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The fish fauna of the Neretva river basin in the western Balkans is representative of the Dinaric karst region and characterized by several endemic and endangered species. Overall the Dinaric karst water systems support 25% of the total of 546 fish species in Europe. The river Neretva and its tributaries represent the main drainage system in the east Adriatic watershed and the foremost ichthyofaunal habitat of the region. The Adriatic basin has 88 species of fish, of which 44 are Mediterranean endemic species, and 41 are Adriatic endemic species. More than half of the Adriatic river basin species of fish inhabit the Neretva, the Ombla, the Trebišnjica, the Morača Rivers and their tributaries, and more than 30 are indigenous. The degree of endemism in the karst ecoregion is greater than 10% of the total number of fish species. Numerous species live in very narrow and limited areas and are vulnerable, so they are included on the Red List of endangered fish of the IUCN. According to Smith & Darwall (2006) the Neretva River, together with four other areas in the Mediterranean, has the largest number of threatened freshwater fish species. == Habitat == The Neretva river with its many tributaries, lakes and marshes provides rich freshwater habitat for its native, as well as for introduced non-native fish species. There are deep canyon as well as wide valley sections with both fast flowing rapids with side-pools, and narrow sections with deep, still waters running slowly. The flowing water can be any combination of fast or slow, deep or shallow, open or protected by canyons, rocks, tree roots and undercut banks, and shaded by vegetation on the bank or exposed to full sunlight. This variation ensures that a relatively large number of fish species are able to find suitable habitat for themselves. Upper reaches of the Neretva basin (Upper Neretva), river with its tributaries runs undisturbed through remote and rugged limestone terrain with deep canyons and steep slopes gorges reaching from 600 to 1200 m in depth. River in these parts is extremely cold, clear and potable, consisting waters of "Class I" ("Class A") purity,〔(【引用サイトリンク】 url=http://www-wds.worldbank.org/servlet/WDSContentServer/WDSP/IB/2005/06/08/000160016_20050608170756/Rendered/INDEX/E1157.txt )〕 with temperature often as low as 7–8 degrees Celsius in the summer months, evidence of almost certainly the coldest river water in the world. In the middle section of the watershed remoteness and ruggedness of the terrain gets even more extreme, especially around small river tributaries, mountain creeks and lakes, however the Neretva river itself is completely flooded throughout entire midsection with four large artificial lakes, and intersected with four large dams. More downstream in the lower reaches (Lower Neretva), the Neretva basin and the river itself comprise remarkable landscape, in which valley from the confluence of its main tributaries of the section, the Buna, the Trebižat and Bregava rivers, then spreads into an alluvial fan, covering more than 20,000 hectares, with specious flat plains or poljes, where water-flow is slow but abundant, with many branches often widened into natural lakes and marshes, and constantly replenish with lots of fresh water from numerous large karstic well-springs. Finally at the Neretva Delta, the river reaches the Adriatic Sea. 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「Fish species of the Neretva basin」の詳細全文を読む スポンサード リンク
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