• Korean Journal of Ichthyology
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• v.11 no.2
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• pp.191-197
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• 1999

Stomach contents of hairtail, Trichiurus lepturus collected in the Nakdong River Estuary were examined quantitatively. T. lepturus was a carnivore which consumed mainly fishes, crustaceans (such as copepods, euphausiids and shrimps) and chaetognaths. Its diets included small quantities of small squids. T. lepturus showed ontogenetic progression of three feeding stages : an initial feeding stage was a planktivorous stage in which copepods were the major food item, followed by a mixed feeding stage in which euphausiids, mysids, shrimps, chaetognaths and fishes were the major food items, and finally a piscivorous stage in which fishes were the major food item. Especially anchovies were heavily selected by large T. lepturus.

• Korean Journal of Ichthyology
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• v.35 no.2
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• pp.113-120
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• 2023

The diet composition of chub mackerel Scomber japonicus were studied using 959 specimens collected in the coastal waters of Jeju Island, Korea from January to November 2022. The size of the specimens ranged from 22.8 to 45.8 cm in total length. S. japonicus were fed mainly on euphausiids that constituted 77.7% in IRI. Fishes were the second largest prey component. Its diet also includes small quantities amphipods, copepods, shrimps, crabs and cephalopods. The diet composition of S. japonicus showed changes in season. The euphausiids feeding rate was highest in summer, whereas the proportion of fishes was higher in winter than in other seasons. The proportion of fishes has increased as the body size of S. japonicus increased, whereas the proportion of euphausiids decreased gradually. As the body size of S. 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.35 no.2
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• pp.129-135
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• 2023

The diet composition of skinnycheek lanternfish, Benthosema pterotum were collected by bottom trawl net in the South Sea of Korea during 2021 (February, May, August, and November) and 2022 (February, April, August, and November). The size of the specimens ranged from 16 to 73 mm in total length. B. pterotum were mesopelagic carnivores that mainly consumed euphausiids and copepods. Its diets included small quantities of amphipods, shrimps, mysids, etc. We calculated the trophic level as 3.16 for B. pterotum. The individuals of small size class (<40 mm) fed mainly on copepods. In the next size classes (40~45 mm, 45~50 mm, 50~55 mm), copepods' proportion decreased and euphausiids increased. In the largest class (55~60 mm and ≥60 mm), the proportion of euphausiids' decreased, and shrimps increased. As the body size of B. pterotum increased the mean weight of prey per stomach (mW/ST) tended to significantly increase (One-way ANOVA, P<0.05).

• Korean Journal of Ichthyology
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• v.35 no.4
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• pp.340-346
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• 2023

The diet composition of Engraulis japonicus were studied using 1,087 specimens collected by set net fisheries and boat seine fisheries in the coastal waters of Tongyeong, Korea. The size of the specimens ranged from 1.9 to 14.7 cm in fork length. E. japonicus was fed mainly on Copepods, which constituted 50.4% of IRI, followed by Euphausiids, which constituted 47.3% of IRI. Graphical analysis of the diet composition showed that E. japonicus was specialist predator. The result of analysis in ontogenetic changes significantly exhibited among size classes (<8.0 cm, 8.0~10.0 cm, 10.0~12.0 cm, ≥12.0 cm). The proportion of Euphausiids increased, as body size of E. japonicas increased whereas the consumption of Copepods decreased. In the Spring, Autumn and Winter, the diet was dominated by Copepods. In the Summer, the diet was dominated by Euphausiids.

• Korean Journal of Ichthyology
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• v.36 no.2
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• pp.182-187
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• 2024

Feeding habits of the large yellow croaker, Larimichthys crocea, was studied using 816 specimens collected by large pair-trawl fishery from June 2021 to May 2022 in the coastal waters of Jeju Island, Korea. The range of total length was 19.8~57.4 cm. Using the IRI, Pisces were mainly prey component constituted 57.5%. Euphausiacea and Macrura were important prey component constituted 23.2% and 18.7%, respectively. There was a significant difference in the change in diet composition by size group. As the L. crocea grew, the feeding rate of Euphausiacea decreased and the feeding rate of Pisces increased. There were also significant differences in the changes in diet composition by seasonal group. The most important prey species for L. crocea in the winter and spring were Pisces, in the summer it was Macrura, and in the fall it was Euphausiacea. As a result of analyzing the feeding relationship between size groups and season groups, L. crocea showed significant differences in the interaction between size groups and season groups.

• Korean Journal of Ichthyology
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• v.19 no.1
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• pp.44-50
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• 2007

The feeding habits of sandfish, Arctoscopus japonicus were studied by examining the stomach contents of 2,115 specimens collected between April 2003 and March 2004 in the East Sea of Korea. The standard length (SL) of the specimens ranged from 9.8 to 22.9 cm. The main prey items of A. japonicus were amphipods, mysids, cephalopods and fishes. They showed ontogenetic changes in feeding habits. Individuals of small size (9~16 cm, SL) fed mainly on small prey organisms such as mysids and amphipods. However, more cephalopods and fishes were consumed with increasing fish size (16~23 cm, SL).

• Korean Journal of Ichthyology
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• v.35 no.4
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• pp.278-284
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• 2023

The feeding characteristics of chub mackerel, Scomber japonicus was studied using 827 specimens caught in the Yellow Sea of Korea during Autumn season from October to December 2021 and September to November 2022. The size of the specimens ranged from 21.1 to 45.1 cm in total length. S. japonicus was a carnivore that consumed mainly on fishes, such as Engraulis japonicus (%IRI=67.9). Its diet also includes small quantities of copepods, amphipods, euphausiids, cephalopods, mysids, shrimps, and crabs, etc. The estimated trophic level of S. japonicus was 3.84. The proportion of fish had increased as the body size of S. japonicus increased, whereas those of euphausiids, copepods and amphipods decreased gradually. As the body size of S. japonicus increased, the mean weight of prey per the stomach (mW/ST) tended to increase (One-way ANOVA, F=2.382, P<0.05).

• Korean Journal of Ichthyology
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• v.10 no.2
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• pp.176-183
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• 1998

Spawning ecology and feeding habits of Maurolicus muelleri in the Korean waters were studied. M. muelleri spawned continuously throughout the year showing a peak in August. Major spawning ground of this species was the southeastern sea of Korea. The fecundity observed from the ovaries of M. muelleri showed a range of 5,072 to 32,117, and the average number of eggs per one spawning time was approximately 250. M. muelleri was a zooplanktivore which fed mainly on copepods. Its diets also included various crustaceans such as amphipods, euphausiids, shrimps and mysids.

• Journal of the Korean Society of Marine Environment & Safety
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• v.29 no.5
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• pp.520-524
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• 2023

Regalecus russellii, which spends most of its life in the deep sea, occasionally appears in coastal waters. However, the reasons for its appearance remain unclear. In Korea, R. russellii mainly appears along the eastern coastal waters, and most of them are caught in fishing gear, such as gill nets, or are stranded on the shore; nevertheless, the frequency of appearance is extremely low. Even if found, this species is often identified to be morphologically similar to Trachipterus ishikawae, and comprehensive analysis to identify the species through sample collection is limited. Consequently, information on the biological characteristics of R. russellii appearing in the coastal waters of Korea is scarce. Herein, the anatomical characteristics of R. russellii caught in a gill net off the Gangwon-do coast on March 14, 2023, were analyzed, and coastal water temperature was measured using an ocean buoy. Our results showed that the individual was male, its total length was 320 cm, body weight was 27.52 kg, body length was 26.62 cm, gonad weight was 619.45 g, and liver weight was 218.71 g. The stomach was full of euphausiids. The water temperature changed drastically at 15-30 m roughly a week before the R. russellii individual was caught, and the subsurface water temperature was lower than 10 ℃. Our findings provide baseline data to understand the ecological characteristics of R. russellii appearing along the eastern coast of the Korea.

• 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).