• Title/Summary/Keyword: Muraenesox cinereus

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Profile of Plasma Estradiol-17β According to Ovarian Development of the Pike Eel, Muraenesox cinereus (갯장어 Muraenesox cinereus의 난소 발달에 따른 혈중 Estradiol-17β 변동)

  • Kim, Dae-Jung;Kim, Yi-Cheong;Son, Maeng-Hyun;Lee, Jung-Uie;Son, Sang-Gyu;Han, Chang-Hee
    • Journal of Life Science
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    • v.19 no.12
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    • pp.1851-1854
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    • 2009
  • This study correlated changes in the plasma levels of estradiol-$17{\beta}$ (E2) with changes in the gonadosomatic index (GSI) and ovarian development during the annual reproductive cycle of the pike eel Muraenesox cinereus, collected at the Tongyung coast region. Ovarian maturity was classified based on histological observations; the perinucleolus stage (November to February), the oil droplet stage (March to April), the early vitellogenic stage (April to May) and the late vitellogenic stage (June to October). Seasonal changes in the GSI were correlated with water temperature and reflected the degree of ovarian maturity. Plasma E2 levels were correlated with changes in the GSI, which increased from April to a peak in July, and the levels remained comparatively high until October. These data indicated that changes in the GSI and plasma E2 levels are correlated with the annual ovarian activity of the pike eel. In this study, however, female pike eels were not collected during the spawning stage. Therefore, spawning of this species seemed to be closely related to its migration toward the deep sea of offshore.

Reproductive ecology of the sharp toothed eel in the southern Korean waters (한국 남해에 서식하는 갯장어, Muraenesox cinereus (Forsskal)의 생식생태)

  • Cha, Hyung Kee;Seo, Young Il;Oh, Taeg Yun;Kim, Heeyong;Lee, Sun Gil;Choi, Mun Sung
    • Journal of the Korean Society of Fisheries and Ocean Technology
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    • v.48 no.3
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    • pp.217-226
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    • 2012
  • Reproductive ecology of the sharp toothed eel, Muraenesox cinereus was investigated based on the samples captured in southern Korean waters from January 2010 to December 2011. Gonadosomatic index began to increase in April, and reached maximum between July to August. After spawning it began to decrease from October. Reproductive season was estimated to April-September, with peak in July. Fecundity was proportional to the size of the female, with the clutch size varying from 56,000 eggs in the smallest female (anal length, 27.0cm) to 1,400,000 eggs in the largest (anal length, 49.5cm). Size at 50% sexual maturity ($AL_{50}$), determined from mature females, were 21.9cm. Annual reproductive cycles of this species could be divided into four successive stages; immature stage (October-February), maturing stage (March-May), mature stage (June-August) and spent stage (August-October).

Comparison of Food Component between Conger eel (Conger myriaster) and Sea eel (Muraenesox cinereus) as a Sliced Raw Fish Meat (생선회로서 붕장어 (Conger myriaster) 및 갯장어 (Muraenesox cinereus)의 식품성분 비교)

  • KIM Jin-Soo;OH Kwang-Soo;LEE Jung-Suck
    • Korean Journal of Fisheries and Aquatic Sciences
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    • v.34 no.6
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    • pp.678-684
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    • 2001
  • In Korea, the conger eel, Conger myriaster and sea eel, Muraenesox cinereus have been eaten as a sliced raw ash meat for a long time. This study was carried out to compare the food component and sensory differences of the conger eel and sea eel as a sliced raw fish meat. The yield and ash content of conger eel were slightly higher than those of sea eel, and no significant differences in moisture, crude protein and crude lipid. The major fatty acids of conger eel were 16:0 ($19.9\%$), 18 : 1n-9 ($36.1\%$) and 22: 6n-3 ($8.3\%$), while those of sea eel were 16:0 ($24.0\%$), 16: 1n-7 ($12.1\%$) and 18:1n-9 ($21.9\%$), The contents of (n-3)-fatty acids were low in all of the two samples. The contents of total amino acid in the conger eel and sea eel were 19,147.2 mg/100 g and 18,527.1 mg/100 g, respectively. The major amino acids of two samples were aspartic acid, glutamic acid and lysine. The chemical score in protein of conger eel was higher about $6\%$ than that of sea eel, and the Ca and P contents of conger eel were also higher than those of sea eel. Although the nutritional value of conger eel as a sliced raw fish meat was generally higher than that of sea eel, the sensory scores in taste and texture of conger eel were lower than those of sea eel.

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Morphogenetic Identification of Eel's Larva (Leptocephalus) Collected by Set net in Namhae, Korea (남해 정치망에서 채집한 엽상자어(Leptocephalus)의 형태 및 유전학적 특성)

  • Chang-Gi Hong;Kyeong-Ho Han
    • Journal of Marine Life Science
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    • v.8 no.2
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    • pp.128-135
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    • 2023
  • The present study was tried to identify whether the eel's larva was close to a conger (Conger myriaster), a pipe conger (Muraenesox cinereus) or four species of Anguilla. Experimental fishes were collected by set net in the gulf of enggang, Namhae, Korea from May to June. Their morphological characteristics were compared with adult fishes of a conger, a pipe conger and four species of Anguilla. For genetic classification, DNA was isolated and amplified by using 12S rRNA and 16S rRNA primer set. The PCR products were direct sequencing in both directions. The nucleotide sequences were analyzed using softwares. As results of morphological measurement on eel's larva, the percentages of head length and preanal length against total length were similar with a conger. Based on the nucleotide sequences, the phylogenetic tree also revealed a close relationship to a conger. Therefore, eel's larva, caught in Namhae from May to June, was identified into a conger's larva.

Changes of Fishing Ground of the Large Pair Trawl Fishery off Korean Waters (한국 근해 쌍끌이대형저인망어업의 어장 변화)

  • Lee, Dong-Woo;Choi, Kwang-Ho;Kang, Sukyung
    • Korean Journal of Fisheries and Aquatic Sciences
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    • v.46 no.6
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    • pp.917-922
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    • 2013
  • Changes in fishing ground of the large pair trawler were investigated by year, month and species off Korean waters. We used catch data by sea-block lat.${\times}$long.:$30^{\prime}{\times}30$) of the National Fisheries Research and Development Institute (NFRDI) and monthly fishing production statistics of Korean statistic information service from 1990 to 2007. In the 1990s, the demersal fish like Larimichthys polyactis, Collichthys sp, Portunus trituberculatus and Muraenesox cinereus were the dominant species, and in the 2000s, they were changed from demersal fish into pelagic fish like Scomberomorus niphonius, Scomber japonicus, Engraulis japonicus and Todarodes pacificus. Species composition of catch showed temporal variation by cluster analysis deviding into 4 period, 1990-1994, 1995-2000, 2001-2003 and 2004-2007. Fishing ground in the 2000s was decreased up to 2/3 in the 1990s, while the density of catch in the fishing ground in 2000s was higher than the 1990s.

Hearing Ability of Sharp Toothed Eel Muraenesox cinereus caught in the Southern Korean Waters (남해 연안에서 어획된 갯장어의 청각 능력)

  • Ahn, Jang-Young;Lee, Chang-Heon
    • Journal of Fisheries and Marine Sciences Education
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    • v.25 no.2
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    • pp.341-348
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    • 2013
  • The auditory thresholds for 7 specimens of the sharp toothed eel Muraensox cinerus were measured at 5 frequencies by heartbeat conditioning method using pure tones coupled with a delayed electric shock. The audible range of the sharp toothed eel extended from 80Hz to 300Hz with the best sensitivity around 80Hz and 100Hz. In addition, the auditory thresholds over 200Hz increased rapidly. The mean auditory thresholds of the sharp toothed eel at the test frequencies of 80Hz, 100Hz, 200Hz and 300Hz were 87dB, 86dB, 105dB and 126dB, respectively. Auditory masking was determined for the sharp toothed eel by using masking stimuli with the spectrum level range of about 70~80dB (0dB re $1{\mu}Pa/\sqrt{Hz}$). According to white noise level, the auditory thresholds increased as compared with thresholds in a quiet background noise. The noise spectrum level at the start of masking was distributed at the range of about 64dB within 80~100Hz. Critical ratio ranged from minimum 24dB to maximum 40dB at test frequencies of 80Hz~200Hz.

DNA Analysis of mtDNA COI Gene in the Sharp-toothed Eel (Muraenesox cinereus Forskal) from Yeosu, Jinhae, Jeju, Goseoung, Jangheung and Haenam Populations in Korea Using PCR-aided RFLP

  • Oh, Taeg-Yun;Jeong, Sun-Beom;Cho, Eun-Seob
    • Journal of Environmental Science International
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    • v.20 no.4
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    • pp.551-554
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    • 2011
  • The production of the sharp-toothed eel by commercial catch off waters of Korea is annually declined after 1978. This study was carried out to obtain the stock management of the sharp-toothed eel using the PCR-aided RFLP method. The mtDNA COI gene was amplified using species-specific primers and PCR product was observed to 700 bp. Amplified DNA fragments were treated with six kinds of restriction enzymes (BaeHI, EcoRI, PstI, Ksp22, HinfI and HaeIII). The treatment of HaeIII showed a distinct PCR product between Yeosu/Jinhae/Jeju/Goseoung and Jangheung/Haenam populations that were observed from 300 to 400 bp in reference to 100 bp molecular marker. However, DNA fragment within populations had an identical pattern. The phylogenetic homology is 82% between two populations inferred from RFLP PCR product pattern using NTsysPC ver. 2.1. The use of HaeIII plays an important role in discriminating populations. It is thought that adults after over-wintering in the southern part of Jeju migrate to the Yeosu, Jinhae and Goseoung regions to spawn instead of to southwestern waters. Individuals within populations showed a relatively active genetic mixing and migration regardless of geography. However, the genetic ancestor of Jangheung and Haenam populations is appeared to be more adjacent to China or Japan than Jeju.

Seasonal Variation of Lipids and Fatty Acids of Sharp Toothed Eel(Muraenesox cinereus) (갯장어의 일반성분과 지방산의 계절적 변화)

  • 안창범;신태선
    • Journal of Life Science
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    • v.12 no.3
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    • pp.233-241
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    • 2002
  • Seasonal variation of uraenesox cinereus) muscle was investigated. Crude lipid content varied from 3.85 to 12.59 g/100g, comprising the highest content in November. The major fatty acids of total lipid, neutral lipid, and phospholipid were C16:0, C23:0, C16:1, C18:1, C20:5, and C22:6, but in phospholipid, Cl8:3n-6 was also the major fatty acid. The C22:6 content of the neutral lipid was much lower compared to that of the total lipid and phospholipid. The content of polyunsaturated fatty acids (ranged from 73.93 to 66.23%) in phospholipid was higher than that of any other lipid fraction. In glycolipid, C20:1 and C14:1 were higher compared to those of any other lipid fraction, but C20:5 and C22:6 were lower. The annual average ratio of n-3 to n-6 of total lipid, neutral lipid, phospholipid, and glycolipid was 10.82, 12.27, 6.63, and 6.50, respectively. The particular trend of seasonal variation of fatty acid composition was not showed in total and neutral lipid. However, the samples caught in September and November had a high crude lipid content with a significantly lower content of polyunsaturated fatty acids in phospholipid. Also, the content of monounsaturated fatty acids in glycolipid was lower in samples of September, November, and January.

Seasonal Variation in Abundance and Species Composition of Fishes Collected by a Beam Trawl around Naro-do, Korea (남해 나로도 주변해역에서 조망에 채집된 어류의 종조성과 계절변동)

  • KIM Jong-Bin;CHANG Dae-Soo;KIM Yeong-Hye;KANG Chang-Keun;CHO Kyu-Dae
    • Korean Journal of Fisheries and Aquatic Sciences
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    • v.36 no.4
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    • pp.378-388
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    • 2003
  • Seasonal variations in abundance and species composition of fish assemblage around Narodo were examined. Fish samples were monthly collected by a beam trawl from December 2000 to November 2001. A total of 62 fish species representing 37 families were collected. Of these, Thryssa kammalensis, T. hamiltoni, Chaeturichthys hexanema, Johnius grypotus, Leiognathus nuchalis, Cynoglossus robustus and Setipinna taty were dominant species comprising $82\%$ of the total number of individuals. Species diversity indices ranged from 1.2 to 2.2 showing the highest values from September to November 2001. The fish assemblage was divided into three different groups by cluster analysis of the fourteen dominant species. The main residence species were J. grypotus, L. nuchalis, C. hexanema, C. robustus, Setipinna tenuifilis, T. kammalensis and Ctenotrypauchen microcephalus. Of the temporal species T. hamiltoni, Liparis tanakai and Erisphex pottii were collected In spring, and Muraenesox cinereus and Trichiurus lepturus were in summer and autumn. Principal component analysis revealed that seasonal variation in the fish assemblage was attributed to the abundance of temporal species due to seasonal variation of environmental factors such as water temperature and ecological pattern (polagic/demersal) of fish species.

Seasonal Bycatch Variations in the Shrimp Beam Trawl Fishery of Coastal Wan-do, Korea (완도 해역의 새우조망어업에서 발생한 부수어획물의 계절적 변동)

  • Oh, Chul-Woong
    • Korean Journal of Fisheries and Aquatic Sciences
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    • v.43 no.1
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    • pp.69-77
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    • 2010
  • We examined shrimp and bycatch species composition in the shrimp beam trawl fishery off Wan-do, Korea(in the major or fishing ground)from December 2004 to November 2005. We observed a total of 103, 072 individuals in 96 taxa. By densities of individuals, 96.97% were shrimps, 1.20% decapods, 1.10% fish, 0.30% cephalopods and 0.43% other species. By catch weight, 57.29% were shrimps, 26.33% fish, 6.82% decapods, 4.64% cephalopods and 4.92% other species. In spring, the dominant bycatch species by biomass were Okamejei kenojei, Lophiomus setigerus, and Charybdis bimaculata. In summer, the dominant species were Charybdis bimaculata, Muraenesox cinereus, and Paralichlhys olivaceus. In autumn, dominants were Okamejei kenojei, Conger myriasler, and Sefipinna tenuifilis, and in winter they were Okamjei kenojei, Chaeturichthys stigmatias, and Sillago japonica. Bycatch species composition and individual species abundances differed significantly among seasons, probably indicating that variations were related to the life history characteristics of bycatch species. The diversity index was highest in October (2.797) and lowest in July (1.012). The July dominance index (0.569) was much higher than in other months; evenness was highest in September (0.856) and lowest in July (0.374). During the study period, the bycatch-to-shrimp ratio of this fishery varied from 0.063 in February 2005 to 11.031 in May 2005, with a mean of 3.363 These temporal variations may be linked 10 variations in reproductive behaviors and migration patterns of the marine animals sampled.