• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.50 no.2
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• pp.139-146
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• 2014

Feeding habits of white croacker, Pennahia argentata, were analyzed by using the stomach contents of 153 specimens caught by bottom trawl from May 2011 to March 2012 in the Sejon island, Korea. To know feeding habits of the white croacker, P. argentata, a species composition and it's fluctuation were analyzed based on growth. White croacker, P. argentata caught in the area composes 15 species. The most species in an number of the prey was Macrura which was occupied at 66.4% from whole prey, the second most species was Pisces which was occupied at 20.3%. The most species in an wet-weight of the prey was Pisces which was 49.3% out of the whole specimens. The second most species was Macrura which was 43.3%. The frequency occurrence of the prey was Macrura which was 68.6%, the next one was Pisces which was 28.8%. The highest Index of Relative Importance (IRI) of the prey was Macrura which was 78.2%, the next one was Pisces which was 28.8%. A number of the prey per specimen of small, middle and large class were 1.3, 1.5, 1.7, respectively. A wet weight of the prey per specimen of small, middle and large class were 0.2, 0.6, 0.2 g, respectively.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.6 no.1_2
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• pp.20-26
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• 1973

Authors have investigated the monthly distribution of vibrio flora in sea water, mud, fish and shellfish in the public beaches at the suburbs of Busan in order to determine the possible origins of food poisoning. The results are summarized as follows: 1. The monthly distribution shows that V. parahaemolyticus occurs from May to November and V. alginelyticus all the year round. 2. A total of 40 strains of Vibrio flora were isolated from 40 sea water samples, 25 strains from 40 mud samples, If strains from 88 shellfish samples, and 3 strains from 30 fish samples. 3. More strains were isolated from the samples collected at Yongho and Suyeong that at the other localities. 4. A total of 80 strains of Vibrio flora, isolated from 198 samples, were divided into two groups : V. perahaemolyticus with 20 strains and V. alginelyticus 60 strains.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.48 no.3
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• pp.362-367
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• 2015

We followed the development of Pacific herring Clupea pallasii larvae after natural hatching in Korean coastal waters off Dadaepo, where the water temperature was $9^{\circ}C$. Twenty days after hatching, the larvae had (i) reached a total length (TL) of 10.8-12.2 mm, (ii) developed 9-11 dorsal fin rays, and (iii) branched melanophores along the dorsal line of the gut in the anterior half of the body and along the posterior half of the dorsal and ventral line. Thirty days after hatching, the larvae had reached 12.2-13.5 mm TL, and the number of dorsal fin rays had increased to 13-14. Thirty-five days days after hatching, the larvae had reached 14.0-14.7 mm TL, and the posterior ends of their notochords had begun to flex upward. Forty-five days days after hatching, the larvae had (i) reached 15.6-15.9 mm TL, (ii) a complete set of dorsal fin rays (15-16), (iii) 12-13 anal fin rays, and (iv) branched melanophores along the dorsal part of the lateral surfaces of the head behind the caudal terminus. Preflexion, flexion and postflexion stage larvae had TL values of 13.5 mm, 14.0-15.3 mm, and 15.6-15.9 mm, respectively.

• Journal of the Korean Society of Marine Environment & Safety
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• v.4 no.2
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• pp.69-83
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• 1998

Sea transportation has long been a vital component of the transport systems of the world. The great majority of imports and exports to and enlarge their national merchant marines. This effort is meant partly to arrest earlier trends of having their trade carried by ships from outside the region and partly to promote regional integration and improve the national balance of payments. However, sea transportation has been exposed to various types of threats on the high seas, in coastal waters and in port areas. Piracy is any robbery or other violent action, for private ends and without authorization by public authority, committed on the seas. Because piracy has been regarded as an offense against the law of nations, the public vessels of any state have been permitted to seize a pirate ship, to bring it into port, to try the crew(regardless of their nationality or domicile), and, if found guilty, to punish them and to confiscate the ship. Piracy has occurred in all stages of maritime history. The increased size of merchant vessels, the improved naval patrolling of most ocean highways, the regular administration of most islands and land areas of the world, and the general recognition by governments of piracy as an international offense resulted in a great decline in piracy in the 19th and 20th centuries. Piracy has, however, occurred in the 20th century, and the practice of hijacking ships has developed into a new form of piracy. The number of incidents of sea piracy against ships reported was 229 in 1997. Since 1991, 1,051 such acts have been reported. The purpose of this research is to examine the origin and development of the piracy to understand the current situation of such violence on the seas. In addition, what should be done by international community will be presented to prevent the piracy in the future.

• The Korean Journal of Malacology
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• v.13 no.1
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• pp.43-54
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• 1997

1994년 1월부터 12월까지 1년간에 걸쳐 우리 나라 서해안 비인만의 조간대에서 채집된 떡조개, Dosinorbis(Phacosoma) japonocus(Reeve)를 대상으로 성숙 및 산란시기를 규명하기 위해 생식소 여포지수(GFI)및 생식소지수(GI)의 월별변화, 생식주기, 월별 난경 조성 및 성비를 조사하였다. 본 종은 자웅이체이고, 생식소는 중장선 하부와 소화맹낭 그리고 섬유성 결체조직과 근섬유에 의해 치밀하게 구성된 외측 근섬유층 사이에 위치하고 있다. 산란기 추정을 위해 조사된 GFI와 GI의 월별변화 양상은 생식주기와 일치하는 경향을 보였다. 난경 55-65$\mu\textrm{m}$인 성숙란들은 젤라틴성 막에 의해 둘러싸여 있다. 본 종의 생식주기는 초기활성기 (12-2월), 후기활성기(2-5월), 성숙기(5-8월), 부분산란기(6-8월)그리고 퇴화 및 비활성기(8-12월)의 연속적인 5단계로 나눌 수 있었다. 산란기는 수온 및 먹이이용 가능성과 밀접하게 관련되어 있는 것으로 보이며, 산란은 수온이 2$0^{\circ}C$ 이상인 6월부커 8월까지 일어났고, 산란성기는 6월과 7월이었다. 산란기는 단지 그 해 하계에만 일어남으로써 1년에 1회의 산란기를 가지나 그 산란 빈도 횟수는 1년에 1회의 산란계절 중 2회 이상 일어나는 것으로 추정된다. 암.수 개체들의 성비는 통계 처리한 결과 1:1(x$^{2}$=0.08, P>0.05)로 나타나 암.수간 성비에 차이가 없었다.

• The Korean Journal of Malacology
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• v.20 no.1
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• pp.65-73
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• 2004

Gametogenesis, changes of gonad bulk index (GBI), monthly variation in oocyte diameter, reproductive cycle and spawning with lunar cycle of the top shell, Trochus niloticus were investigated by histological examination. The specimens were sampled in the coastal waters of Chuuk Island, Micronesia, form November 1999 to September 2000. T. niloticus is a gonochorism, and the female and male were present in an approximately 1:1 ratio (p > 0.05). The ovary contained with the oocyte of yolk stage, the testis composed of the spermatid and spermatozoa at around the year. Monthly GBI were higher at February, March, April and June than the other months. Major spawning occurred between April and May, and June and July but the individuals of partially spawning were presented throughout the year. GBI with lunar cycle were higher at the full moon than the other lunar phase. These results suggest that the spawning occurred between the full moon and last quarter moon.

• Journal of the Korean Society of Marine Environment & Safety
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• v.22 no.7
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• pp.807-813
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• 2016

The Maritime Traffic Safety Audit Scheme was institutionalized in 2009 to provide for professional surveys, measurement and the evaluation of navigational hazards that might occur in coastal waters in the course of marine work. Related researches that dealt with the reform of the Maritime Traffic Safety Audit Scheme found that there were no rules or regulations for verifying whether marine work conformed to audit results and reviewing the exactitude of ship handling simulations which were a crucial part of the scheme. According to the necessity of adopting an ex post facto management system in the field of maritime traffic, this study analyzed the similar audit acts such as the Natural Environment Impact Audit Scheme and the Road Traffic Safety Audit Scheme, and proposed specific articles for revising Maritime Safety Act in order to break out from the institutional inertia of the current Maritime Traffic Safety Audit Scheme. It is expected that a newly proposed legal system for verifying the performance of audit results and the exactitude of audits will help improve maritime traffic safety by eradicating potentially hidden hazards related to marine work.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.35 no.4
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• pp.356-365
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• 2002

One of the most important factors that cause eutrophication is nutrient materials containing nitrogen and phosphorus which stem from excreation of terrestial sources and release from sediment. Therefore, to improve water quality, the reduction of these nutrients loads should be indispensible. At this study, the three-dimensional numerical hydrodynamic and ecosystem model, which was developed by Institute for Resources and Environment of Japan, were applied to analyze the processes affecting the eutrophication. The residual currents, which were obtained by integrating the simulated tidal currents over 1 tidal cycle, showed the presence of a typical counterclockwise eddies between Gyewha and Garyuk island. Density driven currents were generated westward at surface and eastward at the bottom in Saemankeum area where the fresh waters are flowing into, The ecosystem model was calibrated with the data surveyed in the field of the study area in annual average. The simulated results were fairly good coincided with the observed values within relative error of $30\%$. The simulations of DIN and DIP concentrations were performed using ecosystem model under the conditions of $40\~100\%$ pollution load reductions from pollution sources. In study area, concentration of DIN and DIP were reduced to $59\%$ and $28\%$ in case of the $80\%$ reduction of the input loads from fresh water respectively. But pollution loads from sediment had hardly affected DIN and DIP concentration, The $95\%$ input load abatement is necessary to meet the DIN and DIP concentration of second grade of ocean water quality criteria.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.16 no.2
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• pp.75-81
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• 1983

The studies on the age determination of the spottybelly greenling, Agrammus agrammus, caught in the shore of Tongbaeksom were done by the articulative fossae of the vertebra through a stero-dissecting microscope. For determining annunli the vertebra had been cleaved lengthwise in the dorsoventral direction. Half of the vertebra had been fixed on Canada balsam with the flat side directed upwards. The alternation of two zones on the vertebra was observed. One is wide and light-colored, and the other is narrow and dark-colored. The annual layer, where the dark-colored zone shifts to the light-colored one, was appeared extending from July to August once a year. Study of the growth of A. agrammus was carried out by the method of back calculation from the vertebra.

• Fisheries and Aquatic Sciences
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• v.15 no.1
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• pp.1-8
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• 2012

The geographical distribution of the toxic blue-lined octopus (commonly known as the blue-ringed octopus), Hapalochlaena spp., around the East/Japan Sea was investigated. Observation records of the octopus were gathered using commercial search engines on the Internet. A questionnaire to complement and enhance the base data was conducted that targeted fishermen from areas where the octopus was most likely to occur, i.e., the southeast coast and islands of Korea in the East/Japan Sea. Overall, 32 observational records of the blue-lined octopus were found from Korea and Japan. In Korea, only one record, from 2003, was found on a website; none of the 240 fishermen who participated in the questionnaire reported seeing blue-lined octopus. However, a total of 31 observations of the blue-lined octopus from 2004 to July 2010 were found from 17 different regions in the East/Japan Sea and neighboring waters in Japan. Twenty-two cases were from coastal Honshu Island, and nine were from the west coast of Kyushu Island, Japan. The northern distributional boundary of the blue-lined octopus on the Japanese coast was off Fukui Prefecture around latitude $36^{\circ}$10' N. Our results indicate that the blue-lined octopus is distributed extensively along the Japanese coast, at a low frequency, in the East/Japan Sea.