力爭上游 Swimming Upstream
Story and comic created by CCFamily.
Alaska salmon have a very interesting life. They swim from the rivers and streams to the Pacific Ocean, and back again, to die at where they were born. They are swimming from fresh water to salt water and back again.
After they hatch, Alaska salmon swim downstream towards the ocean. Their bodies change to adapt to the seawater. They spend several years swimming in the ocean. Once they have fully matured, they re-adapt to fresh water and swim back up the streams, rivers or even waterfalls to reach their birthplace. Once they get back to the stream they were born, they breed and lay their eggs. After spawning they generally die within a week and this is when their lives come to an end.
Reference: Cambridge Dictionaries Online (Learners')