4. AN IMPLEMENTATION PROGRAMME FOR THE FUTURE

The construction of the proposed facilities will probably take all of the remaining time between now (February 1985) and the end of the immediate project extension (July 1986). It is therefore important to begin some short-term activities in anticipation of the availability of the new facilities. The following work plan is proposed and distinctly possible in view of the practical experience of the staff to date.

4.1 Tilapia Production

A number of large fibreglass units have been on site unused for some twelve months. These units can be used to begin the demonstration production of Tilapia with a goal of attaining 0.5 t/month to be sold through local markets.

The tanks can be set up on hard flat ground adjacent to the existing trailers. The tanks should be either embedded in sand, or placed on fabricated concrete slabs. One tank was set up on slabs and filled on 20 February 1985 without any problem for a 10 t unit. The raceways will require more care because of their length and method of jointed construction, but should also prove no problem if the foundations are well prepared for these 16 t units. The small 1.5 t units can also be set up on the sand base. The tanks could be arranged in any way, but it might be an advantage to set them up so that they can be covered with a shaded plastic ‘greenhouse’, fabricated cheaply from plastic pipe stretchers as cross beams, and covered with plastic sheeting and shade cloth. Drainage canals will be necessary, but these can be crudely dug with a backhoe, and lined with plastic sheeting. The affluent water can be discharged back to the sea across the beach. Additional pumps and water lines will be required to supply the units.

The tanks will fulfill the need for additional adult breeding pools, hatchery and juvenile production units, acclimation units, and grow-out units. The existing nursery tanks will also be used.

Complete records of the environmental parameters (temperature, pH, dissolved oxygen, salinity) will be kept on a daily basis for all tanks. A monthly record sheet will be designed and duplicated and kept fastened to the side of each tank, suitably protected.

Complete records of the livestock in the tank will be maintained (stocking date, density, feeding rate) together with bi-weekly data on growth from a sample of at least 100 individuals removed from the unit, weighed and measured. These records will be maintained by the project biologist who will have the responsibility of this sub-project. It is not anticipated that the production goal of 0.5 t/month will be realized until 1986, but all effort should be made to regard this as a prime activity of the Fish Farming Centre, and it is necessary to keep complete records from the first day so that reliable data are developed for broodstock resources, fry production each month, grow-out time, feed consumption, etc. Although labour costs are important, it will not be possible to make accurate comparisons for the future as this is a government project. However, there could be a specific attempt to determine the number of hours in each day required for certain functions; e.g., it might take two men three hours each day to feed all the fish when the farm is operating at full capacity; or one man needs two hours to collect all the daily records for environmental parameters.

4.2 Cage Culture

Immediate plans must be implemented to improve the sea cage operations offshore and begin to work in farming modules. It is recommended that the planned objective is to replace the existing single cage units spread about the lagoon, with a single module of twelve experimental cage units complete with a working platform.

Such a module can be purchased overseas, e.g., from companies in the USA, the UK, or Norway. Alternatively, the module can use an existing design and then be constructed locally under the direction of an engineer. However, it is important that the cage module looks professional as well as being responsive to the intended production work.

A module of twelve net cages, each about 10 m³ which is the preferred working size of the present operations, will provide a system of replicate test units which will be used to confirm fully (or otherwise) the observations which have been made in the past three years. The trials could be repeated, for example, with replicated tests for the polyculture of Tilapia and siganids to check if the two species do perform better together. The twelve cages might therefore be set up as follows:

It should be noted that all the densities begin equal by weight - not by the numbers of fish involved. The fish will also come from the same sample pool to negate the influence of age or size differences. However, they should all be of approximately the same age and size at the start of the trial.

This experiment would occupy all the cage module, leaving no space for other activities. It could therefore be modified, but not in terms of reduced replications. For example, only six units might be used at first and the remainder of the work performed when the first is completed. This has some disadvantages, as different pools of fish will be used, but is acceptable.

Again, it is important that full records are maintained on a daily basis, seven days of the week.

4.3 Surveys

Two survey projects should be started.

The first survey should be an attempt to determine the water circulation system within the offshore lagoon. This is important in order to determine the best location for the first and subsequent modules of sea cages, and to locate an emergency point source of good quality seawater if required by the site. As one member of the national staff of the project has his degree in oceanography there is no need at this point to specify how a current circulation survey should be carried out. However, the starting point for the survey should be the quantity and distribution of the seawater entering the lagoon through the newly opened channel in the outer reef. This survey should be started as soon as possible in anticipation of the construction and siting of the sea cage module, planned to be ready by end May 1985.

The second survey should be the continuing attempt to locate and capture the wild fry of the siganid. Previous attempts and the records indicate that this effort has not been sustained. A total collection of 17 000 fry is not productive and, if this is indicative of the low level of the natural resource, then it would emphasize the importance of a hatchery. Having shown the correlation between the appearance of the fry and the lunar phases, a series of four well planned and well manned fry surveys should be conducted through the peak periods (April to August).

4.4 Collection of Broodstock

The long-term requirements for mature broodstock of rabbitfish, mullet, and grouper can be started by a sub-project on capture and maintenance in captivity. Three or four of the presently used sea-cages can be used to house the adults until the module is constructed and located in the lagoon. Fish traps should be built for work along the outer reef, or alternative methods (diving with nets, or netting alone) proposed. This work can be started at once, as it will take many months of effort to develop the skills to be successful. The traps can be cheaply constructed from wooden framing and wire mesh. The traps must be inspected at least daily.

4.5 Laboratory Work

Increased efforts are required to improve the standards of laboratory work. This includes the need for the space to clean and maintain the laboratory equipment. The new laboratories are nearing completion, and this will ease the situation. However, it is desirable, even now, to have one place set aside for the measurement of any water quality data, cleaning and maintaining the apparatus and equipment used for these measurements, and for examining fish and other livestock for diseases, etc. Also, there appears as yet to be no planning or statement of equipment needs and apparatus for the new laboratories nearing completion.

4.6 Administration and Planning

It is anticipated that the main facilities will be constructed by the end of the present fiscal and project period, namely July 1986. The project will then be faced with the next fiscal period of four years, from July 1986 to mid-1990. It is important that the administration and planning requirements are firmly established by May 1985 and a proposal for project renewal is ready to present to the government at that time. No further capital construction is required in this next period, although additional cage modules may be regarded as capital funds. The proposal will therefore require completed work plans which, for the most part, should be based on what has been described in this section, together with increased emphasis on the culture practices for marine fish in the hatchery.

Management of the fish farming centre could be improved by the preparation of some working manuals for the anticipated increased number of technical staff who will be employed when the construction is completed in 1986. Technical manuals on the following activities could be compiled throughout the remainder of 1985, and finalized in 1986, ready for the new staff. Possible subjects could be (i) methods for the capture and handling, and subsequent transportation, of siganid fry; (ii) techniques for breeding Tilapia and the production of fry; (iii) acclimation procedure for introducing Tilapia fry into seawater; (iv) the routine collection of water quality data and site parameters; (v) the collection of the experimental data. It should be noted that a large part of background information for these manuals, including the format sheets for collecting data, is obtainable in the FAO series on methodologies for fisheries biology. The major goal some time in 1986 will, of course, be a complete working manual on the production of Tilapia to offer to the private sector.

The Fish Farming Centre should continue to maintain its good library (although some evidence of the use of the books would be desirable), and its supply of trade magazines and scientific journals. However, the Centre has little or no information on available equipment, e.g., types of cages available, pumps, filter units, nets, scientific apparatus, etc. It is recommended that the Centre immediately writes for catalogues and brochures from major suppliers of important farming equipment, and becomes included on mailing lists. The trade magazines and the Buyers Guide of AQUACULTURE magazine, which is published each December, will supply most of the names and addresses of the main manufacturers. All the brochures should be properly filed for easy reference.

4.7 Summary of Work Plan, March 1985 to July 1986