Northern Rockhopper Penguin
Encyclopedia
The Northern Rockhopper Penguin, Eudyptes c. moseleyi, is usually considered a subspecies
of rockhopper penguin
, although fairly recent studies show evidence of distinction from the Southern Rockhopper Penguin
group Eudyptes c. chrysocome/E. c. filholi.
A study published in 2009 showed that the world population of the Northern Rockhopper had declined by 90% since the 1950s. For this reason, the Northern Rockhopper Penguin is classified as an endangered
.
, after research published in 2006 demonstrated morphological
, vocal and genetic differences between the two populations. Molecular datings
suggest that the genetic divergence with the Southern Rockhopper penguin may have been caused by a vicariant
event caused by a shift in the position of the Subtropical Front
during the mid-Pleistocene climate transition.
Analysis of a part of a mitochondrial control region
from a Northern Rockhopper Penguin found on the Kerguelen Islands
showed that it may have come from Gough Island, 6,000 km away, and that the Southern and Northern Rockhoppers are genetically separate, though some individuals may disperse from their breeding colonies. Many taxonomists have yet to recognize the split, although some are beginning to do so.
and Gough Island
in the south Atlantic Ocean
.
and other things such as crustacean
s, squid
, octopus
and fish
.
in a range of locations from sea level or on cliff sides, to sometimes inland.
The current population is estimated to be between 100,000-499,999 breeding pairs at Gough Island, 18,000 to 27,000 pairs at Inaccessible Island, and 3,200 to 4,500 at Tristan da Cunha. In the Indian Ocean, the population was 25,500 pairs on Amsterdam Island, and 9,000 pairs on St Paul Island in 1993; there has been no information available on population trends there since the 1990s. Declines at the Atlantic Ocean sites show a decline of 2.7 per cent per year; the drop in the population at Gough Island has been described as equivalent to the loss of 100 birds every day since the 1950s.
A study published in 2009 showed that the world population of the Northern Rockhopper had declined by 30% since the 1950s, possibly because of climate change
, changes in marine ecosystem
s and overfishing
for squid and octopus by humans. Other possible factors in the decline include disturbance and pollution from ecotourism
and fishing, egg-harvesting, predation from introduced House Mice
Mus musculus and predation and competition from Subantarctic Fur Seal
s Arctocephalus tropicalis.
The Northern Rockhopper Penguin is classified as Endangered because of the decline in numbers over the last three generations (or 30 years).
ran aground on Nightingale Island
, spilling tons of heavy crude into the ocean. The crew was rescued, but the ship broke up, leaving an oil slick that surrounded the island, threatening its population of rockhopper penguins. Nightingale Island has no fresh water, so the penguins are being transported to Tristan da Cunha
for cleaning.
Subspecies
Subspecies in biological classification, is either a taxonomic rank subordinate to species, ora taxonomic unit in that rank . A subspecies cannot be recognized in isolation: a species will either be recognized as having no subspecies at all or two or more, never just one...
of rockhopper penguin
Rockhopper penguin
The rockhopper penguins are three closely related taxa of crested penguins that have been traditionally treated as a single species and are sometimes split into two or three species. Not all experts agree on the classification of these penguins...
, although fairly recent studies show evidence of distinction from the Southern Rockhopper Penguin
Southern Rockhopper Penguin
The Southern Rockhopper Penguin group , are two subspecies of rockhopper penguin, that together are sometimes considered distinct from the Northern Rockhopper Penguin...
group Eudyptes c. chrysocome/E. c. filholi.
A study published in 2009 showed that the world population of the Northern Rockhopper had declined by 90% since the 1950s. For this reason, the Northern Rockhopper Penguin is classified as an endangered
Endangered species
An endangered species is a population of organisms which is at risk of becoming extinct because it is either few in numbers, or threatened by changing environmental or predation parameters...
.
Taxonomy
The Rockhopper Penguin Eudyptes chrysocome is sometimes considered two species, Northern and Southern Rockhopper PenguinSouthern Rockhopper Penguin
The Southern Rockhopper Penguin group , are two subspecies of rockhopper penguin, that together are sometimes considered distinct from the Northern Rockhopper Penguin...
, after research published in 2006 demonstrated morphological
Morphology (biology)
In biology, morphology is a branch of bioscience dealing with the study of the form and structure of organisms and their specific structural features....
, vocal and genetic differences between the two populations. Molecular datings
Molecular clock
The molecular clock is a technique in molecular evolution that uses fossil constraints and rates of molecular change to deduce the time in geologic history when two species or other taxa diverged. It is used to estimate the time of occurrence of events called speciation or radiation...
suggest that the genetic divergence with the Southern Rockhopper penguin may have been caused by a vicariant
Vicariance
Vicariance is a process by which the geographical range of an individual taxon, or a whole biota, is split into discontinuous parts by the formation of a physical barrier to gene flow or dispersal. Vicariance of whole biotas occurs following large-scale geophysical events such as the uplift of a...
event caused by a shift in the position of the Subtropical Front
Subtropical Front
Subtropical Front is a term used in Oceanography to describe a boundary between water systems based on temperature and salinity.- Northern Subtropical Front :A subtropical front in the Pacific Ocean lying between 25 and 30 degrees north latitude....
during the mid-Pleistocene climate transition.
Analysis of a part of a mitochondrial control region
D-loop
In molecular biology, a displacement loop or D-loop is a DNA structure where the two strands of a double-stranded DNA molecule are separated for a stretch and held apart by a third strand of DNA. The third strand has a base sequence which is complementary to one of the main strands and pairs with...
from a Northern Rockhopper Penguin found on the Kerguelen Islands
Kerguelen Islands
The Kerguelen Islands , also known as the Desolation Islands, are a group of islands in the southern Indian Ocean constituting the emerged part of the otherwise submerged Kerguelen Plateau. The islands, along with Adélie Land, the Crozet Islands and the Amsterdam and Saint Paul Islands are part of...
showed that it may have come from Gough Island, 6,000 km away, and that the Southern and Northern Rockhoppers are genetically separate, though some individuals may disperse from their breeding colonies. Many taxonomists have yet to recognize the split, although some are beginning to do so.
Distribution and habitat
More than 99% of Northern Rockhoppers breed on Tristan da CunhaTristan da Cunha
Tristan da Cunha is a remote volcanic group of islands in the south Atlantic Ocean and the main island of that group. It is the most remote inhabited archipelago in the world, lying from the nearest land, South Africa, and from South America...
and Gough Island
Gough Island
Gough Island , also known historically as Gonçalo Álvares or Diego Alvarez, is a volcanic island in the South Atlantic Ocean. It is a dependency of Tristan da Cunha and part of the British overseas territory of Saint Helena, Ascension and Tristan da Cunha...
in the south Atlantic Ocean
Atlantic Ocean
The Atlantic Ocean is the second-largest of the world's oceanic divisions. With a total area of about , it covers approximately 20% of the Earth's surface and about 26% of its water surface area...
.
Food and feeding
The Northern Rockhopper Penguin feeds on krillKrill
Krill is the common name given to the order Euphausiacea of shrimp-like marine crustaceans. Also known as euphausiids, these small invertebrates are found in all oceans of the world...
and other things such as crustacean
Crustacean
Crustaceans form a very large group of arthropods, usually treated as a subphylum, which includes such familiar animals as crabs, lobsters, crayfish, shrimp, krill and barnacles. The 50,000 described species range in size from Stygotantulus stocki at , to the Japanese spider crab with a leg span...
s, squid
Squid
Squid are cephalopods of the order Teuthida, which comprises around 300 species. Like all other cephalopods, squid have a distinct head, bilateral symmetry, a mantle, and arms. Squid, like cuttlefish, have eight arms arranged in pairs and two, usually longer, tentacles...
, octopus
Octopus
The octopus is a cephalopod mollusc of the order Octopoda. Octopuses have two eyes and four pairs of arms, and like other cephalopods they are bilaterally symmetric. An octopus has a hard beak, with its mouth at the center point of the arms...
and fish
Fish
Fish are a paraphyletic group of organisms that consist of all gill-bearing aquatic vertebrate animals that lack limbs with digits. Included in this definition are the living hagfish, lampreys, and cartilaginous and bony fish, as well as various extinct related groups...
.
Breeding
It breeds in coloniesBird colony
A bird colony is a large congregation of individuals of one or more species of bird that nest or roost in close proximity at a particular location. Many kinds of birds are known to congregate in groups of varying size; a congregation of nesting birds is called a breeding colony...
in a range of locations from sea level or on cliff sides, to sometimes inland.
Population and threats
A study published in 2009 showed that the world population of the Northern Rockhopper had declined by 30% since the 1950s, possibly because of climate change
Climate change
Climate change is a significant and lasting change in the statistical distribution of weather patterns over periods ranging from decades to millions of years. It may be a change in average weather conditions or the distribution of events around that average...
, changes in marine ecosystem
Marine ecosystem
Marine ecosystems are among the largest of Earth's aquatic ecosystems. They include oceans, salt marsh and intertidal ecology, estuaries and lagoons, mangroves and coral reefs, the deep sea and the sea floor. They can be contrasted with freshwater ecosystems, which have a lower salt content. Marine...
s and overfishing
Overfishing
Overfishing occurs when fishing activities reduce fish stocks below an acceptable level. This can occur in any body of water from a pond to the oceans....
for squid and octopus by humans. Other possible factors in the decline include disturbance and pollution from ecotourism
Ecotourism
Ecotourism is a form of tourism visiting fragile, pristine, and usually protected areas, intended as a low impact and often small scale alternative to standard commercial tourism...
and fishing, egg-harvesting, predation from introduced House Mice
House mouse
The house mouse is a small rodent, a mouse, one of the most numerous species of the genus Mus.As a wild animal the house mouse mainly lives associated with humans, causing damage to crops and stored food....
Mus musculus and predation and competition from Subantarctic Fur Seal
Subantarctic Fur Seal
The subantarctic fur seal is a fur seal found in the southern parts of the Indian and Atlantic Oceans. It was first described by Gray in 1872 from a specimen recovered in northern Australia—hence the inappropriate tropicalis specific name.- Description :The subantarctic fur seal is...
s Arctocephalus tropicalis.
The Northern Rockhopper Penguin is classified as Endangered because of the decline in numbers over the last three generations (or 30 years).
2011 oil spill
On March 16, 2011, the Maltese-registered freighter MS OlivaMS Oliva
The MS Oliva was a bulk carrier launched in 2009. On 16 March 2011 the ship went aground off Nightingale Island, Tristan da Cunha, in the South Atlantic, while on a voyage from Santos, Brazil to China with a cargo of soya beans....
ran aground on Nightingale Island
Nightingale Island
Nightingale Island is an island in the South Atlantic Ocean, 3 km² in area, part of the Tristan da Cunha group of islands. They are administered by the United Kingdom as part of the overseas territory of Saint Helena, Ascension and Tristan da Cunha....
, spilling tons of heavy crude into the ocean. The crew was rescued, but the ship broke up, leaving an oil slick that surrounded the island, threatening its population of rockhopper penguins. Nightingale Island has no fresh water, so the penguins are being transported to Tristan da Cunha
Tristan da Cunha
Tristan da Cunha is a remote volcanic group of islands in the south Atlantic Ocean and the main island of that group. It is the most remote inhabited archipelago in the world, lying from the nearest land, South Africa, and from South America...
for cleaning.