• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.34 no.3
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• pp.320-327
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• 1998

The feeding habits of jack mackerel, Trachurus japonicus, collected from the Nakdong River estuary from February 1987 to January 1988 were studied. Jack mackerel(4~15cm SL) was a planktivore which fed mainly on copepods, amphipods and mysids. Its diets included small quantities of decapods, euphausiids, polychaetes, chaetognaths and fish larvae. Paracalanus parvus. Acartia clausi and Calanus sinicus were the three most abundant copepod species found in the stomach contents of jack mackerel. Jack mackerel showed ontogenetic changes in feeding habits. Small individuals of the fish(4~7cm SL) preyed heavily on copepods. However, the portion of copepods in stomach contents decreased with increasing fish size, and this decrease was compensated by an increased consumption of amphipods and mysids.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.26 no.3
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• pp.266-278
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• 1993

Ecological and taxonomical studies on the copepods were reviewed in order to dake data bases on the species composition, abundance, distributional pattern, and seasonal variations of copepods in the South Sea of Korea. Total 179 species have been reported in this area. The dominant species in the coastal waters and embayments, such as Acartia clausi, Paracalanus parvus, Oithona similis, and Oithona nana, were different from those reported in the offshore waters around Cheju Island. Indicator species of the South Sea were also discussed in this paper. Copepod abundances were higher in the coastal waters, up to more than 390,000 individuals/$m^3$(collected with a $150{\mu}m$ mesh net), than in the offshore waters. There were two types of temporal variations in copepod abundances in the coastal waters, i.e., bimodal abundance peaks in spring and fall, md unimodal peak during summer to early fall.

• Ocean Science Journal
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• v.43 no.2
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• pp.67-79
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• 2008

We investigated the relationship between mesoscale spatial distribution of environmental parameters (temperature, salinity, and sigma-t), chlorophyll-a concentration and mesozooplankton in the Yellow Sea during May 1996, 1997, and 1998, with special reference to Yellow Sea Bottom Cold Water (YSBCW). Adult calanoid copepods, Calanus sinicus, Paracalanus parvus s.l., Acartia omorii, and Centropages abdominalis were isolated by BVSTEP analysis based on the consistent explainable percentage (-32.3%) of the total mesozooplankton distributional pattern. The copepods, which accounted for 60 to 87% of the total abundances, occupied 73-78% of the copepod community. The YSBCW consistently remained in the northern part of the study area and influenced the spatial distribution of the calanoid copepods during the study periods. Abundances of C. sinicus and P. parvus s.l., which were high outside the YSBCW, were positively correlated with the whole water average temperature (p<0.01). In contrast, the abundances of C. abdominalis and A. omorii, which were relatively high in the YSBCW, were associated with the integrated chl-a concentration based on factor analysis. These results indicate that the YSBCW influenced the mesoscale spatial heterogeneity of average temperature and integrated chl-a concentration through the water column. This consequently affected the spatial distribution pattern of the dominant copepods in association with their respective preferences for environmental and biological parameters in the Yellow Sea during spring.

• 한국해양학회지
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• v.29 no.4
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• pp.366-375
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• 1994

Distribution of zooplankton was investigated at 30 stations in Asan Bay, an embayment in the western coast of Korea, seasonally in August and October of 1991, and January and April of 1992. Abundances of zooplankton ranged from 240 to 1,458 indiv./m$^3$. Copepods were the predominant constituent, which comprised 88% of total zooplankton abundance. Acartia bifilosa dominated from fall to spring, A. pacifica in summer and Paracalanus parvus in fall. Abundances of zooplankton were related with phytoplankton standing crops and larval fish. In spring, when phytoplankton standing crops were high, zooplankton abundances were highly correlated with phytoplankton standing crops (r$^2$=0.66, p<0.01, n=30). Results of cluster analysis based on the abundance data of zooplankton showed that the study area was divided into two areas, i.e., outer-bay and inner-bay.

• Korean Journal of Environmental Biology
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• v.22
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• pp.11-29
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• 2004

This study was conducted bimonthly from June 2001 to June 2003 to investigate the seasonal variation of the zooplankton community in Gwangyang Bay, Zooplankton were collected at 9 stations using a NORPAC net from surface layer. The zooplankton community consisted of 47 taxa and the mean abundance was 6,205 inds. $m^{-3}$ during the survey period. The maximum abundance was observed to be 20,060 inds. $m^{-3}$ in June 2002 and the minimum in August 2001 with 630 inds. $m^{-3}$. Copepods were the predominant constituent, wihich comprised 4.6~84.1% (mean 38.2%) of the total zooplankton abundance. Dominant species of copepods were Acartia omorii, Acartia erythraea, Centropages abdominalis, Paracalanus parvus. Paracalanus parvus dominated from June 2001 to December 2002. A red tide causative dinoflagellate, Noetiluca scintillans, dominated from June 2002 to February 2003, Acartia omorii and Centropages abdominalis dominated in winter and spring seasons. While, Acartia erythraea dominated in summer and fall seasons. In June and August, Cladocerans and Cirriped larvae dominated. The abundance of zooplankton according to the tidal cycle showed considerable fluctuations with a range of 2,768~15,856 inds. $m^{-3}$ $(\risingdotseq$ 5.7 times).

• Korean Journal of Environmental Biology
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• v.36 no.4
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• pp.525-537
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• 2018

The Korean coast is divided into the West Korea Coastal zone (WKC), the South Coastal zone of Korea (SCK), the East Korea Coastal zone (EKC), and Jeju Coastal zone of Korea (JCK). Each coastal zone has different marine environment characteristics. This study analyzed zooplankton data of KOEM (Korea Environment Management Corporation) collected in the Korean coastal waters the spring and summer of 2015 and 2016. In spring, water temperature was lowest in the JCK, and gradually increased in the order of EKC, SCK, and WKC, while in summer lowest in WKC and increased in the order of EKC, SCK, and JCK. Salinity was lowest in WKC which had many rivers flowing inland, and increased in the order of SCK, EKC and JCK in spring. In summer it was lowest in JCK and increased toward WKC, SCK, and EKC. In summer, Chlorophyll-a concentrations were generally low, but was lowest in JCK in spring. In the study area, a total of 77 species occurred, of which 50 species did in spring and 65 species in summer. The number of species was lowest in JCK and highest in SCK in spring and summer, respectively. Paracalanus parvus s. l. was the most dominant species or the second dominant species in Korean coastal areas in spring, but it was predominant in summer. In addition, in spring Acartia hongi, Calanus sinicus, Oithona similis were predominant in WKC, Oithona similis and Corycaeus affinis in SCK, O. similis and Corycaeus sp. in EKC, C. affinis and O. setigera in JCK. In summer Corycaeus spp., O. similis, A. hongi, Tortanus forcipatus were predominant in WKC, C. affinis, Pseudodiaptomus marinus in SCK, O. similis, A. omorii, Corycaeus sp. in EKC, and A. steueri, A. pacifica, Oithona sp., C. sinicus in JCK. The copepod community in the Korean coastal areas were classified into four areas, WKC-western SCK, eastern SCK, EKC and JCK according to differences in environmental factors such as water temperature, salinity, Chl-a concentration, and suspended matter concentration of each coastal area.

• Journal of the Korean Society of Marine Environment & Safety
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• v.16 no.4
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• pp.369-379
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• 2010

Zooplankton community structure and copepod production in Seomjin River estuary were investigated at 10 stations along the salinity gradients from May 2009 to February 2010. Total zooplankton taxa were identified to be 31 in the study area and seasonal average abundance of zooplankton was $4,151\;ind.{\cdot}m^{-3}$ during the study period. Zooplankton community was mainly composed of coastal species in dry season. However, brackish species dominated in upper or middle part of this estuary in flood season. This study showed that the growth rates of Acartia spp. and Paracalanus parvus s.l. measured from field experiments were regulated by the variations of Hater temperature and salinity; The annual copepod production estimated by dominant copepod species was $3.49\;g\;C{\cdot}m^{-2}yr^{-1}$, and the relatively high production value could be explained by the high phytoplankton standing stocks and the mass occurrence of coastal and brackish species with relation to various salinity gradients in Seomjin River estuary.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.30 no.2
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• pp.225-238
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• 1997

Zooplankton distribution in the front zone was investigated in the East Sea of Korea (Sea of Japan). More than 100 taxa appeared in the study area, which was far diverse appearance being compared with those in West (Yellow Sea) and South Sea of Korea. In Nov. 1994, Paracalanus parvus, Oikopleura spp., and Noctiluca scintillans, which preferred warmer environment, predominated at the collection sites in the front zone, especially at warmer surface layer. But in Nov. 1995, when the surface water temperatures were about $2^{\circ}C$ lower than those of the previous year, cold water species of copepod Metridia lucens, immature forms of Calanus and Sagitta, and crustacean eggs dominated in the collection sites in front zone, which were geographically not Identical with those of the previous year. Vertical distributional patterns were not coincide among the taxa. This suggests that zooplankton has different specific habitat characteristics with temperatures. In general, those taxa with preference of warmer environments showed high probability of co-occurrance with low abundances while those that preferring colder environments showed low probability of co-occurrance with high abundances. It seems that warm water contributes to the high diversity of zooplankton in the front zone while cold water does to the high biomass.

• The Sea:JOURNAL OF THE KOREAN SOCIETY OF OCEANOGRAPHY
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• v.17 no.2
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• pp.95-111
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• 2012

Relationship between plankton assemblage and environmental factors in a semi-closed Chunsu Bay was examined. Temporal changes in phytoplankton assemblage was rather drastic than those found in most Korean coastal area in the Yellow Sea primarily due to the seawater temperature (T) and nutrient input from the dikes nearby. Freshwater discharge seemed to cause winter time increase of Diatoms (February) and summer time increase of Dinoflagellates at surface (July to August). Structural change in cell size with time was also found in Diatom. Zooplankton community structure was also changed with season probably due to the food concentration, seawater temperature and salinity (S). From principal component analysis (PCA) of zooplankton distribution, it was postulated that seasonal environmental changes such as T and S could explain about 32% of variability in zooplankton distribution along with phytoplankton cell numbers, while freshwater discharge could explain about 17%. Comparing with past data of 1985-1986, 1991-1992, the distributional patterns and percent composition of major species, Acartia hongi, Paracalanus parvus sensu lato and Centropages abdominalis, were similar. However, the abundances have been increased more than three times. The composition of other taxa than copepods showed significant changes.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.30 no.3
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• pp.413-422
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• 1997

To know the food chain of an intertidal community, feeding habits of Acanthogobius elongata were studied by analyzing stomach contents. A. elongata were monthly collected and the environment conditions of the habitat were investigated in the intertidal zone of Naecho-do, Kunsan from July 1993 to June 1994. Ratio of stomach contents to weight of A. elongata was $1.78\%$, and fullness of stomach showed a similar value to ratio of stomach contents to weight. Fullness of stomach was increased twice a day in the morning and the afternoon. The most important food item was copepods amounting to $54\%$ of the total stomach contents. Of these, Paracalanus parvus was most abundant in spring, Calanus sinicus in summer, Acartia sp. in autumn, and Calanus sinicus in winter. Degree of overlapping for the food items between seasons was not very high, except between spring and summer. There were little differences in feeding habits among the size groups. For all size groups of A. elongata, the occurrence rates of copepods, decapods, molluscs and cirriped larvae were high. As the fish grows, those of amphipods, polychaete larvae, isopods, cumaceans and stomatopods increased gradually. The importance index of the major food items was in the order of Calanus sinicus, Corycaeus affinis and Acartia sp..