banded kōkopu

File:Galaxias fasciatus by Joseph Drayton.png

Banded kōkopu are a stout-bodied fish, with a large head and mouth. The fish are strong, rounded and fleshy. Like other galaxiids, the dorsal and anal fins are positioned close to the tail fin, which is short and square. The caudal peduncle is short and deep, with thick fleshy flanges which join the tail fin.{{cite book|last1=McDowall|first1=R.M.|title='The Reed Field Guide To New Zealand Freshwater Fishes|date=2000|publisher=Reed|location=Auckland|isbn=0-7900-0725-8|page=NUMBER}}

Adults are usually a dark, earthy brown or olive brown, with pale yellow vertical bands along the body. The belly is light coloured and unpatterned. Behind the operculum and above the pectoral fin is a silver or white mark, and sometimes a darker mark behind this. The bands either fade out top and bottom, or fork and crisscross the back of the fish. In small fish the bands are usually numerous and along the whole body, but in adults the bands become narrower and are often restricted to the rear third of the body.{{cite book|last1=McDowall|first1=R.M.|title=New Zealand Freshwater Fishes: A natural history and guide|date=1990|publisher=Heinemann Reed|location=Auckland|isbn=0-7900-0022-9}} Although the bands change as the fish ages, the placement and shape of the bands are consistent enough to be used for individual identification over several years.{{cite journal|last1=Hustler|first1=K.|title=Individual identification and visual indicators of breeding condition of banded kokopu (Galaxias fasciatus) in an urban New Zealand stream|journal=New Zealand Journal of Marine & Freshwater Research|date=2014|volume=48|issue=1|doi=10.1080/00288330.2013.826700|pages=15–23|s2cid=84892795}}

Medium and juvenile giant kōkopu can sometimes be mistaken for banded kōkopu, as they can also develop vertical stripes. The easiest way to differentiate between the two species is that banded kōkopu have a white or silver mark immediately behind the operculum, above the pectoral fin, and giant kōkopu do not.{{cite book|last1=McQueen|first1=S.|last2=Morris|first2=R|title=A Photographic Guide to Freshwater Fishes of New Zealand|date=2013|publisher=New Holland|location=Auckland|isbn=978-1-86966-386-5}} Also, the markings of banded kōkopu either fork and spread across the back of the fish, or fade out top and bottom, while the markings on giant kōkopu never fork, and have a crisp edge all the way around. Juvenile shortjaw kōkopu may also be mistaken for a very pale and poorly marked banded kōkopu, but the small mouth of the shortjaw is diagnostic.

Banded kōkopu are found only in New Zealand and just a handful of spawning sites are known. In 2018 a new spawning site was discovered in a tributary of York Stream, Nelson, where fish habitat and passage restoration has been carried out as part of Project Maitai.

In Nelson banded kōkopu occupy creeks and tributaries in lowland coastal flats and can penetrate inland to take refuge in pools/undercut banks in tributaries with over hanging vegetation.

Banded kōkopu are diadromous, spending the first 3–4 months of life at sea, before migrating back to freshwater as whitebait of {{Convert|40–45|mm|in|abbr=on}} in length.

Banded kōkopu become sexually mature at two or three years old. They spawn in adult habitats during flood events in autumn and early winter, laying the {{Convert|2|mm|in|abbr=on}} diameter eggs amongst flooded vegetation and leaf litter on the edge of the stream.{{cite journal|last1=Charteris|first1=S|last2=Allibone|first2=R|last3=Death|first3=R|title=Spawning site selection, egg development, and larval drift of Galaxias postvectis and G. fasciatus in a New Zealand stream|journal=New Zealand Journal of Marine and Freshwater Research|date=2003|volume=37|issue=3|doi=10.1080/00288330.2003.9517184|pages=493–505|s2cid=129117686|doi-access=free}}{{cite journal|last1=Mitchell|first1=C|last2=Penlington|first2=B|title=Spawning of Galaxias fasciatus Gray (Salmoniformes: Galaxiidae)|journal=New Zealand Journal of Marine and Freshwater Research|date=1982|volume=16|issue=2|doi=10.1080/00288330.1982.9515955|pages=131–133|doi-access=free}} As the flood recedes the eggs are left to develop out of the water; the high humidity provided by the vegetation keeps them moist. After three to four weeks the embryos are fully developed and require a second flood to stimulate them to hatch, and the larvae are carried to sea on the floodwaters. They live amongst and on the plankton for 3–4 months before returning to freshwater.

Juvenile banded kōkopu can detect and are attracted to odours produced by adults. This suggests they have the ability to discriminate species-specific pheromones during their migratory phase, which alerts juveniles to suitable habitat based on the presence of adults.{{Cite journal|last1=Baker|first1=C. F.|last2=Montgomery|first2=J. C.|date=2001-05-01|title=Species-specific attraction of migratory banded kokopu juveniles to adult pheromones|journal=Journal of Fish Biology|language=en|volume=58|issue=5|pages=1221–1229|doi=10.1111/j.1095-8649.2001.tb02281.x|issn=1095-8649}}

Banded kōkopu can live for at least nine years,{{cite journal|last1=Hopkins|first1=C|title=Age-related growth characteristics of Galaxias fasciatus (Salmoniformes: Galaxiidae)|journal=New Zealand Journal of Marine and Freshwater Research|date=1979|volume=13|issue=1|doi=10.1080/00288330.1979.9515779|pages=39–46|doi-access=free}} possibly longer, and spawn multiple times over their lifetime.

Banded kōkopu are largely nocturnal, and may be easily and unobtrusively observed night, ideally using red light.McCullough, C. D. & Hicks, B. J. (2002). Estimating the abundance of banded kokopu (Galaxias fasciatus Gray) in small streams by nocturnal counts under spotlight illumination. New Zealand Natural Sciences 27: 1-14p. Banded kōkopu may also be observed during the day if undisturbed.

Juvenile banded kōkopu are one of five species of galaxiid caught and eaten as whitebait.

{{Reflist}}

• Martinez-Capel, F.; McCullough, C. & Hicks, B. J. (2004). On a regional model for nocturnal habitat requirements of banded kokopu (Galaxias fasciatus) in the North Island, New Zealand. Fifth International Symposium on Ecohydraulics. Aquatic Habitats Analysis & Restoration. International Association of Hydraulic Engineering and Research (IAHR), 109-116. {{ISBN|90-805649-7-4}}.
• {{ITIS |id=623448 |taxon=Galaxias fasciatus |accessdate=6 June 2006}}
• {{FishBase | genus = Galaxias | species = fasciatus | month = March | year = 2006}}

{{Commons}}

• [http://www.terranature.org/kokopuBanded.htm New Zealand native freshwater galaxiid fish, Banded kokopu] TerraNature, Auckland 2010

{{Taxonbar|from=Q44502}}

Category:Galaxias

Category:Endemic freshwater fish of New Zealand

Category:Fish described in 1842

Category:Taxa named by John Edward Gray