The Mission visited 13 countries bordering the Mediterranean during the period October 1978–February 1979 to determine the state of aquaculture in the region and the possibilities for initiating or expanding culture of various species.
Several methods of culture of fish, crustaceans, or molluscs are used at present in the region or appear to have potential in the future. (See Annex I)
2.1.1 Lagoon culture
This system, traditional in the Mediterranean region, is based on the migration of sea bass (Dicentrarchus labrax), sea bream (Sparus auratus), mullet (Mugil spp.), sole (Solea vulgaris), and other species into coastal lagoons in the spring and their return to the sea in the autumn. Eels (Anguilla anguilla) make a similar migration, but remain in the lagoons several years. The fish are captured in a simple trap when they attempt to return to the sea and all are sold regardless of size.
2.1.2 Valli culture
This system, developed in the area of Comacchio and Venice, Italy, is an improvement over lagoon culture. Water level and salinity are controlled and fry collected in other areas are stocked in embanked portions of lagoons, termed “valli arginata”. The fish are harvested in complex weir systems, called “lavorieri”. Undersized fish are held over winter in deep trenches with supplemental feeding and released into the valli to grow for a second summer.
2.1.3 Pond culture
Pond culture of fish is a recent development in the Mediterranean countries and is now practised on a limited scale in France, Israel, Italy, Spain and Egypt. Experimental pond culture is underway in Tunisia. In this system, earthen ponds, provided with water at ambient temperature and salinity, are stocked with fish (fry or fingerlings) or shrimp (post-larvae or juveniles) collected from the wild or produced in hatcheries. In some cases, nursery ponds are used to rear the fish from fry to fingerling size, or shrimp from post-larvae to juveniles, before stocking in grow-out ponds. Supplemental feed is usually provided, but for some species, natural food is produced within the ponds by fertilization. When the fish or shrimp reach marketable size, they are harvested by seining or by draining the ponds.
2.1.4 Cage culture
Culture of sea bass and sea bream is a recent innovation in the region and is now being attempted on an experimental basis in Cyprus, France, Israel and Yugoslavia. In this system of culture, floating cages or fenced enclosures, usually made of synthetic netting or wire screen, are placed in protected areas to grow fish to market size. Small fish, collected from the wild or produced in hatcheries, are held in the cages or enclosures and supplied with feed, usually floating or sinking pellets or chopped fish.
2.1.5 Controlled environment systems
This is the most sophisticated and intensive aquaculture system in which fish, shrimp or even molluscs are kept in tanks or raceways and supplied with high-quality water of satisfactory salinity and optimum temperature for year-round growth. Some systems include reconditioning and re-use of water to reduce requirements for water or heating. In some cases, the tanks or raceways are insulated or enclosed in a building or greenhouse to maintain satisfactory temperatures. Artificial feeding is required. Stocking is at a high level to maximize production per unit of area, because of the high capital cost of these systems. France and Italy are the two countries in the region which have made some progress in the application of this technology, particularly for the culture of sea bream and sea bass, and in Italy for eels. Tunisia has also started experimental work in the culture of shrimps in controlled systems.
2.1.6 Mollusc culture systems
Oysters and mussels traditionally are grown off-bottom in the Mediterranean region, where the tidal amplitude is slight. Spat or juveniles are suspended in various ways from fixed structures (platforms, tables, or racks) or from floats or rafts. Oyster and/or mussel farming is now carried out on a commercial or an experimental scale in all countries of the region, except Egypt and Libya.
Clams are grown on-bottom in areas where the substrata and water currents are suitable. Clam culture is done on a small scale in France and on an experimental basis in Spain and Italy. The technology is still in the early stages of development.
Aquaculture ventures, at experimental and commercial levels, were found in most of the 13 countries surveyed, but varied in the stage of development, species grown, and methods used, as shown in Table 1.
2.2.1 Commercially viable aquaculture
At the present time, there are examples of economically successful lagoon culture for sea bass, sea bream, sole, mullet and eel in seven of the 13 countries, including Egypt, France, Greece, Italy, Spain, Tunisia and Turkey. Lagoon culture of mullet and eel is also economically successful in Yugoslavia.
Valli culture of sea bass, sea bream, sole, mullet and eel is commercially viable in Italy, the only country where this method has been applied.
Pond culture of eels has become economically successful in Italy and is being tried on an experimental basis in France.
Pond culture of sea bass at a commercial level is being tried in France, Italy and Spain, but the economic viability has not yet been fully determined. Similar commercial ventures to grow sea bream have been started in Italy and Spain and experimental pond culture of sea bream has begun in France and Israel.
Mullet culture in ponds is reported to be economically successful in Egypt and Israel, where they are reared in polyculture systems with carp and tilapia. Commercial ventures for mullet farming have begun in Italy, but in Tunisia it is still in an experimental stage.
Sole culture in ponds is being studied in France.
Pond culture of shrimp, Penaeus kerathurus and P. japonicus, using post-larvae reared in hatcheries, is attempted on a commercial level in France, but the profitability of the operation has yet to be demonstrated. Experimental culture of shrimp in ponds is in progress in Israel, Italy and Spain, and hatchery experiments have begun in Greece.
Cage culture of sea bass is being tried in experiments in Cyprus, France, Israel and Yugoslavia. Similar experiments with sea bream are in progress in France and Israel.
Controlled environment systems, still in the experimental stage, are being developed for eel in Italy, sole in France, and shrimp in France and Spain. Commercial ventures, using controlled environment systems, are being tried for sea bass and sea bream in France and Italy, but it is too early to determine their profitability.
Oyster (Ostrea edulis and Crassostrea gigas) and mussel (Mytilus galloprovincialis) culture, using various off-bottom systems, is economically successful in France, Greece, Italy, Spain, Tunisia and Yugoslavia. Oyster culture is also economically successful in bays along the Atlantic coast of France, Morocco and Spain.
STATE OF AQUACULTURE IN THE MEDITERRANEAN REGION
|Cyprus||Egypt||France||Greece||Israel||Italy||Libya||Malta||Morocco||Spain||Tunisia||Turkey||Yugoslavia||No. of countries|
A = Commercial - profitable
B = Commercial - profitability unknown
C = Experimental, Government, University or Industry
Oyster culture has been tried, on an experimental basis, in Cyprus, Israel and Malta, and mussel culture in Malta and Morocco.
Although clams are harvested from natural stocks, in several countries, aquaculture has been tried on a commercial basis only in France and experimentally in Italy and Spain.
The production of various species of fish, including sea bass, sea bream, mullet, sole and eel, is largely from lagoon culture or in Italy from valli culture. Eels are also grown commercially in ponds in Italy and ventures to rear sea bass and sea bream in ponds are being started.
Aquaculture statistics are difficult to obtain as most countries keep catch records by species or groups of species and not by the method of production or capture. Also, in most cases, part of the supply of these species is from capture fisheries and part from aquaculture. Therefore, it has been necessary to estimate aquaculture production of various species in the countries bordering the Mediterranean (Table 2) based on published statistics and information gathered in each country during the aquaculture survey. A notable exception is Tunisia, where complete records of lagoon culture are kept by Office National des Pêches.
Production of oysters and mussels is recorded by most countries and it is assumed that all reported landings are from aquaculture. However, some countries include oysters and mussels and other molluscs in the category “bivalvia”.
In total, aquaculture produces over 12 000 t of sea bass, sea bream, mullet, sole and eel, approximately one half of the regional supply. All of the region's oysters and mussels, some 21 000 t, are produced by aquaculture (Table 2).