Oyster

An oyster is a type of animal that belongs to the group of mollusks, which are soft-bodied animals with hard shells.

Oysters are bivalves, which means they have two shells that are hinged together.

Oysters live in saltwater or brackish habitats, where they filter water through their gills and feed on tiny organic particles.

Oysters can produce pearls, which are layers of nacre that cover an irritant inside the shell.

Oysters are also edible and considered a delicacy in some cultures.

• Some types of oysters are able to produce pearls, which are shiny and valuable objects that form inside their shells when a foreign material irritates their tissue.

• Their role as filter feeders, which means they draw water over their gills and remove algae and other particles from it.
  Individual oysters can filter up to 190 litres of water per day, and help maintain the balance and health of the marine ecosystem.

• Their taste and nutritional value, which vary depending on the environment they grow in.
  Oysters are considered a delicacy in many cultures, and are eaten raw or cooked in various ways.
  Oysters are also high in protein, calcium, iron, and zinc, and contain omega-3 fatty acids that are beneficial for the heart and brain.

Oysters are salt-water or brackish-water bivalve molluscs that live in marine or coastal habitats around the world.

They usually cluster on hard surfaces, such as rocks, piers, or old shells, and form reefs that provide shelter and food for many other marine species.

Oysters belong to different families, such as Ostreidae (true oysters), Pteriidae (pearl oysters), and Spondylidae (spiny oysters).

Some oysters are edible and considered a delicacy, while others produce pearls or have ornamental shells.

Oysters feed by filtering algae and other particles from the water, and can improve water quality and prevent erosion.

Oysters are threatened by overharvesting, habitat loss, pollution, and diseases, and need to be protected and restored to maintain their ecological and economic value.

• True oysters ( Ostreidae ), which include the edible oysters, such as the European flat oyster, the eastern oyster, the Olympia oyster, the Pacific oyster, and the Sydney rock oyster.
  These oysters have a flat, round, or oval shell, and are usually found attached to rocks or other surfaces in shallow waters.

• Pearl oysters ( Pteriidae ), which are not closely related to true oysters, but are harvested for the pearls they produce.
  These oysters have a thin, smooth, or scaly shell, and are usually found in deeper waters, often in coral reefs.
  The largest pearl oyster is the Pinctada maxima, which can grow up to 30 cm in diameter.

• Saddle oysters ( Anomiidae ), which have a thin, flat, or curved shell, with a hole or notch on one side.
  They attach themselves to other shells or objects by a cement-like substance.
  Saddle oysters are also called jingle shells, because they make a sound when shaken.

• Windowpane oysters ( Placunidae ), which have a transparent, glass-like shell, that is used to make decorative items, such as lamps, windows, or jewellery.
  They are also called capiz shells, after the Philippine province where they are abundant.

• Spiny oysters ( Spondylidae ), which have a thick, spiny, or warty shell, that can be red, orange, yellow, or purple.
  They are also called thorny oysters, and are prized for their colourful shells, which are used to make jewellery or ornaments.