• Journal of the Korea Institute of Military Science and Technology
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• v.13 no.5
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• pp.941-949
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• 2010

The present study investigated the swimming pattern and appendage postures of a copepod species, Calanus sinicus, which prevails in the south-east sea of the Korean peninsula, by employing a digital holographic particle tracking velocimetry(PTV) technique. The results showed that the copepod Calanus sinicus had various swimming patterns such as hover, hop, sink, cruise, and downward cruise. Most frequent pattern was the 'hop and sink'. The average swimming speeds ranged from 1.1 to 45.7 body-lengths/s, and the corresponding flow Reynolds number ranged from $10^0$ to $10^2$.

• Ocean and Polar Research
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• v.44 no.3
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• pp.261-267
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• 2022

We derived a length-weight relationship for Calanus sinicus off Busan, Korea in spring to estimate the biomass of the C. sinicus population around Korean waters, and compared it with the previously derived equations. The developmental stages and prosome length of C. sinicus used in the relationship ranged from 1,376-1,540 ㎛ for copepodite 4 (CIV), 1,753-1,971 ㎛ for copepodite 5 (CV), and 2,160-2,283 ㎛ for adults (CVI). Dry weight and carbon content were measured from a total of 26 replicates. Length-weight relationships derived in the present study are as follows: log C = 3.342 log PL - 9.449, log DW = 3.394 log PL -9.219, where C is carbon content (㎍), DW is dry weight (㎍), and PL is prosome length (㎛). When comparing the present regression equation of length-weight for C. sinicus with the previous one, our regression equation showed an average carbon estimate to a given range of mean prosome length. The length-weight relationship of C. sinicus in the present study can be used to better estimate the biomass of the C. sinicus population in the coastal waters of Korea.

• 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..

• Journal of the korean society of oceanography
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• v.33 no.1-2
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• pp.28-34
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• 1998

Variations in abundance, size and population structure of Calanus sinicus were studied in the southern waters of Korea in connection with hydrographic conditions during 1991-1992. Abundance was high in April and low in August. This species was concentrated inshore of a coastal temperature front, or around the temperature front in April. The 1st-3rd copepodites dominated in February and April, and adults in August. The mean population stages in February and April were younger than those in other survey months. This suggests that this species mainly reproduced during winter-early spring. In prosome length, the 1st-4th copepodites were larger in April than in other survey months, and the 5th copepodite and adult were the largest in February. Mean prosome length of C. sinicus showed weak inverse relationship with sea water temperature, but it was not statistically evidenced.

• Ocean and Polar Research
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• v.38 no.4
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• pp.303-314
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• 2016

We tested the combined effects of increased partial pressure of $CO_2$ ($pCO_2$) and temperature on the reproduction and survival of the copepod Calanus sinicus from Asan Bay, the Yellow Sea under laboratory conditions to understand the impact of acidification on copepods. Egg production rate, survival rate, and fecal pellet production of C. sinicus were not affected by 1305 ppm $pCO_2$ or with combined treatments of temperature and $pCO_2$, including $8^{\circ}C$ and 289 ppm $pCO_2$ (ambient), $8^{\circ}C$ and 753 ppm $pCO_2$ (high $pCO_2$), $12^{\circ}C$ and 289 ppm $pCO_2$ (high temperature), and $12^{\circ}C$ and 753 ppm $pCO_2$ (greenhouse), for 5 or 10 d of exposure. However, egg hatching success of C. sinicus decreased significantly in the greenhouse treatment compared with the ambient or the high $pCO_2$ treatments. These results suggest that a combined treatment ($pCO_2$ and temperature) affected egg viability more than a single treatment($pCO_2$).

• 한국해양학회지
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• v.27 no.1
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• pp.11-18
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• 1992

To study on feeding behavior of copepods, Calanus sinicus and Acartia clausi(A. omorii), variations of filtering rate and rate of food intake with the changes of phytoplankton concentrations and time progress were measured in laboratory. Filtering rates of the two species of copepod declined with increasing of the food concentration and the averaging filtering rates C. sinicus and A. clausi were 2.42m/ copepod/hr., 3.37 ml/copepod/hr. respectively. And the rates of food intake increased with food concnetration up to a critical concentration. At higher concentrations, the rates of food intake were somewhat variable but kept the constance levels. Filtering rates of copepods with time progress didn't show diel feeding rythms and generally decreased. But filtering rate of A. Clausi increased by the increment of feeding in a few hours. consequently, two copepods showed similar tendency in the rate of food intake and filtering rate with phytoplankton concentrations. However, the measured values appeared differently. And the two species of copepod with time progress showed the non-continuous feeding behavior.

• Proceedings of the Korean Society of Fisheries Technology Conference
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• 1998.06a
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• pp.359.1-359
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• 1998

• Journal of Fisheries and Marine Sciences Education
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• v.29 no.3
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• pp.869-877
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• 2017

The monthly variations of zooplankton community were investigated at 12 stations near Tongyeong and Namhaedo in the South Sea of Korea from April to July, 2012. Zooplankton samples were collected by a plankton net (RN80) from near the bottom to the surface. Zooplankton community consisted of 97 taxa, and the mean abundance ranged from $213inds.m^{-3}$ in July to $426inds.m^{-3}$ in April. Copepods constituted 38.98% of zooplankton abundance, and included 39 species. Calanus sinicus, Corycaeus affinis, Paracalanus parvus s.l., copepodids, Evadne nordmonni, Podon leuckarti, cirriped nauplii, Muggiacea sp., Diphyes sp., and Zonosagitta bedoti were dominant species. Of these, Calanus sinicus was the most abundant throughout the study period, being constituted 18.6% of total zooplankton abundance. The density variations of dominant species between stations and months were correlated with the environmental factors. Zooplankton community varied with by sampling months, being influenced by monthly oceanographic variations.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.24 no.6
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• pp.472-482
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• 1991

Seasonal distributions of zooplankton were investigated in Asan Bay, Korea. Labidocera euchaeta, Sagitta crassa, Calanus sinicus, Acartia omorii were dominant taxa throughout the year with seasonally varying percent compositions. Bivalve veliger larva (fall), Decapoda larva (spring and summer), and Paracalanus Parvus, Evadne tergestina (summer) were also dominated during contain period. The patterns of time dependent vertical distributions of one major taxon, A. omorii, showed seasonal differences, i.e., it showed the trends of normal vertical migration in winter and reversed vertical migration in spring. At surface layer day time abundances were equal or less than night time abundances in general.

• Ocean and Polar Research
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• v.43 no.4
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• pp.269-277
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• 2021

We investigated mesozooplankton community in the Yellow Sea in summer immediately after the typhoon passed. Total mesozooplankton density ranged from 1,323 to 6,397 ind. m^-3 and the biomass ranged from 3 to 28 mg C m^-3 by stations. The dominant species of the research area were Paracalanus parvus s.l., Oithona atlantica, Acartia omorii, Oikopleuridae, Sagittoidae juvenile and Calanus sinicus in that order. Mesozooplankton community was divided into two groups by cluster analysis : the stations located in coastal and open seas as one group, and the stations located in the middle into another group. The number of species, density and richness of mesozooplankton were significantly lower in the middle region. Mesozooplankton density and biomass were not significantly correlated with chl-a concentrations, unlike previous studies in spring and autumn. This community characteristic in summer may be due to the passing of the typhoon, or other environmental influences.