Reproduction and culture of sea cucumber in South Korea

Video credit: Hisham El Gazzar (Egypt) Description: Abdel Rahman El Gamal (Founder of the video channel) The video was filmed in a sea cucumber hatchery in South Korea. The leading farmed species is (Apostichopus japonicus) known as Dolgi Haesam. Also, the orange-footed sea cucumber (Cucumaria frondosa) has been tried. The hatchery-produced seed are either released in natural waters in stock enhancement programs or grown in farming facilities. Typically, the broodstock are collected from the wild about 60 days before the spawning season and then placed into conditioning tanks at ambient seawater temperatures and then increasing water temperature by one degree °C/day until reaching 15-18 °C, by then, animals are ready to spawn. During that period, sea cucumber potential spawners are fed a commercial diet which mainly consists of powdered algae such as Spirulina spp. or Dunaliela spp. Feeding stops a day before the spawning that is induced by a thermal shock through an immediate exposure of the animals to warmer water of about 3 to 5°C higher. Once eggs are laid and fertilized, the fertilized eggs are scooped using nets with appropriate mesh sizes depending on the species, and transferred to culture rectangular tanks with around 5 x 3 meters and about one-meter depth. According to published reports, the above-mentioned tank holds up to a million larvae. The newly hatched larvae are fed a special diet of microalgae according to their age. After approximately seven to eight days, the free-swimming larvae are close to the settlement stage and hence settling plates made from clear corrugated PVC sheets are placed in the larvae rearing tanks. Upon settlement, different feed is provided to the new juveniles consisting of a mixture of mud or bentonite, yeast, and powdered algae. The sea cucumber juveniles are grown on the settling plates for about a year before transferring them to either the wild in stock enhancement programs or to sea cages for grow-out.