At the beginning of 2024, the Fisheries Research Institute achieved significant research results, namely the successful development of artificial breeding technology for Doederleinia berycoides, commonly known as rosy seabass. In response to the trend of scarce fishery resources and to enhance the competitiveness of Taiwan's aquaculture industry, the Fisheries Research Institute has launched a resource enrichment plan and developed several important species along the coast for research. After introducing the black croaker in 2022 and the narrow-barred Spanish mackerel in 2023, the breeding technology research and development of the rosy seabass was completed in 2024. Currently, it is possible to stably breed fish collected from the deep sea and hatch fish fry of more than 3 cm through artificial insemination technology, which is an important foundation for increasing Taiwan's coastal fishery resources and strengthening its aquaculture technology.
Doederleinia berycoides, commonly known as rosy seabass, belongs to the Acropomatidae family and is distributed in the Western Indo-Pacific region. It is a fish species of high economic value found along the continental shelf slopes near Taiwan. It mainly inhabits depths of 100–600 m and is captured with fishing gear, gill nets, and bottom trawls. Currently, only Japan has implemented the hatching and stable cultivation of wild fish seedlings through artificial insemination, starting in 2013, and has released fish seedlings every year since then. The Fisheries Research Institute has found that there is a significant difference in body size between the females and males of this fish species, with an average body length of 31.8 cm and 24.2 cm, respectively. Those with a body length of 28 cm or more are almost exclusively females, with the reproductive peak occurring in September and October. Due to the pleasing white color and high economic value of the meat, the average annual price in large individual production areas ranges from NTD 1400 to NTD 1700 per kilogram, and it can even reach nearly NTD 2000 per kilogram. Its meat is delicate and rich in oil, with a fragrant aroma, and it can be cooked by simple dry frying, steaming, or grilling over fire. It is also a popular high-end ingredient in sashimi and sushi restaurants (known as white tuna belly meat in Japan), showing the importance attached to it. According to fish market trading data, the annual trading volume of rosy seabass is 31–63 metric tons, of which about 95% is from Hualien Fishing Port and Taitung New Port, with a small portion from Toucheng, Yilan. Due to the low overall catch but high market demand and the lack of breeding technology for this fish species in Taiwan, long-term fishing pressure may cause resource changes. In 2023, the Fisheries Research Institute organized experts in marine and aquaculture fisheries to collaborate with the captains of eastern fishing boats. After obtaining fish seeds at a depth of 200 m, the marine team took care of them and raised them. The fish were transported using low-temperature and clean deep-sea water from the original storage facility, and the fertilized eggs were obtained through artificial insemination by aquaculture experts in Donggang. Despite multiple failures, the researchers worked tirelessly to achieve successful breeding. In January 2024, the body length of the fish fry was successfully cultivated to more than 3 cm, and the seedlings were steadily fed with bait, indicating the completion of the development of artificial breeding technology.
The Institute hopes that the cultivation techniques and experience of this batch of fish fry will be helpful for future resource enrichment planning for this species. Through fish fry proliferation and release methods, resources can be returned to the sea, not only increasing the fishery output value of this high economic value fish species but also reducing the pressure on fishery resources and making them sustainable.
Photo 1. Rosy seabass parent fish at Donggang Aquaculture Research Center
Photo 2. Rosy Seabass fry hatched from fertilized eggs
Photo 3. Juvenile rosy seabass fish under cultivation