How do salmons and eels survive in both marine and fresh water?
Salmons don’t die because they’re in fresh water but because the females just die after reproduction in some species, that’s just the way it is. These fishes are both Diadromous meaning they constantly migrate between fresh and salt water. Some salmon are Anadromous meaning they grow in salt water but move up rivers to breed. Some salmon populations of the same Anadromous species can live their entire lives in fresh water. The American Eel is Catadromous meaning they grow in fresh water but breed in salt water. Almost all fishes osmoregulate, that is they have adaptations that either helps them preserve body fluids or discharge them constantly to maintain the right amount of fluids in their body. This part can get complicated and you don’t necessarily need to know it. But basically these diadromous fish have another set of adaptations that allow them to move between marine and fresh waters. Some, like the salmon for instance, may have modified kidneys that adapt to both conditions. The
