4.1.1 In the Mediteranean countries finfish aquaculture means mostly culture of sea bass and sea bream since, of the species currently fished and reared in the region, they are the most attractively priced. Traditional aquaculture activity in brackish-water lagoons accounts for 35% to 65% of bass and bream sold in the main European markets (FAO, 1987)1. Up to now only a modest part of these are cultured under intensive or semi-intensive conditions (1522 t against 6069 t, according to FAO, 1987) 1.
4.1.2 The following proposals are intended as back-up for the development of sea bass and sea bream aquaculture based on the use of more intensified rearing techniques, as practised throughout the Mediterranean coast.
The two on-growing systems described can easily fit in with existing aquaculture activity in Iskenderun Bay, which has until now been limited to lagoon management.
4.1.3 Fishing activity in the lagoon is confined to the use of wooden traps located at the exit to the sea, and is limited to a period covering autumn and winter. All fish are sold without recovery of smaller sized fish for overwintering and successive restocking (as is practised in the Italian “vallicultura” system).
Figure 5. Earthwork for a 16-ha shrimp unit
4.1.4 In these circumstances, it is possible to develop a model for semi-intensive culture of sea bream. Initial development can be based on the exploitation of the natural stock of fry or undersize fish which arrive seasonally at the mouth of the lagoons. The system proposed is based on seawater pumping (up to 20% daily water renewal), and feeding with crumble and pellet food, supplemented by natural organisms growing in the ponds.
4.1.5 The second model is a more sophisticated, vertically integrated system. It includes a hatchery as an autonomous source of fry and has an on-growing unit based on reinforced concrete raceways which allows stocking of fish at high densities.
4.1.6 The review of existing data on sea bathymetry as well as of wind and wave strength and direction (see Annex 1, Figures 6, 9, 10), together with the results of some survey trips, indicate that floating cage culture cannot be considered a viable option. Suitably sheltered conditions for cage systems do not exist along the coasts of Iskenderun Bay.
4.1.7 It is thought that the supply of wild fry and yearlings would be adequate for the needs of the proposed farms, at least for the first years of their operation. The existing lagoons and deltas and the status of catching activity at the traps strongly suggest the presence of an underexploited wild stock. In the early stages of development of aquaculture it is advisable to reduce investment costs by using existing natural resources.
4.1.8 As designed in the intensive model, and foreseen in the semi-intensive model, the establishment of one or more hatcheries is, however, considered to be essential in the medium-term for two reasons: (a) to avoid overexploitation of wild stocks with resultant harmful effects on traditional lagoon—based aquaculture and (b) to provide the new farming activities with a more reliable source of fry which is vital for highcapital, intensive production systems.
4.1.9 The relatively high sea water temperature found in Iskenderun Bay during winter should result in better growth patterns for fish, compared with what is observed in other areas of the Mediterranean. Other major advantages offered by the area are the following:
Availability of land along the sea shore, owned by private individuals or by the state and unexploited for other purposes.
Presence of clay soil in some areas, mainly around the lagoons and salt marshes.
Proximity to Adana airport, for export of fresh produce to the prime markets.
Proximity to services such as H.T. power line, processing plants, transport companies, animal feed factories.
4.2.1 Rationale: Sea bream is far more suitable than sea bass for semi-intensive rearing, because of its specific feeding habits. The low density in ponds and the combination of natural and artificial food will produce a better conversion rate and growing pattern.
4.2.2 The model proposed consists of a farm covering an area of 17 ha, 12 of which are ponds, comprising:
4.2.3 Production Capacity. The full production capacity of the farm will be 60 t at an average density of about 0.5 kg/m3. The average individual weight of market size fish is expected to be 400 g after 18–20 months, starting from 1 g fry (Annex 3, Table 11). The harvesting period will be late summer-autumn, and will depend on market conditions and on the size diversity of the stock produced. The marketing strategy suggested is to sell 100% of produce to the Italian market in a fresh, whole form. The full production will be reached by the fifth year. By purchasing yearlings at the end of the first year it will be possible to produce 38 t of market size fish by the end of the 2nd year.
4.2.4 Design details. Semi-intensive culture of sea bream will be based on purchasing wild or hatchery-produced fry and on successive stocking into nursery ponds (size 30 × 70 × 1.5 m or 2 100 m2)1. After approximately 10–12 months the overwintered yearlings are harvested, graded and transferred into 10 on-growing ponds (size 80 × 120 × 1.5 m or 9 600 m2) for the final growth stage up to market size2. Harvesting will be by draining ponds by gravity. In the nursery ponds wild fish are progressively adapted to dry feed (crumble and pellet). Water is pumped from the sea through an intake concrete pipe moored to the sea bottom and inserted off-shore into a rocky breakwater. The pipe feeds an earth basin where two submersible/ horizontal pumps are located. The pumps lift water to a still basin (concrete) from which a concrete pipe will carry water by gravity to feed the nursery and on-growing ponds. At the outlet of each pond there will be a monk through which water will be discharged by gravity to a drainage channel. The final outlet will be set at approximately 900 m from the intake. Feeding will be performed by an automatic feeder trailed by a small tractor. The same tractor will be used for lifting pumps for maintenance, lifting nets during harvesting, etc. A refrigerated 5.0 t truck will be used to ship harvested fish to the market (or to the airport) and a 1.0 t pick-up will be used for general purposes.
Four buildings are provided: one for the generator set, close to the pump house, one as a food store/workshop (75 m2), one as a general store/ packaging area (80 m2) and the last for staff accommodation (70 m2).
The electricity supply will be provided by a H.T. line (probably 30 kw) and transformed on the site to 440 V, 3-phase. A generator set will be available in the event of break-down of the normal power supply.
The suggested pond construction strategy is based on a simple clearing/filling-up programme, with simultaneous movement of earth to elevate pond dikes. The discharge channel will be dug below actual ground level.
4.3.1 Rationale: Of the prime Mediterranean species, sea bass (Dicentrarchus labrax) has the best performance when cultured by intensive methods. In recent years the techniques for controlled reproduction and on-growing have been applied on a commercial scale and high yields per unit area have been achieved for example in Italian and French farms.
4.3.2 The proposed unit is integrated vertically reproducing almost the whole life cycle of the fish from egg to market size. Basically it includes the following:
4.3.3 Production Capacity. Starting from 22.5 t of fish harvested year 1, the farm can reach full production of 100 t/year by year 3. The expected average individual weight of 300 g should be attained after 20–22 months, starting from 1 g fry. As for the sea bream farm, the harvesting period will be autumn/winter and the most promising market Italy. The hatchery, built in year 1, shall be able to produce its first crop at the beginning of year 2 (500,000 sea bass fry). It reaches full production in year 4, with 1,000,000 fry, 70% sea bass and 30% sea bream. Seed which is surplus to the annual demand of the on-growing unit will be sold to other farmers in Turkey or abroad.
4.3.4 Design details. The intensive culture of sea bass is based on stocking wild or hatchery reared fry in reinforced concrete raceways and feeding them exclusively with pellet food and some trash fish flesh. A high water exchange rate is usually provided and the design of tanks should maximize self-cleaning of settleable particles. The production cycle starts when 1 g fry are first placed into 52 pre-growing tanks (size W 1.50 x H1.40 × L 20 m or volume 42 m3) where they attain an average weight of 75 g within the first winter1. The yearlings are harvested, graded and transferred successively into 38 on-growing tanks (size W 2.50 × H 1.75 × L 40 m or volume 175 m3) where they reach market size (300 g) within 10 months. The final fish density will be approximately 15 kg/m3.
Harvesting can be easily carried out by net, after lowering the water level of the tank. Each tank can produce some 2.6 t of fish each year. As sea bass is a fish which is difficult to handle, the harvesting programme should be based on harvesting one complete tank at a time. Feeding will be carried out by 2 or 4 solar powered automatic feeders per tank, depending on size. Food quantities should be continuously adjusted according to observed feeding habits and growth patterns. The rearing environment should be checked daily for the main parameters of temperature, dissolved oxygen, total ammonia nitrogen and pH levels.
A high water flow (up to 1.7 m3/sec) is generated by 3 pumps working alternatively, with one acting as a spare (individual flow 0.85 m3/sec, H=6 m). The pumping station is placed at the inner part of the water intake channel. The channel extends to the sea, where it is protected by two breakwaters1.
From the pumping station the sea water is carried to the raceways by means of two concrete channels, one for each growing stage. The two channels feed the raceways by gravity, and by gravity the overflow water is then discharged into drain channels. The concrete drain channels collect waste waters from the tanks and transfer them to the settling pond. The 1.5 ha lagoon is thought to act as both setting unit and self-purification unit. Such a pond presents suitable conditions for the semi-intensive culture of sea bream and in this way some 10 t per year can be added to the total production of the farm.
Owing to the high residence time, settleable particles (uneaten food, feaces) will be separated from incoming waste waters. The natural planktonic and benthic communities, together with fish such as mullets, will purify the water, thus avoiding any pollution effect on the sea. The final discharge will be carried out by another channel to the sea and this will be sheltered off-shore by two breakwaters.
The electric energy supply will be provided by a H.T. line, transformed to L.T. (440 V, 3 phase) on the farm site. Fresh water supply and sewage drainage systems are also foreseen. A generator set will assure energy for the pumps when normal supplies are interrupted. A service building (525 m2) will include a food store, a chilled room and deep freeze, a packaging room, general store and changing room with services for workers. Offices will be located on a second floor. A separate building will serve as staff accommodation.
A tractor with crane and a 5.0 t refrigerated truck will permit harvesting and shipment of fish for market. A smaller tractor with trailer will carry the food to fill the automatic feeders. A minibus and a car will serve for staff transport.
4.3.5 Hatchery. The hatchery building (1 308 m2) will contain all the production units which are needed to obtain 1 g fry: live food culture, spawning, larval rearing and weaning. In addition, there will be a laboratory and a feed processing room.
The water supply will be provided by autonomous pumps which will be attached to the on-growing water distribution system. Normal daily water need will be 435 m3, maximum need will be 2 690 m3 (when the weaning unit operates on a flow-through basis). The external broodstock unit and the internal maturation/spawning unit will have a flow-through circuit. The larval rearing and weaning units will be linked to autonomous recycling systems, thus giving savings on water heating. Down-flow biofilters will avoid harmful accumulation of ammonia in the system. The weaning unit will have the option of operating on an open-circuit basis, when external water temperature permits.
The water supply for the live food mass culture unit and the make-up water will be filtered under pressure on selective gravel and diatom powder filters to optimize water quality.
The hatchery will be able to operate using its own stock of wild breeders, maintained in suitable tanks. At the beginning of the spawing season (autumn) breeders are caught, selected and hormone-treated to produce spawning. Spawn will occur in the internal tanks: fertilized eggs will be automatically collected, selected and transferred to the hatching tanks. After hatch takes place larvae will be fed by plankton previously cultured in an adjacent unit. The live foodmass culture consists of the rearing of phytoplankton (unicellular algae) and zooplankton (rotifers and naupliar stage of Artemia salina) in a controlled environment. Filtration and sterilization of water, together with addition of air, CO2 and selected nutrients, will assure the optimal medium for the organisms' growth.
During the rearing and early weaning stages of larvae, the water will be recycled. To maintain the best environmental conditions in the system, water will be sterilized (U.V. rays), heated to the desired temperature (heat exchanger), oxygenated (air blowers and pure oxygen imput) and purified (polyurethane foam filter bed). Thirty cylindrical tanks with conical bottoms (2 x m3) for larval rearing and 16 fiberglass raceways (10 m3) for weaning will be used.
The hatchery will be able to produce in a full year 1,000,000 fry, of which 30% will be sea bream and 70% sea bass. On-growing to market size will require 500,000 fry: overproduction of seed will be sold to other on-growers1.
1 Full hatchery production will be reached in the fifth year
The farm will operate with 20 full-time staff (3 management) and 52 man/months of part-time staff per year.
4.4.1 As with shrimp farming, there are clearly several major constraints to the development of sea bass and sea bream farming as proposed in the above models.
The principal constraints arise from the high capital and operating costs involved in establishing units which are of a sufficient scale to enable independence of operation from production to marketing.
Another major constraint in starting up in a new area such as Iskenderun Bay is the lack of technical expertise.
4.4.2 At best, these constraints would limit the development of marine fish aquaculture to large private sector companies with sufficient funds available for diversification into aquaculture.
If, on the other hand, public support was available to reduce the effect of these constraints, the development of an industry based on local private entrepreneurs, including fishermen's cooperatives, operating either small-scale or large-scale production units and sharing central seed, marketing and other services, would be possible.
In the particular case of intensive cultivation of sea bass, the feasibility of different systems should be investigated in order that more cost-effective models might be identified.
4.4.3 To bring this about with sea bream and sea bass farming, the following government supports would be required:
For sea bream:
Financial assistance to reduce capital costs of farm construction (pond construction, power supply, equipment)
Provision of short-term technical assistance and training
Financial assistance for the establishment of joint processing and marketing schemes
Promotion of the capture of wild fry from coastal waters in the short-term and investment in hatchery facilities in the medium term
For sea bass:
Financial assistance to reduce the capital costs of farm construction
Provision of long-term technical assistance and training
Financial assistance for joint processing and marketing schemes
Investment in hatchery/demonstration facilities to be operated by either public sector or private sector organizations
