In Spain there are 5,025 establishments with aquaculture productions and 5,274 establishments that have had cultivation of some species, although they may not be in production. The establishments in marine aquaculture production are 4,847, of which 1,118 are located in brackish intertidal zones, while only 178 are of continental aquaculture. The most numerous types are vertical cultivars (3,579), followed by horizontal cultivars (1,150), those located on mainland (163), those in natural enclaves (89) and those in cages (44 ). Aquaculture production generates revenues of 526.1 million euros per year, with an intermediate consumption of 369.2 million euros. The income generated by aquaculture is estimated at 132.3 million euros. There are more than 18,800 people working in Spanish aquaculture, while the annual work units (UTA) reach 5,714. Spanish aquaculture production has a high degree of concentration and is dominated by some of the large Spanish fishing groups, along with subsidiaries of multinational companies and a few specialists. In the case of mussel production, the situation is completely opposite, since there is a great atomization, with about 1,340 farms and around 3,570 tanks.