19.08.2022, 17:22

Optimizing Shocker set to handle ocean tuna

Optimizing Shocker set to handle ocean tuna

The new Shoker is compact and lightweight with only one electronic circuit. Photo: VDT.

According to Mr. Tran Van Vinh, deputy director of the Subdepartment of Fisheries in Binh Dinh, Japan provided the local fishermen with automatic fishing hooks and pulse generators (Shocker kit) to preserve the ocean tuna's freshness to meet the standards of the Japanese market.

Due to oxygen depletion, tuna frequently thrash aggressively after being hauled onto the deck after being caught. In order to preserve the quality of tuna, fishermen discharge pulse generators along the fishing line in order to capture the fish's head.

The equipment operator begins running electric shocks on the fish, prompting it to lay motionless owing to clinical death. Before the fish is frozen, the fisherman must remove the fish's tail fin, gills, and internal organs by cutting the abdomen open. This ensures that the fish will be thoroughly preserved when marinated.

According to Mr. Vinh, the primary component that determines the quality of tuna is how the fish is marinated. When battling, tuna's body temperature is between 38 and 40 degrees Celsius; however, when the organs are removed, the fish's body temperature maintains between 26 and 32 degrees Celsius. After being rinsed with salt water, the fish were put in a 16 to 20-degree Celsius soaking tank.

After 5 minutes, the fish is placed in the basement to drop to 3-5 degrees Celsius, soaked for another 20-30 minutes to allow the fish to chill, then removed, ice placed in the fish's stomach, and stored in a cold cellar.

However, the Shoker set donated by Japan for application on ocean tuna fishing boats operated by Binh Dinh fishermen is not particularly successful due to the equipment's battery-powered nature and the frequent lack of energy, not to mention its weight.

The traditional ocean tuna fishing of Binh Dinh fishermen. Photo: VDT.

Recently, the Ministry of Science and Technology conducted the project "Research, develop, and manufacture pulse generator in ocean tuna processing according to Japanese technology" in order to perfect this equipment for fishermen in Binh Dinh to use on specialized vessels for tuna fishing. Hung Vuong Electromechanical and Construction Joint Stock Company is the implementation unit (Quy Nhon City).

Two technical experts were dispatched by the Subdepartment of Fisheries in Binh Dinh to accompany two specialized tuna fishing vessels in order to train fishermen on how to utilize the equipment and document the entire testing procedure.

Mr. Vinh noted that four sets of Shocker kits had been utilized on the two fishing vessels since August 8. Each new Shoker set utilizes an electronic microchip system, which is compact, and based on fishing vessel's power, thus, there is no shortage of electricity. 

The ocean tuna caught by Binh Dinh fishermen were selected for export to the Japanese market. Photo: VDT.


"Hung Vuong Electromechanical and Construction Joint Stock Company sent the tuna sample to the Institute of Aquaculture at Nha Trang University for analysis. The result would show whether the quality of tuna caught with the Shocker set is superior to that of tuna caught without the Shoker set.", said Mr. Tran Van Vinh, deputy director of the Subdepartment of Fisheries in Binh Dinh. 


Author: Vu Dinh Thung

Translated by Linh Linh