The Research Institute for Aquaculture II has developed a production process for breeding and trial farming of the giant clam – a highly valuable seafood species that has traditionally only been harvested from the wild.
High Economic Value of the Giant Clam
Master Nguyen Quoc The from the Research Institute for Aquaculture II states that the giant clam, also known as the king clam, is a bivalve mollusk primarily found in tropical marine areas, preferring muddy or sandy substrates rich in organic matter.
The giant clam has significant nutritional value (high protein content along with amino acids, omega-3, omega-6, iron, etc.) and high economic value (live prices range from 500,000 to 700,000 VND/kg). In Vietnam, wild giant clams are mainly found in areas less affected by waves, such as the mangrove forests where freshwater flows from Ba Ria – Vung Tau, Can Gio to Ca Mau.
Currently, giant clams are primarily harvested from the wild, which does not meet market demand and is gradually declining. Therefore, the research team at the Research Institute for Aquaculture II has initiated a project titled “Research on Developing Breeding Techniques and Trial Farming of the Giant Clam” to lay the groundwork for the development of giant clam farming.
The giant clam has been successfully cultured.
Parent giant clams were collected from natural sources in the coastal areas of Can Gio and Tien Giang. The team selected healthy individuals to be raised in composite plastic tanks to stimulate reproduction and larval rearing.
Specifically, giant clams were stimulated to spawn using thermal shock (the parent clams were placed in tanks with water colder by 10 degrees Celsius compared to normal rearing tanks and aerated vigorously for 45 minutes).
After the giant clams released eggs and sperm, the eggs were collected into a separate tank for further experiments (hatching, larval rearing, and breeding). Conditions during this phase included salinity levels of 28 – 32‰, pH levels of 7.8-8, dissolved oxygen (DO) levels of 4-6mg/L, with dried algae as feed.
Once the giant clams reached sizes of 2.5 – 4cm, they were trial-farmed in tidal flats. After 12 months of farming, the average length was around 11cm, and the weight was 50g (natural giant clams typically measure 10 – 15cm in length and weigh between 70 – 150g per adult).
Based on the results of the giant clam farming trials on tidal flats, the research team has established a commercial farming process with parameters such as seawater salinity from 20 – 25‰, pH of 7.5 – 8, DO above 4mg/L; the bottom substrate is a thick layer of loose sand with minimal mud; and a stocking density of 10 clams/m².
The water in the farming ponds must be well-circulated, with minimal stagnation, free from the influence of freshwater sources during the rainy season, and unaffected by industrial and household waste, ports, or water transport vehicles.
Simultaneous Cultivation and Marine Environmental Cleansing
Master Nguyen Quoc The emphasizes that the farming location must also consider the availability of natural feed, preferably in areas with rich and diverse phytoplankton and high levels of suspended organic matter. Ideal farming sites are often located near small river mouths with moderate water flow.
The giant clam is a soft-bodied mollusk with two shells, distributed from Van Ninh to Cam Ranh. The meat of the giant clam is delicious and has high economic value (selling prices range from 450,000 to 550,000 VND/kg), thus it is at risk of over-exploitation. As a filter feeder, it consumes phytoplankton and organic detritus, which contributes to the cleaning of the marine ecological environment.
The successful research and production of giant clam seeds and commercial farming not only add to the species available for aquaculture, create jobs, and increase income for local people but also contribute to the regeneration and conservation of natural resources, reduce exploitation pressure, and maintain sustainable coastal marine ecosystems.
The giant clam has superior advantages compared to other aquaculture species, such as low-cost breeding; commercial farming incurs no feed costs, leading to high economic profits. The results of this project will establish a new farming profession, diversify aquaculture species, create jobs, and increase income for local communities.
Additionally, it is possible to utilize closed shrimp hatcheries that have ceased operations due to losses to produce artificial giant clam seeds. This will also contribute to the restoration of aquatic resources and improve the quality of the farming environment.
During the evaluation meeting, the scientific council agreed to continue developing the project to refine the technical process for breeding and commercial farming of the giant clam, thus opening new avenues for aquaculture.
However, the research team notes that further studies are needed to understand the natural living conditions to optimize farming conditions and supplemental feed for giant clams.
