• Ocean and Polar Research
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• v.32 no.4
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• pp.411-426
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• 2010

The seasonal variations in the zooplankton community of the southern coastal waters of Korea were investigated seasonally in May, August, November 2005, and February 2006. A total of 74 taxa were sampled, with an average abundance ranging from 2,426~23,793 indiv./$m^3$, among which Noctiluca scintillans predominated. Noctiluca scintillans, Acartia omorii, Acartia erythraea, Paracalanus parvus s. l., Centropages abdominalis, Tortanus forcipatus, and Pseudevadne tergestina were the most abundant species detected. Zooplankton diversity was high around the inner regions during the summer, but it was relatively low in the stations located in the outer regions in the autumn. Non-metric multidimensional scaling (nMDS) revealed significant differences in the structures of the zooplankton community among the three regions. Our results showed that the seasonal variations in zooplankton communities in the southern coastal waters of Korea were attributable to seasonal changes in temperature, salinity, chlorophyll a concentrations, and N. scintillans blooms; additionally, this particularly study area might have been specifically influenced by the appearance of the Tsushima Warm Current.

• Korean Journal of Ecology and Environment
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• v.52 no.3
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• pp.231-244
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• 2019

Zooplankton is essential biological assemblage in understanding the structure and function of aquatic ecosystems, since it plays as a linkage between primary producers and higher trophic level organisms such as fish. Although zooplankton has planktonic characteristics, the sampling and treatment methods for its community analyses are more complicated and variable compared with phytoplankton due to its high diversity in body size and species-specific depth selection behaviors. In the present paper, we reviewed representative classical methods for field sampling and treatments of freshwater zooplankton in relation with quantification of its community structure, and suggested appropriate methods depending on various research objectives.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.23 no.2
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• pp.141-144
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• 1990

Seasonal change in the reproductive pattern of the marine Cladoceran Podon polyphemoides, was studied using materials collected monthly during the period from January to December 1986 in Yongil Bay, Korea. The relative abundance of P. polyphemoides exceeded $10\%$ of total zooplankton in July. While the species remained as a minor components of the zooplankton community during the other periods of occurrence from June to December. Occurrence of sexual individuals of P. polyphemoides (males and gamogenetic females) in higher proportion in cold months ($30\%$ in November and $40\%$ in December) suggests that resting egg production of this species is largely confined to cold monthis in Korean waters as an overwintering strategy.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.31 no.5
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• pp.749-759
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• 1998

Distribution of zooplankton abundance was studied in the front zone in the East Sea in November, 1996, Averaged total abundance in the front zone was less than that in the nearby cold surface water areas but more than that in the nearby warm surface water areas. The number of taxa was the greatest in the upper layer of mixing. Abundance and the number of tun in the front zone were contributed by the cold water and the warm water, respectively. Inspite of the differences in sampling time (day vs night), the species composition and abundance distribution were similar at two sites within cold or warm water area, However, they were quite different at two sites in the front zone although the sampling time of the day was the same. from this, the history of mixing was believed to be the most important factor for the species composition and abundance distribution in the front zone. Zooplankton distribution in the study area was mainly controlled by the dominant cold water Copepod Species Metridia paoifica, the only taxon that showed significant diet vertical migration. Most other taxa showed no significant diel vortical migration, Seawater temperature also affected zooplankton distribution. Positive correlations in the warm area, weak negative correlations in the cold water area, and no significant correlation in the front zone were obtained in general between the seawater temperature and the abundances of the major taxa.

• 한국해양학회지
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• v.29 no.4
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• pp.376-382
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• 1994

Seasonal distribution of zooplankton community in Inchon Dock, an artificially closed marine embayment has been studied. Samples were collected monthly during the period from December 1989 to December 1991 at four stations in the dock and compared with that at a single station in neighbouring waters of the Yellow Sea. Copepods dominated both in and outside of the dock all the year round, except in late autumn and early winter when protozoans outnumbered. dominant species were Oithona davisae, Acartia bifilosa, Paracalanus crassirostris, Noctiluca scintillas and Tintinnopsis tubulosa. A sharp decline in the abundance was observed in summer 1990 in the dock apparently due to oxygen deficiency (anoxic condition). Although no distinct deference in the abundance of zooplankton was observed between populations in and outside of the dock except in summer 1990, waters out of the dock showed to have a prosperity in species number throughout the year. Moreover, four species of copepods, Centropages abdominalis, Pseudodiaptomus marinus, Tortanus forcipatus and T. spinicaudatus occurred solely at the outside of the dock.

• Korean Journal of Ecology and Environment
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• v.55 no.4
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• pp.274-284
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• 2022

Through sample-size-based rarefaction analyses, we tried to suggest the appropriate degree of sample concentration and sub-sample extraction, as a way to estimate more accurate zooplankton species diversity when assessing biodiversity. When we collected zooplankton from three reservoirs with different environmental characteristics, the estimated species richness (S) and Shannon's H' values showed different changing patterns according to the amount of sub-sample extracted from the whole sample by reservoir. However, consequently, their zooplankton diversity indices were estimated the highest values when analyzed by extracting the largest amount of sub-sample. As a result of rarefaction analysis about sample coverage, in the case of deep eutrophic reservoir (Juam) with high zooplankton species and individual numbers, it was analyzed that 99.8% of the whole samples were represented by only 1 mL of sub-sample based on 100 mL of concentrated samples. On the other hand, in Soyang reservoir, which showed very small species and individual numbers, a relatively low representation at 97% when 10 mL of sub-sample was extracted from the same amount of concentrated sample. As such, the representation of sub-sample for the whole zooplankton sample varies depending on the individual density in the sample collected from the field. If the degree of concentration of samples and the amount of sub-sample extraction are adjusted according to the collected individual density, it is believed that errors that occur when comparing the number of species and diversity indices among different water bodies can be minimized.

• Animal Systematics, Evolution and Diversity
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• v.9 no.2
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• pp.91-102
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• 1993

The genus Oithona was investigated taxonomically in samples collected from 10 regions of the Korean waters. In result, 18 species of the genus Oithona were identified, and a key table on 18 species was given. Of these following nine species were new records for Korean waters: Oithona atlantica, 0 . attenuata, 0 . davisae, 0. hamata, 0. longispina, 0 . oculata, 0 . simplex, 0. tenuis, 0. vivida.

• Journal of the Korean Society of Marine Environment & Safety
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• v.15 no.4
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• pp.339-344
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• 2009

The joint cruises of six times between Korea and China were carried out for a better understanding of the environmental and oceanographical characteristics of the Yellow Sea for 6 years from 1998 to 2003. Zooplankton samples were collected one time per year at 24 stations on 3 lines of the Yellow Sea. The aim of this study is to understand the seasonal fluctuation of zooplankton community in the Yellow Sea. There is no trend on the spatio-temporal distribution of zooplankton. Copepoda, the major taxon of the Yellow Sea, was high in distribution in the eastern part and Chaetognatha in the western part of the Yellow Sea. In this results, the dominant copepods were Calanus sinicus, Paracalanus parvus s.l., Oithona atlantica, and Corycaeus affinis during the study periods. The density fluctuation of these dominant species may be an important factor in determining the fisheries resource of the Yellow Sea.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.45 no.2
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• pp.173-179
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• 2012

The common squid $Todarodes$ $pacificus$ is a dominant species in Korean waters, where it is captured preponderantly by the angling fishery. The spawning and nursery grounds of $T.$ $pacificus$ extend from the southern East Sea to the northern East China Sea. Consequently, the environmental conditions in this area during the spawning and nursery seasons might affect the abundance of $T.$ $pacificus$. This study, analyzed the relationship between the distribution of zooplankton and the abundance of $T.$ $pacificus$ and variation in the squid angling fishing grounds in Korean waters. There was a positive relationship between the fluctuations in zooplankton and the catch per unit effort (CPUE; $kg{\cdot}day^{-1}{\cdot}person^{-1}$) of the angling fishery in the East Sea of Korea. The main fishing season is from July to December and the CPUE was closely related to the zooplankton biomass in April in the East Sea. Recently, the center of the squid jigging ground has moved drastically from the area around Ulleung Island to the northern East Sea. We postulate that the fishing grounds of the squid angling fishery will move farther north with climate change.

• Journal of Ecology and Environment
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• v.32 no.4
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• pp.257-265
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• 2009

We estimated monthly and annual secondary productivity of pelagic zooplankton in Lake Paldang and Lake Cheongpyong. Secondary productivity was calculated by combining estimated zooplankton biomass and biomass-specific productivity for each site and depth from March to November 2008. In addition to somatic production, we measured production of eggs and exuviae for three dominant species: Daphnia galeata, Bosmina longirostris, Cyclops sp. In terms of biomass, B. longirostris was dominant in Lake Paldang in April and May, B. longirostris showed explosive biomass growth, especially in May. In June and July, B. longirostris and D. galeata were both dominant. Lake Cheongpyeong showed much lower zooplankton biomass than Lake Paldang. In August, there was little or no biomass in both lakes probably due to heavy rain. The Gyeongan River contributed most of the secondary productivity and B. longirostris contributed the most secondary productivity in Lake Paldang. D. galeata also contributed in the Gyeongan River, the South Han River and at the Paldang Dam in spring and fall. Overall, Lake Cheongpyeong showed lower secondary productivity than Lake Paldang. B. longirostris made the largest contribution to secondary productivity in the Cheongpyeong Dam area while D. galeata contributed the most near Nami Island. Somatic production constituted ~80% of the total secondary productivity (the sum of somatic, egg and exuvia production) for D. galeata and B. longirostris. Although production-to-biomass (P/B) ratios were usually <<1 B. longirostris sometimes showed very high P/B ratios, probably due to fish predation. D. galeata showed much lower P/B ratios than B. longirostris after the summer at most sites.