• 한국수산과학회지
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• 제46권4호
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• pp.445-453
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• 2013

Walleye pollock Theragra chalcogramma fisheries in Korean waters have changed dramatically during the last three decades: the highest catches occurred in 1981, followed by continuous decreases through the 1990s, ending with a complete collapse of the population in the 2000s. The major spawning ground of walleye pollock is located in North Korean waters, and some juveniles (called nogari in Korean, <300 mm) migrate to the south for feeding and growth. Since the 1960s, Korean fishermen have often caught juveniles, and the weight (metric tons) of juvenile catch was recorded from 1975-1997. However, because the walleye pollock were not aged, the population age structure was not delineated. We developed a model to estimate the number of walleye pollock of each size class based on catch statistics of adults and juveniles, the catch proportion of each size class, and length and weight information on specimens collected by Danish-seine and drift-gill-net fisheries. The model results demonstrated that the recruitment size of walleye pollock was consistently within the 200-250mm size class, and the highest number of this size class occurred in 1981, although values greatly fluctuated interannually. The number of juvenile pollock was 10.4 times higher than that of adult pollock during 1975-1997. The total yield of juvenile pollock was 0.95 million tons, which was equivalent to about 68.2% of total pollock production. The number of juvenile pollock caught during the same period, however, was 16 billion, comprising about 91.2% of the total number caught. Such high fishing pressure on juvenile pollock is considered one of the main factors causing the collapse of the pollock population.

• 생명과학회지
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• 제29권4호
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• pp.428-435
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• 2019

알래스카 산 대구(Gadus chalcogrammus)는 대구과(family Gadidae)의 해산어종이다. 알래스카 명란 원료, 고추장 명란, 발효 명란을 증류수와 에탄올로 추출하여 2, 2- diphenyl - 1- picrylhydroazyl (DPPH), 하이드록시 라디칼(OH), 산화질소(NO)의 항산화 소거능을 평가하였다. 철 이온 환원력(FRAP)을 조사하였다. ABTS+ 소거능은 Brand-Williams 등의 방법에 따랐다. 고추장 명란의 증류수 추출물의 DPPH 소거능은 1.0 mg/ml 농도에서 71.9%였으며 에탄올 추출물에서 소거능은 73.7%였다. 발효 명란의 증류수 추출물의 DPPH 소거능은 1.0 mg/ml 농도에서 78.0%였고 에탄올 추출물에서 소거능은 78.4%였다. 명란 원료의 증류수 추출물과 에탄올 추출물의 DPPH에 대한 최소 저해 농도 값($IC_{50}$)은 각각 11.65 ug/ml과 11.47 ug/ml이었다. 명란 원료, 고추장 명란, 발효 명란의 에탄올 추출물의 OH 소거능은 1.0 mg/ml 농도에서 70.9%, 79.0, and 80.6%였다. 명란 원료의 증류수 추출물과 에탄올 추출물의 NO의 최소 저해 농도 값은 11.45 ug/ml과 11.41 ug/ml였다. 본 연구 결과, 고추장 명란과 발효명란은 원료 명란 보다 높은 DPPH, OH, NO 소거능을 나타내었다. 고추장 명란과 발효 명란은 자연 라디칼 소거능이 있어 식품으로써 항산화 보충제가 될 수 있을 것이다.

• Food Science and Biotechnology
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• 제16권4호
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• pp.549-556
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• 2007

The study was carried out to examine on the refiner discharge from Alaska pollock as a collagen resource by characterizing biochemical and functional properties of collagen. The refiner discharge from Alaska pollock surimi manufacturing was a good resource for collagen extraction according to the results of total protein, heavy metal, volatile basic nitrogen, collagen content, amino acid composition, and thermal denaturation temperature (TDT). TDT of acid soluble collagen from refiner discharge showed $20.7^{\circ}C$, which was similar to that of collagen from Alaska pollock muscle and was higher than that of collagen from Alaska pollock skin. TDT of acid-soluble collagen from refiner discharge was, however, lower than those of skin collagens from warm fish and land animal. Acid-soluble collagen from refiner discharge of Alaska pollock could be used as a functional ingredient for food and industrial applications according to the results of water and oil absorption capacities, and emulsion properties. In addition, if the thermal stability of the acid-soluble collagens is improved, collagen from refiner discharge from Alaska pollock could be more effectively used.

• Journal of the Korean Data and Information Science Society
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• 제27권2호
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• pp.305-314
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• 2016

이 연구에서는 드립페인팅(drip painting)으로 유명한 잭슨 폴록(Jackson Pollock)의 작품과 이와 흡사한 형식을 가진 한국 앵포르멜 작업 (Korean Informel art)들에 나타난 프랙탈 차원 (fractal dimension)에 대한 분석을 시도하였다. 구체적으로 폴록과 한국 작가들의 프랙탈 차원이 다를 것이라는 가설을 통계적으로 검정하기 위해 30개의 폴록 작품과 45개의 한국 작가들의 작품을 사용하였다. 그 결과 폴록에 비해 한국 작가들의 프랙탈 차원이 통계적으로 더 높은 것으로 나타났다. 이는 폴록에 비해 한국 작가들의 작품의 패턴이 (세밀한 척도에서) 보다 평면적이라 해석될 수도 있을 것이다.

• 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.

• 한국수산과학회지
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• 제52권3호
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• pp.199-208
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• 2019

The present study compared the sensory and physicochemical characterizations of Alaska pollock Theragra chalcogramma roe according to the L, M, S, 2S, KA, KB, KC, and G grades. The mean weights of the Alaska pollock roe were 81.2 g (74.1-85.7 g) in the L grade, 48.4 g (41.1-54.8 g) in the M grade, 38.6 g (33.5-45.6 g) in the S grade, 29.3 g (25.7-34.2 g) in the 2S grade, 45.7 g (41.4-50.0 g) in the KA grade, 41.4 g (37.7-46.1 g) in the KB grade, 38.3 g (36.0-42.6 g) in the KC grade, and 15.0 g (14.2-15.6 g) in the G grade. The results of the sensory (transparency, physical damage, texture, and odor) and physicochemical (moisture, amino nitrogen and volatile basic nitrogen contents, Hunter redness, and texture) evaluations revealed that, in the normal group, the quality of Alaska pollock roe was highest in the L grade followed by the M, S, and 2S grades whereas, in the cut-group order, the quality was highest in the KA grade followed by the KB, KC, and G grades. The present results suggest that the L, M, S, 2S, KA, and KB grades could be used for high-quality Alaska pollock roe products.

• Fisheries and Aquatic Sciences
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• 제12권3호
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• pp.163-170
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• 2009

This study was conducted to obtain the gelatin fraction with a high anti oxidative activity from Alaska pollock surimi by-products using a two-step enzymatic hydrolysis and ultrafiltration. Among gelatin hydrolysates from refiner discharge of Alaska Pollock surimi, the highest antioxidative activity (81.5%) resulted from gelatin hydrolysate sequentially treated with Pronase E and Flavourzyme each for 2 hr. However, no difference was seen in the anti oxidative activity of the second hydrolysate (Pronase E-/Flavourzyme-treated hydrolysate) when compared to the permeate fractionated through a 10-kDa membrane. The results suggest that the Pronase E-/Flavourzyme-treated hydrolysate from refiner discharge gelatin of Alaska pollock surimi can be used as a supplementary raw material for improving health functionality.

• 한국축산식품학회지
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• 제39권3호
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• pp.503-509
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• 2019

The aim of this study was to compare the effects of number of washes and salt addition on the meat quality in protein recovered from Alaska Pollock compared with pork leg. Various properties of protein recovered from Alaska Pollock (C, washed twice, no salt) and pork leg (T1, washed twice, no salt; T2, two washes, salt added; T3, washed four times, no salt; and T4, washed four times, salt added) were assessed in this study. Pork leg samples exhibited better color (more whiteness, less yellowness) than Alaska Pollock samples. In pork leg samples, four washes (T3, T4) during processing yielded whiter, less yellow protein than two washes (T1, T2). Overall, the textural property measures were higher in pork leg samples (T2, T3, and T4) than in other samples. Breaking force, jelly strength, and folding resistance were significantly higher in salt-treated pork leg samples (T2, T4) than in the other samples. Our findings demonstrate that protein recovered from pork leg has better color parameters, and physical strength compared with Alaska Pollock-derived protein. A higher number of wash steps and treatment with salt during processing were furthermore found to yield better color, and physical strength in the protein samples.

• 해양환경안전학회지
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• 제26권2호
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• pp.195-205
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• 2020

동해 명태 서식처 환경은 한랭기와 온난기를 교차하며 변동을 지속하고 있다. 특히 1980년대 후반 이후 수온은 급격히 상승하였으며, 2000년대 후반 이후 다시 하강하는 특성을 나타내었다. 반면, 명태 주요 산란장이 위치한 동한만과 어장 중심이 형성되는 동해 중부 연안의 수온은 서로 다른 변동 특성을 나타내었다. 동한만의 겨울철 수온은 1980년 후반 이후 급격히 상승하였으며, 2000년 후반 이후 다시 하강하는 특성을 나타내었으며, 이러한 장기 변동특성은 2월과 3월에 더욱 뚜렷하였다. 반면 어장의 중심이 형성되는 동해 중부 연안의 수온은 1990년대 중후반 이후 지속적으로 상승하였으며, 2000년 후반 이후 수온이 하강하는 특성은 뚜렷이 나타나지 않았다. 이러한 산란장과 어장의 수온변화는 명태 자원량과 변동 특성이 유사하였다. 특히 산란장의 수온 변화는 난과 자·치어를 포함한 초기 생활사 시기의 생존율에 영향을 미치는 주요 인자로 작용한다. 1980년대에는 명태의 산란에 적합한 환경이 조성되는 면적과 지속시간이 평년보다 증가하였으며, 반대로 동해에 서식하는 명태의 자원량이 급격히 감소한 1980년대 후반 이후에는 산란장 면적과 적합한 환경이 지속되는 시간이 급격히 감소하였다. 명태 자원량 변화는 서식처의 물리적 환경변화와 유의한 상관성을 가지며, 특히 산란장의 수온 상승에 따른 산란에 적합한 환경이 조성되는 면적과 지속시간의 감소 그리고 어장의 축소는 명태 자원량 변화에 영향을 미치는 주요 인자로 작용하였다.

• 한국환경보건학회지
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• 제44권3호
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• pp.259-266
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• 2018

Objectives: Considered the "national fish" in Korea, the walleye pollock (Gadus chalcogrammus) has disappeared in the East Sea (Sea of Japan), a main habitat and fishing ground for the species. The reason for the disappearance is still a matter of controversy. This study was performed to investigate the long-term relationship between the walleye pollock catch and various meteorological and oceanographic factors in these waters. Methods: Fishery data on walleye pollock and data on meteorological and marine environmental factors over the 30 years (1981-2010) were obtained from the official national database. Time series analysis and correlation and regression analyses were performed to study the relationships. Results: Both air temperature and sea surface temperature in the East Sea rose over these 30 years, and the latter became more prominent. Salinity and dissolved oxygen showed a tendency to decrease while concentrations of nutrients such as nitrite nitrogen and nitrate nitrogen showed an increasing tendency. Sea surface temperature, air temperature, atmospheric pressure, and wind grade were negatively correlated with the catch size of walleye pollock (p<0.05), but salinity was positively correlated (p<0.001). Conclusion: The results of this study indicate that climate change, especially ocean warming, affected the habitat of walleye pollock. The results also indicate that lower sea surface and air temperatures, milder wind grade, and higher salinity were preferred for the survival of the fish species. It is necessary to pay attention to changes of the ocean ecosystem in terms of environmental pollution as well as seawater temperature.