Seashore wildlife habitats exist from the Tropics to the Arctic and Antarctic. Seashores and beaches provide varied habitats in different parts of the world, and even within the same beach. Phytoplankton is at the bottom of some food chains, while zooplankton and other organisms eat phytoplankton. Kelp is also autotrophic and at the bottom of many food chains. Coastal areas are stressed through rapid changes, for example due to tides.
British seashores
The coasts around Great Britain and the sea nearby are of international significance. Animal life varies from large whales, dolphins and porpoises, grey seals and common seals, through to microscopic animals. There are more than 200 species of fish, ranging from small fish like blennies through to basking sharks that are the second largest shark in the world.
Habitats include areas of landslips, beaches with sand, shingle and rock, cliffs, coastal lagoons, isolated sea stacks and islands, muddy estuaries, salt marshes, submaritime zones (i.e. land influenced by sea spray) and the sea itself. British coasts are affected by strong winds and in some areas large waves. British tidal ranges are large compared to some other parts of the world. Sheltered shores support different life from exposed shores.
Non-flowering plants range from microscopic plants through to seaweed or kelp up to 5 meters in height. Many animals feed on kelp and kelp provides sheltered habitats for yet others. Sea grass is the only type of flowering plant that grows in British seas, but it nonetheless forms vast beds.
Invertebrates in coastal Britain are very diverse and include brittle stars, hermit crabs, mussels, prawns, sponges, sea anemones and sea squirts. Efforts are made to conserve rare plants and animals in nature reserves.
Cliffs, islands and sea stacks are a habitat for breeding sea birds such as guillemots, kittiwake and razor bills, as well as rock doves which can live inland as well. Peregrine falcons hunt the doves. Estuaries provide a habitat for waders and ducks, especially in winter.
West African seashores
The coastline of West Africa extends from Senegal to Gabon and like many other coastlines worldwide, it is characterized by a variety of ecosystems (Yankson and Kendall, 2001). Common on this coast are sandy shores interspersed with rocky shores and several rivers, which empty into the Gulf of Guinea. Well-known rocky beaches on the West African coast include Cape Verde in Senegal, Cape Three Points in Ghana and Mount Cameroun. There are other smaller rocky beaches and between them are sandy beaches, which may be small, or extensive (Yankson and Kendall, 2001). On the coast of Ghana for instance, the greatest extent of almost continuous rock shore is on either side of Cape Three Points and stretches from the Ankobra River in the west to Sekondi in the east, a distance of about 45 miles. The west of the Ankobra is characterized by sandy beaches extending through Ivory Coast. Also, between Takoradi and Prampram, 150 miles to the east, sandy shores dominate but rocky shores of limited extent occur in several places, notably in the region of Cape Coast and Elmina and in the Accra area. At the east of Prampram, sandy beaches stretch almost continuously along the eastern coast of Ghana and throughout Nigeria until a rocky shore is met with again in the Cameroons (Gauld and Buchanan, 1959).
Various surveys of the West African seashore have found barnacles and gastropods dominating the invertebrate community (Gauld and Buchanan, 1959; Yankson and Akpabey, 2001; Yankson and Kendall, 2001; Lamptey, Armah and Allotey, 2009).
Three species of barnacles, namely Cthamalus dentatus, Megabalanus tintinnabulum and Tetraclita squamata are found on the West African rocky shores. C. dentatus is the common barnacle of open coasts. They have a kite shaped opening to the shell. Six plates are clearly visible in isolated individuals. The plates have projecting ribs giving the animal a star-shaped outline. Recently settled animals are a pale brown color but as they age, they quickly become dirty white. C. dentatus have no calcareous base between the body of the animal and the rock surface (Edmunds, 1978; Yankson and Kendall, 2001).
Tetraclita squamata tends to be conical in shape and can reach a large size (25mm or more in length). Unlike Chthamalus species, it does not occur in vast sheets of interlocking animals. The plates making up the shell become fused as the animal grows and in large specimens can be difficult to distinguish. The plates are perforated by rows of fine holes. This species is often heavily overgrown by algae (Yankson and Kendall, 2001).