54 December 2011 Seahorse aquaculture in Viet Nam Truong Si Ky1 Seahorse inhabit mainly the Indo-Pacific Ocean in coral reefs and seagrass beds at the depth 5 – 20m. The species composition of seahorse in the tropical and temperate zones is about 46 species (Lourie and Kuiter 2008, Randall and Lourie 2009). Seahorse fry are pelagic and settle near the bottom at a size of 35 – 40 mm, subsisting mostly on zooplankton as prey, mainly copepods. Adults prefer to catch benthic organisms, Amphipoda and Palaemonidae. In tropical zones, seahorse spawn year-round (Woods 2003, Poortenaar et al. 2004) , with peak spawning season varying between species and their distribution. Most seahorse species are listed in Appendix II of CITES (Convention on International Trade in Endangered Species of Wild Fauna and Flora), effective May 2004 (Heather and Martin-Smith 2010). This affords the seahorse a degree of protection from gross practices that threaten their survival in the wild. These species are targeted by divers for medicinal applications as well as for aquarium collection. Seahorse are also a frequent incidental catch by trawlers. Dried seahorse are popular in traditional chinese medicine (TCM), as curios and as a food delicacy (Vincent 1996). It is estimated that more than 20 million dried seahorse are traded annually in the world (Vincent 1996). Live seahorse, when sold as aquarium pets, are marketed at 6 – 8 cm, but for TCM, the popular size is 12 -16 cm. Most dried seahorse are exported to China and Hong Kong, normally valued at US$150 – 350 /kg (2010). Viet Nam has exported about 6.5 t seahorse per year as of 1995 (Giles et al. 2005) and over the span of a decade, this volume has steadily declined in direct correlation to the ever-decreasing population of seahorse in the wild. It is believed that seahorse populations have declined more or less 50 percent in last ten years, brought on by the corresponding increase of trawling vessels. Given these circumstances, the culture of seahorse presents itself as one of the best measures to attain sustainability of these species, while meeting market demand (Truong 1996, Payne and Rippingale 2000). However, the ecological and social implications of aquaculture are not always straight-forward (Heather and Martin-Smith 2010). For conservation reasons, in Viet Nam, seahorse broodstock from F1 generation are kept in cages and these animals daily produce approximately 1,000 fry, naturally let out to the sea. In addition, hundreds of cultured healthy seahorse are released to the Fig 1. Seahorse changing color H. kuda sea, where these animals can actively search for ideal habitats. Seahorse aquaculture began in Viet Nam in 1990 with only one species, the Hippocampus kuda. At present, seven species of seahorse are found in local waters (Truong 1998, Lourie et al. 1999), of which 6 species (H. kuda, H. comes, H. trimaculatus, H. kelloggi, H. spinosissimus ans H. histrix) are cultured; and of these, only the first three species are succesfully cultured to a large scale. In Fig 2. Broodstock seahorse H. histrix (Continued on page 56)
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