The contribution of aquaculture to the global supply of fish, crustaceans and mollusks, has increased at a rate of about 8.8% per year since 1970. In global terms, aquaculture production is equivalent to about half of all fish consumed in the world, with China being the largest world producer.
National aquaculture is an important alternative to traditional ways of supplying fish, being considered a strategic sector by the Government. Portuguese aquaculture is well positioned to take advantage of a national market that is a major consumer of fish and a Community market that is highly deficient in fishery products. Portugal has a tradition of mollusc farming, production of fresh and salt water fish, modern technology, committed entrepreneurs and geographical and climatic conditions, suitable for these activities.
Among the main "species" produced in aquaculture in our country, the bivalves produced in an extensive regime represent a significant part of the national production. The aquaculture development strategies incorporate many of the recommendations contained in codes of practice for responsible aquaculture, with the verification that in our country, companies and professionals in this subsector share the same type of concerns and principles defended by their European counterparts. Coordination efforts between authorities are evident in order to direct the development and application of policies, regulations and procedures, in the sense of environmental, economic and social sustainability of aquaculture activity.
The objectives for European aquaculture aim to create jobs, make quality and healthy products available to consumers, promote health and animal welfare standards for cultivated species and ensure the environmentally balanced development of aquaculture activity. Aquaculture, provided it is properly exercised, should not be considered as a threat to the ecosystem, nor should its future be mortgaged in favor of other activities using the same coastal areas.
There is undoubtedly a place for the sustainable development of this activity from the perspective of integrated management of coastal areas.
The product obtained is a mixture of various salts precipitated from sea water, in which sodium chloride predominates. It is an essential raw material for many purposes, being part of the group of big-five raw-materials, however, due to its specific characteristics, most of the national production of sea salt in Portugal is destined for food purposes. The techniques used to take advantage of natural resources in some coastal areas of Portugal are based on the use of renewable energy (solar and wind energy).
The technological processes employed range from the use of traditional methodologies (artisanal production), to the use of heavy and automated machinery, reflected in the dimensioning of the production units. These units, called salt pans or marine, are made up of a set of reservoirs built on land and on impermeable soils, implanted in marshland areas. Feeding seawater to the first evaporation reservoirs takes advantage, as a general rule, of the tides.
The flow of water to increase the graduation / concentration of salt, due to evaporation by the heat of the sun and the wind, continues along the next reservoirs until the crystallizers, where the sea salt is deposited. The movement of water uses the gravitational potential of the first reservoirs, whose topographic shares are higher than the others, gained by taking water from the highest tides or by pumping.