The following section presents recommendations which deal with how the Johor State GIS information base is to be expanded in technical and operational terms. It also covers the requirements for further use of the GIS approach for land and water use planning in other states.
Obtain information from existing culture operations to better establish siting criteria specifications:
This project has sought information to verify the GIS results from commercial aquaculture enterprises at the end of the project and as a means of verification. In future, the siting specifications on existing aquaculture should be compiled ahead of the GIS analyses in order to enable better specification of site selection criteria before analyses commence. Every effort should be made to visit all existing sites and arrange interviews with managers, technologists, operators and owners.
Pursue analyses of the SPOT and other satellite data; alternatively, use airborne multispectral scanner data for the same purposes:
Satellite (or airborne multispectral scanner) data are potentially very useful for the land and water use GIS, especially in the Johor State situation where the large-scale maps are from the mid-1970s and by now well outdated in terms of information on land uses and infrastructure. The most useful aspects of satellite data are that they are up-to-date and more detailed than survey maps. Some of the kinds of information most useful to assess site suitability are land cover and land uses. This information, in turn, can be used to estimate site preparation costs and site purchase costs. Further, land uses adjacent to the site will indicate dangers from pesticide pollution (e.g., from nearby padi) and other possible water quality problems from domestic or industrial wastes.
Apart from aquaculture development, satellite imagery can be used to inventory and monitor aquaculture. For example, individual ponds on a 15 ha shrimp farm site could be readily identified as could cage culture units in the Straits of Johor using SPOT imagery. Thus, used in combination with other information in a GIS, satellite data can be a tool for aquaculture management as well as for development.
Because the use of mangroves and other wetlands for aquaculture is a sensitive issue, mangrove limits need to be made part of the GIS data base. Where good-quality soils and other suitability aspects of shrimp farming point to siting in mangroves, the site has to be planned to do the least damage to the ecosystem, to be 100 m from the coastal fringe and to occupy less than 20 percent of the total area. Nautical charts do not show mangrove shoreward limits. The 1:63 360 large-scale topographic maps do show the limits of mangroves, but much time and effort would be required to digitize them and to join the resulting files in the data base. Moreover, these maps are outdated and probably do not accurately show the existing limits of mangroves. The state map shows only reserved areas, not all of which are mangroves. Mangrove limits can be most easily obtained from the existing satellite imagery. An advantage of using satellite imagery is that individual mangrove species can be identified. Therefore, aquaculture can be sited among the least productive and least valuable species. For areas of the state without satellite coverage, mangrove limits could be obtained from aerial photography by videodigitizing.
With regard to opportunities for the culture of molluscs and for the cage culture of fish, the already available satellite data can be used to assess the limits of sediment plumes. For example, the apparent high turbidity caused by sand mining in Sg. Johor is evident on the SPOT image examined by the project. Such high turbidity could rule out fish or mollusc farming in the vicinity.
Satellite data can be used to identify areas of consistently high primary production. Such areas could be advantageous for mollusc culture. However, SPOT data for this purpose would be prohibitively expensive because of the large number of repeat observations required. Weather satellite data (AVHRR) could be used and would be economical as one scene covers the entire peninsula and the cost is only a fraction of that of Landsat and SPOT. Perhaps an arrangement could be made with the Malaysia Meterological Service to acquire AVHRR CCTs at a reduced cost after they are used for weather forecasting. Coverage is daily and thus there is a good opportunity for obtaining cloud-free data during any time period. The best resolution available, 1.1 km2, is suitable to indicate coastal areas with high productivities. An additional advantage of using this approach is that the same information would be useful for fishery resources surveys. Therefore costs could be apportioned between the two services.
AVHRR data can be processed by the ERDAS software already to hand.
Expand information on water quality:
The information on water quality arrived too late for full use to be made of it. However, there are marine data sets which contain a wide variety of information useful for deciding on the suitability of water quality for coastal aquaculture in addition to the pH, BOD, NH3-N, and salinity criteria considered herein. Among these are heavy metals, pesticides and bacteria. Furthermore, the Fisheries Department at FRI, Glugor is investigating the build-up of contaminants in cage-cultured fish. These data, where they show that dangerous, or potentially dangerous build-ups occur, could be used to delimit areas where coastal aquaculture should not be developed.
One staffmember of the pollution unit at FRI should be assigned part-time to the multidisciplinary team to analyse the raw data FRI itself holds, data from DOE and that which can be gleaned from site selection reports (see also Section 4.2.4). Another area in which the pollution unit could make a valuable contribution to the information base is to assess the link between agriculture crop type, pesticides used on them and the magnitude of danger to aquaculture development. Crop types as determined from land-use maps, from satellite imagery, or from aerial photographs could then be used as siting criteria.
Improve the assessment of the impact of heavy rainfall on acidity:
The effect of rainfall on pond acidity was investigated by relating total annual rainfall to the distribution of soils with acid potential (pH rating “poor”, range 3.6–4.5). However, experience from the Johor area points to the use of monthly or daily rainfall data as a better approach to establish the areas of the state most at risk from acidities aggravated by heavy rainfalls. There are 28 rainfall stations in Johor. A preliminary analysis of one year's data indicates that there were some 15 cases of monthly rainfalls exceeding 400 mm, the amount which seems to induce acidity sufficiently severe to affect survival and growth of shrimp. At least 3 years of data should be analysed to determine the locations with the highest rainfall during a month, or shorter interval. With the results of this analysis, rainfall isohets can be established and entered in the data base. The 3 years selected should be examined in terms of how they reflect the overall trends in rainfall (high-rainfall years, low-rainfall years).
Expand the GIS to other aquaculture opportunities in Johor:
Much of the work required to expand the GIS to include opportunites for coastal aquaculture additional to semi-intensive shrimp farming and floating cage culture has already been completed. For example, the water quality information can be easily interpreted for cockle, mussel and oyster culture as can bathymetry, shelter, infrastructure and salinity.
When the project was conceived it was believed that a general land and water use geographical information system for the entire peninsula would be a logical follow-up to the Johor State aquaculture development GIS. The purpose was to give priority to the production of land and water use data bases for other states. However, because of the large quantity of varied and detailed information available at state level and because land allocation for aquaculture development is a state government function, it now appears that a state-by-state approach would best serve Malaysia's needs. Therefore, it is recommended that the GIS aquaculture development work proceed on a state-by state basis.
Experience from this project indicates that the present hard disk capacity is inadequate for the large amounts of data which need to be processed for aquaculture land and water use planning. It is estimated that about a half of the time required for the analyses made by the project was used in saving and retrieving information from floppy diskettes because of the lack of space to accommodate files on the hard disk. The ERDAS software uses about 16 MB of a total present capacity of 30 MB. In addition, processing of satellite digital data is severely limited. In effect, only small portions of complete images can be analysed at a time and thus the synoptic value of the imagery is lost. It is recommended that the hard disk capacity be expanded to at least 80 MB.
Experience from this project has shown that a location convenient to information needed to build the data base would result in more efficient use of time and personnel. Because much of the information required comes from central Government sources, the Department of Fisheries in Kuala Lumpur is the location of choice. Alternatively, the equipment could be moved from state to state as analyses proceed.
The project has shown the value of a team approach to assemble and analyse information for aquaculture development. However, the scope and reliability of the results could be significantly improved by broadening the range of team expertise. The team should consist of a biotechnologist, an aquaculture engineer, and an ERDAS operator as full-time members. Part-time members should include an economist, and experts in aquaculture extension, water quality and soils. The extensionist should have daily contact with fish, mollusc and shrimp farmers at the state level. His practical, first-hand knowledge is to be used to identify site-related advantages and problems. He should also help the other team members to decide on the weights to be given to various criteria for siting and to adjust the specifications on the siting criteria according to local conditions.
Ultimately, all site selection decisions express themselves in capital investment and operating costs. There is thus ample justification for an economist to be a team member. This project has demonstrated the importance of economics in decisions with regard to shrimp farm development on soils with different texture and pH characteristics. There is a need to analyse other siting criteria from an economic viewpoint. An economist could play an additional essential role to define the social benefits accruing to the local community due to the employment and income generated by aquaculture development.
It is recommended that other part-time team members include an expert on water quality and pollution and a soil scientist. The activities of these team members are discussed more thoroughly in the section on expansion of the data base.
Preparation of a state land and water use GIS for aquaculture development naturally falls into two different kinds of work. The first is the acquisition, compilation and preliminary analyses of the data. The second is the computer-automated data entry, analyses and reporting. Completion of the state aquaculture plans for Peninsular Malaysia can be streamlined by assigning two people to undertake the data collection and preparation for one state while the multidisciplinary team is completing the analyses for another state. The data preparation group should consist of one person who works in the state. He should be familiar with information sources within the state government, districts, local central government offices, universities and private aquaculture enterprises. The other member should know sources of information in and around the central Government in Kuala Lumpur.
Digitizing maps is time-consuming and slows project output. In order to speed-up GIS preparation, technicians should be employed in map-digitizing. Digitizing is not a task which demands unusual skills, but it does require patience and careful attention to detail. Along with technician digitizers, a digitizing board and software installed on another computer would free the main computer and software for full-time GIS analytical work. ERDAS Inc. (or Gould, Singapore) should be contacted to determine the feasibility of “offloading” the digitizing module from the present software (Figure 3) and installing it on a separate PC. An additional high-resolution monitor would not be required because the editing could be done on the existing system.
Given that the recommendations above are implemented, each state's aquaculture development GIS could be completed in about 6 weeks, including reporting. As experience is gained, each succeeding state could be completed more rapidly. The central Goverment information needed to complete the state-level analyses can be gathered together all at one time (e.g., large-scale maps, water quality data, nautical charts, meterological observations, soil maps and explanations, etc.) thus saving much time and effort.
