Diversity of marine invertebrates in the Kingdom
Marine invertebrates represent the largest of wildlife group in terms of diversity and abundance in the Kingdom, and they still need many intensive studies as the available information about them is limited. Some of these animals are microscopic and some are visible, some of them are covered with shells, such as clams and snails, and some of them cover their bodies with a thick hard crust, such as: crabs, and some have thick skin that protects them, such as: Polychaeta.
Marine invertebrates can be divided into the group of Porifera, such as sponges, a group of Mollusks, such as snails and shellfish, and a group of Echinoderm, such as Starfish and Sea urchins.
The trade and fishing of natural pearls has decreased in the Arabian Gulf since the late 1930s due to the competition of artificial pearls. Limited quantities of oysters, squids, cuttlefish and octopuses are on the market. Seven types of crustaceans are also sold in the market, including lobsters, prawns, shrimps and crabs.