There are 15 000 km of coastline and large coastal lagoons of some 52 000 ha in Greece. There is no information available in Greece on the migration or catches of the glass eel (the unpigmented stage, which can be captured in brackish or freshwater shortly after having left oceanic water). However, elver (the pigmented stage found in brackish or freshwater, and possibly including more than one year class) are captured at the fixed traps in lagoons such as those in the Messolonghi, Amvrakikos or Kavalla regions.
No selection is carried out at the traps; the harvest of eels comprises large silver eels (1–2 kg in weight) and also small-size eels (3–100 g). Mixed eels are sold to the broker. The price for the mixed stock was 1 000–1 300 Dr/kg in 1986. These are then graded later by the broker and sold for consumption or restocking, either locally or abroad. If smaller sized eels are graded out specifically, they could be used as seedfish for intensive eel culture.
In Greece there are 59 800 ha of natural lakes, 31 000 ha of artificial lakes and 640 ha of other areas, such as rivers, fish-farms, etc. In addition, there is an estimated area of 60 000 ha of all kinds which could be exploited. Despite the important potential, the recorded production from inland waters in 1983 amounted to only 13 500 t of various species, of which about 30 percent were trout. Only 4 percent were eels in spite of climatic conditions which are favourable almost all the year round for eel culture. The production of eels comes mainly from lagoons where the fish are extensively cultured without any artificial food supply.
The consultant could not visit an artificial lake of Kremasta near Karpenisi. There is an eel-farm using cages in this lake. Cage culture of eel can be introduced in suitable natural lakes or reservoirs.
Subterranean water resources are available in most of the country, but these resources are utilized mainly for trout culture at present. Water temperatures of some of the trout-farms are 16–18°C all the year round. These waters could also be used for eel culture, providing growth rates were sufficient to justify capital and operating costs.
Tsanaka's eel-farm near Arta is at present the only intensive eel culture farm. The farm produced about 2 t in 1986 and will increase production to 15 t in 1987. There is a good and abundant supply of subterranean water (17–18°C), suitable for flowing water eel culture.
The commercial trout farm in Simboli Seron near Kavalla is supplied with spring water of 16–17°C at about 700 l/s. The owner would like to culture eel in his ponds, currently 3 of 70 m2 and 21 of 150 m2. The farm has a good potential for eel production, with a capacity for at least 50 t annual production.
There are also warmwater resources such as hot springs. These hot water resources are used principally for human consumption and for medical purposes. A hot spring area near Kavalla was visited. There are four springs in Loutra Eleftheron (42°C); water from two springs runs into the river without any utilization. At another site, in the area of Cessani near Xanthi, the water temperature is 77.3°C. The heat energy of these springs is utilized partly in greenhouses for vegetable production. It would also be possible to utilize this heat energy in artificially heated intensive eel culture, which may improve the cost-effectiveness of production through higher growth rates.
There might also be some potential for intensifying production of eels in brackishwater lagoons. This would normally involve the use of low-lift pumps to circulate water within earth ponds. However, the energy cost of pumping, and the environmental and ecological variability of the lagoon environments may make this difficult.
The total production of marine fisheries in 1983 amounted to about 97 000 t, including a large variety of species, such as sardine, mackerel and anchovy. However, most of these fish are consumed directly by the people. Since their price is not cheap, the use of raw fish as eel feed as practised in Japan is likely to be difficult.
However, three types of formulated eel feed are available in Greece, imported from Italy. The price is 130 Dr/kg1 at present. A survey of basic materials has shown that most of the ingredients necessary for formulating a complete eel diet are available on the Greek market. Imported fish-meal is also available, as it is used in large quantities for commercial food production (mainly for poultry and pig). Attention has to paid, however, to the quality of this fish-meal, given the special requirements of eel feed. Only finely milled and sifted materials of good protein and fat quality can be used.
In the Japanese formulated eel feeds, alfa potato starch is used as a binder and carbohydrate source. This important material is not directly available in Greece, but can be imported from some West European countries. The availability and quality of vitamin/mineral premix was not ascertained; until sources of known suitability are established in Greece, it would be preferable to import supplies from other West European countries.
One operational aspect of great importance is the source of seedfish supply. Either glass eels or elvers can be used. No information on glass eel migration was available, though it is likely that glass eels migrate to some extent into the coastal areas, lagoons, or river mouths as elvers are harvested in the lagoons. Studies on the stock of glass eels and their migration would be essential in supporting intensive eel culture from local resources.
At present, as the demand for glass eel or elver is not big, eel farmers could obtain seedfish from around the lagoon traps in Greece, or from abroad. As the present catches of mixed sized eels is about 800 t, glass eel or elver supplies sufficient for 500–1 000 t aquaculture production might be obtainable from local sources, if sufficiently developed.
Formulated eel feeds imported from Italy are available in Greece; the price (130 Dr/kg) is cheaper than the equivalent Japanese eel feed (250 Dr/kg). However, raw feed supply is limited.
As most of the ingredients of a formulated eel feed are available on the Greek market, feed could be manufactured in Greece using locally produced ingredients. Depending on market demand, this could be done in the near future. The quality of local feed could be established by running feeding experiments.
Exchange: $US 1.00 = Dr 132 (July 1987)
At the private farm of Mataranga near Lake Trichonis, most of the eel stocks were lost last year, due to high stocking rates, insufficient water supply and the lack of aeration.
At a fish trap in the eastern part of the Klissova lagoon, receiving waste water from the city of Messolonghi, considerable quantities of harvested eels have been lost during the stocking periods, because of the high stocking rate (1 500–3 000 kg per cage of 2 × 3 m, depth of 50 cm), poor water quality and lack of additional water supply or aeration.
The reasons for these losses are clearly found in the lack of basic knowledge concerning the practical techniques of intensive eel culture; this has only just been started in various locations in Greece. It is obvious that suitable instruction and training for farmers are needed. It is recommended that if the industry is to develop further, suitable candidates should receive further training locally, or obtain specialized training in other countries.