7. GENERAL OBSERVATIONS, CONCLUSIONS AND RECOMMENDATIONS

7.1 FEASIBILITY OF CONSTRUCTING EARTHERN PONDS

The preliminary observations made by the consultant have given indications regarding the type of soil, seepage rates, tidal range and nature of intertidal region and the extent of land available on the coast for developmental purposes. The sandy nature of the soil, the limited extent of land available after providing for the proposed tourist development plan, the narrow tidal range and the lack of any freshets flowing into the sea show that the construction of conventional type of earthern ponds for coastal aquaculture of fin fish and shell fish will not be an economically viable proposition in the area. Hence the possibility of limited and intensive culture by the use of floating structures in selected shallow areas of the Gulf have to be considered.

7.2 FISH SEED ABUNDANCE AND DISTRIBUTION

The results presented in this report indicate that oyster spatfall takes place in certain sectors of the Gulf, larvae of bivalves, including oysters, and fish eggs and larvae (undetermined species) appear in the plankton and juveniles of perches frequent the clear shallow areas in large numbers. Hence, as the first part of detailed feasibility studies to be taken up, it will be essential to make round the year observations on the seasonal abundance, distribution and fluctuations in the seed of both finfish and shellfish in the Gulf.

Among the different finfish and shellfish present in the Gulf and northern part of the Red Sea, three goups appear to be suitable for consideration in feasibility studies. They are the oysters, perches and mullets. The seed investigations concerning these groups should cover all aspects of the problem in order to gather comprehensive information. For this purpose one collection centre may be set up in each of the sectors and in each of them regular observations may be made as follows:

For studies on the settlement of oyster spat, test collectors made of asbestos and plastic sheets and oyster and scallop shells nay be fixed at each centre and bi-weekly observations made. Simultaneous observations on the growth and fattening of oysters should be made both under natural conditions and in trays suspended on one raft each in the four areas marked X in Fig. 2.

7.3 EXPERIMENTAL STUDIES ON OYSTER CULTURE

Any pilot programme aimed at culturing oysters in the Gulf of Aqaba should take up only the modern technique of off-bottom culture. The traditional method of bottom culture will not be economically attractive here in view of the very narrow shallow water areas and the nature of the sea bottom.

Clear waters are generally characteristic of coral seas. During the period of the present observations the phytoplankton content of the Gulf of Aqaba was low, while the primary productivity and zoo-plankton production were satisfactory. The productive cycles in coral seas turn very rapidly as the algal reproductive rates are not restored by sinking of the algae or by vertical mixing, and the bottom is fairly rich, facilitating continuous regeneration of nutrients. An interesting feature in the Gulf of Aqaba is that while the primary and secondary production rates seem to be good, the tertiary production, according to data so far available, does not appear to be commensurate. This aspect deserves detailed investigations.

For studies on different types of oyster cultch material, spat collectors made of the undermentioned material may be tried:

1. Asbestos sheets
2. Ferro-concrete
3. Tarred timber
4. Plastics
5. Fibre glass

The size of the plates used is known to have effect on the nature and growth of spat and hence different dimensions like 50 cm × 50 cm, 25 cm × 25 cm, 10 cm × 10 cm and 100 cm × 5 cm may be tried

6. Oyster shell strings
7. Scallop shell strings
8. Shells in trays

Vertical spacing in between the successive oyster shells or scallop shells will have to be standardized and for this purpose plastic tubes of different lengths like 5–10, 10–15, 15–20 and 20–25 cm should be used as spacers.

During the initial phase of the studies 12 rafts made of buoyant material and covered with plywood or synthetic sheets, and provided with outriggers for suspending the oyster cultch would be necessary. The strings may be of nylon or galvanised wire (12–16 gauge) and should pass through the pairs of shells kept back to back, with the spacer in between each pair. Different lengths of strings may be used in order to arrive at the optimum level, both for settlement and fattening. If the vertical distribution of oyster larvae can be established as a result of initial seed investigations, the depth of the cultch strings may be regulated accordingly.

Data so far gathered indicate that maximum settlement of spat may be expected in Sector I and hence concentrated efforts may have to be made in this area for collection of seed oysters.

Oyster culture programme

A programme for limited and intensive culture of oysters may be taken up in the coastal waters. The present survey has indicated that culture on rafts and trays can be tried in four areas of the Gulf, marked X in Fig. 2. Due consideration has been given to topographical features, wave action, human interference and future development plans for Aqaba South coast, in suggesting these areas. Trials on keeping cultchless oysters in trays, baskets and cages may also be made.

After the initiation of the programme, the possibility of obtaining stocks of juveniles from outside sources may be considered, taking care to prevent the introduction of parasites and diseases.

Simultaneously, controlled breeding of oysters may also be tried by physical stimulation, chemical methods and biological techniques. The fecundity of oysters varies from species to species and in some cases a single female may produce several million eggs at a time. In hatchery operations the eggs are to be kept in troughs till the straight hinge stage, after which they should get attached to suitable material and kept in post-settling tanks until attaining a length of about 0.25 cm, after which they can be transferred to rafts.

The entire programme of experimental oyster culture should be taken up initially for a period of three years.

7.4 PLAN FOR THE ESTABLISHMENT OF AN AQUARIUM

During the discussions held with the Director General of the Department of Veterinary and Animal Health, regarding the possible developmental activities on the Gulf of Aqaba Coast, it was pointed out that the establishment of a modern aquarium with facilities for taking up experimental studies on aquaculture and related training programmes, may be considered. Accordingly, the basic details for such an establishment were worked out and are given in Appendix 1.

7.5 EXPERIMENTAL FINFISH CULTURE

As has already been emphasised, there is no scope for large-scale cultivation of finfish in the coastal region. If the proposed seed investigations reveal that natural seed resources of perches are adequate, intensive culture of selected species may be tried in two experimental ponds and also in cages fixed to rafts at coastal areas marked X in Fig. 2.

Supply of artificial feed and forage fish will form an important component of such investigations. Cotton seed cake as available in the country, is reported to have a crude protein content of about 40 percent and slaughter house and factory wastes, among other items, can be combined with the same to try out an economical artificial feed.

7.6 STAFF REQUIREMENTS

At present there are no trained personnel in the Department of Veterinary and Animal Health to take up any of the programmes recommended above. It is essential that at least two officers with necessary basic qualifications should receive proper training in general fishery science and modern methods of aquaculture. For conducting the studies outlined in the preceding paragraphs, the undermentioned staff will be required.

(i) For the proponed seed investigations:

These investigations will have to be conducted for a period of one year, under the guidance of an expert. Two local officers, both having basic biology qualifications and one of them with adequate knowledge of chemistry also, should be associated with this programme.

(ii) For the different feasibility studies proposed:

7.7 COST ESTIMATES

Based on the local schedules, as were made available to the consultant from different sources, the following approximate estimates have been worked out: