Opening session
The workshop session was opened at 9:00 o'clock at GERMA PALACE Hotel (MALTA) on June 1st 1991. Prof. Carmello AGIUS the director of the National Aquaculture Centre of MALTA, welcomed all the participants. He was honored by the holding of the first scientific workshop of MEDRAP II. in his country. It reflected the importance given by the Maltese Government to aquaculture development. He mentioned that aquaculture development in the Mediterranean is severly handicapped by the lack of technology in producing juvenile fish on an industrial scale. This workashop will try to plot the route as to future research, in order to introduce new species, new technics and even new types of fish products on the markets. It is being organised with a great deal of foresight at a time when prices of the established species, as sea bass and sea bream, are still relatively high.
Finally, he wished to all participants a pleasant stay in MALTA and a very good workshop.
The Project Coordinator, Mr. Hassen AKROUT, called upon to congratulate the country organiser of such an important session, his Excellency, the Minister of Agriculture and Fisheries for his high interest to attend this opening session of the workshop.
He mentioned that diversification of aquaculture products, is particularly important because of its impact on the development of aquaculture production, on its economical aspects and on its contribution to food security and self-sufficiency.
This forum of highly competent scientists, can be considered as the first step to the constitution of the Research Sub-network. It will urge us to think about the conception and the mechanism of this sub-network.
In his welcome speech, the Honorable Minister of Agriculture and Fisheries of MALTA, pointed out the fast expansion of aquaculture throughout the Mediterranean region. This expansion is necessitated by the increasing demand for fresh fish coupled with the decreasing wild fish catches. Such spread has been made possible by the establishment of industrial scale production of marine fish fry, such as sea bass and sea bream. This workshop is therefore most timely in execution, it will give the Experts an opportunity to share views on the experience and future plans in this regard. This cooperation should result in a planned development of aquaculture in the region.
MALTA's potential in the field of aquaculture, is considerable, especially on intensive systems and offshore fish farming.
His Excellency, added that all the best will be done to make the stay memorable. He wished a full success for the work and declared the workshop open.
Designation of officials and adoption of the agenda
Prof. Carmello Agius, the National Coordinator of MALTA, the host country, was designated, by all participants, Chairman of the meeting and Dr. Ali Kather, Director of Marine Research Centre (EGYPT) Vice Chairman.
The Chairman proposed the designation of a reporting committee, which was approved by all participants. It is composed of :
| - | Dr. Jaime Menezes | (PORTUGAL); |
| - | Dr. J. Dujakovic | (YUGOSLAVIA) |
| assisted by : | ||
| - | Dr. O. Beji | (MEDRAP II) |
| - | Dr. S. Gashout | (Sub-regional Coordinator) |
The agenda was approved after slight modifications concerning the order of different items.
Work Technical Sessions
Mr. O. BEJI (MEDRAP II) who introduced the workshop, mentioned that the diversification of aquaculture production, will be scientifically treated respectively in research and experimentation on new reared species and new rearing technics in both open and closed systems, with reference to what is present applied in the Mediterranean.
The workshop on Diversification of aquaculture production will allow :
- the exchange of experiences and solutions to different problems;
- the update of information to the participants;
- the constitution of the first step in the establishment of the Research Sub-network;
- the elaboration of a common strategy in the matter.
The main objectives of diversification of species, are to improve the productivity, to preserve some precarious species by increasing, their capacity to resist against health problems and to satisfy marketing and nutritional needs.
The main objectives of diversification of rearing technics, are to produce a cheaper animal proteïn, and to develop the exploitation of local potentialities.
Mr. Ferlin (Ifremer - FRANCE), presented the status of present aquaculture production in the Mediterranean region and enumerated the problems to be solved to reach a successful aquaculture products level. He presented also some aquaculture technology used in various Mediterranean countries. On those themes, the said that aquaculture is an old activity in the Mediterranean:
- shellfish farming in GREECE (flat oyster): 5th century B.C;
- fish farming in EGYPT: 3000 B.C;
- carp farming :12th century in YUGOSLAVIA, FRANCE, ITALY, etc…;
- trout farming: 19th century in FRANCE and ITALY, but a new development and a rapid increase of production was occuring since 1960.
1- Causes of development
| - | Fish market | : | Europe : 22 Kg/cap/yr, but large range (8,5 – 43 Kg) Other Mediterranean countries: less developped : 3–15 kg/cap/yr |
| - | Space | : | Mediterranean :900 000 ha of lagoons and salt-pans. Tunisia: 75 000 ha; Turkey: 35000 ha ; Greece :30 000 ha Freshwater bodies :several million hectars (France :120000 ha ) |
| - | Men | : | Shellfish culture in France using coastal population Carp culture in Europe, with heavy works during winter, using rural population |
| - | Research development | : | New technologies, basic research in genetics, nutrition, etc … |
| - | Finance | : | Large impact of national and EEC policies |
2- Modern development history
| - | Growing | : | Collection of fry of spats-fertilization 12th–18th century |
| - | Semi controlled reproduction | : | Carp, oyster 19th century |
| - | Feeding | : | natural (wastes) - artificial 1900–1960 |
| - | Controlled | : | Fresh water fishes, molluscs, crustaceans-marine fishes 1950–1980 |
3- Present situation
Freshwater aquaculture
East Central European countries: Cyprinidis Syria, Egypt
History
Cyprinidis : religious origin (no meat consumption during lent-time and on Friday), use of marginal land, uneasy transportation of marine fish.
During 14th–15th, very large development in Central Europe (surface area : 2–3 times present one), than all European countries.
Decreasing activities with the development of marine fisheries, new preservation technologies, transportation, etc…
Other species: (Sturgeon, salmonids, catfish, tilapia, mullets, eel): needs for diversification during the 20 th century
Technology and sites
Cyprinidis, Tilapia, Mullets Large earth pond in Egypt, Yugoslavia, Greece; cage-culture in Yugoslavia-semi-intensive in France, Greece, Egypt.
Eels, strugeon, catfish: Use of heated water (power station, iron factory), in intensive ponds in italy and France
New development
New species:salmonids, hybrids, etc…
Production and market
| - | Trout | : | 120 000 T in Western Europe |
| - | Carp | : | 4 00 000 T in Eastern Europe (including USSR) |
| - | Eel | : | 5 000 T in Italy, Germany, Denmark |
| - | Catfish | : | 1 800 T in Italy |
Shellfish farming
History
Technology and sites
New development
Production and market
Markets : France, Spain, Italy, Yugoslavia
Marine aquaculture
History
Development of salmonids in saltwater in Northern Europe
Technology and sites
New development
New species : red sea breams, large sea breams, tunas
New technology : semi-intensive ponds; offshore technology : boats, immerged cages ; warm water (power station) or ground water
Production and market
Turbot (mostly in the Altantic regions ):less than 500 T(Scotland, France, Spain)
Mediterranean fishes (sea bass, sea bream ): around 6700 t in EEC in 1990 and around 1000 – 1200 Tin other Mediterranean countries
After this general introduction, the workshop treated the technical aspects of the diversification of the production.
The new reared species theme was presented firstly. Mr.II DUJAKKOVIC from Institute of Oceanography and Fisheries - Yugoslavia, presented a communication on artificial production and rearing experiments on Dentex dentex.
In fact, several studies were conducted to evaluate the conditions required for the control production, especially at the Larvae and post-Larvac stages. Both sexes matured spontaneously in capacity, giving small quantities of gametes. A positive but not syncronised response to hormonal injection (H.C.G.250 I.U/KG) was observed. The average eggs number per female, was 58,000/Kilo/wet Weight.
Twelve days after, feedings on only zooplankton proved to be unsufficient, so rotifiers and artemia were enriched with fish meal and Cod Liver Oil.
At 16 days stage, Artemia is introduced but rotifiers were still given at a reduced quantity.
From day 25, Larvae were fed with enriched adult artemia and artificially dry food.
At 60 days, the larvae was used on the artificial food.
It may be concluded that the introduction of artificial food at larvae stage seemed to be benefitial as it showed a 11% increase in survival rate.
Mrs.Rafika BEDOUI (INSTOP-Tunisia presented a communication on artificial production of juvenile sole (solea senegalensis), She mentioned that in Tunisia, rearing of solea senegalensis, has been realized since 1989 in order to:
produce larvae at large scale and proceed to semi intensive rearing;
succeed massive artificial production of juveniles to repeople natural environment,
The preliminary results showed that :
- the first month rearing was successfully realized ;
- larval mortality was observed at about 40 days of age.
To overcome this problem, different actions were proposed particularly on technic, trophic and physiologic levels.
Mr. G. GEORGIOU (Cyprus) presented three experiments on Puntazzo puntazzo, Pagrus major and Siganidae in his country.
The different stages of the life cycle of Puntazzo puntazzo, were examined as a first priority in the study objectives, Diversification of the species, comes in a further stage. The broodstock of Puntazzo puntazzo, was collected from the wild, as juvenile and reared for a year and a half before spawning.
The spawning started naturally by the end of October and continued till the end of December during which good quality eggs were observed.
Final survival rate during larval rearing reached 11,6%.
During the fattening stage, Puntazzo, puntazzo reached the average weight of 100g within 9 months from hatching, 150g within one year and 214g within 18 months. This growth rate compared favourably with that of Sparus auratus was higher than that of Dicentrarchus labrax. . The market potential, the most decisive factor, still remained to be determined.
Mr. G. Goergiou mentioned in his introductory communication on Pagrus major, that one day old larvae of the red sea bream , were imported from Yugoslavia in the beginning of May for experimental culture.
The study of the life cycle, the culture, the potential markets and the production on a private scale were the objects fixed for such experiment.
Larval rearing was managed successfully,. The growth rate during the first year of prefattening and fattening was very high, reaching within thirteen months of rearing the average weight of 240g, This was significantly higher than that of sea bream and sea bass which were farmed under the same conditions at the « Department Experimental Marine Aquaculture Station»at Meneou.
Judging from the biological data known up to this stage, as well as the comments on its market demand, it appeared that this Japanese species would have good potentials for commercial culture in Cyprus.
The third communication was on aquaculture potentials of Siganidae in Cyprus.
In the Mediterranean, the family Siganidae is represented with two species, Siganus rivulatus and Siganus luridus. Both came from the Red sea and are herbivorous species suitable for polyculture with carnivorous fish, like sea bass and sea bream.
Fry supply from the wild, was not a dependable source. Several diets like fresh vegetables, mainly clover and artificial dry food were used successfully for rearing rabbit fish under controlled conditions. In polyculture conditions, in cages, juveniles collected at the size of 5g reached the commercial size of 200g within one year.
In Cyprus the reproduction of Siganidae, was managed both naturally and induced method. Eggs were benthic with a diameter of 600 mm. Larval length at hatching is 1,8 mm. Several methods and diets, like rotifers of various sizes, bakers yeast, several species of Phytoplankton or combinations of the above, were tried for larval rearing, but without success, Larval mortality started on day five and by day six it reached 100% in all their efforts.
Mr. A. KATHER (N.A.C Abassa - Egypt presented instead of Dr. M.A. SALAH, a first communication on the low salinity tolerance by thinlip grey mullet and a second on stocking density levels for mullet.
The low salinity tolerance by thinlip grey mullet (Liza ramada) was mainly due to the fry transport aclimatisation to Wadi EI Rayan lakes. Great losses occured in mullet fry especially during the first week after transplantation.
The aim was then, to establish an applicable aclimatisation system for extensive fry transport in order to reduce the overall losses.
Mr.Kather added that studies would be carried out in the future to design a more solid system.
The second communication on stocking density levels for mullet, Rabbit fish and Pagrus Fry, in which he mentionned that the effect of different stocking density of three marine fish species Liza ramada; Risso; Siganus rivulatus and Pagrus haffare; C & V) fry for fingerlings production was studied, Fish fry of the different species were stocked in 16m 2 bottom pens made of 2 mm mesh plastic netting materials in the nursing pond at lake Quaroun, EI Fayoum province, Fish fry (16 – 24 man long) were stocked in five different stocking densities, 250/m 2, 200/m, 150/m, 100/m and 50/m2. Feeding of fry was basically on green water and fermented dried pigeon droppings.
Results of the study showed that the best highest stocking density was 150/m 2 for mullet, 50/m2 for both rabbit fish and pagrus. Further, surveys were required for studying the performance of fry of these species in mixed nursing at different stocking rates.
Mr. LAZZARI (ENEA, Italy) gave some notes on the aquaculture development of the yellow tail
(Seriola dumerili) . The results on fertilization and the observation of larval stages, were never put on
record before, and constitute a relevant base for next studies.
Fish campaign allow the increase of biological knowledge of this species, which is a candidate for
intensive aquaculture in the Mediterranean basin. The experience they had done on the species, with
concern to the experimental farming, Giovanardi (1984), should be inserted in a
Regional policy for the development of the marine valuable species.
Prof. C. AGIUS (N.A.C, Malta), in his communication on saltwater Tilapia culture, pointed out the relatively high minimal temperature tolerance which did not permit year round survival in some regions, and the uncertain consumers acceptibility. In their experience, this culture could be considered good for their commercial production, and could increase their market value in the Mediterranean region provided they sought ways to overcome these problems.
Mr. E.M TALBAOUT (MAROST-Marocco) presented a communication on management of a shellfish hatchery (flat oyster and European clam ). He also treated the growth rate and mortality of oysters in Nador lagoon. Culture of flat oyster was studied in the lagune of Nador (Morocco) during the period : August 1989 – June 1991. The environmental factors operated to be suitable to highgrowth of the Oysters.
The spats of about 0,3 g of whole weight reached 69g and 127,5g 12 months and 22 months later respectively.
The oysters grown in the «basket system» compared top those stuck on wires, showed better growth and higher survival rates but low index condition.
The mortality rates, during the first phase (6months of growing), and the second phase (16 months) were 18,7%and 41,1% respectively.
The hatchery production technics of flat oysters and European clam spats were also described.
Mr. P.Y.HAMON (IFREMER Palavas, France) presented a communication on suspended mussel cuture in the french Mediterranean, in which he mentionned that suspended culture of the Mediterranean mussel Mytilus galloprovincialis, was traditionally developed, since the early 1920's, in coastal lagoon sand sheltered bays. The first culture trials, in the open sea, began around 1975, and led to the definition of performing longline suspension culture system, allowing an increasing production from 1985 on, with an objective of 20000 to 30000 tons within ten years.
Culture areas
- Traditional culture: besides secondary sites, like the Gulf of Fos of the Etang of Sales-Leucate, the Etang of Thau remained the most important traditional site. One third of its 5 meters deep, 7 500 ha coastal lagoon, is devoted to mollusc culture. 2 800 suspension culture tables are installed, laden with a total reared biomass averaging 35 000 tons (Crassostrea gigas 30 000 t, M. galloprovincialis 4000 t).
- Offshore facilities: several culture concessions totalizing 2000 ha, have been granted along the Gulf of Lion coast, by depths or 20to 30 meters Main sites by decreasing importance are Sète-Marseillan, Aresquiers, Vendres, Gruissan, Port-Vendres. 200 longlines are presently under exploitation, out of theoretical capacity of 560.
The technics:
- In lagoons the culture system is based on frames called «tables», 50 meters long and 12 meters wide, consisting of 3 rows ofII rails each, driven mechanically into the bottom. These rails, delimitating 20 square, bear transversal beams and poles, on which are hung the culture ropes (50 ropes per square, their length ranging from 2,5 to 6 meters according to the water depth).
- For the open sea, a specific offshore suspension culture system technology has been designed by IFREMER and regional Agencies, 200 to 300 meters long underwater longlines are moored on 7to 14 concrete blocks strengthened by chains and iron stakes, The longline, 5 meters beneath the surface, is laden with 1,5to 2,5 culture ropes per meter of longline, the ropes length ranging from 4to 6 meters. Yields at harvest reach 30 to 40 tons per long line, with production of 6to 10 kg per meter of culture ropes, According to the season of stocking the rope and the initial size of seeds, the growth duration varies from 4 to 12 months.
Evolution of the enterprises
The traditional farms are as family type enterprises, employing 2 to 4 persons for cultivation operations, and also packaging and marketing. Offshore facilities, first operated in close relationship with farmers of Thau lagoon, are becoming more and more independant, their mechanization proceeds rapidly, along with the increase of landings, by the building of highly specialized boats (barges) well equipped with hydraulic gears.
Production tendencies and constraints
The most noteworthy feature of these last ten years is the steadily increasing production of offshore mussels (landings of 10 tons in 1980, estimated at 8000 tons in 1990), whereas the biomass under culture in Thau lagoon decreased from 12000 tons in 1980 to around 4000 tons in 1990. Offshore production is expected to be doubled or tripled in the short term, meeting the objective of 20000 to 30000 tons by the end of the century, thus contributing to alleviate the deficit of mussel production in France (34000 tons imported in 1988, for a whole production of 50000 tons).
The main constraints for this Mediterranean mussel production consist in periodic summer distrophic crisis («malaigue» )in Thau lagoon, and the abnormal development of the toxic Dinoflagellate Dinophysis acuminata in the open sea, sometimes leading to the temporary suspension of sales for periods from 2 weeks to 2months.
The presence of the protozoan Marteilia maurini in mussels of most culture sites justifies a histopathological and parasitological survey, although its pathogenic action has not yet been demonstrated.
Fig. 1: culture areas in the French Mediterranean.
Dr. J. MENEZES (PORTUGAL), in his communication presented instead of Dr. I. ARROBAS, the portugese experience on rearing :Penaeus japonicus, mentionned that Penaeus Japonicus was introduced in Portugal in 1985, following the recommendation of the ICES code of Practice of Introduction and Transfers of Marine Organisms.
Several experiences in five sites on the central and south cost, were realized through extensive and semi-intensive regimes. The results achieved, 200–300 kg/ha in extensive and 60–700 kg/ha in semi-intensive, evidenced the suitability for shrimp culture.
Otherwise, semi-intensive production may be improved prefattening the post larvae until 1–2 g weight, which can allow 2 crops, April to July August to December, reaching up to1–3t/ha at least.
After finishing all communications on new reared species, Mr.J.MUIR (University of Stirling-Scotland) began an new them eon new rearing technics. II e made two communication.
The first on aquaculture technologies in which he mentioned that some of the caracteristics of current and emerging aquaculture technologies were reviewed, and their suitability and potential for use in the Mediterranean Region were considered.
Bio-management systems:
- Intensification of existing systems this is often the most cost effective way of developing production and upgrading efficiency; this is usually achieved by steady «incremental» improvement technics.
- Maximizing utilization of space : eg. by increasing numbers of spawning cycles of species in hatcheries, by scheduling production to make best of facilities.
- Bio manipulation of natural and man made aquatic systems : this will require considerably greater knowledge of the relationships between aquaculture stocks and their eco systems.
- Integration between intensive and extensive farms of production systems are already being developed her , eg. nutrient outputs from intensive farms can be used as inputs to less intensive farms.
- Enhancement of fishery/aquaculture systems ;the use of aquaculture technics in natural or artificially created fishery areas.
Technological systems:
- Offshore cage systems; several systems have been developed mainly for salmonids; these may be feasible for Mediterranean finfish but need to be quite carefully evaluated.
- Mechanisation has been one of the most important developments in modern, large scale aquaculture units, and requires to be extended to Mediterranean species and systems.
- Intensive recycling systems, the principles for these are well developped; many are relatively expensive and technologically complex; more recent developments of self-contained systems may provide more promising prospects.
The second communications on technology choice in which he mentioned that:
Aquaculture is developping rapidly in the Mediterranean Region and investment and production, particularly in sea bass and sea bream, has already reached levels where concern, is being expressed for profitability and security of the industry. In this context the choice and use of technology for these species or for other fish and shellfish species, will have to be made within careful regard to efficiency and cost-effectivencess. The developments of such technology will also require a good appreciation of the constraints and influences which are likely to occur in the industry.
The paper reviewed the relationships between the technology development process and the state of aquaculture sector, the relationship between development, production price and profitability, and the main factor likely to stimulate and suppress further growth.
In summarising the various factors involved for developing technology, the following trends are identified:
- efficiency;
- minimised environmental impact;
- flexibility;
- standardisation;
- sensitivity;
The following systems are likely to be most important or the future:
«Bio-management» systems
- intensification of existing systems;
- maximising utilisation of space;
- bio-manipulation of natural and man made aquatic systems;
- integration between intensive and extensive forms of production;
- enhancement of fishery/aquaculture systems.
«Technological» systems
- offshore cage systems;
- mechanisation;
- intensive recycle systems.
Mr. M. SPAGNOLO (IREPA - Italy in his communication on Economic and marketing aspects of aquaculture production , out lined increasing efforts of MEDRAP Countries in the collection of Fishery statistics, but the fish Trade needs to he defined.
Economical analysis and Marketing statistics, should be exchanged between the member countries, to evaluate the consumers preferences in each region, in order to increase and improve the production of the species of interest in aquaculture.
All these communications were followed by interesting discussions as well as by a round table, in which each participant of the member countries, presented a brief note on the status of research in aquaculture development in his country, in accordance with the different themes of the programme.
It was noted that, some participants encountered some difficulties regarding the English language and therefore could not participate to the discussion with the same spirit.
Some participants at the workshop presented their personal works with a restricted information. The importance of the advanced aquaculture research and the experiments of each country which should have been submitted and compared during the workshops had been disregarded. But in general, the workshop of Malta had reached its objectives. Indeed it led to the implementation of the first step in creating the research subnetworks.
The level of the research on diversification of the aquaculture production, vary from a country to another. It is also noted that research on that field, is more experienced in Yugoslavia and Cyprus than in the other member countries.
According to various figures presented at the Workshop, Spain, an Associated country, has an important aquaculture production. Besides the shellfish, they produce, sea bream, sea bass, clams and shrimps.
With regards to research field, Spain is using all their endeavour in controlling the farming technics of news species. Italy and France came after at a lower level.
During the session, sub-groups (sub-networking) have been established to work closely, on common or complementary research programmes, related to the farming of new species i.e :
- farming of Dentex dentex are of interest to Yugoslavia, Cyprus and Tunisia;
- culture of Seriola and Corryphenes in offshore cages are of interest to Italy, Malta and Yugoslavia;
- culture of mullet and its artificial reproduction in Egypt and Tunisia;
- Farming of oyster are of interest to Portugal and Morocco.
Other sub-groups and themes may be identified in further meetings organised by MEDRAP. It is recommended, at a further stage, to deeply examine the following selected themes:
- the different institutions, laboratories and personnel to choose for the subnetworks;
- common and-or complementary research program for the different sub-groups. Objectives should be defined in those programmes to be reached at a short or medium term, tasks repartition and the realisation timing without omitting the financial implication to the above.
At another stage, sub-groups should ensure, in coordination with the Sub-regional Coordinators and the Project Coordinator, the elaboration of a long term programme necessary to the perennity of the sub-networks.
