Algae dominated habitats occur in the eastern intertidal and subtidal areas of the Bahrain main island and around Hawar islands. The four main types of algae identified during the fieldwork are Green algae, Red algae, Brown algae and coralline algae. This class represents one or more type of algae as the dominant habitat associated with hard substrate or soft substrate.

Coral reefs play an important role as a habitat for some of the reef fish species and a high diversity of other organisms. The variety of corals in Bahrain and the Arabian Gulf is not great if compared with many other tropical seas, covering only about 1% of the subtidal area in the Arabian Gulf. They still provide the marine environment with a highly complex community, with many species.

About 30 species; 19 genera of corals are found in Bahrain covering less than 5% of the reef areas in Fasht Al Adhm, Fasht Al Jarim and Khor Fasht. The most healthy and diverse coral reefs in Bahraini waters are located in Fasht Abu-thama, which is about 75 km north of the main land. Live corals are therefore not abundant in the off-shore areas of Bahrain, and most of the existing stands are under threat.

Figure 3. Dense seagrass bed (mainly Halodule uninervis), from an area south of Fasht-al-adhm, critical habitat for the endangered species of dugongs and green turtles

Bahrain seagrass beds cover a large area of the sea bottom and provide a nursery ground for many important marine species. The majority of the seagrass habitats in Bahrain territorial water are located in the eastern subtidal waters, mainly south of Fasht Al-Adhm. The second largest seagrass beds are found in the western subtidal areas. Figure 4 Dense coverage of seagrass species (mainly Halophila ovalis) near Hawar island Seagrass plays in important role in maintaining the ecosystem balance. It is the main diet for the endangered species, Dugong dugong and green turtles. They also absorb nutrients from coastal run-off and stabilise sediment, helping to keep the water clear.

Seagrasses are flowering plants which mostly occur on sandy substrates. There are three species of seagrass, which are well known in Bahrain. These species are Halodule uninervis (Forsskal) Ascherson, Halophila ovalis (R. Brown) Hooker, Halophila stipulacea (Forsskal) Ascherson.

Figure 4. Dense coverage of seagrass species (mainly Halophila ovalis) near Hawar island

Sand represents all grain size of sand such as fine, medium, coarse, gravel and mixed grains sand. This habitat exists in the intertidal zone, and shallow and deep subtidal zone

Mud is a fine sedimentary material (silt and clay), usually comprising both organic and inorganic material, and mixed with water. Usually, it occur as mudflat in the intertidal zone. Mudflat is a habitat of accumulated sediment, dominantly of a clay or silt grain size exposed at low tide.
This type of habitat is highly productive and important for some coastal species especially crab, molluscs and worms which is a feeding source for seabirds.

This represents exposed rocks, occurring in the intertidal areas, and rock reef exposed to waves in the subtidal area. This habitat is also important for hosting many rocky shores species such as crabs

Mangrove plants, which are represented by a single species, Avicennia marina are under threat of extinction due to extensive land reclamaition locally (Price and Vousden, 1985). The only area where this plant can be found is in Tubli Bay. The other mangrove plants occur in Dohat Arad as an artificial habitat after transplanting this plant to this area in the mid 1990s by the Fisheries Department in Bahrain.This habitat class represents mangrove trees as dominated species, occurring in the coastal areas. Usually the substrate associated with mangrove is mud or mud and sand. Salt marsh is usually occurring behind mangrove stand in the supratidal area too.

This class represents live corals and cover over less than 75% of the habitat. The live coral is usually associated with rock pavement as a substrate and mixed with sand.

This class generally represents algae (less than 75% cover) associated with sand, or a rock pavement covered by sand (green algae found with sand & red and brown algae found with hard rock substrate).

This class is representative of areas covered by a mixture of fine soil grain sizes, consisting mainly of fine sand and silt.

This class contains a mixture of many types of habitats such as seagrass, algae, rock, sand and mud, occurring in varying proportions and within a depth of 0 to 8 meters. Many Large patches within the study area fall into this category, (due to the natural mixed occurrence of marine habitats), in addition to the cut-off limits used to accept pure habitat stands (i.e. 75 %).

This class is represented by salt marshes vegetation, occurring in the coastal areas mostly in the supratidal zone. The substrate associated with salt mash is sand or mud and sand. In most cases the salt marshes usually occur in the supratidal behind mangrove.

Sabkha is flat coastal landform with distinctive soil structure including salt crust, which is often broken and forced up into ridges. This type of substrate is highly saline and does not support vegetation except microscopic bacteria, and algae, which live below the soil surface. Sabkha is usually a low land, which occurs in the coastal areas mostly in the supratidal zone.

This class is one of the dominated classes that occur in coastal and subtidal areas. It is characterized by a flat hard bottom, covered by a layer of sand. The thickness of the top sand varies from one area to another.

This class represents the areas that are covered by mud (fine sediments in the form clay or silt), and which are found in more than 8 meters sea depth.

This class is represented by areas deeper than 8 meters, and is covered by one or more of all the habitats, mixed in varying proportions.