Meeting Abstract
Populations of commercial shrimps were investigated near Kanghwa Island, where influenced by freshwater input of Han-River, in the mid-western coast of Korea. Shrimps were monthly collected by a stow-net at three stations from April to December in 2012. Zooplankton was also sampled to investigate the larval recruitment of the shrimps in the research area. Water temperatures and salinities were simultaneously measured, using an YSI. Water temperatures ranged from 3.7-27.2°C, which was the highest in August and the lowest in April. Salinities were fluctuated during the summer months from 16.4-28.7 PSU, being resulted from river freshwater inputs. Shrimp harvests were relatively higher in September and October while they were relatively lower July and August than other months. Among shrimp species, Exopalaemon carinicauda and Leptochela gracilis were dominant in March to July, while Acetes chinensis was dominant from September to November. In December, Palaemon gravieri and E. carinicauda predominated. Mean carapace length of A. chinensis and E. carinicauda increased from March to July. Small sizes of A. chinensis occurred from September. Mean carapace length of L. gracilis increased from March to June and a new generation was recruited in July. Any larvae of above commercial species was not found from plankton samples. A. chinensis, L. gracilis and E. carinicauda had two generations while P. gravieri had one generation in a year. In conclusion, the population structures of commercial shrimps varied with species and seasons in the research area. Also, larvae of above commercial shrimps might not be recruited from locally produced populations.
