• Journal of Life Science
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• v.11 no.5
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• pp.470-475
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• 2001

The larvae of Nitocra spinipes Boeck, 1865 were reared at 2$0^{\circ}C$ and 33.3$\textperthousand$ in the laboratory. These species passed through six nauplii stages and the first copepodid appeared in 8-10 days. Nauplii of N. spinipes is distinguished by characteristics of the appendage setation and caudal setae. The number of segments of antennal and mandibular exopodites in harpacticoida is discussed within familial level.

• Korean Journal of Ichthyology
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• v.27 no.1
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• pp.33-38
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• 2015

The diet composition of Leiognathus nuchalis were studied using 350 specimens collected from October 2010 to September 2011 in the coastal waters of Gadeok-do, Korea. L. nuchalis was carnivorous feeder that consumed mainly copepods, crab larvae, and shrimp larvae. Its diet also included small quantities of polychaetes, amphipods, euphausiids, bivalve larvae, and gastropod larvae. The size of L. nuchalis ranged from 3.0 to 9.8 cm in body length (BL). L. nuchalis underwent an ontogenetic dietary shift. 3~5 cm size individuals fed mainly on copepods. 5~7 cm size individuals fed mainly crab larvae and shrimp larvae. 8~10 cm size individuals fed mainly polychaetes. The size increases, the weight of food organisms are constantly increased.

• Journal of the Korean Society for Marine Environment & Energy
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• v.9 no.3
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• pp.160-167
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• 2006

Harpacticoid copepod Tigriopus japonicus is widely distributed in coastal waters of Korea and plays important role in marine trophic structure as a first consumer. In this study, a series of experiment were conducted to test the potential of the species as a standard test species for marine bioassay. Tolerance on salinity and pH, sensitivity on the reference materials(copper sulfate and cadmium chloride) and response on the ocean dumping materials(waste sludge) we re tested to identify if the species satisfy the basic criteria as standard species for marine bioassay. The nauplius of the species($100{\sim}200{\mu}m$) showed wide tolerance on salinity with >90.0% survival rates exposed to $5.0{\sim}35.0psu$ for 48 h. Wide adaptability on pH's were also observed from 6.3 to 8.2 with >90.0% survival rates during the test. $LC_{50}$ values for copper sulfate and cadmium chloride were $3.6{\pm}0.7ppm,\;1.7{\pm}0.8ppm$, respectively. The variations in mortality between replicates were less than 10.0%. Comparison of $LC_{50}$ values indicated that T. japonicus nauplius was lower sensitive to copper sulfate than the most marine crustaceans included copepods, however, the sensitivity of test animal to cadmium chloride higher than the adults of copepod T. japonicus, Paracalanus parvus, and marine rotifer Brachinonus plicatilis. There were significant concentration-response relationship in the mortality of T. japonicus nauplius using the elutriates of three ocean dumping materials(industrial waste sludge). 48 h $LC_{50}$ values we re $31.1{\pm}1.1%$ for the elutriate of sludge from leather processing company and $54.4{\pm}15.1%$ for that of dye production company. Based on the above experimental results, bioassay using benthic harpacticoid T. japonicus nauplius must be a good estimation tool for marine ecotoxicological assessment of waste or chemicals. Wide tolerance on the salinity and pH, and significant linear relationship between concentration and response(mortality) supported the high potential of the species as a standard test species.

• Korean Journal of Ichthyology
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• v.13 no.4
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• pp.223-229
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• 2001

Feeding habits of juvenile Sillago maculata, collected from the tropical seagrass beds in Cockle Bay, Queensland, were studied. S. maculata (0.5~9.5 cm SL) was a carnivore which consumed mainly gammarid amphipods, crabs and copepods. Its diets included small quantities of polychaetes, shrimps, fishes, isopods and cumacean. S. maculata showed ontogenetic changes in feeding habits. Small individuals preyed mainly on copepods, crab larvae and gammarid amphipods. While the portion of the stomach contents attributable to polychaetes, crabs and fishes increased with increasing fish size, consumption of copepods and crab larvae decreased progressively. Gammarid amphipods were the most selected prey item for all size classes.

• Journal of Environmental Impact Assessment
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• v.26 no.3
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• pp.207-216
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• 2017

Several bioassays have been performed for assessment of the impact of polluted sediments. The direct exposure method using sediments is limited by difficulty controlling feeding and its effects on organisms. Furthermore, only macro-organisms and benthic organisms are used. To evaluate the potential application of sediment elutriate as a complementary strategy for impact assessment, copepods, small organisms with a short life cycle, were exposed to sediment elutriates, and several end-points were measured. As a result, sediment elutriates prepared from polluted sites caused growth retardation in marine copepods. In terms of molecular biomarkers, antioxidant-related and chaperone protein gene expression levels were increased in a dose- and time-dependent manner. Thus, we suggest that sediment elutriate tests can provide an effective alternative for toxicity assessment using whole sediment samples. Further studies are required to obtain sufficient data for future applications.

• Journal of Aquaculture
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• v.18 no.2
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• pp.86-91
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• 2005

Three haptophyte algae, Isochrysis galbana, Prymnesium parvum and P. patelliferum were offered to the marine copepod Tigriopus japonicus as food. Growth rate of larvae, egg production, mortality and comsumption rates of T. japonicus were measured for each of the haptophyte species offered. The growth rate of larvae, egg production and algal ingestion of T. japonicus fed on P. parvum and P. patelliferum were much lower than those fed on I. galbana and corresponding high mortality rates were also observed during the experimental period. The harmful effects observed during the present study indicate that bloom-forming haptophyte algae, P. parvum and P. patelliferum are not suitable feed species for culture of copepod, T. japonicus.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.26 no.3
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• pp.258-265
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• 1993

Monthly changes in the occurrence and infection levels of a parasitic copepod Acanthochondria yui(Poecilostomatoida, Chondracanthidae) on a gobiid fish Acanthogobius flavimanus were studied for a year from April 1990 to March 1991. This parasite was not found on the fish for four months from September to December. Prevalence of the parasite increased from $2.9\%$ in January to $88.9\%$ in June. Relative density and mean intensity also increased from January to June. Prevalence of A. yui increased with host size. A. flavimanus samples were never found carrying A. yui larvae of three copepodid stages(CI to CIII), although a few CIV and CV larvae were identified from April and May samples. This indicates that A. flavimanus was not the sole host of A. yui. Adult females and copepodites of A. yui were usually found in the gill arch($74.8\%$) and gill filament($80.6\%$), respectively. This suggests that copepodites select the gill filament as the most suitable place on their host A. flavimanus, and the adult females move toward the gill arch.

• The Sea:JOURNAL OF THE KOREAN SOCIETY OF OCEANOGRAPHY
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• v.5 no.3
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• pp.233-237
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• 2000

The complete postembryonic development of nauplius stages of Paramphiascella vararensis T. Scotf (Copepoda: Harpacticoida) is described and illustrated based on specimens cultured in laboratory. The nauplii of P. vararensis feed on powder of a green algae, Ulva perusa. This species is metamorphosed to the stages of nauplius. Development from the nauplius stage to the nauplius stage take about 12 days under culture conditions of 33-34 ppt of salinity, 22-23$^{\circ}$C of temperature and feed on the algal powder. In the nauplius stages of P. vararensis, the rudiment of maxillule appeares at the third nauplius stage, and maxilla appeares at the fifth nauplius stage.

• The Sea:JOURNAL OF THE KOREAN SOCIETY OF OCEANOGRAPHY
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• v.13 no.2
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• pp.129-139
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• 2008

Marine ecotoxicological standard method was applicated using marine rotifer and benthic copepod as primary consumer of marine ecosystem. Marine rotifer, Brachionus plicatilis and benthic copepod, Tigriopus japonicus were designated as standard test species with the endpoints of 24hr neonate mortality (24hr $LC_{50}$) and 48hr population growth (48hr $EC_{50}$) for rotifer, and 48hr nauplius mortality (48hr $LC_{50}$) for benthic copepod. Tests method was referred to those of ASTM (American Society for Testing and Materials) with the replacement of test species which are widely distributed in Korean waters. The two species showed a wide tolerance on salinity ($5{\sim}35\;psu$) and can be easily cultured in small space even they were not as sensitive as in the mortality test using the nauplius of marine invertebrates. However, these species revealed the significant "concentrationresponse relationship" tested with ocean disposal wastes, and reproducibility using cadmium as standard reference material between laboratories. Accordingly, these two species have good potential as test species for marine ecotoxicological test species. Also, we strongly recommend that at least one of these species be included in the test species of "battery test" in marine bioassay.

• Korean Journal of Environmental Biology
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• v.20 no.1
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• pp.46-54
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• 2002

We observed zooplankton community to understand variations in the species composition and abundance in Gangjin Bay. Samples were collected bimonthly from February to November 1999 at 10 stations in Gangjin Bay of the southern part of Korea. Zooplankton communities consisted to nine taxa and mean biomass was 2,028 indiv. $m^{-3}$. The maximum abundance was observed to be 5,496 indiv. $m^{-3}$ in February and the minimum in November, 78 indiv. $m^{-3}$. Copepods dominated and most diverse in Gangjin Bay. Seasonal fluctuation in the copepod abundance varied between 42 and 4,159 indiv. $m^{-3}$. Dominant species are Acartia omorii, Centrophages abdominalis, Paracalanus indicus and A. steueri. Cladoceran also dominated and the maximum abundance was 765 indiv. $m^{-3}$ in April. A. omorii and Oithona davisae dominated in February, A. omorii, Eurytemora pacifica, Evadne nordmanni and Podon polyphemoides in April, Tortanus dextrilobatus and decapod nauplius in June, Paracalanus indicus, E. tergestina and Penitia avirostris in August and A. erythraea and P. indicus in October. In November, P. indicus and Sagitta crassa dominated.