Seagrass is a type of submerged aquatic vegetation that evolved from terrestrial plants and has become specialized to live in the marine environment. It is generally found in the shallow subtidal zone of the coastal environment, although occasionally may be exposed to the air during very low tides. The extent of a seagrass bed depends on factors such as substrate, temperature, water clarity and protection from wave energy. Since seagrass beds are almost always under water (except under exceptionally low tides), fish have access to them all the time. Seagrass beds are areas of high productivity and are important to fish and other organisms as a direct or indirect source of food. The queen conch and fish such as the scrawled filefish, sharpnose puffer, keeled needlefish and ocean surgeon are some examples of species that eat grass blades directly. Other fish find their food in these habitats by feeding on detritus from decomposing leaves, invertebrates, small fish, and/or shellfish that can be found attached to their leaves or living within the plants. Some snappers and parrotfishes, for example, move to seagrass beds at night to feed on small fishes, crustaceans and other organisms.
Seagrasses also provide living space, refuge from predators, and essential nursery areas to commercial and recreational fishery species and to a great number of invertebrates that live within or migrate to these habitats. Juvenile stages of many fish species spend their early days in the relative safety and protection of seagrasses. For example, the young of redband parrotfish and redtail parrotfish are usually found in seagrasses where they find the necessary protection and food. By forming extensive plant carpets, seagrass beds can diminish the effects of strong currents, providing protection to fish and invertebrates and preventing the erosion of bottom areas. |
