Cobia Culture In Taiwan

The Cobia (Rachycentron canadum), also known as lemonfish or ling, is distributed in tropical warm waters worldwide. It can reach to 1.3 m but individuals have reached 2 m long and 68 kg in weight. Cobia are one the most highly-prized recreational species in many countries, including the U.S.

The artificial breeding of cobia in Taiwan was first recorded in 1992. Mass seed production technique was developed in 1997. It has fast became one of the most favorable species in the domestic offshore cage culture. Later, sea farmers in Japan imported cobia seed and started to culture in sea cages off Okinawa.

The seed production of cobia was 3 million in 1999 from 4 hatcheries, as compared to 1.4 million in 1998. About 2 million seed were exported to Japan, Peoples Republic of China (PRC), and Viet Nam. The rest, 1 million seed were stocked locally by 28 cage farmers. The present market price is US$ 0.5 per seed (10 cm) and US$ 6.0 per kg of adult (6-8kg).

Cobia broodstock typically spawn before sunset. The diameter of the fertilized egg is 1.4 mm of which is the largest size among the marine finfish under culture. With water temperatures ranging 24-26 ℃, the eggs would hatch after 30 hr. The newly hatched larvae are 3.5 mm long with black dark brown color. Three days later, the larvae reached 5.1 mm and began to feed with rotifer, artemia larva, copepod, and Acetes sp. After 25 days of cultivation, cobia can grow to 6-7 cm and be acclimatized to artificial feeds. Most fingerlings will reach 9-10 cm after 45 days of culture.

In nature, young cobia initially feed on benthic animals such as fish, crab and cephalopod, but once they grow out they switch to a diet of mostly fish. Under cultured condition, cobias are easily trained to consume dry or moist pellet feed. They could attain to 1 kg after culturing for 6 month, 5-6 kg for 1 year and 8-10 kg at second year in cage. The FCR (food conversion ratio) of cobia in sea cage was estimated to be 1.5 when using moist pellet, 48% protein and 18% fat.

The Taiwanese has foreseen the potential of cobia culture. Three approaches are undertaken:

• To promote and expand domestic/foreign marketing and processing channel.

• To carry out R&D on high FCR moist pellet feed, vaccine, and seed transportation techniques.

• To eliminate the smuggling of fishery product from PRC.

Fig. 1. Adult cobibia.

Fig. 2. Cobia embryos.

Fig. 3. Newly hatched cobia larva.

Fig. 4. Cobia juveniles, 10 cm in length.

Fig. 5. Cobia sashimi.

Fig. 6. Roasted cobia.

Fig. 7. Taiwanese type sea cage.

Fig. 8. Norwegian type sea cage.