Freshwater mixed with seawater that naturally occurs in estuaries where rivers meet the seas. Mangroves and marsh waters are also natural brackish water habitats, home to certain species of fish such as mudskippers. However, brackish water can also be produced by human activities–particularly the construction of dikes and the flooding of coastal marshlands for freshwater prawn farming. In these cases, brackish water can become an environmental problem as it is hostile to the growth of many plant species.