Why can’t fish survive outside water?
Have you ever wondered why fish cannot survive outside water?
Fish are specially adapted so that they can breathe under the water. They have special organs called gills.
Gills are bars of tissue at each side of the fish’s head. They carry masses of finger like projections that contain tiny blood vessels.
The fish gulp in water through their mouths and pass it out through the gills. The gills are rich in blood, and they extract oxygen from water and pass it into the fish’s blood.
In this way the gills have the same function as the lungs of air-breathing animals. But these gills would not work without the aid of water.
Now you know why fish can’t survive outside water. Let’s find out how much you know about Salmon.
Salmon have a natural instinct to return to the place they were born to lay their eggs (to spawn).
This is a safe place, usually a quiet area of a river, where young salmon can grow.
The adult salmon stop feeding when they first reach fresh water, so they gradually become weaker and weaker.
They often wear themselves out trying to reach the exact place they want to deposit their eggs.
The young salmon remain in the river for a few months, then make the journey to the sea. They stay there for up to four years, then the cycle begins all over again.