Differences between Culturing Mud Crabs versus Pacific White Shrimps | Business Insights
For the past few years, we have observed disease-stricken shrimp ponds (L. vannamei) that have converted to mud crab aquaculture. This is not surprising given the high price of mud crabs at the moment. However, there are still pros and cons to any given species. In this article, we will be exploring the difference between the culture of L. vannamei versus Scylla spp.
The first distinction between the L. vannamei or the Pacific White Shrimp versus Scylla spp. Or the mud crab is the prices. The Pacific White Shrimp are considered more a staple while the Scylla spp. is more of a delicacy. This is not surprising as prawns are typically consumed in your average household while crabs are occasionally consumed during the festive seasons. The average selling price for L. vannamei (50-60 count/kg) is about 5-7 USD/kg (depending on region), while the average selling price for mud crab (at 500gram/crab) is about 14-15 USD/kg. The sizes chosen for comparison are the typical size which farm operators will end their culture cycle. Bigger sized shrimps or crabs will fetch a higher price, but might not be economical to produce due to higher feed conversion and mortality.
Pricing alone is insufficient to decide between the culture species, as another factor of consideration is the crop yield. Crop yield is defined as the amount of yield (in terms of weight) that can be produced from one unit of area (typically in m2). The major factor determining crop yield in aquaculture is the space requirement needed for the particular species. This is also commonly known as stocking density which is the number of animals stocked in one unit area (m2). Here lies the significant difference between the L. vannamei versus Scylla spp. in the stocking density and crop yield. Post hatchery L. vannamei can be stocked up to 2500-3000 PL/m3 while Scylla spp. can only be stocked up to 30-50 crablets/m3. The huge difference is due to the highly cannibalistic nature of the mud crab that hinders the farm from overstocking. While the Pacific White Shrimp is also considered a cannibalistic species, they are a lot milder in comparison to the Scylla spp.
Apart from pricing and yield, another interesting factor for consideration is the risks involved in the business. For aquaculture, the risk for disease poses a grave threat to farm operators and the industry as a whole. Good biosecurity, clean water, and disease-free environment are precursors to suppress an outbreak of diseases. Nevertheless, it can be difficult to maintain or obtain due to operational and management issues. Therefore, an important aspect of disease prevention also depends huge only on the immune systems of the farmed organisms. It is generally accepted that the immune sy