Oysters – Crassostrea gigas
The hollow oyster is a bivalve mollusk. The flesh (soft part) is protected by two asymmetrical calcareous valves. They are twice as heavy as water and are composed of about 95% calcium carbonate. The oyster usually sits at the bottom of the sea on its left valve, which is concave. The right valve on the top is generally flatter. It is in the anterior part that there is a robust elastic ligament that allows the opening of the valves. The adductor muscle that links the valves closes them tightly. This North Pacific species is currently grown in a significant number of nations with temperate or even subtropical climates. These locations are covered from the West Pacific to Australia, New Zealand, and the North American Coast, from California to British Columbia. It has also been adapted in South America, but particularly in Europe (France) and North Africa.
Mussels – Mytilus galloprovincialis and Perna perna
Mussels are equivalents bivalve mollusks and very inequilational, their forms ranging from triangular to flabelliform, devoid of hinge teeth. The hooks are at the anterior end. The ligament is developed but the adductor muscles are vestigial. These two mussel species cohabit on the Moroccan coast and are typically consumed by riparian people. The Mediterranean mussel (M. galloprovincialis) is at its southern geographic boundary, whereas the African mussel (P. perna) is at its northern geographic limit.
Clam – Ruditapes decussatus
The Ruditapes decussatus clam is a bivalve mollusk, naturally distributed in estuarine and lagoon areas in most of the Mediterranean and Atlantic basin. It lives in the sandy-muddy substrates of the paralic environments and the less agitated sites of the coast. Its optimum growth temperature is between 23°C and 26°C and its optimum salinity is between 32 and 40. It can withstand wide variations in temperature and salinity (up to 11). Clams are one of the most sought-after species on the European market. For example, in Morocco in recent years, stock abundance and density have declined due to a variety of factors, including variations in environmental characteristics, predation and mainly pressure from intensive fishing