• Korean Journal of Fisheries and Aquatic Sciences
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• v.52 no.4
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• pp.424-429
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• 2019

Two juvenile (9.48 and 10.11 mm in standard length) specimens of the lanternfish Notoscopelus japonicus, belonging to the family Myctophidae, were collected from the waters around Busan and Jeju Island in February 2017. This species is characterized by having melanophores along the dorsal side of the body and one photophore (PO5) in front of the pelvic fin. It is distinguished from Benthosema pterotum in having many melanophores on the dorsal side and a single photophore (PO5) on the trunk. N. japonicus is also distinguished from its congeneric N. resplendens and N. caudispinosus in having no melanophores at the base of the anal fin. Analyzing 521 base pairs of the 16S rRNA sequence, the specimens were identical to N. japonicus adults from Japan (K2P distance <0.004). This is the first record of N. japonicus in Korea, and we propose a new Korean name "Deung-jum-saet-bi-neul-chi" for this species.

• Fisheries and Aquatic Sciences
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• v.23 no.7
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• pp.18.1-18.10
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• 2020

During June 2017, we collected two postflexion larvae (6.01 and 7.56 mm in standard length [SL]) and two juveniles (7.72 and 9.62 mm SL) belonging to Myctophidae in the waters of Jejudo Island. Those four individuals were identified as Diaphus garmani, which had not been reported in Korea. They were distinguished from Benthosema pterotum by melanophores in the abdominal cavity (absent in D. garmani vs. present in B. pterotum) and the development of photophores (developed in D. garmani vs. rudimentary in B. pterotum) when shorter than 10.0 mm SL. Analysis of 16S rRNA sequences showed that the sequences of four individuals matched those of adult D. garmani (Kimura 2-parameter distance: 0.6-0.8%). This is the first record of larvae and juveniles of D. garmani in Korean waters, and we propose a new Korean name, Gar-ma-ni-sat-bi-neul-chi.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.30 no.5
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• pp.719-729
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• 1997

Stomach contents of bigeye tuna, Thunnus obesus, and yellowfin tuna, Thunnus albacares, caught by longlining in the western tropical Pacific were analyzed to examine their foods and to compare their feeding behavior. The food species of both bigeye and yellowfin tunas were primarily fishes, crustaceans, and cephalopods. A total of 15 fish, 6 crustacean, and 1 cephalopod species were identified from their stomach contents, of which lantern fish (Myctophum sp.) was the most important food for both tuna species. No significant differences in species composition of food items between bigeye and yellowfin tunas were observed, indicating that in the same habitat the tunas have a similar feeding behavior. However, while they showed a remarkable similarity in diet composition, significant quantitative differences on the basis of IRI values were observed in several diet species, such as Myctophidae, Alepisauridae, Oplophoridae, Gammaridae, and Onychoteuthidae.

• 한국해양학회지
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• v.23 no.1
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• pp.41-52
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• 1988

Eleven of 52 species were relatively abundant in the mesopelagic and upper bathypelagic layers in the Rockall Trough and Porcupine Seabight. The fish belonging to the families Gonostomatidae, Myctophidae and Sternoptychidae were the most abundant. During the daytime most members of these three family groups occurred in the depth of 300-900m. Over this depth range gonostomatids and sternoptychids were almost mutually exclusive while gonostom$\grave{a}$tids and myctophids showed much greater overlap, as did myctophids and sternoptychids. During the night the distribution of these three families were relatively well separated, myctophids occurring in the surface 100m, sternoptychids at 200-500m and gonostomatids at 500-900m. Generally vertical pattern in the number of species in both areas was similar through day and night with the highest number occurring at 500-900m. The numerical abundance in the epipelagic layer was greater at night than during the daytime, while it was greater in daytime in the upper mesopelagic layer. There was no great diel change in the lower mesopelagic layer. Most of diel migrators in the upper layers of waters at night appear to be mainly from the upper mesopelagic layer. In some species larger individuals tend to occur in the deeper water than smaller ones, suggesting habital segregation with size.