• The Sea:JOURNAL OF THE KOREAN SOCIETY OF OCEANOGRAPHY
• /
• v.12 no.3
• /
• pp.191-199
• /
• 2007

Seasonal variation in species composition of fish in the Saemangeum Reservoir was determined using seasonal samples collected by an otter trawl from April 2006 to February 2007 after the dike construction, and compared with the data obtained during the dike construction in 2001-2002. A total of 35 species, 8,960 individuals and 53,084.4 g of fish were collected during the study. Of the fish collected, brackish and coastal fishes such as Konosirus punctatus, Synechogobius hasta and Repomucenus lunatus, and migrant fishes such as Engraulis japonicus and Scomberomorus niphonius predominated in abundance accounting for 95% in the total number of individuals. Fish species composition and abundance showed a similar seasonal trend to those in the other western coastal waters of Korea. The resident species were mainly collected in spring and in autumn. The number of species and biomass were high in summer by the large amount of catch of migrating species. Catch was low in winter and only 2 species were collected. A brackish and coastal fish, K. punctatus and two migrant fishes, E. japonicus and S. niphonius were abundantly collected after the dike construction. However, the dominant fishes during the dike construction such as Leiognathus nuchalis, Neosalanx jordani and Chaeturichthys stigmatias were rarely collected. Fish density was $1,149\;inds./10,000m^2\;and\;12,644g/10,000m^2$ during the dike construction, and increased 6 times in the number of individuals ($7,467\;inds./10,000m^2$) and 3 times in biomass ($44,237g/10,000m^2$) after the dike construction. Annual species richness (R) and species diversity (H') decreased from R=0.0160 and H'=2.47 during the dike construction in 2001-2002 to R=0.0038 and H'=1.11 after dike construction in 2006-2006, respectively. These changes seemed to be related to the reduction of the saline area and degradation of water quality in Semangeum Reservoir after the dike construction.