The booming Chinese seafood sector provides enormous prospects for international seafood producers. Growing Chinese consumer demand and limited domestic production and fishing in Chinese seas have resulted in a rise in Chinese seafood imports year after year.

According to official Chinese data, seafood consumption is not evenly distributed throughout China. Consumption is strong along the eastern coasts such as Fujian, Hainan, and Shanghai where per capita seafood intake reaches 25 kg in regions. However, consumption is low on inland areas due to a lack of refrigeration for transportation.

As the demand for fresh fish in suburban China grows, some inland towns have seized the opportunity by establishing seafood farms in urban regions rather than conventional coastal areas. The trend might have profound implications for the development of the seafood industry. Several factors drive this effort.

One main reason is that fresh shrimp are difficult to get in inland city seafood markets in the afternoon.

Zhou Mi, a seafood store owner in Wuhan, said that “This seafood is brought from coastal areas such as Guangdong and Hainan. It takes considerable time to deliver. They will only remain alive here for a short period.”

“By the time shrimp arrive at the market, they have often journeyed thousands of kilometers, and seafood distributors must deal with them in less than a half-day. Unlike fish or shellfish, which may remain in a tank for at least two days, seafood store operators must take greater risks when stocking shrimp,” he added.

Chen Qi, a Seafood Seller, said: “We don’t keep these shrimp till late in the afternoon since they rapidly die. Otherwise, we are going to suffer financial losses.”

“If the seafood can be grown locally, the cost will be lower. It would be fantastic if everyone could eat shrimp on a daily basis, just as they can eat vegetables.” he added.

Chen Zhiguo, Wuhan Ocean Star Co., Ltd.’s deputy manager, said: ” We can grow shrimp here all year. Furthermore, by utilizing extra power from the local plant, we may drastically cut our operational expenses while increasing our earnings.”

“With local government funding, this type of seafood farming will become more popular in the next years. On the other hand, merchants can bring fresh fish closer to customers,” he added.

Cao Guangfa, a shrimp breeding technician of Wuhan Ocean Star Co., Ltd, said: “The shrimp require a temperature range of 26 to 29 degrees for optimal growth. Saltwater is brought in from coastal regions like Shandong and Shanghai. The farm automates production using feeding equipment and algorithms. This is the largest factory in China‘s southeast area.”

“The shrimp seeds were just two millimeters long when they came to the farm. They are now as large as my hand after being reared here for two months, and you will find them at those seafood stores and on your dinner table in less than a week,” he added.

According to the authority, some larger and more diversified indoor fish farms are in construction, which means that several varieties of locally farmed seafood may soon be delivered to the door on the same day.

Inland Seafood is devoted to providing consumers with a constant supply of high-quality food that is transparent, traceable, sourced from well-managed farms and fisheries, and produced and harvested responsibly. Therefore, it is hoped that this type of farms may help reduce the environmental impact of traditional ocean-based aquaculture practices.

Jaber Bin Abdul Bari
Department of Oceanography, NSTU

The post Inland and indoor seafood farms are gaining popularity in China appeared first on Seafood Network BD.

Recirculating Aquaculture System (RAS) is a water recycling and reuse device that removes suspended debris and metabolites. This approach is utilized for high-density fish production, requiring the least amount of land and water. This method is a novel approach to fish farming. Rather to the regular fish farming, this approach rears fish in large numbers in indoor tanks with a ‘managed’ environment. Recirculating aquaculture is essentially a method of growing fish or other aquatic organisms by reusing water in the production process. The technology is based on the employment of mechanical and biological filters, and the process can be applied to any aquaculture species.

Principle of Recirculating Aquaculture System:

The culture water in a recirculating aquaculture system is continuously cleansed and reused. The system components for purifying water either remove or convert the created waste products, which include solid waste, ammonium, and CO2. Following that, the cleansed water is oxygenated artificially through air pump and returned to the fish tanks. However, it is not possible to build a completely closed recirculating system. Non-biodegradable garbage must be removed, and evaporating water must be replenished. Nonetheless, recirculating systems can reuse 90% or more of the culture water.  The reconditioned water circulates throughout the system, and no more than 10% of the system’s total water volume is replaced daily.

The quantity and quality of feed, as well as the kind of filtration, play a significant role in the administration of recirculating systems. In recirculating systems, several filter designs are used, but the primary purpose of all filtration is to remove metabolic wastes, excess nutrients, and particles from the water and ensure good water quality for aquatic species. When planning and investing in aquaculture systems, it is critical to consider all elements. Because the selection of biological filtration is influenced by a variety of circumstances (for example, available space, outdoor temperature, energy expenses, and so on).

Is it beneficial to use RAS in aquaculture?

Recirculating aquaculture system are intended to control the environmental aspects of production by continuously filtering, treating, and recycling water, enhancing operational efficiency while lowering pollution and disease threats. RAS have low land and water requirements, allowing high stocking densities, but they require enormous amounts of energy, resulting in high production costs and waste disposal issues. This methods are usually advantageous when the benefits in fish performance outweigh the additional expenditures. Recirculating aquaculture system grow-out operations are increasingly focusing on species with high market value.

Constrains of RAS:

There are infrastructures, feed, and staff requirements that must be met in order to employ RAS grow outs:

• Good quality fish feed, ideally high protein and fat extruded diets with high digestibility, must be provided.
• For implementing RAS, technically capable employees are required.
• If the power goes out, there must be a constant, uninterrupted backup power supply.
• When compared to ponds and raceways, the capital cost of establishing a recirculating aquaculture system is significant.
  

Suitable species for RAS:

• Baramundi/ Asian Seabass/Bhetki
• Tilapia
• Pangas
• African catfish
• Shrimps
• Clams

However, it is advocated to promote Backyard Recirculating Aquaculture Systems (RAS) in order to stimulate small-scale fish farmers and entrepreneurs and to facilitate fish production in urban and semi-urban areas where land and water are scarce. The fish farmer must grow as many fish as possible within the built-in capacity in order to compete economically and efficiently with the considerable capital investment in the recirculating system.

Farhana Islam
Agriculturist, Researcher
Fisheries Resource Management, CVASU

The post Facts of Recirculating Aquaculture System appeared first on Seafood Network BD.