Cobia, Rachycentron canadum (biology – distribution – aquaculture) – Video

Credit of the video: Glenda Vélez Calabria (Colombia) Description: Abdel Rahman El Gamal
This video was taken in mundo marino and te mostramos lo que pasa en el fondo, Colombia

Introduction: Cobia, Rachycentron canadum, is the only species of the family Rachycentridae. Other common names for cobia include black kingfish, black salmon, lemonfish, and sergeant fish as well as cobie and bonito (in Spanish) and mafou (in French). Cobias are a popular recreational and commercial species. They reach lengths of 50-120 cm, with a maximum of 200 cm.

While cobias are more common at weights of up to 20s kg, there could be few heavier specimens which could reach up to 60 kg. Cobias grow quickly and have a moderately long life span. Cobias are intensely curious fish and show no fear of boats. Both cobia sexes have moderately long lives of 15 years or more.

Distinctive Description: The family name Rachycentridae, from the Greek words rhachis meaning “spine” and kentron meaning “sting,” is an allusion to these dorsal spines. On the jaws, tongue and roof of the mouth there are bands of villiform (fibrous) teeth. Cobias lack the air bladder. The large pectoral fins are normally carried horizontally, so that, as seen in the water they may be mistaken for a small shark.

Distribution and habitats: Cobia is distributed worldwide in tropical and subtropical warm-temperature seas, except for eastern Pacific. Cobias prefer water temperatures between 20 — 30 C and are found in various habitats: coral, rocky reefs, wrecks, harbors, buoys, anchored boats and other structures. Cobias are able to tolerate a wide range of temperatures (eurythermal) 1.6 and 32.2°C, and salinity (euryhaline) 5.0 – 44.5 ppt.

Feeding habits: Cobias are opportunistic and carnivore feeders. Their food consists of crabs (their favorite food), crustaceans, cephalopods, and small fishes such as mullet, eels, jacks, snappers, pinfish, croakers, grunts, and herring.
Their predators of cobias are dolphin fish (Coryphaena hippurus) that is known to feed on immature cobia. Also, the shortfin mako sharks are known to feed on adult cobia.

Reproduction and life history: Cobias are pelagic spawners. During spawning which takes place diurnally, cobia broodstock release eggs and sperm into offshore open water and/or in estuaries and shallow bays? Eggs are buoyant, spherical of (1.2 mm in diameter). Fertilized eggs float freely with water currents until hatching that takes place after 24-36 hours after fertilization. The planktonic larvae develop their mouth and eyes in about 5-7 days and by then they become active feeders.
Cobia females are batch spawners whereas females are capable of spawning up to 20 times during the spawning season with intervals of about one to two weeks. The fecundity estimates range from about 400,000 — 2 million eggs per batch.

Cobias (females and males) mature at the age of about 2 years. However, there are reports indicating that cobia males may mature at earlier age of one year. In general, all males would be mature by age 2, while most females mature at about 3 years and before the age of 4.

Utilization: Cobias are good food fish for human consumption and is typically marketed fresh, frozen, or smoked. Cobias enjoy a premium price for their firm texture and excellent flavor. Due to their solitary nature, cobias are usually caught in small quantities. In regard to recreation, Cobia is considered an excellent game fish. Cobias are also caught incidentally by shrimp trawlers.

Danger to Humans: Due to the sharp dorsal spines, care must be taken when handling these strong fish to avoid injury.

Aquaculture: Cobia, Rachycentron canadum, is considered one of the most suitable candidates for warm, open-water marine aquaculture in the world. Their rapid growth rate, as well as the high quality of the flesh makes cobia potentially one of the most important marine fish for future aquaculture production.

Currently, cobias are being cultured in nurseries and grow-out offshore cages in many parts of Asia, in US, Mexico and Panama. In Taiwan, 100–600 g cobias are cultured for 1–1.5 years to reach 6–8 kg in size which is suitable for export to Japan. Currently, around 80% of marine cages in Taiwan are devoted to cobia culture. China and Vietnam are actively engaged in cobia aquaculture.

References: Wikipedia, Oceanario de Lisboa, Marine fish identification portal


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