1. Nature of the problem
In its attempt to appraise aquaculture systems and their contribution to the Government's development objectives, the Mission is faced with the problem of appraising several culture systems, from several points of view, simultaneously.
The problem is illustrated in Tables 4, 5 and 6 (of the main text). Table 4 will be studied as an example. It shows how the culture systems contribute to five Government development objectives: (1) increase in local fish supply; (2) creation of employment; (3) improvement in foreign exchange; (4) participation of rural population in economic growth; and (5) use of under-utilized natural resources. The Mission has expressed the degree of contribution by each culture system in a qualitative fashion (large, medium, small, etc.). The problem is how should these qualitative judgements be added up in order to establish the “total” contribution of any particular aquaculture system? The Mission is confronted with the same problem when attempting to appraise systematically the magnitude of Government inputs (in Table 5) and risks (in Table 6).
2. Constraints to solutions
The problems that are addressed here are “political”, in nature. The evaluation of the relative importance of development objectives is the prerogative, and duty, of Governments. The Mission's weighting of these objectives will not continue to reflect Government preferences as these change. It must be therefore possible for the Government to re-do the analysis on the basis of its values (for resource use, risks and/or development achievements), when it so desires. This fact imposes two immediate constraints on any solutions to the two problems outlined above. First, the methodology must be easy to understand for those who should base their decisions upon its results. Second, it must be easy to use the methodology.
3. Proposed procedures
The Mission has proceeded as follows in order to rank the culture systems:
In Tables 4, 5 and 6:
The contribution to each development objective, use of each Government resource, and exposure to each type of risk has been appraised quantitatively or qualitatively, for each culture system (each occupying one line in the tables).
Each qualitative and quantitative appraisal has been given a numerical value, i.e., 1, 2 or 3.
The columns (in each of the tables) have been assigned numerical values, reflecting their relative importance.
The “column” values have been multiplied with “line” values, to obtain a combined value that reflects e.g. not only the extent of the use of a particular resource but also the importance of the use of that resource compared to the use of other resources.
The values for each culture system (“line”) have been added up to obtain a total.
Each culture system has been classified as either “high”, “medium” or “low” (for each of Tables 4, 5 and 6) and these summary qualitative judgements entered into Table 7.
Table 7 thus, is a summary of Tables 4, 5 and 6. To that summary has been added two columns reflecting the Mission's views on the expected economic viability of the culture systems. An inspection of Table 7 will show some culture systems, as perhaps, “better” than others. However, the conclusions that can be drawn from an inspection of the table are not clear and would most likely vary from person to person.
In order to arrive at a more definite ranking, steps (ii) through (vi) of the procedure outlined above for Tables 4, 5 and 6 are repeated. For step (ii) the following values were used:
| high/large | medium | low | |
| Expected achievements | 3 | 2 | 1 |
| Use of resources | -3 | -2 | -1 |
| Risks | -3 | 0 | 3 |
Expected economic viability was classified into one of five situations. Each situation was given a value, from high to low: 3; 1.5; 0; -1.5; -3. If it was found likely that the economic viability of culture systems would improve during the 80's it was given a value of 1; if no change, a value of 0.
For step (iii) the following values were used:
| Expected achievements: | 3 |
| Use of resources: | 2 |
| Risk: | 1 |
| Economic viability: | 3 |
| Changes in economic viability | 1 |
Step (iv) gives the following table:
| Expected achievements of development objectives (3) | Use of Government resources (2) | Risk (1) | Expected economic viability (1980) (3) | Possible changes in economic viability (1) | Total | |
| Culture of fish in seasonal tanks | 9 | -6 | 3 | 4.5 | 1 | 11.5 |
| Pond-culture of freshwater fish | 6 | -4 | 3 | 0 | 1 | 6 |
| Establishment of carps in major tanks (reservoirs) | 3 | -4 | 3 | -4.5 | 0 | -2.5 |
| Large-scale corporate culture of shrimps in ponds | 6 | -2 | -3 | 4.5 | 1 | 6.5 |
| Small-holder shrimp culture in ponds | 9 | -6 | -3 | 9 | 1 | 10 |
| Culture of marine fish in enclosures (pens or cages) | 9 | -4 | 0 | 0 | 0 | 5 |
| Culture of molluscs | 9 | -4 | 3 | 0 | 1 | 9 |
| Culture of seaweeds | 9 | -4 | 0 | 4.5 | 1 | 10.5 |
| Aquaculture in salterns | 3 | -2 | 0 | 4.5 | 0 | 5.5 |
| “Valli” culture | 6 | -2 | 3 | 0 | 0 | 7 |
The last column of the above table gives the totals for the culture systems, step (v) above. The last step (vi) then consists in appraising the result. Four culture systems have “totals” from 9 to 11.5. The Mission has classified them as of top priority. The four culture systems with totals between 5 and 7 have been assigned second priority, while the two systems with totals below zero have not been included in the strategic plan.
