Kokopu
Encyclopedia
Kokopu is a common name used for three species of fish of the genus Galaxias. They are found in the rivers, lakes and swamps of New Zealand
for which they are endemic. Kokopu are galaxiid
s and like others members of that family lacks scales and has a thick, leathery skin covered with mucus
. Kokopu inhabit streams with plenty of cover (e.g. logs and overhanging boulders) but can also be found in swamps and larger waterways. They mostly feed on invertebrates that live in the stream beds but also eat insects that fall into the water and will move into the open at night for feeding.
There are three known species of Kokopu in New Zealand:
Kokopu live for between 5 and 10 years but can reach in excess of 21 years. They spawn
in leaf debris in stream beds or during spring tides and the eggs hatch about 30 days after being laid. The hatchlings are carried downstream where they spend a short period of time in the sea and return to streams after four to five months. Kokopu sprats are keenly sought by fishers as whitebait
for consumption as a delicacy and are caught in fine meshed nets.
Kokopu depend on the natural environment, principally in forested environments, and so have become less common as New Zealand has been cleared of much of its native forest and swampland as a result of colonisation and farming development since the late 19th century. Nevertheless, recognition of the value of biodiversity
and the preservation of natural areas in National Park
s and reserved conservation areas promises to maintain the species.
Kokopu suffer from the introduction of trout species that were introduced into New Zealand for sport fishing purposes during the first half of the 20th century by various acclimatisation societies
. Research has indicated that where trout have become established then kokopu are unlikely to be found. Nevertheless, since the kokopu, on average, is smaller in size than trout then where stream and swamp environments cannot support trout and are still in forested areas, kokopu are likely to be found.
New Zealand
New Zealand is an island country in the south-western Pacific Ocean comprising two main landmasses and numerous smaller islands. The country is situated some east of Australia across the Tasman Sea, and roughly south of the Pacific island nations of New Caledonia, Fiji, and Tonga...
for which they are endemic. Kokopu are galaxiid
Galaxiid
The Galaxiidae, also known by the anglicised name as galaxiids, are a family of mostly small freshwater fish in the southern hemisphere. The majority of species live in Australia or New Zealand, some are also found in South Africa, South America, Lord Howe Island, New Caledonia and the Falkland...
s and like others members of that family lacks scales and has a thick, leathery skin covered with mucus
Mucus
In vertebrates, mucus is a slippery secretion produced by, and covering, mucous membranes. Mucous fluid is typically produced from mucous cells found in mucous glands. Mucous cells secrete products that are rich in glycoproteins and water. Mucous fluid may also originate from mixed glands, which...
. Kokopu inhabit streams with plenty of cover (e.g. logs and overhanging boulders) but can also be found in swamps and larger waterways. They mostly feed on invertebrates that live in the stream beds but also eat insects that fall into the water and will move into the open at night for feeding.
There are three known species of Kokopu in New Zealand:
- Giant kokopuGiant kokopuFor a general article about all 3 kokopu.The giant kokopu, Galaxias argenteus, is a galaxiid of the genus Galaxias, found only in New Zealand. It grows to a length of up to 45 cm and is the largest member of the Galaxiidae family. It is also one of the five species that occur in the whitebait...
, Galaxias argenteus - Banded kokopuBanded kokopuFor a general article about all 3 kokopu.The banded kokopu, Galaxias fasciatus, is a galaxiid of the genus Galaxias, found only in New Zealand, including the Chatham and Stewart/Rakiura islands...
, Galaxias fasciatus - Shortjaw kokopuShortjaw kokopuFor a general article about all 3 kokopu.The shortjaw kokopu, Galaxias postvectis, is a galaxiid of the genus Galaxias, found only in New Zealand, apart from the Chatham and Stewart/Rakiura islands. It grows to a length of up to 26 cm....
, Galaxias postvectis
Kokopu live for between 5 and 10 years but can reach in excess of 21 years. They spawn
Spawn (biology)
Spawn refers to the eggs and sperm released or deposited, usually into water, by aquatic animals. As a verb, spawn refers to the process of releasing the eggs and sperm, also called spawning...
in leaf debris in stream beds or during spring tides and the eggs hatch about 30 days after being laid. The hatchlings are carried downstream where they spend a short period of time in the sea and return to streams after four to five months. Kokopu sprats are keenly sought by fishers as whitebait
Whitebait
Whitebait is a collective term for the immature fry of fish, typically between 25 and 50 millimetres long. Such young fish often travel together in schools along the coast, and move into estuaries and sometimes up rivers where they can be easily caught with fine meshed fishing nets...
for consumption as a delicacy and are caught in fine meshed nets.
Kokopu depend on the natural environment, principally in forested environments, and so have become less common as New Zealand has been cleared of much of its native forest and swampland as a result of colonisation and farming development since the late 19th century. Nevertheless, recognition of the value of biodiversity
Biodiversity
Biodiversity is the degree of variation of life forms within a given ecosystem, biome, or an entire planet. Biodiversity is a measure of the health of ecosystems. Biodiversity is in part a function of climate. In terrestrial habitats, tropical regions are typically rich whereas polar regions...
and the preservation of natural areas in National Park
National park
A national park is a reserve of natural, semi-natural, or developed land that a sovereign state declares or owns. Although individual nations designate their own national parks differently A national park is a reserve of natural, semi-natural, or developed land that a sovereign state declares or...
s and reserved conservation areas promises to maintain the species.
Kokopu suffer from the introduction of trout species that were introduced into New Zealand for sport fishing purposes during the first half of the 20th century by various acclimatisation societies
Acclimatisation society
Acclimatisation societies were societies created in order to enrich the fauna of a region with animals and plants from around the world. The first such society was La Societé Zoologique d'Acclimatation founded in Paris in 1854 by Isidore Geoffroy Saint-Hilaire. Such societies spread quickly around...
. Research has indicated that where trout have become established then kokopu are unlikely to be found. Nevertheless, since the kokopu, on average, is smaller in size than trout then where stream and swamp environments cannot support trout and are still in forested areas, kokopu are likely to be found.