• 수산해양기술연구
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• 제51권3호
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• pp.340-347
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• 2015

The Commission for Conservation of Antarctic Marine Living Resources (CCAMLR) is utilized to manage krill resources using acoustic data collection and a scientific observer program operating on the fishing boats. However, the acoustic data were contained seriously noise, example of background, spike, and intermittent noise, due to purpose of fish boats. In this study, the noise removal techniques were confirmed the potential of the acoustic data analysis. Acoustic system and frequency used in the survey were commercial echosounder (ES70, SIMRAD) and 200 kHz split beam transducer. Acoustic data were analyzed using Echoview software (Myriax), and general data analysis and new noise removal method was used. Although a variety of noise, most of the noises have been removed using the noise removal processing. We confirmed the possibility of analyzing the acoustic data obtained from fish boats. The results will be useful for analysis of the acoustic data acquired from krill fishing boats.

• 한국수산과학회지
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• 제50권1호
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• pp.65-76
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• 2017

Since the late 1990s, walleye pollock Gadus chalcogrammus fisheries in Korean waters have been considered collapsed. Although many fisheries scientists suspect that the collapse might have been triggered by overexploitation of juvenile pollock or environmental changes, such conjectures have been neither tested nor investigated, partially because of limited data on the population. There has been no survey of the population, and the ages of fish in fishery catch have rarely been identified. Instead, fishery catch data from 1975-1997 included information about two life stages, 'juveniles and adults,' and data on catch-per-unit-effort (CPUE) during 1963-2007 and those on fish length and weight during 1965-2003 had been sporadically collected from commercial fisheries. To test hypotheses about the collapse of the pollock fisheries, we used a statistical linear model with juvenile CPUE as the response variable, and abiotic (e.g., water temperatures) and biotic factors [e.g., adult pollock, flatfishes (Pleuronectidae sp.), and sandfish (Arctoscopus japonicus) CPUEs] as the explanatory variables. The model results indicated that depletion of the pollock population was associated with both biotic (adult pollock and flatfishes abundance) and abiotic factors (mid-water temperatures in February and October). We further interpreted the results from ecological and biological perspectives, suggesting possible mechanisms.

• Preventive Nutrition and Food Science
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• 제20권1호
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• pp.67-72
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• 2015

Squid is one of the most important commercial fishes in the world and is mainly utilized or consumed as sliced raw fish or as processed products. The biofunctional activities of enzymatic squid meat hydrolysate were determined to develop value-added products. Enzymatic squid hydrolysate manufactured by Alcalase effectively quenched 1,1-diphenyl-2-picrylhydrazyl radical, hydroxyl radical, and hydrogen peroxide radical with $IC_{50}$ values of 311, 3,410, and $111.5{\mu}g/mL$, respectively. Angiotensin I-converting enzyme inhibitory activity of squid hydrolysate was strong with an $IC_{50}$ value of $145.1{\mu}g/mL$, while tyrosinase inhibitory activity with an $IC_{50}$ value of 4.72 mg/mL was moderately low. Overall, squid meat hydrolysate can be used in food or cosmetic industries as a bioactive ingredient and possibly be used in the manufacture of seasoning, bread, noodle, or cosmetics.

• Fisheries and Aquatic Sciences
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• 제12권1호
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• pp.49-53
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• 2009

We conducted a histological analysis to investigate the influence of nutritional changes on melano-macrophages (MMs) accumulation in the kidney of sub-adult rock bream (Oplegnathus fasciatus). Four experimental groups were established (initial control, control, fed and starved), and fed commercial feed amounting to 1-3% of their body weight for 2 weeks prior to initiation of experiments. Kidney MMs with dark brown pigment were randomly observed in the kidneys of starved fish, increasing rapidly after 4 weeks, while deposition levels remained low throughout the experiment in the control and fed groups. These results suggest that catabolic tissue breakdown is a major factor contributing to the formation of pigments within MMs. Results also suggest that the degree of MMs deposition in the kidney can be used as alternative indicators in identifying starvation in wild and cultured rock bream.

• Fisheries and Aquatic Sciences
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• 제17권1호
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• pp.137-143
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• 2014

The hairtail (currently recognized as Trichiurus lepturus in Korea) is one of the most important commercial fish species in Korea, Japan, China, and Taiwan. Because the amount of catches has been steadily declining, we must determine the early life stages of the hairtail from the viewpoint of resource management. Furthermore, the taxonomic status of the hairtail is unclear among ichthyologists, potentially creating management difficulties. Therefore, the purpose of this study was to compare morphological and molecular information on eggs, larvae, and adults of hairtail from Korea with that of T. lepturus from the Atlantic Ocean, and to review the taxonomic status of the hairtail. A total of 510 base pairs of the mitochondrial DNA cytochrome oxidase subunit I sequences of 12 eggs, 2 larvae, and 11 adults of the hairtail from the Korean waters clearly matched those of Trichiurus japonicus adults (d = 0.000-0.014) from the East China Sea rather than those of T. lepturus (d = 0.100-0.110) from the Atlantic Ocean. Our results also showed that larvae of the Korean hairtail are different than those in the Atlantic Ocean in having no melanophores along the ventral edge of the lower jaw. Therefore, our findings suggest that the hairtail in the Korean waters may not be T. lepturus, but T. japonicus.

• 한국수산과학회지
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• 제31권3호
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• pp.386-392
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• 1998

액젓의 객관적인 품질평가 기준을 설정하기 위하여, 전통적인 방법에 따라 발효 숙성시킨 멸치 액젓과 시판 멸치 액젓의 일반성분, 총질소량, 아미노산 함량, SDS-PAG전기영동을 통한 특정 펩티드의 면적을 측정하였고, 아울러 액젓 원료어의 판정을 위해 등전점 전기영동을 시도하였다. 멸치 액젓의 수분 함량은 대조구가 가장 낮은 $60.5\%$였으며, 시판 제품은 $65.5\%\~69.2\%$로 큰 차이가 없었으나, 총질소 함량은 시판 제품간에 비교적 큰 차이를 보이고 있었다. 액젓에 잔존하는 단백질의 함량은 Y사의 제품이 비교적 높은 $0.353mg/m{\ell}$ 였으며, 나머지 시판 제품은 $0.093mg/m{\ell}\~0.293mg/m{\ell}$의 범위였다 한편 SDS-PAG 전기영동상에서는 J사를 제외한 모든 액젓 제품에서 분자량 55,600 및 46,900 dalton의 band가 검출되었으며, 전기영동상에 나타난 단백질 band는 제조회사에 관계없이 거의 비슷한 형태를 나타내고 있었다. 그리고 등전점 전기영동에서 멸치 액젓은 등전점 5.6에 해당하는 펩티드가 공통적으로 존재하며, 특징적인 band임을 확인하였다. 따라서 아미노산 및 저분자 질소 화합물의 첨가 여부가 정량적인 값에 영향을 미치지 않는 전기영동 상의 특정 band의 면적비를 측정함으로서 인위적인 질소화합물의 첨가, 액젓 희석 여부 판정이 가능 할 것으로 판단되었다. 그리고 전 질소 함량, 아미노산 함량 및 SDS-PAG 전기영동 상에 있는 특징적인 55,600 dalton에 해당하는 펩티드 면적비의 상관관계는 멸치 액젓의 품질판정을 위한 기준으로 활용 가능함을 제시하고 있다.

• 한국수산과학회지
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• 제39권1호
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• pp.9-15
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• 2006

As a part of the investigation for utilizing pearl oyster by-products, a rapid salt-fermented pearl oyster using commercial enzyme was prepared and also examined on the characteristics. The salt-fermented pearl oyster prepared by optimal condition, which was prepared by mixing of minced pearl oyster, 15% salt, and 1% $Protamex^\circledR$ and fermented for 4 weeks, was superior in hydrolysis degree (28.7%) and ACE inhibitory activity (92.6%) to salt-fermented pearl oyster prepared by other conditions, such as the use of whole tissue, different enzymes $(Alcalase^\circledR,\;Neutrase^\circledR\;and\;Flavourzyme^\circledR)$, different salt concentrations (20 and 25%), and different fermentation periods (2, 6 and 8 weeks). There were, however, some shortcomings with this product. It showed a dark green color and an unfavorable bitter taste. These shortcomings were improved by the addition of seasoning paste. The calcium and phosphorus contents of the seasoned salt-fermented pearl oyster were 64.2 mg/100 g and 71.6 mg/100 g, respectively, and the calcium content based on phosphorus was a good ratio for absorbing calcium. The total amino acid content of the seasoned and salt-fermented pearl oyster was 7,054 mg/100 g and the major amino acids ware aspartic acid (555.1 mg/100 g), glutamic acid (1,131.2 mg/100 g), alanine (658.2 mg/100 g), and lysine (695.5 mg/100 g). The seasoned salt-fermented pearl oyster, along with angiotensin I converting enzyme (ACE) inhibitory activity (98.3%), also showed a recognizable level (87.5%) of anti-oxidative activity.

• 한국어류학회지
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• 제22권3호
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• pp.147-153
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• 2010

대구 치어(평균 36.5 g)의 수온 (9, 11 그리고 $13^{\circ}C$)에 따른 절식 (fasting)과 식후(post-prandial) 총암모니아성 질소 (total ammonia nitrogen, TAN) 배설의 일간 패턴과 배설률을 조사하였다. 실험어는 10일 이상 실험 수온에서 순치한 후 각 실험 수온 조건의 암모니아 배설 측정 시스템으로 옮겨 TAN 배설률을 측정하였다. 절식 TAN 배설은 72시간 절식 후 측정하였고, 식후 TAN 배설은 상품 사료(단백질 함량 40.6%)를 하루에 두 번(08:00, 16:00h), 7일간 공급한 뒤 측정하였다. 실험어 사육수조 유입수와 배출수를 2시간 간격으로 24시간 동안 채수하여 TAN을 분석하였으며, 모든 실험 조건은 3반복으로 실시하였다. 절식 및 식후 TAN 배설 모두 수온 상승에 따라 증가하였다 (p<0.05). 절식 시 시간당 평균 TAN 배설률은 수온 9, 11 그리고 $13^{\circ}C$에서 각각 9.3, 11.0 그리고 $11.9mg\;TAN\;kg\;fish^{-1}\;h^{-1}$이었고, $11^{\circ}C$와 $13^{\circ}C$가 $9^{\circ}C$에 비해 유의적으로 높았다 (p<0.05). 식후 시간당 평균 TAN 배설률의 경우 수온 9, 11 그리고 $13^{\circ}C$에서 각각 23.0, 31.6 그리고 $45.4\;mg\;TAN\;kg\;fish^{-1}\;h^{-1}$으로 나타났다. 최대 평균 TAN 배설률은 최초 사료 공급 10시간 후 나타났으며, 수온 9, 11 그리고 $13^{\circ}C$에서 각각 38.0, 52.9 그리고 $77.5\;mg\;TAN\;kg\;fish^{-1}\;h^{-1}$이였다. 수온 9, 11 그리고 $13^{\circ}C$에서 섭취한 질소에 대한 TAN 배설 비율은 각각 43.9, 46.4 그리고 48.4%로 나타나 $11^{\circ}C$와 $13^{\circ}C$가 $9^{\circ}C$에 비해 유의적으로 높았다(p<0.05). 이상의 결과에서 수온은 대구 치어의 질소 대사에 유의한 영향을 미치는 것으로 나타났다.

• 한국어병학회지
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• 제15권1호
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• pp.25-35
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• 2002

Effects of medicinal herb extract on nonspecific immune responses, hematology and disease resistance against Edwardsiella tarda in olive flounder, Paralichthys olivaceus were evaluated. Wormwood, Artemisia asiatica NAKAI and barrenwort, Epimedium koreanum NAKAI were mixed at a ratio of 7 : 3 (w/w) for 2-herbs extract and wormwood, barrenwort, Korean forsythia, Forsythia koreana NAKAI, chrysanthemum, Chrysanthemum zawadskii var. latilobum KITAMURA, peppermint, Mentha arvensis L. var, piperascens MALINV., great burnet, Snaguisorba afficinalis L., Lizard tail. Saururus chinensis BAILL., mulberry, Morus alba L., and star anise, Illicium varum HOOK, f, at the same weight for 9-herbs extract. Two-herbs of 9-herbs extract were prepared by heating after adding 10㎖ of distilled water per g of the herb mixtures. Fish (10.3$\pm$2.5g) were fed the experimental diets supplemented with the 2-herbs or 9-herbs extract at the different concentrations of 0%, 0.1%, 0.5% and 1% per kg diet for 12 weeks. Lysozyme and bactericidal activities of serum, and hematological characteristics were examined during experimental period. After feeding test period, all experimental groups were challenged with E. tarda. Lysozyme activity from the fish fed the diet supplemented with 0.1% or 0.5% of 2-herbs extract was significantly higher than the control. But there was no difference both in bactericidal activity and hematology among each group. Sixty seven % of relative percent survival values (RPS) in the group fed the diet supplemented with 0.1% of 2-herbs was higher than the other group and the control. These results suggest that supplenmentation of 0.1% of 2-herbs extract to a commercial diet may enhance disease resistance in olive flounder. Although both 0.1% and 0.5% 9-herbs extract did not improve non-specific immune reponses, they could enhance disease resistance of 53% RPS, respectively.

• Ocean and Polar Research
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• 제39권4호
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• pp.257-267
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• 2017

Although Pacific mackerel (Scomber japonicus) is an important commercial species in Korea, its recruitment mechanism remains largely unknown. Diel vertical positioning of larvae in the water column, which is affected by their specific gravity and the surrounding water density, may help to provide an understanding on recruitment success through predator avoidance and prey availability. The specific gravity measurement on Pacific mackerel eggs and larvae would seem to be essential information necessary to learn about the transport process from spawning to nursery grounds, and consequently the recruitment success. Eggs were artificially fertilized, and larvae were fed with rotifer when their mouths opened 3-4 days after hatching. We conducted the experiment using a density gradient water column to measure the ontogenetic changes in specific gravity from fertilization to 10 days after hatching. Egg specific gravity was stable during most of the embryonic period, but a sudden increase to $1.0249g\;cm^{-3}$ happened just before hatching. However, the specific gravity of newly hatched larvae was much lighter ($1.0195g\;cm^{-3}$), and specific gravity tended to increase continuously after hatching. Comparison of specific gravity with seawater density reveals that eggs and newly hatched larvae can float in the surface layer of the ocean. For the later period of the experiment, the specific gravity showed a cyclic diel pattern: the highest in the evening while the lowest at dawn. The fullness of larval stomach may be responsible for the observed differences in specific gravity, because stomach fullness was lower (40-60%) at midnight, and higher (80-85%) in evening. The diel pattern of specific gravity might provide clues regarding how larvae match the diel vertical migration of prey organisms.