Kang, Young Shil ㆍ Seung Heo ㆍ Hyungchul Kim West Sea Fisheries Research Institute, NFRDI Zooplankton distribution, abundance and biomass relative to oceanographic condition in the Yellow Sea

ABSTRACT The spatial distributions of important zooplankton groups and biomass were studied in the Yellow Sea with concerning on oceanographic conditions to understand the status of ecosystem as a basin scale. Zooplankton abundance and biomass were estimated in October~November 2003 and 2005 by both countries, Korea and China. Seawater temperature, salinity and chlorophyll-a concentration were also estimated. Zooplankton biomass was higher in 2005 than in The high zooplankton biomass was mainly concentrated at the southeastern coast in 2003 and the southwestern coast in Zooplankton was composed of 21 taxa in 2003 and 17 taxa in Even though the numbers of identified taxa were different between both years, the dominant taxa were similar in both years. Of these zooplankton taxa, the dominant taxa were as follows: Copepoda, Chaetognatha, Thaliaceae, Euphausiid, Amphipoda and Appendicularia. The spatial distribution pattern of Copepoda was similar to that of zooplankton biomass. Fish larva and eggs were found in 2005, while not in It was mainly distributed at the northwestern coast. Chlorophyll-a concentration was also higher in 2005 than in Its spatial distribution pattern was similar to that of zooplankton biomass. Sea surface temperature decreased toward the northern area with range 15~20ºC in both year. Sea surface salinity was lower in 2005 than in 2003, in particular the most southeastern area. Contrasted to the sea surface salinity, salinity at 50 m depth was higher in 2005 than in The high saline water was mainly concentrated at western coast. It can be concluded that zooplankton production is closely related to the coastal area and low saline water in the Yellow Sea.

BACKGROUND AND OBJECTIVE  “ Korean-China Cooperative Research on the Yellow Sea Environment ” Based on the 2 nd Committee of Korea-China Cooperative Environmental Research in May, 1995 Began to research survey from 1997  To know spatio-temporal variation of zooplankton in relation to oceanographic condition in the Yellow Sea Zooplankton biomass and abundance Zooplankton community

MATERIAL AND METHOD  Period: October, 2003 and 2005  Parameters : Environmental factors: Temperature, Salinity Chlorophyll-a and nutrients Zooplankton: Biomasses with wet, dry and ash -free weights/ Abundance of zooplankton taxa  Statistics: PCA, SOM etc. <Fig. Map showed survey area and sampling stations>

RESULTS

<Table.Correlation between environmental factors and zooplankton biomasses in 2003>

<Table.Correlation between environmental factors and zooplankton biomasses in 2005>

< Fig.. Principal component ordination of 21 taxa of zooplankton and correlation between each axis and environmental factors in 2003>

< Fig.. Principal component ordination of 17 taxa of zooplankton and correlation between each axis and environmental factors in 2005>

< Fig.. Dendrogram calculated with 21 zooplankton taxa by Euclidean distances Ward ’ s method in 2003.> CICII-1CII-2CIII

< Fig.. Dendrogram calculated with 17 zooplankton taxa by Euclidean distances Ward ’ s method in 2005.> CI CII CIII

C B C B B B C C C C C A A C B D A A A B B B B C D D D D D D D D

< Fig.. Relationship between areas demarcated by SOM analysis Environmental factors in 2003> Dry_weight : KW-H(3,32) = , p =

B B B D D D D C B A B B C C B A A D A D C C C C D D C B A A C B

< Fig.. Relationship between areas demarcated by SOM analysis Environmental factors in 2005>

CONCLUSION  Zooplankton was identified to 21 taxa in 2003 and 17 taxa in 2005  Zooplankton biomass was higher in 2005 than in 2003, and the high zooplankton biomass was mainly concentrated at the southeastern coast in 2003 and the southwestern coast in  Zooplankton was closely related to temperature and chlorophyll-a in 2003 and salinity in  The Yellow Sea was demarcated 3 or 4 sub-areas based on zooplankton communities in 2003 and 2005.