Jellyfish fisheries in northern Vietnam

The aim of this study is to describe jellyfish fisheries (JF) in Thanh Hoa, the northern part of Vietnam. Information was accumulated based on an interview with the owner of a private jellyfish processing factory (JPF) and fishermen, sampling animals, and through reports of fishery statistics. The JF season begins in April and finishes in May. Two species, Rhopilema hispidum and Rhopilema esculentum are confirmed as commercially exploited with the former species being caught in much higher abundance than the latter. Cyanea, Chrysaora, Sanderia, and Aequorea were also by caught but not used for processing. Jellyfish are cut into three parts, the bell, the oral-arms, and the stem (fused part of the oral-arm), which are processed separately using salt and alum at the JPF. The number of Rhopilema jellyfish collected by fishermen is estimated as 800,000-1,200,000 indiv. per fishery season, suggesting that the fishery may have an impact on jellyfish populations in the area. On the other hand, the JF has resulted in substantial economic benefits to fishermen, the JPF and thus the local economy. In a jellyfish-rich year, the income of fisherman can reach 31-75 USD/day or 1,200-3,000 USD during the JF season, which could sustain their living for the rest of the year. However, the JF also put fishermen into a financially unstable condition because they have to rely on jellyfish occurrence, which shows high inter-annual variation, and market price set by brokers who purchase their product. Statistics provided by the Sea Product Processing Company indicates that the export amount of jellyfish tripled from a total of 1,500 tones in 1995 to 4,600 tones in 2005.