Theme B: Modelling and assessing the effectiveness of releases for fisheries management and conservation
9. EFFECT ASSESSMENT OF FISHERY STOCK ENHANCEMENT IN GUANGDONG COASTAL WATERS
Chen Pimao*, Qin Chuanxin, Tang Zhenzhao, Yu Jing, Shu Liming, Li Xiaoguo
South China Sea Fisheries Research Institute
Chinese Academy of Fishery Sciences
231 Xingang Road west, Guangzhou, Guangdong, 510300, P R China.
cpmgd@yahoo.com.cn
14.473 million fish fry including Lutianus sanguineus, Pagrosomus major, Mylio macrocephalus and Sparus latus and 96.32 million shrimp larvae including Penaeus monodon, P. chinensis, P. penicillatus and P. merguiensis were released across 21 locations in the coastal waters of East Guangdong, Pearl River Estuary, West Guangdong and Beibu Gulf in Guangdong Province. Released fish and shrimp were sampled through a combination of market surveys, fishing log-book surveys and fishery independent gill net surveys. The growth and abundance of stocked species were used to assess the effectiveness of fishery enhancement, and estimate enhancement carrying capacity. The combined fishing production, output value and input-output ratio reached 192.64 tons, 19.5851 million RMB and 1:11.19 respectively for the four species of released shrimp during the first two years post-release, and reached 344.94 tons, 41.1918 million RMB and 1:5.68 for the four species of released fish during the first three years post-release. Fisherman gained an income increase of 6800 RMB per year, revealing a significant improvement in economic return. Shrimp and fish surviving to sexual maturity was approximately 1.217 million shrimp (after 2 years) and 228 thousand fish (after 3 years), which could contribute to the spawning stock and help achieve the goals of sustainable development and development of a healthy ecosystem.
Stock enhancement carrying capacity was estimated at 12.20 million, 58.41 million, 6.31 million, 19.15 million, 47.12 million, 18.04 million, 68.20 million and 34.92 million for Lutianus sanguineus, Pagrosomus major, Mylio macrocephalus, Sparus latus, Penaeus monodon, Penaeus chinensis, Penaeus penicillatus and Penaeus merguiensis respectively. Actual enhancement quantities were about 1/7 and 1/2 of the fish and shrimp enhancement carrying capacity. Based on the result the quantity of enhancement should be increased.
Enhancement in Guangdong Coastal water in 2010 occurred after a Fishing-Prohibited Period of the South China Sea, to increase the economic benefit and ecological results of enhancement. Enhancement and recapture strategies should be adjusted to align with the optimal values determined from this survey.
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