Lagoon life Lagoons that are open to the sea may have many of the same corals, fish and other sea life as the ocean itself. As the conditions in a lagoon get more variable and more extreme, the number of kinds of things that can live there will get smaller and smaller, although those things that can live there may get to be more common. The life of lagoons may be more productive and abundant than in the sea outside if there are nutrients that go into it from the land, or if it is able to accumulate nutrients because it is protected. The shallow lagoon bottom is often covered with beds of seagrass or seaweed, and reef corals may grow on the lagoon edges and on patch reefs within it. It may provide important breeding or feeding areas for fish or other animals outside the lagoon as well.
Some lagoons support fisheries that are very important for the island.
They may have bait fish that can be used to fish for tuna. Certain lagoons have important beds of pearl oyster. Others may have shellfish that are collected locally for food. If a lagoon becomes too closed, however, there may not be enough water exchange and the lagoon may become stagnant and support much less life. There may even be no oxygen left on the bottom for animals to live.