出典:Wiktionary
出典:Wikipedia
出典:『Wikipedia』 (2011/06/20 20:39 UTC 版)
The rainbow trout (Oncorhynchus mykiss) is a species of salmonid native to tributaries of the Pacific Ocean in Asia and North America. The steelhead is a sea run rainbow trout (anadromous) usually returning to freshwater to spawn after 2 to 3 years at sea. In other words, rainbow trout and steelhead trout are the same species. The fish is sometimes called a salmon trout. Several other fish in the salmonid family are called trout, some are anadromous like salmon, whereas others are resident in freshwater only.