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Three edible parts of the giant clam and kidney (inedible) of the giant clam as described by Tongans.
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... This is a reasonable assumption given that market studies indicate an annual market potential at several hundred tonnes of meat (e.g. Tisdell and Wittenberg, 1990a,b; Shang et al., 199 1). Furthermore, it is likely to be more profitable for the farm to supply the market on a continuous basis rather than at widely spaced intervals . ...
The paper estimates the internal rate of return of investment in a giant clam farm involved in the ocean phase of mariculture as a function of the period of ocean growout of Tridacna gigas. The ocean farm is assumed each year to place 100 000 seed clams of approximately 1 year of age. The optimal length of time to hold them depends on the farm-gate price of clam meat and is estimated to be 11 years when they are sold at $A5 per kg. This yields an estimated internal rate of return of 18.0% and maximises the net present value or capitalised value of the farm. If 40% drip loss occurs in the meat the internal rate of return is 11.25% and the optimal period to hold batches of clams is 14 years.
... Industry supply and demand curves for farmed giant clam products are not as yet firmly established so any indication using this method will be subject to some speculation. However, using data obtained from surveys in Australia and New Zealand it is estimated that the size of the potential Australian market for giant clam meat is at least 3,000t per year at a retail price per kg of $10 -$12 (Tisdell and Wittenberg, 1990a,b). Assuming that clam meat sells for $5 per kg in situ or at the farm-gate, it is estimated that a standard ocean-based clam farm putting down 100,000 clam seed per annum can earn an internal rate of return of 19.5% per annum on its investment assuming that it buys clam seed at 75c each. ...
... Firstly, the potential size of the market is not yet known with certainty; therefore, there is uncertainty about the practical scale of operating a commercial farm. From marketing studies undertaken (see Tisdell and Wittenberg, 1990), it appears that the meat output of a farm of the size hypothesized in this study could be absorbed by the potential market. ...
... If market demand is very large a single farm could not satisfy the market as reef availability would in the end become a constraint. It would seem from the evidence gathered by marketing studies (Tisdell and Wittenberg, 1990) that the Australian market could absorb the yearly output target of the enterprise hypothesized in the present study: an enterprise with a steady stock of clams around 500,000-600,000 when the farm is fully operational. An area of around 12-13 ha of reef should be sufficient to accommodate the above stock of clams. ...
... From Figure 2, it can also be seen that even if the sale of the clams takes place at a price of $3/kg, the operation still generates a positive net present value. Notice that $3/kg is a very low farm-gate price or in situ price if compared with a possible retail price of $10-$12/kg that could be fetched on the Australian market for the flesh (Tisdell and Wittenberg, 1990). ...
... In a previous survey, which evaluated the possible demand for giant clam meat in Australia amongst Tongans (Tisdell and Wittenberg, 1990) ...
Cl em Tisdell This chapter examines the status of, and potential demand for giant clams in four coastal villages in Bali and Java, Indo-nesia. Data were obtained from direct interviews with 228 household heads during the period April-July 1990 using a standardised questionnaire. It was found that in the areas surveyed natural stocks of giant clams have been severely depleted due to overexploitation. Results indicate that the demand for giant clam meat by Indonesian coastal dwellers is substantial and that they are interested in adopting giant clam mariculture for subsistence, semi-subsistence and small-scale commercial purposes. However, they have little or no knowledge about the techniques involved. Given the favourable attitude of interviewees to clam mariculture, its economics in Indonesia merit further investigation so as to determine farming methods suitable for local conditions. In the absence of giant clam mariculture in Indonesia, it is difficult to see how adequate supplies of giant clams for direct use and for traditional industries such as tile manufacture can be found and sustained.
