Question

What are estuaries? How they are suitable for both marine and river fish to live?

Answer 1

An estuary is a partially enclosed body of water where saltwater from the seas or oceans mixes with the freshwater of the river. In freshwater, salinity is nearly zero and in seawater salinity is high. Hence at this place, there are fluctuations in salinity that is suitable for the life of marine and river fish.