• Title/Summary/Keyword: Trachurus japonicus

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Diet composition and trophic level of jack mackerel, Trachurus japonicus in the South Sea of Korea (한국 남해에 출현하는 전갱이(Trachurus japonicus)의 위내용물 조성과 영양단계)

  • KIM, Do-Gyun;SEONG, Gi Chang;JIN, Suyeon;SOH, Ho Young;BAECK, Gun Wook
    • Journal of the Korean Society of Fisheries and Ocean Technology
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    • v.57 no.2
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    • pp.117-126
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    • 2021
  • Diet composition and trophic level of Trachurus japonicus were studied using 417 specimens collected by trawls, set nets and purse seine fisheries from March 2019 to February 2020 in the South Sea of Korea. The size of T. Japonicus ranged from 7.0 to 49.8 cm in total length. T. japonicus were a carnivore that fed mainly on euphausiids and pisces. In eddition, T. japonicus fed on small quantities of cephalopods, crabs etc. T. japonicus showed ontogenetic changes in feeding habits. The proportion of euphausiids decreased inversely proportional to body size whereas the consumption of pisces gradually increased. As body size of T. japonicus increased the mean number of prey per stomach and the mean weight of prey per stomach tended to increase, but the mean number of prey per stomach was not significantly different. As a result of the feeding strategy analysis, T. japonicus were specialized feeders with pisces and euphausiids as their dominant prey. The trophic level ranged between 3.57 ± 0.54 and 3.91 ± 0.65, and increased asymptotically with size of specimens. The average trophic level of the T. japonicus was 3.79 ± 0.61.

Diet composition of juvenile Trachurus japonicus in the coastal waters of Geumodo Yeosu, Korea (여수 금오도 주변해역에 출현하는 전갱이 (Trachurus japonicus) 유어의 위내용물 조성)

  • KIM, Heeyong;LIM, Yu Na;JEONG, Jae Mook;KIM, Hyeon Ji;BAECK, Gun Wook
    • Journal of the Korean Society of Fisheries and Ocean Technology
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    • v.51 no.4
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    • pp.637-643
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    • 2015
  • The diet composition of juvenile Trachurus japonicus were studied using 195 specimens collected from 2013 (May, June, July, and September) to 2014 (May, June, and July) in the coastal waters of Geumodo, Yeosu, Korea. The size of juvenile T. japonicus ranged from 4.3 to 15.2 cm in body length (BL). Juvenile T. japonicus was carnivorous and crustaceans predators that consumes mainly consumed copepods. Its diet also included small quantities of decapods, cirripedians, nematods, chaetognathans, fishes, amphipods, cumaceans, ostracods and euphausiids. The graphical method for feeding strategy revealed that juvenile T. japonicus is an opportunistic and specialized predator on copepods, especially Corycaeus. affinis, and showed narrow niche width. Juvenile T. japonicus showed ontogenetic diet change. Small size group individuals (4.3-8.0 cm BL) mainly consumed copepods. The portion of this prey item decreased in the large size group (8.0-15.2 cm BL), and this decrease was paralleled with increased consumption of decapods.

Feeding Habits of the Jack Mackerel Trachurus japonicus in the Southern Sea of the Republic of Korea (한국 남해에서 출현한 전갱이(Trachurus japonicus)의 식성)

  • Lee, Ye Ji;Lee, Jeong Hoon;Lee, Young Hye
    • Korean Journal of Fisheries and Aquatic Sciences
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    • v.54 no.1
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    • pp.64-72
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    • 2021
  • The feeding habits of the Japanese jack mackerel Trachurus japonicus were studied in the Southern Sea of the Republic of Korea. To assess the effects of season, sampling was conducted in February (winter), May (spring), and August (summer), 2020. The total length of each fish was measured in 1 cm intervals. Diet composition showed the highest species diversity during winter. Diet composition changed from copepods to euphausiids as the total length of jack mackerel increased, except during winter. The most important seasonal prey were copepods in winter and summer and euphausiids in spring. Species diversity of the zooplankton community structure was highest in winter. Among the zooplankton communities, copepods were dominant in all seasons. Species with a high electivity index in all seasons were relatively large zooplankton of ≥2 mm. Jack mackerel had ontogenetic diet change, exhibited diet selectivity depending on size, and its feeding habits were affected by the zooplankton community structure.

Development of the Duplex PCR Method of Identifying Trachurus japonicus and Trachurus novaezelandiae (다중 PCR 분석법을 이용한 전갱이속 어종의 신속한 종판별 분석법 개발)

  • Park, Yeon Jung;Lee, Mi Nan;Kim, Eun Mi;Noh, Eun Soo;Noh, Jae Koo;Park, Jung Youn;Kang, Jung-Ha
    • Journal of Life Science
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    • v.28 no.9
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    • pp.1062-1067
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    • 2018
  • Reliable labeling of fish products can reassure consumers regarding the identity and quality of seafoods. Therefore, techniques that can identify adulteration or mislabeling are valuable. To rapidly identify two Trachurus species, Trachurus japonicus and Trachurus novaezelandiae, a highly efficient, rapid, duplex polymerase chain reaction (PCR) having two species-specific primers simultaneously was identified. This species-specific primer focused on a single nucleotide mismatch in the 3'-terminal base of a primer designed in the mitochondrial cytochrome c oxidase (COI) subunit I DNA. To optimize the duplex PCR condition, gradient PCR reactions were conducted to determine the primer annealing temperature and the primer concentration. The PCR's product was observed on the gel, suggesting that DNA molecules may be useful in differentiating the two species. The length of the amplification fragments were 103 bp for Trachurus japonicus and 214 bp for Trachurus novaezelandiae, which, along with the species-specific primer visualized by agarose gel electrophoresis, enabled accurate distinction of the species of the Trachurus genus. These results indicate that the duplex PCR, which has a species-specific primer based on single nucleotide polymorphism (SNP), can be useful for rapidly differentiating the two species of Trachurus. This duplex PCR analysis is simple, rapid, and reliable, and could be beneficial to protecting consumers' rights.

Age and Growth of Jack Mackerel Trachurus japonicus off Jeju Island, Korea (제주 인근해역에 서식하는 전갱이(Trachurus japonicus Temminck et Schlegel)의 연령과 성장)

  • Lee, Dong Jin;Kang, Sukyung;Jung, Kyung-Mi;Cha, Hyung Kee
    • Korean Journal of Fisheries and Aquatic Sciences
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    • v.49 no.5
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    • pp.648-656
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    • 2016
  • The age and growth of jack mackerel Trachurus japonicus caught by large purse seine fishery were studied during August 2004 and May 2005. Otoliths of 472 fish were observed under reflected light, and translucent zones made on the post-rostrum axis were regarded as annual marks. Monthly changes in the marginal index indicated that the translucent zone was formed once a year, mainly in March-April, which was coincident with the peak spawning time of jack mackerel. The estimated ages were 0-6 years, corresponding to a fork length (FL) range of 13 to 38 cm. Most obtained individuals were 2-year-old fish, followed by 1-year-old fish. The mean fork length at age from otolith reading (sex combined) was applied to the von Bertalanffy equation and growth parameters were estimated: L = 38.29 cm FL, k = 0.31 years−1, t0 = −0.81 years.

Species composition and variation of catches by a set net in the coastal waters of Sinsan, Jeju Island (제주도 신산 연안 정치망 어획물의 종조성 및 어획량 변동)

  • LEE, Seung-Jong;HAN, Song-Heon;KIM, Maeng-Jin
    • Journal of the Korean Society of Fisheries and Ocean Technology
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    • v.57 no.1
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    • pp.25-33
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    • 2021
  • Species composition and variation of catches in the coastal waters of Sinsan of Jeju Island were determined using samples collected by a set net from May 2014 to October 2015. During the survey period, a total of 55 species (51 species, 35 families and 11 orders in fishes, 4 species, 2 families and 2 orders in cephalopods) were occurred, and Perciformes (28 species) were dominant fishes in this area. In the number of individuals and biomass, the small pelagic fishes such as Trachurus japonicus and Scomber japonicus were occurred abundantly, and both species accounted for 95.9% of the total catch by a fishing logbook of a set net. In the results of length-frequency distribution of small pelagic fishes caught by a set net in Sinsan, T. japonicus showed a range from 3.5-19.1 cm (average 8.8 cm) and S. japonicus showed a range from 7.0-25.6 cm (average 16.8 cm). In addition, these were mostly immature fishes.

Species Composition and Distribution of Set-net Catches on the Coast of Dapo, Geoje Island (거제도 다포 연안 정치망 어획물의 종조성 및 주요 어종의 분포 특성)

  • Jung, Kyung-Mi;Lee, Dong Jin;Kang, Sukyung;Choi, Kwang Ho
    • Korean Journal of Fisheries and Aquatic Sciences
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    • v.47 no.6
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    • pp.997-1005
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    • 2014
  • We analyzed annual and seasonal variations in fish species composition and distribution patterns using both daily catch and quantitative analysis data collected from a set-net fishery over a period of two years (2011-2012) on the coast of Dapo, Geoje Island. Set-net fishing season in this area is from May to November, and the annual yield based on the daily catch data was 171,412 kg in 2011, and 102,611 kg in 2012. In total, there were 46 species (belonging to 36 families and 12 orders) in 2011, and 41 species (belonging to 25 families and 9 orders) in 2012. The dominant species in terms of numbers were Trachurus japonicus, Engraulis japonicus, Clupea pallasii, Scomber japonicus, and Sphyraena pinguis. The range in fork length for T. japonicus and E. japonicus was from 3.2 to 23.9 cm, and from 2.6 to 13.3 cm, respectively. The fork length of recruiting juveniles to the Dapo set-net fishing ground ranged from 4.6 to 7.8 cm (median) for T. japonicus, and from 4.1 to 5.0 cm (median) for E. japonicus. The fact that most of the fish caught from the two species were at immature growth stages implies that the coast of Dapo can act as a nursery area for these migratory species.

Temporal Variation in Species Composition and Abundance of Fish Assemblages in Masan Bay (마산만 해역에서 서식하는 어류군집의 종조성 및 출현량 변동)

  • Kwak, Seok Nam;Huh, Sung-Hoi
    • Korean Journal of Ichthyology
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    • v.19 no.2
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    • pp.132-141
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    • 2007
  • A total of 27 fish species were collected by a gill net in Masan Bay. The dominant fish species were Konosirus punctatus, Mugil cephalus, Engraulis japonicus, Psenopsis anomala, Lateolabrax japonicus, Leiognathus nuchalis, Chelon affinis, Trachurus japonicus, and these accounted for 87.6% of the total numbers. The numerically dominant fish species made up 95.4% of biomass. These were primarily juvenile species or early larger species. Temporal variation in both species composition and abundance was large: the peak number of fishes occurred in March 2005 and July 2005, whilst biomass of fishes was the highest in September 2005 and November 2005. Fish numbers as well as biomass was lowest in November 2005. Temporal changes in the abundance of fishes corresponded with temperature. A gill net can be used as an alternative fishing gear to collect pelagic fishes commercially, although a gill net has a strong selectivity for the target fish species or for size.

Catch variation of a set net fishing ground in the coastal waters off Neungpo, Goeje Island (거제도 능포 정치망 어장의 어획물과 어획량 변동요인)

  • Cha, Byung-Yul
    • Journal of the Korean Society of Fisheries and Ocean Technology
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    • v.45 no.4
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    • pp.211-222
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    • 2009
  • The fisheries resources by a set net in the coastal waters off Neungpo, Goeje Island from 2003 to 2004 were studied to determine species composition and catch variation. The main fishing period by a set net were from April to December in 2003 and from May to December in 2004. A total weight of 48 species caught through the survey period was 540,688.0kg. Most of them were 44 species of fishes and a few were 4 species of cephalopods. Dominant species was Trachurus japonicus accounting to 57.5% in total catch. Sub-dominant species were Trichiurus lepturus(12.9%), Engraulis japonicus(10.6%), Scomber japonicus(6.9%), Clupea pallasii(4.5%), Todarodes pacificus(2.8%) and Parapristipoma trilineaturm(1.3%). The remnant species showed a low catch, indicating the catch had less than 1% in total, respectively. T. japonicus and T. lepturus were caught throughout the survey period, but C. pallasii, Gadus macrocephalus, Oncorhynchus keta in low temperature season and Thunnus obesus in high temperature season. The fishing ground temperature was 11.7-24.0${^{\circ}C}$ in range and the catch by a set net was higher in autumn than in spring and in summer with the variation of fishing ground temperature. The annual catch by a set net was much higher in 2004 than in 2003 due to high temperature(>17${^{\circ}C}$) and the recruitment of T. japonicus from offshore seas. Therefore we concluded that the catch of Neungpo fishing ground by a set net was highly related to the variation of T. japonicus catch with fishing ground temperature.