• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.48 no.4
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• pp.479-486
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• 2012

In order to obtain the fundamental data about the behavior of conger by underwater audible sound, this experiment was carried out to investigate the hearing ability of Conger eel Conger myriaster which was in the coast of Jeju Island by heartbeat conditioning method using pure tones coupled with a delayed electric shock. The audible range of conger eel extended from 50Hz to 300Hz with a peak sensitivity at 80Hz including less sensitivity over 200Hz. The mean auditory thresholds of conger eel at the frequencies of 50Hz, 80Hz, 100Hz, 200Hz and 300Hz were 105dB, 92dB, 96dB, 128dB and 140dB, respectively. The positive response of conger eel was not evident after the sound projection of over 200Hz. At the results, the sensitive frequency range of conger eel is narrow in spite of swim bladder. Auditory masking was determined for Conger eel by using masking stimuli with the spectrum level range of about 60~70dB (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 including critical ratio at 68dB of white noise from minimum 26dB to maximum 30dB at test frequencies of 80Hz and 100Hz. The noise spectrum level at the start of masking was distributed at the range of about 68dB within 80~100Hz.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.48 no.4
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• pp.417-425
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• 2015

Semi-dried conger eel Conger myriaster is considered as a health food in Korea due to its richness in vitamins, minerals, proteins and omega-3 fatty acids. This study characterize the sanitary quality of commercial semi-dried conger eel for developing high quality semi-dried products and suggested the guideline for controlling the quality. Moisture content ranged from 41.2% to 73.4% (mean: 61.5%), volatile basic nitrogen ranged from 16.1 to 93.6 mg/100 g (mean: 55.1 mg/100 g), and peroxide value ranged from 15.2 to 69.8 meq/kg. Viable cell counts ranged between 6.51 and 8.53 log CFU/g, while the Escherichia coli count ranged from undetectable to 4.6 log CFU/g. Based on these chemical and microbial findings, we suggest that provisions be established for development of high quality semi-dried conger eel as follows: 50-68% for moisture content, < 50 mg/100 g for volatile basic nitrogen content, < 60 meq/kg for peroxide value, and negative for E. coli. Among the 16 commercial semi-dried conger eel products used in this study, the standard-passed product was only GS-L.

• 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.

• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.56 no.1
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• pp.37-44
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• 2020

The change of fishing power index was analyzed to identify the development of the vessel and gear technology that may improve the fishing efficiency of the offshore conger eel pot fishery from 1980s to 2015. Gross tonnage per fishing vessel was rapidly increased annually. The standard of pot was maintained, but the number of pot used rapidly increased by using conger eel pot hauling devices, carrying and loading devices, main line hauler, casting devices and slide type pot. Fish finder system to identify fishing ground information and the conger eel pot hauling devices were modernized, and supply rate was also increased. Therefore, the relative fishing power index in the offshore conger eel pot fishery increased from 1.0 in 1980 to 1.3 in 1990, to 1.8 in 2000 and to 2.0 in 2015. The results are expected to contribute to reasonable fisheries stock management of the offshore conger eel pot fishery.

• Food Science and Preservation
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• v.30 no.6
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• pp.929-943
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• 2023

This study analyzed the variation in vitamin K content in conger eel (Conger myriaster) caught off Tongyeong, Gyeongsangnam-do, Korea, focusing on the influence of size (large and small) and harvest period (monthly throughout 2021). We applied enzymatic extraction and HPLC-fluorescence methods for the analysis of vitamin K₁ (phylloquinone) and K₂ (menaquinone). The vitamin K content in conger eel varied significantly with size and harvest season (p<0.05). In large-sized samples, the phylloquinone content peaked in July (0.80±0.09 ㎍/100 g), while the highest menaquinone content was in May (0.79±0.11 ㎍/100 g). Conversely, in small-sized conger eels, the highest phylloquinone was found in December (1.94±0.15 ㎍/100 g), and the peak menaquinone level was in January (0.66±0.02 ㎍/100 g). The fat content was highest in July for large samples and in January for smaller ones. There was a positive correlation between fat and total vitamin K contents in conger eel (r=0.631, 0.667). Method validation and quality control measures ensured data reliability for vitamin K₁ and K₂ analyses. This study provides reliable information on the size and seasonal variations of vitamin K in conger eels, a staple in the Korean diet. This information is valuable for inclusion in Korea's national food nutrition database and for formulating future national health and nutrition policies.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.53 no.3
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• pp.382-387
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• 2020

This study compared the nutritional characteristics of seasoned laver Pyropia yezoensis with conger eel Conger myriaster seasoning sauce (SL-CES) with those of commercial seasoned laver (C-SL). SL-CES had higher protein and lower ash contents than those of C-SL. However, the moisture and lipid contents did not differ between them (P>0.05). The total amino acid content of SL-CES was 21.79 g/100 g, similar to that of C-SL (21.49 g/100 g). The major amino acids in SL-CES were aspartic acid, glutamic acid, and alanine. The SL-CES contained 125.7 mg calcium, 461.6 mg phosphorus, 2183.7 mg potassium, 9.5 mg iron, and 2.6 mg zinc per 100 g SL-CES. These amounts were all higher than those in C-SL, except for Zn. The major fatty acids in SL-CES were 16:0, 18:1n-9, and 18:2n-6.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.18 no.5
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• pp.439-446
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• 1985

This study was designed to compare the lipid components among wild and cultured eel, Anguilla japonica, and conger eel, Astroconger myriaster. The lipid components of cultured eel were analyzed and compared with those of wild and conger eel. In the content of total lipid, the lipid content in cultured eel was slightly higher than that in wild one, but 2 times higher than that in conger eel. The lipid contents in edible portion of wild and cultured eel were 5 times higher than those in viscera, but the lipid content in edible portion of conger eel showed a similar trend to that in viscera. In the fatty acid composition of neutral lipid in edible portion, percentages of $C_{14:0},\;C_{16:0}\;and\;C_{18:1}$ in cultured eel were higher than those in wild one, while percentages of $C_{16:1},\;C_{18:2},\;C_{18:3},\;C_{20:4},\;C_{20:5},\;C_{22:5}\;and\;C_{22:6}$ lower, and percentages of $C_{18:0},\;C_{20:4}\;and\;C_{22:6}$ in conger eel were noticeably higher than those in wild and cultured eels. In the case of phospholipid in edible portion, percentages of $C_{18:0}\;and\;C_{18:2}$ in cultured eel were higher than those in wild one, while percentages of $C_{16:0},\;C_{16:1},\;C_{18:1},\;C_{18:3},\;C_{20:4},\;C_{20:5},\;C_{22:5}\;and\;C_{22:6}$ lower. The unsaturation (TUFA/TSFA) of neutral lipid was no significant difference among wild and cultured eel, and conger eel, but that of phospholipid in wild eel was higher than that in cultured eel and conger eel. The essential fatty acid content(TEFA) of neutral lipid in edible portion of wild eel was 3 times higher than that of cultured one. but the TEFA of phospholipid in edible portion was no significant difference among wild and cultured eels, and conger eel. The w3 highly unsaturated fatty acid content (w3 HUFA) of neutral lipid in edible portion of wild eel was 2.0 to 2.5 times higher than that of cultured eel and conger eel, but the w3 HUFA of phospholipid in edible portion of wild eel was noticeably higher than that of cultured eel and conger eel. In the ratio (A/B) of fatty acid content (A) in cultured eel to that (B) in diet, the A/B ratios of $C_{18:2}\;w6,\;C_{18:3}\;w3,\;C_{20:5}\;w3\;and\;C_{22:6}\;w3$ were 0.23 to 0.48 much lower than the other fatty acid. Consequently, it is considered that the ratios of w3 HUFA is related to the biosynthesis of polyenoic acid and growth rate of cultured eel.

• Development and Reproduction
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• v.19 no.3
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• pp.163-166
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• 2015

Genomic DNAs were extracted from the muscle of twenty-one specimens of three eel species collected in Anguilla japonica (AJ), Muraenesox cinereus (MC) and Conger myriaster (CM) from the Yellow Sea, respectively. In the present study, 7 oligonucleotides primers generated 191 specific loci in the AJ species, 226 in the (MC) species and 181 in the CM species, respectively. The primer BION-02 generated the most loci (a total of 83), with an average of 11.86 in the AJ species. The specific loci generated by oligonucleotides primers exhibited inter-individual-specific characteristics, thus revealing DNA polymorphisms. With regard to average bandsharing value (BS) results, individuals from Conger myriaster species (0.808) exhibited higher bandsharing values than did individuals from Muraenesox cinereus species (0.729) (P<0.05). The longest genetic distance (0.430) displaying significant molecular difference was also between individual no. 01 within Anguilla japonica eel species and individual no. 04 within Anguilla japonica species. In this study, the dendrogram resulted from reliable seven oligonucleotides primers, indicating three genetic clusters composed of group I (ANGUILLA 01~ANGUILLA 07), group II (MURAENESOX 08~MURAENESOX 14) and group III (CONGER 15~CONGER 21). The existence of species differentiation and DNA polymorphisms among three eel species were detected by PCR analysis. As mentioned above, a dendrogram revealed close relationships between individual identities within three eel species. High levels of a significant genetic distance among three eel species showed this PCR approach is one of the most suitable tools for individuals and/or species biological DNA studies.

• Korean Journal of Food Science and Technology
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• v.19 no.1
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• pp.1-4
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• 1987

A seasonal variations of chemical components and gel forming ability in wild common carp (Cyprinus car-pio) and conger eel (Astroconger myriaster) caught around Pusan, Korea monthly for one year (from May,1984 to April, 1985) were investigated. During a year variation range in the moisture and crude lipid contents were found in conger eel meat showing 61.0-76.6% and 5.4-20.8%, while crude protein, ash and carbohydrate were no appreciable differences . Ail of the moisture of chemical components were nearly constant in wild common carp for 12 months. The contents of moisture were less, while crude lipid were more in conger eel meat from September to February than those of the other months. Qualities of the fish jelly were the best for that months in conger eel. Fish jellies were good for 12 months in wild common carp. Gel forming ability was related to the content of chemical components and fishing season in conger eel.

• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.42 no.1
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• pp.1-10
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• 2006

Present study was conducted to improve the spring frame net trap for conger eel, Conger myriaster which prevents by-catch and protects immature fish. A series of comparative fishing experiment was carried out in water off the south-east coast of Korea from Nov. 2004 to Jul. 2005. And analyzed the amount of catch, by-catch rate, and CPUE, etc. of experimental traps which were the spring frame net traps, sorted four types of flappers. And the compared gear was a plastic conger eel pot. The conclusions were as follows. By-catch rates of spring frame net trap with the compressed flapper bound by nylon mono-filament was about 0-3%. CPUE of spring frame net trap with the compressed flapper was about 50-60% lower than that of traditional and plastic pot. And in case of conger eel that the total length is over 350mm, CPUE was little different on each type of flapper of every mesh size.