• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.50 no.3
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• pp.334-341
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• 2014

The diet composition of juvenile Korean piscivorous chub, Opsariichthys uncirostris amurensis were studied using 277 specimens collected from January to December 2004 in the surf zone of Nakdong river estuary. The size of Opsariichthys uncirostris amurensis ranged from 2.6 to 9.1 cm in standard length (SL). Opsariichthys uncirostris amurensis was carnivore that consumes mainly amphipods and insects. Its diet also included small quantities of polychaetes, fishes, and algae and plants. Opsariichthys uncirostris amurensis showed ontogenetic diet change. Smaller individuals (< 4 cm SL) mainly consumed amphipods. The portion of these prey items decreased with increasing fish size, and this decrease was paralleled with increased consumption of larger preys such as polychaetes and fishes. Insects were preyed moderated values in all size classes. Opsariichthys uncirostris amurensis diet also showed diel change with consuming more on amphipods and polychaetes during day.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.55 no.5
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• pp.583-589
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• 2022

The feeding habits of the marbled flounder Pseudopleuronectes yokohamae were studied using 384 specimens (10.7-52.3 cm in total length) collected from the West Sea, Korea between January and December 2021. P. yokohamae ate mainly polychaeta and gastropoda, incuding teleostei, caridea, euphausiacea, amphipoda and brachyura. The mean number of preys per stomach (mN/ST) showed a statistically significant difference, and the mean weight of prey per stomach (mW/ST) increased as the total length increased. P. yokohamae ate mainly teleostei in spring and winter. P. yokohamae ate mainly euphausiacea in summer and mainly polychaeta in autumn.

• Journal of Ecology and Environment
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• v.48 no.2
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• pp.144-151
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• 2024

Background: This study focused on the diet of Clithon retropictum, level II endangered species in Korea. Since the development of brackish water zones has led to a decline in the population of this species, to obtain information on the ecology of C. retropictum required for its conservation and restoration. To investigate the actual preys of C. retropictum in south coast of Korea, we conducted high-throughput sequencing and metabarcoding techniques to extract DNA from gut contents and periphyton in their habitats. Results: Total 118 taxonomic groups were detected from periphyton samples. 116 were Chromista and Cyanobacteria dominated in the most samples. In gut contents samples, 98 taxonomic groups were detected. Similar to the results of periphyton, 96 were Chromista and Cyanobacteria dominated in the most samples. In the principal component analysis based on the presence/absence of taxonomic groups, gut content composition showed more clustered patterns corresponding to their habitats. Bryophyta was the most crucial taxonomic group explaining the difference between periphyton and gut contents compositions of C. retropictum. Conclusions: Our finding suggests that C. retropictum may not randomly consume epilithic algae but instead, likely to supplement their diet with Bryophyta.

• Journal of Sericultural and Entomological Science
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• v.52 no.1
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• pp.16-24
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• 2014

Taraka hamada is known as the sole aphidophagous lycaenid butterfly in Korea. The species specifically preys upon Ceratovacuna japonica which lives in bamboo forests. During several years, the species has been received attention from the field of industrial insects in order to commercialize as a pet. However, an ecological character of the species have been unclear in Korea. We carried out a survey for basic ecology and distribution of the two species for 2010 to 2012. As the results, both species only cohabit at Pseudosasa japonica in our investigation. C. japonica is widely distributed from the host plant. Population density of T. hamada is synchronized with the density changes of C. japonica. Their densities are gradually decreased from the point to the investigation and significantly declined in mid-june. The maximum population density of both species shows at the basal part of a leaf. The last-larval instar of T. hamada may seem to be reaching at $4^{th}$ stage. The adults of T. hamada are killed within two minutes when they were exposed to the sun.

• Korean Journal of Ichthyology
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• v.24 no.1
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• pp.35-40
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• 2012

The feeding habits of yellowback seabream, $Dentex$ $tumifrons$, were studied using 317 specimens collected in the coastal waters of Busan, from January to December, 2004. The size of the specimens ranged from 10.2 to 27.8 cm in standard length (SL). D. tumifrons had turned out a carnivore and opportunistic predator that consumed mainly shrimps. Fishes were next important prey items. Its diet also included anomurans, amphipods, crabs, echinodermata and cephalopods. Polychaetes, stomatopods, bivalves, ostracods, mysids and so on were minor preys. The individuals of smallest size class (10~13 cm SL) fed mainly on shrimps. In the next size class (13~16 cm SL), the proportion of shrimps decreased, whereas the consumption of anomurans, echinodermata and crabs increased. The proportion of these prey items decreased as body size increased, whereas the consumption of fishes gradually increased. Fishes accounted for almost stomach contents of larger individuals (more than 25 cm SL).

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.13 no.2
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• pp.67-75
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• 2013

Korea has developed coastal farming industry due to the environmental characteristics that its three sides are surrounded by sea. The damage of coastal farming industry caused by Asterias Amurensis with very strong reproductive rate and predaciousness has increased sharply every year. Moreover, Asterias Amurensis preys on living fish and shellfish and so the damage of fishermen is vern greater. In this paper, a method is proposed to extract effectively the features from the image of Asterias Amurensis acquired in the water. Because the proposed method extracts convex features using 6-directional scanning, it selects a fewer number of feature candidates than the conventional one. In addition, after selecting candidate concave points using the extracted convex features and centers of region, the final concave features are extracted. Due to the features of the starfish which lives in groups, individuals of the starfish in the input image are concentrated. Thus, it is significant to minimize the number of feature candidates extracted from the input image. The experimental results indicate an improvement of the proposed feature extraction method over the conventional one as evidenced by the fact that the feature extract was 88 % of the feature candidates.

• Korean journal of applied entomology
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• v.39 no.2
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• pp.59-71
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• 2000

The Asian ladybird, Harmonia axyridis, might be distinguished in biological control agents for the several aphid species in the greenhouses as well as in the fields. Therefore, feeding behavior and predacious capability characteristics were observed. When ladybirds are searching for aphids as their preys, they use the maxillary palpus as contact reception. Otherwise, most of aphids escape from walking or chewing ladybird to other place (mainly move to near-by leaf, or fall down to the under-leaf or ground) instead of plant sucking. Consumed time of ladybirds for searching and feeding prey were significantly different and dependent on their development stage. The ladybird adults ate about 120 green peach aphids and 257 cotton aphids per day. The 3rd instar of ladybirds ate 2,420 and 2,750 eggs of greenhouse whitefly on the cucumber and tomato leaf, respectively, as well. However, ladybird instars taken greenhouse whitefly eggs could not continuously develope to adult, on the other hand, ladybirds taken aphids were normal condition.

• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.51 no.4
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• pp.553-560
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• 2015

The feeding habits of the Pacific bluefin tuna, Thunnus orientalis were examined based on the stomach contents of 330 specimens caught by offshore large purse seine fishery in the southern sea of Korea, 2011. The size of Pacific bluefin tuna used in this study ranged from 34.1 to 67.3 cm in fork length (FL). The percentage of empty stomachs was 41.8%. The main prey items were Pisces and Cephalopoda based on percentage IRI (index of relative importance). The main fish preys were Trachurus japonicus, Bregmaceros japonicus, Engraulis japonicus, and Cephalopoda were Todarodes pacificus, Loligo edulis, Watasenia scintillans. T. orientalis showed ontogenetic change in diet composition. Although Pisces dominated the diet of all length classes the portion of Cephalopoda was relatively higher in size between 40 and 50 cm other than length classes. In terms of seasonal variation in feeding habits, Pisces was the main prey group in all seasons, but Cephalopoda was also frequently consumed during spring and autumn based on %IRI.

• 한국해양학회지
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• v.21 no.2
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• pp.85-91
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• 1986

Diet and feeding patterns of 10 species of gonostomatid fish in the Rockall Trough and Porcupine Seabight, northeastern Atlantic, were investigated as a part of studies analyzing the meso-and upper bathypelagic micronektonic fish communities in these two areas. Copepods were the major food organisms, composing more than 72% in both areas, and ostracods the second most abundant prey organisms (〉13%). The results of stomach content analyses reveals that most of gonostomatids, including two important species, Cyclothone braueri and C. microdon, feed continuously regardless of light cycle and a little at a time. The gonostomatids appear to be planktivores that consume small-sized prey; relative size of most preys was about one-tenth of fish length. These feeding patterns could be an adaptive characteristic of fish living in great deep water where the food items are scarcely present. In general there are no considerable inter-and intraspecific differences, not to mention regional differences, in the feeding of the gonostomatids at both stations except the large specimen of Gonostoma elongatum fed fish. Thus several coexisting species of the gonostomatid fish utilize the same resources, showing competitive relationships.

• Korean journal of applied entomology
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• v.36 no.2
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• pp.166-171
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• 1997

To find out an alternative prey of Orius strigicollis Poppius in the laboratory continuous rearing system, cotton aphid (Aphis gossypii), two spotted spider mite (Tetmnychus urticae) and mold mite (Tyrophagus putrescenriae) were tested as alternative prey. Development and oviposition of 0. strigicollis were observed at 25f l0C, RH 60-80% and 16L:8D. Survival rate and developmental period of the nymphal stages of 0. strigicollis was 81. 6% and 11.6 days when fed on cotton aphid, 56.796, 14.6 days, 42.3% and 16.5 days when fed on two spotted spider mite and mold mite, respectively. Total oviposition of 0. strigicollis was 68.5 eggslfemaie fed on cotton aphid, 46.1 and 26.5 eggsifemale fed on two spotted spider mite and mold mite, respectively. Cotton aphid seems to be most suitable prey for rearing 0 . strigicollis among the three prey species tested.