PREFACE

In the last years Hellas (Greece) has shown an enormous development of fish aquaculture, mainly of sea bream (Sparus aurata), sea bass (Dicentrarchus labrax) and the mussel (Mytilus galloprovincialis). There are 639 aquaculture units (1995’s data) of which the 277 units are of sea fishes culture (sea bass, sea bream) and 25 of them are hatcheries. The ongrowing units produce 38.000 t. and the hatching sections about 92.5 million larvae of total value about 9.8 billion drachmas ( 33.4 million dollars). The continuous development of this type of fish culture has as a consequence the continuous search of new markets in Europe, so is imperative to culture new species in the fishes section, but in the section of crustaceans and molluscs too. As a characteristic point we can report that in 1995 the total fishing production (of frozen and fresh catches and aquaculture) amounted to 170.076 tonnes over 173.368 t (or –1.9%) in 1994 and to 159.250 t. in 1993 (or +6.8%). Production of all fish aquaculture (fish-oysters from sea and fresh waters) amounted to 42.804 t. over 36.094 t. in 1994 (+18.6%) and to 30.62 t. in 1993 (+39.6%).

The international progress of the shrimp culture has reached the 700 tons (the 25% of the total crustacean culture). This production has been achieved in the last 20 years. In Hellas this type of aquaculture has not been developed enough until now. The most convenient species to culture in our country is P. japonicus and the most suitable shrimp farming system is the semi-intensive method. Of course is evident that we have to improve the research in the culture of other species, such as Penaeus monodon, Penaeus kerathurus.

STATISTICS OF CATCH

The elements mentioned below report the total shrimp’s catch in the last years (Table 1).

These elements are taken from the following independent organizations:

• National Statistical Service of Hellas (NSSH): NSSH keeps records of the commercial landings and the number of registered fishing vessels and the information is published, with a 2-3 years lag, in annual bulletins issued from 1964 onwards.
• Agricultural Bank of Hellas (ABH): ABH collects data on active fishing vessels and provides assessments of their landings from 1974 onwards.
• National Company for the Development of Fisheries (ETANAL): ETANAL, a non-profit organization under state control, for the purpose of undertaking activities that would promote the development of fisheries. In practice, its present-day activity is the management of the major Hellenic fishing ports and, hence, ETANAL has been granted by low exclusive jurisdiction over auctions and supervision of related transactions.

The greatest share of this catch comes from the overseas fisheries, especially from Liberia (21 vessels). About 1200-1800 t. of these is exported in France and in other European countries. The rest quantity was caught in North Hellas (Thermaikos gulf, gulf of Chalkidiki, Strimonikos gulf).
 

YEAR	TOTAL CATCH	FROZEN	FRESH	TRAWL NET	RING NET	SEINE NET	OTHER
1974	2375	1754	621	3.35	0.01	0.06	1.1
1975	2433	1752	681	3.11			1.71
1976	2203	1568	635
1977	2667	2086	581	2.62	0.01	0.11	1.25
1978	2611	1919	692	3.08		0.1	1.06
1979	2806	2155	651	2.94		0.02	0.96
1980	2332	1702	630	2.69	0.04	0.07	1.23
1981	2111	1290	821	3.93	0.01	0.01	1.10
1982	2254	1477	777	3.61	0	0.08	0.84
1983	2400	1622	778	3.87		0.12	0.74
1984	2550	1796	754	3.15	0.02	0.20	0.73
1985	3086	2353	733	2.80	0.01	0.12	0.76
1086	4730	2429	2301	3.99	0.02	0.05	1.47
1987	5879	3246	1633	5.13	0.01	0.29	2.06
1988	4357	2602	1755	5.36	0.02	0.01	1.67
1989	3553	2123	1430	4.69		0.06	1.22
1990	3381	1782	1599	4.99	0.01	0.22	0.82
1991	3319	1988	1331	3.99	0.04	0.46	0.54
1992	3691	1472	2219	6.32	0.04	0.21	1.02
1993	3905	2132	1773	6.01	0.01	0.93	0.56
1994	2925	1112	1813	4.08		0.58
1995	5636	3871	1765

 
 The total value of these trading shrimps catches, in the last years (Table 2), was (in million dollars):
 

SPECIES	1990	1991	1992	1993	1994	1995	1990-95
P. kerathurus	0.248276*	0.355172	0.596552	0.444828	0.403448	0.800	2.875.862
P. longirostris	1.182.759	1.237.931	1.889.655	1.679.310	1.982.759	2.710.344	10.682.759

The shrimp (P. longirostris) is the 40% of the total Hellenic crustaceans catches and as concern their financial importance is concerned to the "middle class" in the total fisheries catch, with a value over 10 million dollars. The other species (P. kerathurus) has a much smaller value (about 3 million dollars) and the biggest percentage of this has caught in 1995.

The average selling price per kilo of these species in the last years is given in Table 3 (in dollars):
 

SPECIES	1990	1991	1992	1993	1994	1995
P. kerathurus	3.45			4.20	4.57	3.35
P. longirostris	4.20			3.19	5.04	4.31

 
In 1991 the total shrimps imports were 220 t. of total value about 1.331.034 $.

SHRIMP CULTURE IN GREECE. A REVIEW.

According to the latest research it is known that two shrimp species exist in the Mediterranean Sea. These two species are: Penaeus kerathurus (caramote prawn) and its main fishing grounds are in the N. Aegean Sea – Thermaikos gulf and Thrakiko Sea . The other one is Parapenaeus longirostris – even this exist in the N. Aegean Sea and the Ionian Sea – but it s the almost unique species in the S. Aegean Sea – Cretan Sea. Many years ago, it was evident that there were 5 more species from the same family (Penaeidae) in the Hellenic sea waters which were been "emigrated" from the Indian ocean through the Suez Canal (Lessepsian migration). These species are: P. japonicus, P. semisulcatus, Metapenaeus monoceros, M. stebbingi, Trachypenaeus tapenaeus. At the same time, has been reported that there are some natural population of P. japonicus in the Adriatic Sea and in the region of Cadiz (Spain).

The shrimp is one of the most important catches in the entire world because of his flesh and his commercial value. It is characteristic that the shrimps were the 19.7% of the total imports of the EEC (1993) and their selling prices in Hellas in 1995 were increased about 42% (ABH Report, 1994). From the elements above it is clear that it is urgent to culture these prawns in our country.

The Hellenic climatic conditions are the most favourable for this type of culture if we select a species, which will combine rapid growth rates and a great endurance in the physicochemical condition. It is clear that the details about the reproduction of this species and problems of its culture must be resolved. Additionally, the use of mild sources of energy, or cheaper source of energy (natural gas) during the winter for the water heating is possible to obtain the achievement two generations per year.

PRESENT STATUS

The interesting results about shrimp culture in Hellas have a relationship to efforts in other European countries. Although many problems have already solved, efforts were not successful. In spite of other countries who started their effort to culture shrimps at the same time like us (Egypt, Turkey, Israel, Cyprus, Albania) have already created a small number - but viable - of units. The reasons contributed in this state are:

• The lack of the Hellenic know-how of the shrimp culture
• Expert foreign scientists could help Greek scientists in aquaculture.
• The non existence of a state hatchery (broodstock section, larval rearing section). In spite of the existence of a building in the N. Hellas, this one has never been completed.
• The Ministry of Agriculture and the banking establishments has never encouraged this type of culture.
• The national research centers have never taken the initiative to act in the shrimp rearing
• The Hellenic investors have low economic abilities and always are looking for the money for jam.

The first scientific -experimental efforts- at the end of seventies - on the shrimp culture in Hellas had to do with the reproduction of P. kerathurus (Claoudatos, 1978). But after these efforts have not been followed by some investigative culture in the field. The low growth rate and his lower resistibility in the lower temperatures in comparison with P. japonicus were the main reasons where this species has not cultured in the Mediterranean Sea ( Lumare, 1990). In our days many of these problems have been worked out, so we have to look at the culture of this species again.

The first cultivation effort of P. japonicus in Hellas was an extensive method culture in Psathotopi Artas in Amvrakikos gulf (Ionian Sea) in 1990. Amvrakikos gulf is a shallow semi-enclosed area connected with the Ionian Sea by the Preveza channel (Table 4). The first private hatchery was in Menidi Artas (Amvrakikos gulf) and from this unit in 1993 some adult mature individuals are given to the state hatchery in Pogonitsa (Epirus – W. Hellas). In this unit some researchers tried to reproduce unsuccessfully this species. In the same year a success acclimatisation of P. vannamei has been achieved in Alexandroupolis (N. Hellas) in earthen basins. In 1994 – for the first time – a success acclimatisation and culture of P. japonicus has been achieved both in experimental rate (Kevrekidis et al, 1995) in Porto-Lagos (Ksanthi region – N. Hellas) and in productive rate (Alexandroupolis) (ABH, 1994). In 1994 some postlarvae have been imported from Taiwan in Alexandroupolis unit, but these were affected by the virus White spot disease virus (WSDV) and this production has been destroyed during the first week of cultivation.

In our days the unique unit who works is this of Alexandroupolis town. There is a cultivation of P. japonicus which takes place with a semi-intensive method in earthen basins (100.000 m2). This is the first period when the unit will produce some shrimps and this production will be ready in September of this year (10 t.) The unit has supplied postlarvae of this species from the Spain (P25 ) with a value of 0.03 $ each. The marketable weight will be 18 gr. The food was taken in pellets and no disease appeared during the culture (Kevrekidis, pers. comm.). In Hellas there is not any culture of freshwater shrimp.

TABLE 4: Shrimp culture in Hellas. The unique unit that works is in Alexandroupolis, with P. japonicus.
 

YEAR	REGION	OWNER	SPECIES ORIGIN POSTLARVE	AREA ( x 1,000 m2)	METHOD	WEIGHT
1990	Psathotopi, Arta-Epirus	Private	P.japonicus Spain	70	Extensive	30
1992	"	"	P.japonicus France	100	Semi-extensive	30
1993	Alexandr.	"	P.vannamei U.S.A.		Semi-intensive	11
1994	Porto Lagos	Searching	P.japonicus Menidi Arta		"	7.1
1994	Alexandr.	Private	"		"	20
1996	"	"	P.japonicus Taiwan	80

 

LEGISLATIVE TOPICS

According the official gazette No. 30/28-1-1993, law 4028/86 the minimum technical specifications at which the shrimps units must perform so as to be financed from the Hellenic government, are:

Fresh water shrimp: closed water system - 4000 m2 cement basins – 8 tons per year. Open water system - 10000 m2 earthen basins – 5 t/per year

Sea water shrimp; Semi-intensive: 30.000 m2 of land area or shallow sea water - 15 t. per year. + 5000 m2 land area - 2000000 P25 (15 t. per year). Intensive: 25000 m2 of land area - 20 t. per year – 2000000 P25 (20 t. per year).

PROSPECTS

In Hellas there is high possibility of development of shrimp rearing and the crustaceans in general. This occurs because here there are thousands hectares of brackish lagoons and coastal regions where it is very easy to culture the shrimps with a low budget. The Hellenic climate is very convenient for this culture, with a very long reproductive period (from April to November). The prices in the market are very high in the Hellenic market and in the European market too. For the best development of the shrimp culture in our country I think that must forward:

1. The production of young larvae of the endemic species P. kerathurus (especially from a broodstock comes from the same place) and the enrichment of some sea ecosystems ex. lagoons which has observed a reduction of catches for a long period.
2. Extensive culture of P. kerathurus in adapted enclosured coastal localities
3. Semi-intensive culture of P. japonicus (we have to take care in the damaged postlarvae) in eathern basins. We have to prevent their escape in the open sea. This method is the most right culture method of Penaeidae in connection with the hellenic climatic conditions. Moreover it is the most convenient foe Hellas in relation to economic possibilities of the greek investors. This method will be proved very efficient for the investor with the parallel use of mild sources of energy. The intensive method must be eliminated because of his economical coast. The prescriptions and the installations of this culture must be: the culture should takes place in basins whose their dimensions varying between 2-5 hectars, with an average depth of 1,2-1,5 m. The shrimps density must be in 300 kgr/ha without food supply and 1000-1300 kgr/ha with food supply.

In this point we have to point that any import of any «foreign» species to culture ex. P. chinensis must be excluded.

A question of great weight is the culture of P. japonicus for the following reasons:

• The shrimp P. japonicus is a temperate species that has acclimatized in SE Mediterranean. It’s too often in the greak seas (Kevrekidis ed Kevrekidis, 1996) so his culture it’s very realizable in the hatcheries. If will happens this we can secure a greater proportions of eggs hatching and postlarvae’s variability, so the spawn cost price and the transport cost from the abroad will be reduced.
• This species presents a great resistibility in the physicochemical conditions fluctuations (ex. temperature, oxygen).
• Presents one of the best growth curves in relation with the best species of the Penaeidae family.
• Every Mediterranean country prefers this species and many of the other countries too.
• Is more savoury that P. kerathurus. I repeat that the most right culture method is the semi-intensive. This method is the most favourable, because 1. Is the most frequent all over the world but also in the Mediterranean 2. Secures a great percentage of survival (over than 70%) and after 4-5 months its mean weight arrives the 25 g. This result presupposes a good management of the unit. 3. During the culture – in the growth period – the offered artificial food can be replaced by cheaper sea products who are very abundant in the greak seas, redusing the total culture cost.

ABH Report, 1994. The Greek aquaculture status of 1995. Ministry of Agriculture.

Kevrekidis K., Kevrekidis T., 1996. The occurrence of Penaeus japonicus in the Aegean Sea. Crustaceana 69(7): 925-929.

Kevrekidis K., 1994. The temperate shrimp P. monodon. The alternative cultural proposal in the Mediterranean. Fishing News, April 1994, p. 30-35.

Kevrekidis K., Kevrekidis T., Psaltopoulou H., 1995. Preliminary note of Aqua. Soc., Spec. Publ., no. 23, 222-223.

Kevrekidis K., 1997. The present status of prawn culture in Greece, A review 7 pages, (in press)

Klaoudatos S., 1978. Breeding of P. kerathurus in the laboratory as a proposition to culture them on a commercial scale. Thalassographica,2, 99-113

Lumare F., 1990. Crucial points in research into and commercial production of  shrimps. Mediterranean Aquaculture, eds (Flos R., Tort L., Tores P.), 21-43. Ellis Horwood, N.Y.