Salmon are considered “ anadromous ” which means they live in both fresh and salt water. They are born in freshwater where they spend a few months to a few years (depending on the species) before moving out to the ocean. That’s because when saltwater fish are exposed to freshwater, it can cause their cells to burst.
There are exceptions to the rule however; for example some Atlantic Salmon known as Landlocked Salmon spend their entire lives in fresh water where they live in a large lake or river and migrate into feeder streams to spawn.
They go through a process called smoltification in which salmon prepare for salt water by changes the allow them to retain freshwater in their bodies while in the sea. The reverse the process as they move back into spawning streams . Why can’t fish live in salt and fresh water?
So, why do salmon need salt water to survive?
Because fresh water is low in sodium, salmon need their gill cells to pump it in as they swim downstream. But once they enter the ocean, sodium is overly abundant, requiring them to pump it out. Salmon also have to pump out the chloride ions (Cl-) that result from dissolved ocean salt.
Are freshwater salmon and saltwater salmon the same?
9/4/2019 Freshwater salmon and saltwater salmon are the same species. In North America, these include Atlantic salmon, of which there is just one species, and five Pacific salmon species: coho, chinook, pink, sockeye, and chum. There are, however, many differences in behavior and physiology between freshwater salmon and saltwater salmon.
Can freshwater fish be put in saltwater?
Freshwater fish need to retain salt in their bodies so their urine is very dilute, for most fresh water fish being put into salt water is a death sentence since their bodies cannot flush out the excess salts.