• 한국환경과학회지
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• 제26권2호
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• pp.173-181
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• 2017

Catch data for the common squid (Todarodes pacificus), classified by squid-jigging fisheries per grid (size: $0.5^{\circ}latitude{\times}0.5^{\circ}longitude$), and the water temperature values KODC (Korea Ocean Data Center) were collected for the 1980-2009 period to study the changes in squid distribution and migration with climate regimes (1980s, 1990s, and 2000s). The primary fishing period in the 1990s and 2000s was approximately 2-3 months earlier than that in the 1980s. Especially in the East Sea, the fishing grounds in the 1980s stayed longer at high latitudes than those in the other decades. Moreover, in the 1980s, centers of the fishing ground were located near the Yamato bank (central East Sea), whereas in the 1990s and 2000s, they were situated near the southeastern coast of the Korean peninsula.

• 한국수산과학회지
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• 제39권6호
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• pp.472-479
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• 2006

The sexual maturity and reproductive cycle of the common squid, Todarodes pacificus captured from the East Sea, Korea, between January 2004 and January 2006, were investigated by documenting changes in the gonadosomatic index (GSI), gonad development, and oocyte size frequency distribution. The GSI of females began to increase in July, reached a maximum in August, and then gradually decreased. The GSI of males increased from July to March. Using gonad histological observations, we identified four oocyte developmental stages. The changes in GSI and gonad tissue resulted in the classification of the annual reproductive cycle into the following four successive stages: immature (April to June), growing (June to July), mature (July to August), and ripe and spawning (August to March). According to the oocyte diameter size frequency distribution in the ovary, this species appeared to have asynchronous oocyte development and one spawning time.

• 한국수산과학회지
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• 제51권3호
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• pp.338-343
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• 2018

Recently, commercial catches of the common squid Todarodes pacificus have dramatically decreased in Korean and Japanese waters. The relationship between common squid catches and environmental factors was investigated using squid catches, climate indices and observed seawater temperatures in Korean waters. Common squid consist of three spawning stocks: autumn, winter, and summer. The autumn stock is the largest in Korea, and its main fishing season appears to have shifted from September in the 1980s to October in the 1990s. We observed negative correlations between the spring Southern Oscillation Index and Korean catches and between the winter Pacific Decadal Oscillation and Japanese catches. Despite global warming, no conspicuous increases in October seawater temperatures have been observed at 10 and 50 m in Korean waters since the mid-1900s. Instead, the 50 m water layer of the East Sea appears to be gradually cooling. Moreover, temperatures at 50 m in the East Sea and the South Sea were significantly negatively correlated with squid catches in Korea and Japan, respectively. Our preliminary analysis indicates a link between climate change, seawater temperature, and squid catches in Korean waters, which helps to inform the direction of subsequent research to identify the cause of rapid decreases in this squid resource.

• 한국식품위생안전성학회지
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• 제23권4호
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• pp.314-318
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• 2008

This research aimed to compare the detection methods of Anisakis simplex in Sea fish by polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) and macroscopic inspection. We examined 18 Trichiurus lepturus, 11 Scomber japonicus, and 65 Todarodes pacificus collected from the retail markets in the areas of Uljin, Kyuonggi province and Seoul. As the result of examinations, we found that detection rate of Anisakis simplex by macroscopic observation was 89% in Trichiurus lepturus, 90.9% in Scomber japonicus, 32.3% in Todarodes pacificus. The detection rate of Anisakis simplex by PCR-RFLP was 77.7% in Trichiurus lepturus, 81.8% in Scomber japonicus, 26.1% in Todarodes pacificus. We could conclude that PCR-RFLP method of Anisakis simplex was more specific rather than macroscopic observation.

• 한국수산과학회지
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• 제54권5호
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• pp.769-781
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• 2021

Given data about the annual fishery yield of the common squid Todarodes pacificus, and the catch-per-unit-effort (CPUE) data from multiple fisheries from 2000-2018, we applied a Bayesian state - space assessment model for the squid population. One of our objectives was to do a stock assessment, simultaneously incorporating CPUE data from the following three fisheries, (i) large trawl, (ii) jigger, and (iii) large purse seine, which comprised on average a year about 65% of all fisheries, allowing possible correlations to be reflected. Other objectives were to consider both observation and process errors and to apply objective priors of parameters. The estimated annual exploitable biomass was in the range of 3.50×10⁵ to 1.22×10⁶ MT, the estimated intrinsic growth rate was 1.02, and the estimated carrying capacity was 1,151,259 MT. Comparison with available results from stock assessment of independently analyzed single fisheries revealed a large difference from the estimated values, suggesting that stock assessment based on multiple fisheries should be performed.

• Ocean and Polar Research
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• 제34권2호
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• pp.253-264
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• 2012

In the northwestern Pacific, spawning of the common squid, Todarodes pacificus, occurs at continental shelf and slope areas of 100-500 m, and the optimum temperature for the spawning and survival of paralarvae is assumed to be $18-23^{\circ}C$. To predict the spawning ground of Todarodes pacificus under future climate conditions, we simulated the present and future ocean circulations, using an East Asia regional ocean model (Modular Ocean Model, MOM version3), projected by two different global climate models (MPI_echam5, MIROC_hires), under an IPCC SRES A1B emission scenario. Mean climate states for 1990-1999 and 2030-2039 from 20th and 21th Century Climate Change model simulation (from the IPCC 4th Assessment Report) were used as surface conditions for simulations, and we examined changes in spawning ground between the 1990s and 2030s. The results revealed that the distribution of spawning ground in the 2030s in both climate models shifted northward in the East China Sea and East Sea, for both autumn and winter populations, compared to that of the 1990s. Also, the spawning area (with $1/6^{\circ}{\times}1/6^{\circ}$ grid) in the 2030s of the autumn and winter populations will decline by 11.6% (MPI_echam5) to 30.8% (MIROC_hires) and 3.0% (MPI_echam5) to 18.2% (MIROC_hires), respectively, from those of the 1990s.

• 해양환경안전학회지
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• 제25권1호
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• pp.58-66
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• 2019

서해에서 살오징어(Todarodes pacificus) 유생 분포를 파악하기 위해 2013년 - 2015년 춘계(4월)와 추계(11월) 자원조사선 탐구 20호로 18정점에 대해 CTD 관측 및 지름 60 cm, 망목 $333{\mu}m$의 봉고네트를 이용한 경사 채집을 실시하였다. 조사기간 동안 채집된 유생은 총 4개체로 2014년과 2015년 추계에 각 2개체였으며, 유생의 외투장은 1.5 - 8.3 mm이었다. 조사기간 동안 춘계와 2013년 추계에는 유생이 출현하지 않았다. 유생밀도는 2014년 추계에 $0.1inds./1,000m^3$과 $0.2inds./1,000m^3$, 2015년 추계에 $0.1inds./1,000m^3$과 $0.2inds./1,000m^3$로 나타났다. 유생이 채집된 정점에서 배아발달 및 유생의 생존이 가능한 수온대($15-24^{\circ}C$)는 수심 56 m보다 얕은 곳에 위치하였다.

• Applied Microscopy
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• 제31권4호
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• pp.333-345
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• 2001

두족류 3종(Octopus minor, Octopus ocellatus, Todarodes pacificus)의 성숙정자를 전자현미경을 통해 관찰한 결과 다음과 같았다. 팔완류인 서해박지와 주꾸미의 성숙정자 전체 길이는 각각 $390{\mu}m$와 $125\sim130{\mu}m$정도였고, 십완류인 살오징어의 길이는 $35{\mu}m$정도로 매우 짧았다. 서해낙지는 나선형의 첨체와 약간 굽은 바나나 모양의 머리를 소지하고 있었으며, 주꾸미는 꼬인 첨체와 막대 모양의 긴 머리를 가지고 있었다. 이들 침체 내강에는 규칙적 구조(periodic structure)인 많은 가로무늬가 관찰되었고, 머리의 내강에는 치밀전 (dense plug)을 형성하였다. 그러나 살오징어의 첨체는 전자밀도가 낮은 둥근 모자 모양이 였으며, 머리는 길쪽한 장타원형을 나타내었다. 특히 첨체 하단부에는 2개의 작은 강(cavity)이 관찰되었고, 이들 내강에는 전자밀도가 높은 물질들(juxtanuclear acrosomal materials)로 채워져 있었다. 3종의 성숙정자 중편은 서해낙지와 주꾸미에서 미토콘드리아가 mitochondrial sleeve를 형성하였지만, 두 종간 미토콘드리아의 수는 각각 $11\sim12$개와 $8\sim9$개로 관찰되어 수의 차이를 보였다. 반면, 살오징어는 미토콘드리아가 축사와 분리되어 mitochondrial spur를 형성하였고, 이들 spur내에는 $10\sim13$개의 미토콘드리아와 전자밀도가 높은 물질들이 밀집되어 있었다. 서해낙지, 주꾸미, 그리고 살오징어의 축사는 공히 9+2구조에 9개의 금은섬유가 둘러싸고 있었고, 살오징어의 축삭내에서만 작은 입자형의 글리코겐이 관찰되었다. 금은섬유들은 서해낙지와 살오징어에서는 꼬리의 주편까지만 관찰되었으나, 주꾸미에서는 단편에서도 관찰되었다.

• BMB Reports
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• 제41권3호
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• pp.254-258
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• 2008

Lipase was purified from squid (Todarodes pacificus) liver in an attempt to investigate the possibility of applying the enzyme for biotechnological applications. Crude extract of squid liver was initially fractionated by the batch type ion exchange chromatography. The fraction containing lipase activity was further purified with an octyl-Sepharose column. Finally, lipase was purified by eluting active protein from a non-dissociating polyacrylamide gel after zymographic analysis. Molecular weight of the purified enzyme was determined to be 27 kDa by SDS-polyacrylamide gel electrophoresis. The enzyme showed the highest activity at a temperature range of $35-40^{\circ}C$ and at pH 8.0. The activity was almost completely inhibited at 1 mM concentration of $Hg^{2+}$ or $Cu^{2+}$ ion. Partial amino acid sequence of the enzyme was also determined.

• 한국수산과학회지
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• 제30권5호
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• pp.903-905
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• 1997

Morphological differences were studied using the analysis of covariance between various partial length and mantle length of the common Todarodes pacificus by cohorts in the Korean waters. Analysis of seven morphological characters proved that each cohort has no sexual differences, except significant sexual differences only in the Summer cohort in term of relative growth between mantle length and body weight. The three cohorts represent significant differences in morphological characters.