This individual shows fading vertical parr marks, a characteristic of the parr stage, gradually taking on the silvery sheen of the smolt stage in advance of migrating to the North Atlantic Ocean to feed. Credit: E. Peter Steenstra/USFWS
https://creativecommons.org/licenses/by/2.0CC BY 2.0 Creative Commons Attribution 2.0 truetrue
这幅图片原始出处为Flickr的https://flickr.com/photos/43322816@N08/5197994241 ,作者为U. S. Fish and Wildlife Service - Northeast Region 。经机器人FlickreviewR在2016年2月19日审查后确定为采用cc-by-2.0的协议授权使用。