• Korean Journal of Fisheries and Aquatic Sciences
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• v.55 no.5
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• pp.714-720
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• 2022

A dietary comparison of yellow goosefish Lophius litulon in the South Sea and Yellow Sea was performed by analyzing stomach contents. Using a bottom trawl net from fisheries resources survey vessels of the National Institute of Fisheries Science, 326 individuals were collected from the South Sea and 166 individuals were collected from the Yellow Sea. The total length range of L. litulon was 5.3-68.4 cm for individuals collected from the South Sea and 7.5-55.1 cm for individuals collected from the Yellow Sea. Based on the index of relative importance and the variation in stomach contents by fish size, L. litulon was found to be a piscevore and a spatiotemporally opportunistic feeder fish that fed mainly on pisces. There were differences in the composition of the stomach contents by season, location, and the interaction between the season and the location. Thus, the diet of L. litulon is affected by the prey abundance and prey spectrum of the habitat.

• Korean Journal of Ichthyology
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• v.33 no.1
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• pp.1-7
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• 2021

Using stereo, light, and scanning electron microscopes, we researched the anatomical and histological structure of Chaenogobius gulosus's olfactory organ and compared it to those of sympatric gobies Luciogobius guttatus and Favonigobius gymnauchen. Results revealed the following common characteristics: i) tubular anterior nostril (AN) and flat posterior nostril (PN), ii) a single longitudinal lamella, iii) two accessory nasal sacs (ANS, ethmoidal and lacrimal), iv) abundant sensory epithelium lymphatic cells (LC), v) an eosinophil cell, and vi) a ciliary length a quarter of the knob diameter in the olfactory receptor neuron (ORN). Some characteristics are specific to C. gulosus and different from the other two gobies: i) 0.5~1.0 mm AN and 0.2~0.5 mm PN (vs. 0.2~0.3 mm and 0.2~0.3 mm in L. guttatus; 0.2~0.4 mm and 0.1~0.3 mm in F. gymnauchen), ii) two ANS (vs. absence in L. guttatus; two in F. gymnauchen), iii) abundant LC (vs. low in L. guttatus and F. gymnauchen), iv) low density non-sensory cilia on the lamellar surface (vs. high in L. guttatus; low in F. gymnauchen), and v) a quarter ciliary length to knob diameter ratio in the ORN (vs. mixture of a quarter to equal ratio in L. guttatus; two or three times in F. gymnauchen). From these results, we confirmed the C. gulosus olfactory organ has adapted anatomically and histologically to the sand-rock tidal zone.

• Korean Journal of Ichthyology
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• v.34 no.1
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• pp.57-63
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• 2022

On April. 2016, the anadromous icy goby caught at Shinbong-cheon, Tongyeong shi, Gyeongsangnam-do transported to the laboratory of Korea Institute of Ocean Science and Technology (KIOST) and observed spawning behavior and egg development and larvae. In aquarium, males make the nest under stone and waiting female entering. Fertilized eggs attached under the stone in the nest. Male protected the fertilized eggs until hatching. The size of the club-shaped eggs were 3.2~3.4 mm in the major axis and 0.6~0.8 mm in minor axis (n=10). The eyed eggs were hatched after 168 hrs in a range of water temperatures (18.0~20.0℃). The total lengths of newly hatched larvae were 4.1~4.4 mm (n=5) and these larvae had 32~33 (12~13+20) myotomes and transparent oval yolk. Three days after hatching, the pre-larva (4.9 mm in total length) has opening mouth and rectum. Post-larva with 5.2 mm total length have melanophore on air bladder, rectum, base of membranous caudal fin and 9~10 melanophores ventral row on the tail.

• Korean Journal of Ichthyology
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• v.35 no.1
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• pp.10-19
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• 2023

This study aimed to examine the early life history of Trident goby (Tridentiger brevispinis) by observing their egg development and juvenile fish morphology. The average size of mature eggs was 1.13~1.41 (1.30±0.07) mm (n=30), and 0.70~0.86 (0.79±0.04) mm (n=30) in long diameter and short diameter, respectively. The incubation period at 24±1℃ ranged from 167~228 h. The newly hatched larvae measured 2.31~2.78 (2.51±0.18) mm (n=30) in total length (TL), and their mouth and anus were not yet open. At 3 days after hatching, the preflexion larvae reached 2.84~3.10 (2.98±0.10) mm in TL, where in their yolk absorption was complete and their mouths began to open. At 19 days after hatching, the larvae reached the flexion stage, measuring 4.02~4.62 (4.36±0.19) mm in TL. The tip of their notochord was bent upward. At 30 days post-hatching, the larvae reached the postflexion stage, measuring between 5.04~6.36 (5.76±0.51) mm in TL, with the tip of the caudal fin bent at 45°. After 54 days, the larvae had reached the juvenile stage, measuring between 7.43~9.84 (8.48±0.90) mm in TL, and were differentiated by their constant number of fins (6 first dorsal, 12 second dorsal, 11 anal, and 10 ventral fins). This study found that T. brevispinis had larger fertilized eggs and a greater number of myotomes in hatching larva than similar species. Additionally, the distribution of melanophores in T. brevispinis was distinct from that in other similar species, making it easy to distinguish them morphologically.

• 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.4
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• pp.347-353
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• 2023

Zenopsis nebulosa were collected by bottom trawl net from 20 areas in the South Sea of Korea during 2021 (February, May, August, November). The range of total length was 10.1~50.2 cm and empty stomach rate was 45.8%. The most important prey of Z. nebulosa was Pisces, with Trichiurus japonicus, Trachurus japonicus and Benthosema pterotum. And the second important prey was Euphausiacea. Z. nebulosa showed dietary shift by size class. In the <20.0 cm size class, Trachurus japonicus was dominant prey item. In the 20.0~25.0 cm size class, Trichiurus japonicus was dominant prey item. In the ≥25.0 cm size class, B. pterotum was dominant prey item. Analysis of the mean weight of preys per stomach (mW/ST) increased with individual size.

• Korean Journal of Ichthyology
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• v.26 no.1
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• pp.25-33
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• 2014

This study was conducted to observe the spawning behavior and early life histroy of elegant blenny, Omobranchus elegans reared in the laboratory. The elegant blenny were caught at Dolsan lsland, Yeosu-si, Jeollanamdo from June in 2012. As a result of observeation, male fish attracted female continuously and guide lead to spawning site and clean the surface of inner pant in oyster shell or barnacle shell. Female left after spawning and male protected their eggs until they had hatched out. The fertilized eggs were spherical in shape (mean diameter: 1.06 mm; mean oil globule diameter: 0.24 mm) and transparent. Larvae hatched at 203 hrs 40 mins after fertilization at $25.5{\sim}28.5^{\circ}C$ (mean $27.0^{\circ}C$). The newly hatched larvae were 3.04~3.09mm(mean 3.06 mm, n=10) in total length and their mouth and anus were already opened. They began to eat rotifer and transformed to postarvae stage. 10 days after hatching postlarvae was measured 6.39~6.45mm(mean 6.42 mm, n=10) in total length. 60 days after hatching juvenile was measured 21.5~22.2 mm (mean 21.8 mm, n=10) in total length with dosal fin rays XI-22; ventral fin rays I-2; anal fin rays II-23; caudal fin rays 21; pectoral fin rays 13.

• Korean Journal of Ichthyology
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• v.4 no.2
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• pp.1-25
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• 1992

Taxonomic study of the five species (Acanthogobius elongata, A. flavimanus, A. lactipes, A. luridus and Synechogobius) from Korea was carried out based on morphometric, cephalic sensory canal and ecological characters. Taxonomic revision and classificational keys are provided. Synechogobius hasta is easily distinguished from four species of the genus Acanthogobius in eleven characters, i. e., the number of dorsal and anal fin rays, the transverse scales, the vertebral numbers, the formula of interneural spine of the first dorsal fin, the number of interhemal spine anterior to the first hemal spine, the number of epipleural and pleurals, the ratio of caudal peduncle length, the ratio of caudal peduncle depth and the regular variations in the ratio of body parts with the body length. In the genus Acanthobobius, A. elongata is distinguished from other 3 congeneric species in the ratio of body parts and the oculoscapular sensory canal. Moreover, A. flavimanus differs from other 3 congeneric species in the lateral scales, the transverse scales, the number of predorsal scales, the vertebral number, the number of epipleural and pleurals. Sensory papillae rows of S. hasta is not similar that of the genus Acanthogobius in having a singular sensroy papillae rows. A. elongata has no oculoscapular sensory canal D and A. flavimanus has transverse sensory papillae in cheek, and these are one of the unique characters distinguished form other congeneric species. In the spawning period inferred from gonadosomatic index, A. elongata varied from late March to late June ; A. flavimanus, January to April ; A. lactipes, May to September ; A. luridus, early May to early July and S. hasta, early March to early May.

• Animal Systematics, Evolution and Diversity
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• v.9 no.2
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• pp.151-170
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• 1993

Morphometric, band-pattern and electrophoretic analysis on Cobitis taenia complex were performed to investigate the morphological and genetic differentiation and to clarify their taxonomic status. Intermediate types of band-pattern (C and D type) were more frequently expressed than that of types of C. t. taenia(type A) and C. t. lutheri (type B). Sexual dimorphism of band-pattern was observed not only in C. t. taenia(type A) and C. t. lutheri(type B). Sexual dimorphism of band-pattern was observed not only in C. t. lutheri but also in C. t. taenia and C. t. striata as well. Discriminant function analysis based on 19 morphological characters shows no significant differences among C. taenia complex. The degree of genic variation of C. t. striata was higher ( =1.48, P=31.2%, HD=0.009) than those of C. t. striata was higher( =1.48, P=31.2%, HD=0.082 and HG=0.009) than those of C. t. lutheri ( =1.37, P=2.7%, HD=0.058 and HG=0.065). The average genetic similarities between C. t. lutheri and C. t. taenia-C. t. striata were S=0.62 and S=0.66 respectively and these values indicate that C. t. tanenia has evolved specific level of differentiation. C. t. striata and C. t. lutheri show subspecifc level of close genetic similarity (S=0.82). Based on the divergent time estimate (Nei, 1975) it is assumed that C. t. tanenia was branched off from the other subspecies about two million years before present (MYBP) and C. t. striata and C. t. lutheri were differentiated about 0.6 MYBP. The use of C. sinesis an the scientific name for the Korean C. t. taenia, proposed by Kim and Lee (1988) seems incorrect since they are quite different in the structure of lamina circularis (Vladycov, 1935), the external morphology and distribution (Cheng and Zheng, 1987) and the chromosome number(Yu et al., 1989). Kim and Lee(1988) also argued that C.t. striata and C. t. lutheri should be treated as distinct species but the present study and other reports (Kim and Lee, 1984; Kim and Yang, 1993) do not support it. We conclude that C. t. taenia is a good species and C. t. striata and C. t. lutheri are subspecific status. Their scientific names should be revised in the future.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.32 no.2
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• pp.223-231
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• 1999

Carotenoid pigments of echiurid, Urechis unicinctus were investigated during March, April and May as a part of comparative biochemical studies of carotenoid pigments for the marine organisms other than pisces. Total carotenoid contents were found to be 1.19 mg/100 g in March, 0.98 mg/100 g in April and 0.84 mg/100 g in May, indicating that total carotenoid content was negatively affected by the temperature of sea water that echiurid resided. The carotenoid isolated in March composed of $16.3\%$ diatoxanthin monoester, $14.8\%$ $\beta$-carotene and $12.6\%$ cynthiaxanthin monoester, $8.4\%$ cynthiaxanthin diester, $8.2\%$ zeaxanthin monoester, $7.3\%$ diatoxanthin diester $4.2\%$ astaxanthin $2.9\%$ diatoxanthin, $2.4\%$ triol, $2.3\%$ cynthiaxanthin, $1.7\%$ isocrytoxanthin, $1.5\%$ zeaxanthin diester, $0.8\%$ zeaxanthin and $0.5\%$ lutein. The carotenoid isolated in April composed of $21.9\%$ diatoxanthin monoester, $17.2\%$ cynthiaxanthin monoester and $16.6\%$ $\beta$-carotene $10.9\%$ zeaxanthin monoester, $5.6\%$ cynthiaxanthin diester, $4.9\%$ diatoxanthin diester, $3.1\%$ astaxanthin, $2.4\%$ triol, $2.3\%$ diatoxanthin, $1.7\%$ isocrytoxanthin, $1.5\%$ lutein, $1.1\%$ zeaxanthin, $1.0\%$ cynthiaxanthin and $1.0\%$ zeaxanthin diester. Similarly, the carotenoid isolated in May composed of $25.3\%$ diatoxanthin monoester, $19.7\%$ cynthiaxanthin monoester, $13.0\%$ $\beta$-carotene, and $12.6\%$ zeaxanthin monoester, $5.8\%$ cynthiaxanthin diester, $5.1\%$ diatoxanthin, $3.0\%$ astaxanthin, $2.4\%$ triol, $2.2\%$ diatoxanthin, $1.3\%$ isocrytoxanthin, $1.2\%$ zeaxanthin, $1.1\%$ zeaxanthin diester, $1.0\%$ lutein and $0.9\%$ cynthiaxanthin. Based on these data, monoester-type carotenoids ($37.1\~57.6\%$) and diester-type carotenoids ($11.5\~17.2\%$) of total carotenoids in echiurid were the major carotenoids. Meanwhile, when the sea water temperature was elevated and the contents of total carotenoid in echiurids were decreased, the contents of zeaxanthin monoester, diatoxanthin monoester and cynthiaxanthin monoester were increased, but the contents of zeaxanthin diester, diatoxanthin diester and cynthiaxanthin diseter were decreased, indicating that changes in ester-type caroteoids were differently affected by the sea water temperature.