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Rainbow smelt : ウィキペディア英語版 | Rainbow smelt
The rainbow smelt (''Osmerus mordax'') is a species of fish of the family Osmeridae. Its distribution is circumpolar, and it has been introduced to the Great Lakes, and from there has made its way to various other places. Walleye, trout, and other larger fish prey on these smelt. The rainbow smelt prefer juvenile ciscoes, zooplankton such as calanoid copepods (''Leptodiaptomus ashlandi'', ''L. minutus'', ''L. sicilis''), and other small organisms, but are aggressive and will eat almost any fish they find. They are anadromous spring spawners and prefer clean streams with light flow and light siltation. The rainbow smelt face several barriers. They are weak swimmers and cannot overcome most fish ladders. This prevents them from making it past the dams to the headwater streams where they spawn. The rise in erosion and dams help to decimate the smelt population in the 1980s. There are currently plans to try to reduce damming and to help control erosion. With current efforts to reduce the human impact on this and many other affected species the population is back on the rise. ==Description== The body of the rainbowsmelt is slender and cylindrical. It has a silvery, pale green back and is iridescent purple, blue, and pink on the sides, with a light underside. When full grown, the rainbow smelt is between long and weighs about . Individuals over long are known.
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「Rainbow smelt」の詳細全文を読む
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