was occupied
until 1955 by a rotating series of seven ANARE parties, each of which
spent 12-14 months on the island. On 19 December 1950 the territory
was transferred from Britain to Australia via an exchange of notes,
with the transfer backdated to December 1947. The Australian
government passed the 'Heard Island and McDonald Islands Act' in 1953
to establish a mechanism for the administration of its newly acquired
territory.
The ANARE expedition parties operated a radio outpost and weather
monitoring station on Heard Island and conducted research. Beginning
in 1950 they also bred and trained sled dogs, many of which eventually
supported Australian stations on the Antarctic continent. The ANARE
station, which eventually grew to about 25 buildings, was closed in
1955 to fund the establishment of Mawson Station on the Antarctic
continent. Much of the equipment on Heard Island was also transferred
to Mawson Station.
Nineteen short research expeditions to the island took place between
1956 and 2004. In 1992, one of these expedition parties remained on
the island over the winter for the first time since the closure of the
ANARE station in 1955. Infrequent visits by tourists and private
expeditions have also taken place since 1963. The island was the site
of the 1991 Heard Island feasibility test, which investigated whether
transmission of acoustic signals through the ocean could be used to
study changes in ocean temperatures. The islands were inscribed on the
World Heritage List in 1997. In the same year, the Australian ship
'Austral Leader' began commercial fishing in the surrounding waters.
The Heard Island and McDonald Islands Marine Reserve was established
in 2002 and was the world's largest marine protected area at the time.
The establishment of a marine reserve had been proposed in 2000 as
part of a report commissioned by the Australian government, and was
intended to protect the territory's marine fauna and comply with
Australia's obligations under the Convention on Biological Diversity.
In October 2025 and January 2026 the Australian Antarctic Division
conducted voyages to Heard Island on RSV 'Nuyina', marking the first
environmental management visits to the island in more than two
decades. The scientists conducted wildlife and vegetation surveys,
removed more than one tonne of waste and asbestos from the island, and
installed equipment to allow for remote monitoring of the ecosystem.
The visit provided scientists with confirmation that H5 bird flu had
reached the island.
Governance and administration
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The Territory of Heard Island and McDonald Islands is one of seven
Australian external territories. The islands and the surrounding
waters form an uninhabited strict nature reserve managed by the
Australian Antarctic Division, part of the Department of Climate
Change, Energy, the Environment and Water. Unauthorised entry to the
territory has been prohibited since May 2014, and all visitors to the
islands are required to complete a training program and comply with
quarantine procedures. Despite these restrictions, some unauthorised
landings on the islands are known to have taken place. While the
frequency of these unauthorised visits is unknown, they have been
identified as a potential biosecurity risk to the territory. There
have been just two recorded successful human landings on the McDonald
Islands, which took place in 1971 and 1980. The Heard Island and
McDonald Islands Marine Reserve was established in October 2002 and
was expanded in 2014 and 2025. It now covers an area of about 380000
sqkm and sits within the 410722 sqkm Australian exclusive economic
zone (EEZ) that surrounds the islands.
The Australian parliament passed the 'Heard Island and McDonald
Islands Act' in 1953 to establish a legal framework for the
administration of the territory. This was followed by the 1987 'Heard
Island and McDonald Islands Environment Protection and Management
Ordinance' and then by the first Heard Island Wilderness Reserve
Management Plan in 1995. The territory is governed by the non-criminal
laws of the Australian Capital Territory and by the criminal laws of
the Jervis Bay Territory. Commonwealth laws apply to the territory
only if it is explicitly included within their jurisdiction. The
Governor-General of Australia is also able to issue ordinances for the
administration of Heard Island and McDonald Islands under the 'Heard
Island and McDonald Islands Act 1953'. The 'Environmental Protection
and Biodiversity Conservation Act 1999' serves as the main legislative
framework for the environmental conservation of the territory.
In April 2025, a ten percent tariff was imposed on the territory by
the administration of U.S. President Donald Trump. This was attributed
to erroneous data indicating that the United States had imported 1.4
million U.S. dollars in goods (largely machinery and electrical
imports) from Heard Island and McDonald Islands in 2022. At the time
of the tariff imposition, there had been no known visits to the
islands by humans in approximately ten years.
Maritime boundaries
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The Territory of Heard Island and McDonald Islands includes a
territorial sea extending to a radius of 12 nautical miles from the
islands. This is surrounded by an Australian EEZ with a radius of 200
nautical miles, which borders the French EEZ generated by the
Kerguelen Islands to the north-west. The Heard Island and McDonald
Islands Marine Reserve, which covers about 90 percent of the
Australian EEZ, includes a marine sanctuary zone (IUCN 1a) that
encompasses the islands' territorial seas and a portion of the EEZ
waters to the north of the islands, as well as a 140000 sqkm national
park zone (IUCN II) and a 170000 sqkm habitat protection zone (IUCN
IV). In 2012 Australia proclaimed an extended continental shelf
covering an area of 1130000 sqkm surrounding Heard Island and McDonald
Islands, thereby claiming exclusive rights to harvest its seabed
resources.
Fishery
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While fishing is prohibited within the territorial waters of Heard
Island and McDonald Islands, commercial fishing takes place elsewhere
within the surrounding EEZ. The Heard Island and McDonald Islands
Fishery is managed by the Australian Fisheries Management Authority
(AFMA), which sets quotas on fishing catches and monitors compliance
with the Convention on the Conservation of Antarctic Marine Living
Resources. The species targeted are the Patagonian toothfish and the
mackerel icefish. There are typically about 1-3 vessels harvesting
Patagonian toothfish, primarily using longlines, and about 2-5 vessels
gathering mackerel icefish, largely through trawl fishing, each year.
Two AFMA observers are required to be present on each vessel. Bycatch
of protected species has been identified as a possible threat to the
sustainability of the Heard Island and McDonald Islands Fishery.
Illegal fishing has historically been reported near the islands,
particularly by fishers targeting the valuable Patagonian toothfish.
In October 1997 a vessel was arrested for unlicensed fishing within
the Heard and McDonald Islands Australian Fishing Zone for the first
time. That year, it was estimated that up to 70 vessels may have been
operating illegally in the region. By 2004 eight vessels had been
arrested near the islands, with seven of those arrests involving the
Australian Defence Force. Australian civilian and military vessels
have conducted patrols in the waters surrounding the islands to deter
and respond to illegal fishing. Australia signed a treaty with France
in 2003 to enable cooperation in surveilling and patrolling the waters
around the islands, as well as the nearby French territory of the
Kerguelen Islands. Since the mid-2000s, illegal fishing has reportedly
been eliminated from the waters surrounding the Heard and McDonald
Islands; as of 2019 there had been no reports of illegal fishing
activity since 2006-2007.
Structures and archaeology
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The first known human-made structures on Heard Island were rudimentary
shelters dug into the ground by sealers in the 1850s. By the 1860s,
sealers had begun to build above-ground shelters out of rocks, the
remains of which are still visible on the island. A wooden hut may
also have been constructed on the island by a shipwrecked party in the
late-19th century. Some sealers constructed rudimentary stone
platforms on which to work, while others modified lava caves to use as
shelters.
One of the first conventional structures erected on Heard Island was
Admiralty Hut, built in 1928 by the crew of the whaling ship
'Kildalkey' under commission by the British Admiralty. The hut has
been degraded by the weather over time and is now in ruins. The
remains of the research station occupied by ANARE expedition parties
between 1947 and 1955 have largely been cleared from the site by the
Australian Antarctic Division, with only the ruins of the recreation
hut still standing. More recent expeditions have used temporary
fibreglass shelters that were removed after use, as well as modified
water tanks. Five of these modified water tank shelters remain at Spit
Bay, while two are present at Atlas Cove.
The island contains various pieces of machinery and equipment that
have been left by past research expeditions, including the wreckage of
a landing craft, a bulldozer, diesel generators, fuel barrels, and
water tanks. Wooden debris from the wreckage of sealing vessels can be
found on the shores of the island. There are also various artefacts on
the island left by sealers, including try pots (large pots used for
processing blubber into seal oil) and barrels. Some of these sealing
artefacts have been taken to Australia, and a blubber press from the
island is now held by a museum.
Location and geography
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Heard Island and the McDonald Islands lie in the southern Indian
Ocean, about 4100 km south-west of Perth and 1700 km north of
Antarctica. The closest land is the Kerguelen Islands, a French
external territory, which are located about 450 km to the north-west.
The islands lie on the Kerguelen Plateau, a large igneous province
that covers an area of about 2000000 sqkm. The territory includes
Heard Island, Shag Islet, and the McDonald Islands. The islands are
considered one of the most isolated places on Earth and contain the
only active volcanoes in Australian territory.
Heard Island has an area of around 368 sqkm and is largely made up of
a 2745 m stratovolcano named Big Ben. With the exception of mountains
in the Australian Antarctic Territory, its summit Mawson Peak is the
tallest peak on territory claimed by Australia. The island contains a
second volcanic cone with a height of 706 m named Mount Dixon on the
Laurens Peninsula on the western side of the island. Its eastern side
features a sand spit (a narrow sandbar projecting into the sea) named
Elephant Spit. The island has a width of about 40 km from east to west
and is largely covered by glaciers, with about 70 percent of its land
area permanently glaciated. It contains 15 wetland areas with areas of
5-145 ha, as well as a number of lagoons formed by glacial melting.
These wetlands and lagoons have a total area of about 1860 ha. Various
volcanic features, including lava tube caves and cinder cones, are
present on the island.
The McDonald Islands are a group of smaller volcanic islands located
about 43 km to the west of Heard Island. The group includes three
islands: McDonald Island, Flat Island, and Meyer Rock. After a period
of dormancy of around 75,000 years, volcanic activity resumed on the
islands during the 20th century, with significant eruptions in 1992
and 1997. During the 1990s, this volcanic activity caused the islands
to grow and rise in elevation by nearly , with the main island more
than doubling in size and losing all of its vegetation. Between 1994
and 2004, McDonald Island grew from about 1 sqkm to 2.5 sqkm and
became joined to the nearby Flat Island by an isthmus. The eruptions
also created a new volcanic cone, several lava domes, and pumice
rafts. The island is surrounded by cliffs with heights of up to 230 m
and has no permanent ice cover.
Formation and geology
=======================
Heard Island and the McDonald Islands lie on the Kerguelen Plateau, a
large igneous province rising up to above the surrounding ocean floor
on the Antarctic Plate that began forming about 130 million years ago.
Volcanic activity caused by the Kerguelen hotspot has created various
islands rising above the ocean surface over time, including Heard
Island and the McDonald Islands. A 2016 study estimated that Heard
Island began to develop about 22 million years ago during the early
Miocene period. The volcanic activity that formed Big Ben is believed
to have occurred over the last 1 million years, while Mawson Peak,
Mount Dixon, and the lava cones on the island formed as recently as
the last 10,000 years. The McDonald Islands are also volcanic in
origin and are believed to have formed within roughly the last 100,000
years. Rocks from Heard Island and the McDonald Islands form two
distinct lava series; the newer lavas on Heard Island are primarily
basaltic, while the lavas on the McDonald Islands are phonolitic. The
Heard Island lava series includes basalts, trachybasalts, and
basanites, while the McDonald Islands lava series is characterised by
compounds of phonotephrite, tephriphonolite, and phonolite.
Heard Island's basement is made up of white and pink limestone likely
deposited about 45-50 million years ago during the Paleogene period,
which remains visible on parts of the Laurens Peninsula. On top of the
island's limestone basement sits the Drygalski Formation, a layer of
volcanic rock and sediment about 300-350 m in thickness that formed
around 9 million years ago. The Drygalski Formation forms a plateau
with exposed layers of rock along the island's northern coast.
Volcanic activity on the island over the last million years has added
another layer to the stratigraphy and created Big Ben and Mount Dixon,
which lie on top of the Drygalski Formation's flat eroded base. Heard
Island includes two distinct lava series: the lavas of Big Ben are
primarily composed of alkali basalts, trachybasalts, and basanites,
while the lavas on the Laurens Peninsula feature a distinct isotopic
signature and more basanitic and trachytic compounds. According to one
study, the distinct isotopic compositions of the lavas on Heard Island
indicate that the mantle beneath the island contains traces of
continental crust that were incorporated into the mantle sometime
before the separation of the landmass Gondwana.
Big Ben
=========
Big Ben is a volcanic massif that forms the majority of Heard Island's
landmass. It has a plateau at a height of about 2285 m which is topped
by Mawson Peak, an active volcanic cone. The plateau is believed to be
the result of a sector collapse that occurred some time in roughly the
last 40,000 years. The volcano has a diameter of about and a height
of 2745 m. A 2021 study estimated that the age of two samples of lava
taken from the volcano was around 11,100 and 23,900 years. The volcano
has a relatively low average discharge rate of about 200,000 cubic
metres of magma per year and forms part of one of the world's oldest
plume systems.
Only three parties have successfully reached the summit of Big Ben.
The first ascent was made by the Southern Indian Ocean Expedition in
1965, the second by the 'Anaconda' expedition in 1983, and the third
by the Australian Army Alpine Association in 1999-2000. The volcano
frequently emits smoke and vapour and occasionally releases lava,
typically down its south-western slopes. Flows of lava with lengths of
have occurred roughly once per year since 2008. The volcanic activity
on Big Ben is primarily effusive, characterised by flowing lava,
rather than explosive. Its peak has featured a crater of varying size
and location; between 2000 and 2015 Mawson Peak was topped by an open
crater containing a lava lake with a diameter of , while more recent
observations have suggested that the crater may have been replaced by
a fissure.
Glaciers
==========
alt=Beach with scattered ice chunks, with a glacier and ice cliffs in
the background
Heard Island has been covered by glaciers since as early as the
Miocene epoch and experienced its most recent glacial maximum about
18,000 years ago. Heard Island has 12 major glaciers radiating
outwards from the summit of Big Ben, which are sometimes divided by
barriers of volcanic rock. A 2025 glacier mapping study identified
around 30 glaciers. As of 1999, the longest of these glaciers had a
length of 7 km. Parts of the island's coast are made up of ice cliffs
with heights of up to 30 m. Other glaciers on Heard Island, primarily
those that flatten into a shallow incline, terminate in moraines;
these are primarily composed of sediment and debris, with relatively
little till content. Most of the glaciers flowing from the summit of
Big Ben have a narrow top and a slope of more than 30° near its peak,
reducing to around 5° as they widen on its lower slopes. Due to Big
Ben's steep slopes and the high levels of snowfall on Heard Island,
its glaciers are fast-flowing and have a short residence time of about
100 years. The glaciers' shallowness and fast movement mean that they
are particularly vulnerable to changes in climate.
Many glaciers on Heard Island have retreated by more than 1 km since
1949, leaving substantial lagoons and lakes at their bases. One of the
largest glaciers on Heard Island, Stephenson Glacier, ended in 15 m
ice cliffs in 1954, but by 1963 terminated 100 m from the ocean behind
a land barrier and a lagoon now known as the Stephenson Lagoon. Its
rate of recession increased from an average of per year between 1947
and 1987 to a rate of per year between 1987 and 2000. Another
glacier, Brown Glacier, lost 38 percent of its volume and 29 percent
of its area while retreating by 1.17 km between around 1950 and 2004.
A 2025 study estimated that the annual rate of glacier loss had
increased from 0.25 percent between 1947 and 1988 to 0.43 percent
between 1988 and 2019. Total glacier area declined from an estimated
289.4 sqkm in 1947 to 225.7 sqkm in 2019, with smaller glaciers in
low-lying areas near Laurens Peninsula the most affected.
Climate
=========
The territory of Heard Island and McDonald Islands has an Antarctic
climate. It experiences strong westerly winds, high precipitation, and
heavy cloud cover. Average daily temperatures at Atlas Cove on Heard
Island are between and in winter, and between and in summer.
Monthly wind speeds range from 26 km/h to 33.5 km/h on average, with
maximum daily gusts of up to 180 km/h. The islands experience high
snowfall and rainfall, with an average annual precipitation of (water
equivalent). Between 1948 and 1950 there was an average of just 1.7
hours per day of sunshine, ranging from 0.8 hours per day in June to
2.4 hours per day in November. Rain or snow was recorded on an average
of 300 days each year. The territory has consistently high humidity,
with relative humidity of about 85 percent.
While meteorological data for the island is incomplete, the average
annual temperature on Heard Island is estimated to have increased by
about 0.8 °C between the periods 1948-1954 and 1997-2005. Climate
change is believed to be the main driver of glacier retreat on the
island, although volcanic activity has also been suggested as a
potential contributing factor. Climate change has also led to
significant changes in the island's vegetation due to the creation of
new ice-free land, lagoons, and lakes.
Biodiversity
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Due to the territory's remoteness, scientific surveys of the Heard and
McDonald Islands are infrequent and there is limited recent data on
the islands' biodiversity. About 300 species are known to be present
on Heard Island, although it is likely that there are others that have
not yet been recorded. Heard Island and the McDonald Islands are the
only sub-Antarctic islands that are not home to any species known to
have been directly introduced by humans. Various non-native animal
species have been brought onto Heard Island by humans in the past,
including dogs, sheep, and at least one rat, but none have established
a presence on the island. The islands have relatively low species
diversity. A 2021 study projected that climate change would cause the
populations of penguins, flying birds, and seals on the island to
decline. The population of toothfish in the surrounding waters was
projected to fall by 20-60 percent, while the population of mackerel
icefish was projected to fall by 20 percent.
Flora
=======
The majority of the plant species on Heard Island are non-flowering
plants, including bryophytes (a division of plants that includes
liverworts and mosses) and lichens. At least 62 species of bryophyte
and 90 species of lichen have been recorded on the island. There are
just 12 species of vascular plants on Heard Island, 5 of which have
also been recorded on McDonald Island. About 20 km2 or 5 percent of
the island is covered by vegetation, mostly in low-lying coastal areas
with elevations of less than 300 m. The Antarctic ecologists Dana
Bergstrom and Patricia Selkirk have compared Heard Island to an
archipelago of distinct vegetation communities separated by ice.
Researchers studying plant microfossils on Heard Island have suggested
that several species of plant--including ferns, a podocarp, and a
small herb--were present on the island between the late Eocene and
early Pliocene periods. Volcanic activity over the last million years
disrupted many of these early plant communities, and during colder
periods in the Pleistocene epoch many plant species disappeared from
Heard Island. Today, the level of vegetation on the island is
increasing due to glacier retreat, which is making new land available
for plant colonisation. Vegetation remains absent from some areas due
to high levels of nitrogen, ammonia, and other compounds deposited by
the island's large colonies of seabirds.
The most prevalent vegetation on the island is 'Azorella selago', a
species of cushion plant. The majority of the other vascular plants on
the island are small herbs and grasses, with the exception of
'Pringlea antiscorbutica' (known as Kerguelen cabbage). The island
does not contain any trees or shrubs. 'Pringlea antiscorbutica' is
present largely on gravel and sandy areas with high moisture and
drainage, particularly on moraines. The island's grasses include 'Poa
cookii', a small tussock grass, as well as tufts of 'Poa
kerguelensis'. The island's wetlands are characterised by the presence
of the herb 'Callitriche antarctica'. A non-native grass, 'Poa annua',
has significantly expanded its presence on the island, including on
formerly glaciated land. This expansion has led to fears of potential
displacement of native plants.
The moss species present on Heard Island are relatively uniformly
distributed across the island. The most widespread mosses on Heard
Island are species of 'Dicranoweisia', while other common mosses
include 'Polytrichastrum alpinum', 'Racomitrium crispulum', 'Ditrichum
immersum', and 'Pedinophyllopsis abdita'. Salt-tolerant plants,
particularly the moss 'Muelleriella crassifolia', are prevalent in
coastal areas exposed to sea spray, and many of the rocks on Heard
Island are covered in lichens. As of 2008, 90 lichen species had been
identified on Heard Island, nine of which had not previously been
recorded elsewhere.
Birds
=======
Fifteen flying seabird species are known to breed on Heard Island and
at least fifteen others have been recorded visiting the island. The
species that breed on Heard Island include three species of albatross
and seven species of petrel. The territory is visited by four
endangered seabird species (the northern royal albatross, the
Amsterdam albatross, the Tristan albatross and the grey-headed
albatross), and eight vulnerable species (the southern royal
albatross, the sooty albatross, the Indian yellow-nosed albatross, the
Campbell albatross, the white-capped albatross, the northern giant
petrel, the blue petrel, and the soft-plumaged petrel). The most
abundant flying birds are petrels, while several species of albatross,
including the wandering albatross, have a presence on the island.
There are two types of seabird found only on the island: the Heard
Island cormorant and the Heard Island sheathbill, a subspecies of
black-faced sheathbill. The population of Heard Island cormorants has
been estimated at around 1000 pairs.
Four species of penguin breed on Heard Island: the macaroni penguin,
gentoo penguin, king penguin, and eastern rockhopper penguin. Four
other penguin species have been recorded visiting the islands. There
have been reports of possible emperor penguin sightings on Heard
Island, although none have been confirmed. The population of king
penguins has risen exponentially from a small number of breeding pairs
in 1947 to more than 100,000 pairs in 2004. Heard Island and the
McDonald Islands contain about 21 percent of the world's macaroni
penguins with around 1 million breeding pairs. A 1992 study estimated
that the islands contained about 16,600 pairs of gentoo penguins, or
around 6 percent of the world's total, and at least 1000 pairs of
rockhopper penguins.
Mammals
=========
There are 26 species of marine mammals in the Heard Island and
McDonald Islands region. These include 17 species of cetacean, the
most common of which are fin whales, Antarctic minke whales, hourglass
dolphins, and long-finned pilot whales. Three species of seal breed on
Heard Island: the southern elephant seal and the Antarctic fur seal
breed in significant numbers, while the sub-Antarctic fur seal has
occasionally been seen breeding on the island. Four other species of
seal--leopard seals, Weddell seals, crabeater seals, and Ross
seals--have been recorded visiting the island.
Southern elephant seals are the most common mammal species on Heard
Island. A 1999 study estimated that the population declined by 50
percent between 1949 and 1985, possibly due to a decline in sea ice,
but that it had since stabilised. The population of southern elephant
seals was estimated at around 14,000 in 1992, which was equivalent to
about 30 percent of the total population in the Indian Ocean region.
Fur seals were likely nearly or completely eradicated from the island
by sealers in the 19th century, but recovered to a total population of
about 4500 seals by the 1980s. A population survey in 2000-2001 found
that the Antarctic fur seal population reached a peak nearly 30,000
around the end of February, including a large number of visiting male
seals, and that the population was increasing at an annual rate of
about 10 percent. The same survey recorded a small handful of
sub-Antarctic fur seals, one of which had given birth on the island.
Another survey conducted three years later found that the population
of Antarctic fur seals on the island numbered in the thousands and was
growing at an annual rate of 12-20 percent.
During the summer of 2025-26 influenza A virus subtype H5N1 caused
greater than 75% mortality of baby elephant seals at Heard Island,
with the deaths of over 13,000 pups. The bird flu virus was believed
to have reached the island in August 2025 and also caused elevated
mortality in king and gentoo penguins.
Fish
======
Ninety species of fish from thirty-eight families have been recorded
in the EEZ surrounding Heard Island and McDonald Islands. Notothenoid
fishes, including those in the families Nototheniidae,
Channichthyidae, Bathydraconidae, and Harpagiferidae, make up the
largest number of these species. The region's shallow waters and banks
are home to large populations of notothenoid fishes, while its deeper
waters contain a greater abundance of grenadiers and lanternfishes,
including 'Krefftichthys anderssoni' and 'Electrona antarctica'. The
region is home to at least seven species of chondrichthyans (a class
that includes sharks, rays, and skates); its largest fish is the
southern sleeper shark. A 1983 study identified nine fish species in
the waters nearest to the shores of Heard Island and the McDonald
Islands, with the coastal fish population dominated by 'Notothenia
coriiceps coriiceps' and 'Channichthys rhinoceratus'.
The Patagonian toothfish is prevalent in the waters surrounding Heard
Island and McDonald Islands and is the primary species targeted by
commercial fishers, with five fishing vessels harvesting a collective
maximum quota of 3000 tons in the 2021-2022 season. The toothfish
population surrounding Heard Island and McDonald Islands is
genetically distinct from the populations in the vicinity of Macquarie
Island and South Georgia and does not typically migrate far from the
islands, although toothfish tagged in the Australian EEZ have
occasionally been recaptured in the nearby French EEZ surrounding the
Kerguelen Islands. The region's shallow waters with depths of less
than are home to a greater number of smaller juvenile toothfish,
while its deeper waters contain higher densities of older and larger
fish. The population of toothfish in the Heard Island and McDonald
Islands EEZ is declining; spawning stock biomass was estimated at 45
percent of pre-exploitation levels in 2023, below a management target
of 50 percent.
Invertebrates
===============
There are at least 127 known species of invertebrates on Heard Island,
including 33 species of insects. The island is home to very few flying
insects. The islands support three acalypterate flightless fly
species--'Anatalanta aptera', 'Calycopteryx moseleyi', and
'Amalopteryx maritima'--as well as at least one species of midge from
the genus 'Telmatogeton'. Due to the harsh climate, the insect
population declines by more than 95 percent from its summer peak each
winter. One species of spider, 'Myro kerguelensis', is found on Heard
Island. The islands are also home to at least 10 species of
springtails, one species of thrips, 19 species of lice, and 52 species
of mites. The invertebrates found in bodies of fresh water on Heard
Island include at least 26 species of rotifer, 2 species of
gastrotrich, 2 species of tardigrade, and 1 species each of annelid
and flatworm. Three of the invertebrate species found on Heard Island
are not native: the worm 'Dendrodrilus rubidus', the thrips
'Apterothrips apteris', and the mite 'Tyrophagus putrescentiae'.
External links
======================================================================
*
[https://www.antarctica.gov.au/antarctic-operations/stations-and-field-locations/heard-island/
Heard Island and McDonald Islands], Australian Antarctic Program
*
[https://www.antarctica.gov.au/antarctic-operations/stations-and-field-locations/heard-island/location-geography/mapping/
Heard Island and McDonald Islands mapping], Australian Antarctic
Program
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Original Article: http://en.wikipedia.org/wiki/Heard_Island_and_McDonald_Islands
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