| 翻訳と辞書 |
Galaxiidae
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 Southern Australia or New Zealand, but some are found in South Africa, southern South America, Lord Howe Island, New Caledonia, and the Falkland Islands. One of the galaxiid species, the common galaxias (''Galaxias maculatus''), is probably the most widely naturally distributed freshwater fish in the Southern Hemisphere. They are coolwater species, found in temperate latitudes, with only one species known from subtropical habitats.〔McDowall, R.M. (2006) Crying wolf, crying foul, or crying shame: alien salmonids and a biodiversity crisis in the southern cool-temperate galaxioid fishes? ''Rev Fish Biol Fisheries'' 16: 233–422.〕 Many specialise in living in cold, high-altitude upland rivers, streams, and lakes.
Some galaxiids live in fresh water all their lives, but many have a partially marine lifecycle. In these cases, larvae are hatched in a river, but are washed downstream to the ocean, later returning to rivers as juveniles to complete their development to full adulthood. This pattern differs from that of salmon, which only return to fresh water to breed, and is described as amphidromous.
Freshwater galaxiid species are gravely threatened by exotic salmonid species, particularly trout species, which prey upon galaxiids and compete with them for food. Exotic salmonids have been recklessly introduced to many different land masses (e.g. Australia, New Zealand), with no thought as to impacts on native fish, or attempts to preserve salmonid-free habitats for them. Numerous localised extinctions of galaxiid species have been caused by the introduction of exotic salmonids, and a number of freshwater galaxiid species are threatened with overall extinction by exotic salmonids.〔
==Taxonomic diversity==
About 50 species are in the Galaxiidae family, grouped into seven genera:
抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』
■ウィキペディアで「Galaxiidae」の詳細全文を読む
スポンサード リンク
| 翻訳と辞書 : 翻訳のためのインターネットリソース |
Copyright(C) kotoba.ne.jp 1997-2016. All Rights Reserved.
|
|