Current Status and Exploitation of Wild Spiny Lobsters in Vietnamese Waters

摘要

Seven species of spiny lobsters are found in the Vietnamese East Sea: Panulirus ornatus, P. homarus, P. longipes, P. stimpsoni, P. versicolor, P. penicil-latus and P. polyphagus. Four species - P. ornatus, P. homarus, P. longipes and P. stimpsoni - support a significant commercial fishery. These lobsters are distributed mainly in the central seawaters stretching from Deo Ngang mountain pass at the latitude of 18°N (Quang Binh province) to the spur of Ky Van mountain at latitude of 10°30'N (Vung Tau province). It means that spiny lobsters with high economic value are present in the seawaters of 14 central provinces. This distribution has provided a potential resource of lobsters in these seawaters, but the way lobsters have been exploited has varied because of the different physical geography and the sea-edge topography of each province. Before 1975 and the reunification of Vietnam there appears to have been very little commercial exploitation of spiny lobsters. From 1975 to 1980, spiny lobsters were exploited by diving, using hooks or pitchforks as the major way of catching the lobsters. The annual catch was some tens of hundreds of tonnes per year for the domestic market. Since 1980, lobster fishing gear has improved rapidly to meet the export demand for lobsters. The old style fishing methods were replaced by trawled three- or two-layered nets, and better fishing boats enabled lobsters to be fished from further offshore, leading to catch yields increasing to 500-700 tons per year. This decade was the most prosperous period for exploiting spiny lobsters in the central waters. The size of caught P. ornatus reached 5-10 kg/individual, P. homarus was 3-5 kg/ind. and P. longipes and P. stimpsoni were 1-2 kg/ind. respectively. During the 1990s, the size of the wild lobsters being caught continued to decrease, with more and more of the catch being of a size smaller than that demanded by the export trade. This led to the fishermen along the central coastal zone holding the undersize lobsters in simple net cages to fattened them up to a bigger and more valuable size. As these practices were found to be very profitable, more and more effort went towards catching juvenile lobsters for aquaculture ongrowing. By 2004, the number of net cages culturing lobsters has increased to about 33,000 and the cultured lobster yield is over 2000 tonnes per year. This development has not only created a new type of employment for the local villages, but it has led to more jobs and positively improved the socio-economic conditions of the coastal communities.