• Korean Journal of Ichthyology
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• v.28 no.4
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• pp.267-272
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• 2016

The feeding habits of Chaenogobius annularis were studied based on gut contents analysis of 315 individuals, collected from September 2014 to August 2015 in the tidepools at the intertidal zone of Tongyeong, Korea. The size of C. annularis ranged from 17.0 to 54.0 mm in standard length (SL). C. annularis mainly consumed copepods (especially Tigriopus japonicus). Its diets included seaweeds, cirripeds, mysids and amphipods. C. annularis showed ontogenetic changes in feeding habits. Small individuals fed mainly on copepods. As body size increased, the portion of seaweed increased, whereas the consumption of copepods decreased.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.52 no.4
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• pp.430-436
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• 2019

The diet of Glyptocephalus stelleri was studied using 475 specimens collected in the coastal waters of the East Sea of Korea. The specimens ranged from 6.8 to 43.4 cm in total length (TL). G. stelleri was a crustacean feeder that consumed mainly euphausiids [percent index of relative importance (%IRI)=63.7%]. Polychaetes were the second largest prey component. The diet also included small quantities of bivalves, copepods, amphipods and shrimps. Individuals smaller than 15 cm TL fed mainly on euphausiids. The proportion of euphausiids decreased as body size increased, whereas the consumption of polychaetes increased gradually.

• Ocean and Polar Research
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• v.41 no.2
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• pp.47-61
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• 2019

The Dokdo coast is known for its high biodiversity. However, few studies have examined the biodiversity and macrobenthic community on the subtidal soft-bottom. Therefore, we collected macrobenthos (> 1 mm) using a Smith-McIntyre grab ($0.1m^2$) at 15 stations along the Dokdo coast in September 2016. The sediments consisted of badly sorted (1.7) coarse sand with gravel and the mean sediment grain size was $-0.4{\phi}$. In total, 177 macrobenthic species were collected; their mean density was $1,566ind./m^2$. The number of species and density of macrobenthic fauna decreased significantly with the mean grain size. The dominant species were the amphipods Melita denticulata (16.5%) and Melita shimizui (5.5%), polychaete Salvatoria clavata (5.4%), bivalve Glycymeris aspersa (4.4%), and ophiuroid Ophionereis dubia (4.3%). The dominant macrobenthos species on the subtidal soft-bottom differed from the coastal areas of the East Sea, suggesting that the difference in the sediment grain size affected the macrobenthos. Cluster analysis was performed to divide the study area into four groups, and environmental factors which correlated with species composition and distribution in the study area were the combination of the four parameters of salinity, dissolved oxygen, total organic carbon and depth. A future seasonal investigation is needed to understand the species composition and characteristics of the Dokdo macrobenthos.

• Ocean and Polar Research
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• v.43 no.1
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• pp.45-51
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• 2021

Studies on marine zooplankton diversity and ecology are important for understanding marine ecosystem, as well as environmental conservation and fisheries management. DNA metabarcoding is known as a useful tool to reveal and understand diversity among animals, but a comparative evaluation with classical microscopy is still required in order to properly use it for marine zooplankton research. This study compared crustacean mesozooplankton taxa revealed by morphological analysis and metabarcoding of the cytochrome oxidase I (COI). A total of 17 crustacean species were identified by morphological analysis, and 18 species by metabarcoding. Copepods made up the highest proportion of taxa, accounting for more than 50% of the total number of species delineated by both methods. Cladocerans were not found by morphological analysis, whereas amphipods and mysids were not detected by metabarcoding. Unlike morphological analysis, metabarcoding was able to identify decapods down to the species level. There were some discrepancies in copepod species, which could be due to a lack of genetic database, or biases during DNA extraction, amplification, pooling and bioinformatics. Morphological analysis will be useful for ecological studies as it can classify and quantify the life history stages of marine zooplankton that metabarcoding cannot detect. Metabarcoding can be a powerful tool for determining marine zooplankton diversity, if its methods or database are further supplemented.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.54 no.1
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• pp.73-79
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• 2021

The feeding habits of Chub mackerel Scomber japonicus were investigated using 329 specimens collected from coastal waters of the South Sea of Korea. S. japonicus is mainly a piscivore, consuming small fish such as Engraulis japonicus (%RI: 81.0 %). The diet of Chub mackerel also includes small quantities of thaliaceans, euphausiids, and amphipods. We calculated the trophic level as 3.92 for S. japonicus. The dietary composition of S. japonicus did not show significant differences with size, but differed with season. As the body size of S. japonicus increased, the mean weight of prey within the stomach (mW/ST) increased (One-way ANOVA, P<0.05).

• The Sea:JOURNAL OF THE KOREAN SOCIETY OF OCEANOGRAPHY
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• v.15 no.2
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• pp.68-71
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• 2010

This study was performed in order to obtain basic data of macrobenthic community in continental shelf exclusive economic zone (EEZ), before sand excavation. The species number of macrozoobenthos was 157, mean density was 2,529 ind./$m^2$ and mean biomass was 231.8 $g/m^2$ in November, 2000. The species number of macrozoobenthos was 179, mean density was 3,773 ind./$m^2$ and mean biomass was 391.2$g/m^2$ in February, 2001. Dominant species were Ampelisca sp. and Photis sp. in amphipods, Ophiactis branchygenys in ophiuroids and Nothria sp. and Eunice sp. in polychaetes. In the proportion of feeding types of macrobenthos, surface deposit feeders were most dominant feeding group, and followed by carnivores, subsurface deposit feeders, and filter feeders. Species diversity index (H') was high ranging from 2.5 to 3.5 at most sites.

• Fisheries and Aquatic Sciences
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• v.26 no.10
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• pp.628-636
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• 2023

Stomach contents of three commercially important species, anchovy (Engraulis japonica), small yellow croaker (Larimichthys polyactis) and yellow goosefish (Lophius litulon) were analyzed to investigate difference of prey between Spring and Fall. Trawl surveys for target fishes were conducted at 12 stations by the RV Tamgu-8 in the Yellow Sea-Korean side in Spring and Fall 2008 as a part of the United Nations Development Programme/Global Environment Facility (UNDP/GEF), Yellow Sea Large Marine Ecosystem (YSLME) survey. Stomach contents of 50 individuals of each species were analyzed to species level of prey, if the number of specimens was more than 50 for each species. Fullness and digestion condition of stomach contents were determined by five and six levels, respectively. In anchovy stomachs, 23 species in Spring and 15 species in Fall were identified, respectively. Stomach contents were mostly occupied by copepods and euphausiids, mostly Euphausia spp., calyptopis in Spring while by copepods and amphipods in Fall. In small yellow croaker stomachs, 23 species in Spring and 11 species in Fall were identified. Stomach contents were mostly occupied by copepods and euphausiids in Spring, but by only euphausiids in Fall. Total 368 yellow goosefish (151 in Spring and 217 in Fall) were captured, but stomach contents only in Fall were analyzed. Most of stomach contents were anchovy with small proportion of Hakodate sand shrimp, Tanaka's snailfish, Pacific cod, and miscellaneous things. The present research unveiled that main food items of plankton feeder were distinctly different by species and seasons in the Yellow Sea-Korean side, as coincided with previous reports.

• Korean Journal of Environmental Biology
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• v.27 no.1
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• pp.124-133
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• 2009

The study was performed to investigate the community structure of macrobenthic fauna during June 2005, in Hallyeohaesang National Park from Korea Strait. A total of 284 macrobenthic fauna were collected. The overall average macrobenthic density and biomass were 2,002 individuals m$^{-2}$ and 154.92 gWWt m$^{-2}$, respectively. Based on the Lebris (1988) index, there were 20 species accounting for approximately 47.64% of total individuals. And the highest densities were found in the polychaetes Scoletoma longifolia, Isolda pulchella, Mediomastus californiensis, Minuspio multibranchia, Tharyx sp. 1 and the bivalve Theora fragilis. On the other hand, the top twenty species made up 70.47% of the total biomass while the three most abundant, the echinoderms Schizaster lacunosus, Amphiura vadicola and the bivalve Fulvia mutica. The conventional multivariate statistics (cluster analysis and non-metric Multi-Dimensional Scaling) applied to assess spatial variation in macrobenthic assemblages. As a result of cluster analysis and nMDS ordination, this study area was divided into two different groups of stations and species. In case of station, there are two groups: one is a mud dominated station group and the other is dead shell and sand dominated group. And the 2 faunistic groups were established as follows: 1) a group of relatively higher abundances in mud dominated sediment. There were numerically dominated by the polychaetes Magelona japonica, Sternaspis scutata, Paraprionospio pinnata, Tharyx sp. 1 and the amphipods Monocorophium sinense and Eriopisella sechellensis. 2) a group of relatively higher densities dead shell and sand dominated sediment. These groups were characterized by the polychaetes I. pulchella, M. multibranchiata, the amphipods M. acherusicum, Gammaropsis japonicus and the echinoderm A. vadicola.

• Korean Journal of Ichthyology
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• v.34 no.2
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• pp.113-118
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• 2022

The feeding habits of sandfish, Arctoscopus japonicus were studied using 781 specimens collected by Eastern Sea Danish and gill net from January 2020 to December 2021 in the coastal waters of East Sea, Korea. The size of the specimens ranged from 14.8 to 25.4 cm in total length. A. japonicus were fed mainly on amphipods that constituted 54.7% in IRI. Cephalopods were the second largest prey component. The diets also include small quantities of euphausiids, crabs, shrimps, fishes, and worms. The diet composition of A. japonicus showed changes in season. The cephalopods feeding rate was highest in summer, whereas the proportion of euphausiids was higher in spring than in other seasons. The proportion of cephalopods has increased as the body size of A. japonicus increased, whereas the proportion of amphipods and euphausiids decreased gradually. As the body size of A. japonicus increased the mean weight of prey per the stomach (mW/ST) tended to increase significantly (One-way ANOVA, P<0.05).

• Korean Journal of Ichthyology
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• v.19 no.4
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• pp.318-323
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• 2007

The feeding habits of Pacific cod (Gadus macrocephalus) were studied based on the examination of stomach contents of 192 specimens collected from November, 2005 to January, 2006 in the coastal waters off Gadeok-do, Korea. The size of Pacific cod ranged from 35 to 82 cm in standard length (SL). Pacific cod mainly consumed shrimps such as Eualus spathulirostris, Crogon hakodatei and C. affinis and fishes. Its diet also included small quantities of cephalopods, amphipods, hermit crabs and crabs. Individuals between 35 cm and 45 cm SL mainly consumed shrimps. The portion of shrimps decreased with increasing fish size, and this decrease was paralleled with increased consumption of fishes and cephalopods. In this study we found Syngnathus schlegeli in the stomach contents of many Pacific cod specimens. S. schlegeli is a typical seagrass fish species which inhabits in seagrass beds, This fact means that Pacific cods stay in the seagrass beds during spawning period. Therefore migration of Pacific cod to coastal waters off Gadeok-do during spawning period seems to be a survival strategy for its larvae and small juveniles to stay in seagrass beds which provide with abundant foods and shelters to many commercial fish species.