• Journal of Fisheries and Marine Sciences Education
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• v.2 no.1
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• pp.29-35
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• 1989

It is indispensable for the marine officers who are engaged in the international voyage to make command of maritime English fluently. The Marine Officers Act in Korea which is under ammending in 1989 prescribes the proportion of maritime Englishin English examination is made to be 60% for the 4th and 5th class marine officer-license examination. A concrete syllabus or content of maritime English is not established yet with the exception of a general prescription of minimun knowledge required for certification of marine officers in the IMO/STCW Convention. The authors, who rewrote the maritime English textbook for the course of the fisheries high, schools and the merchant marine high schools, settled the syllabi of nautical English and marine engineering English for the course as follows : 1. The syllabus of nautical English, includes maritime English readings, the IMO English dialogue on port entry, writing of logbooks, night order books, and docking and repair specifications. 2. The syllabus of marine engineering English includes maritime English readings, dialogue on oil supply, writing of engine logbooks and oil record books, standing orders, and docking and repair specifications. The authors propose that the realm of these class marine officer-license examination on maritime English should be limited within in the above mentioned textbook. As maritime English is made to be included in the 4th and 5th marine officer liscence examination since 1989, high schools concerned need to reform the curricula to complete at least 6 units for this subject. On the other hand, the competent authority of this examination must secure questions as much as possible to promote the reliability of them.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.54 no.5
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• pp.808-813
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• 2021

The diet composition of Spanish mackerel Scomberomorus niphonius, was investigated using 853 specimens collected using two-boat trawl, stow net, gill net and set net from January to December 2019 from the South Sea of Korea. The size of the specimens ranged from 25.2 to 114.8 cm in fork length. S. niphonius fed mostly on fishes. Its diets also included small quantities of shrimps, cephalopods, crabs, stomatopods, etc. Among them, Engraulis japonicus was the dominant species. The dietary composition of S. niphonius exhibited significant differences based on their size. The proportion of Trichiurus japonicus increased as body size of S. niphonius increased, whereas the proportion of E. japonicus decreased gradually. As the body size of S. niphonius increased, the mean weight of prey per the stomach (mW/ST) tended to increase significantly (one-way ANOVA, P<0.05).

• Korean Journal of Fisheries and Aquatic Sciences
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• v.54 no.6
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• pp.1000-1006
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• 2021

The maturity and spawning of the common octopus Octopus vulgaris were studied using 317 samples collected monthly from January to December of 2020 from the coastal waters of Yeosu, Korea. The mantle length (ML) of O. vulgaris ranged from 5.1 to 19.7 cm and body weight (BW) ranged from 117.6 to 3,645.4 g. We analyzed monthly changes in sex ratio, gonadosomatic index (GSI), histological maturity stage, and body weight at 50%, 75% and 97.5% group maturity. The sex ratio was 1:1.02, which was not significantly different from the value that expected. Based on histological observation of the gonad development and gonadosomatic index, the spawning periods lasted throughout the year, with peak spawning periods estimated from March to April and July to August. The percentages of sexually mature females estimated using a logistic equation were over 50% at 554.46 g BW, 75% at 1,134.38 g BW and 97.5% at 2,474.22 g BW respectively.

• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.47 no.2
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• pp.139-145
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• 2011

Hydro-acoustic survey was carried out to estimate a fish distribution at marine ranching area and aggregated fish schools at artificial reef area in Oeyeondo, Korea. The survey system was set up with DGPS system, scientific echo sounder (EK60, Simrad Co.), and ECDIS (Mecys. Co. LTD). A track survey and a random survey was respectively applied to the marine ranching area (474.4ha) and to the artificial reef area (within a radius of 300m). As the result, fish distribution and MVBS values in marine ranching area showed that created fisheries resources didn't come to be abundant yet as to appear fish distribution in all of the area. In the artificial reef area, it was, however, able to detect many fish school signals on the top of and around artificial reefs and to confirm the luring effect of artificial reefs.

• Fisheries and Aquatic Sciences
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• v.20 no.9
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• pp.21.1-21.10
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• 2017

The aim of this study was to assess visible implant fluorescent elastomer (VIE) tagging and stress response in marine medaka, Oryzias dancena. The experimental fish were anesthetized individually and marked with red, yellow, or green elastomer at each of the following three body locations: (1) the abdomen, (2) the back, and (3) the caudal vasculature. During 12 months, the accumulated survival rates of fish in the experimental treatments were not different among red, yellow, and green elastomers. The experimental fish retained > 85% of the tags injected in the back, > 70% of the tags injected in the caudal vasculature, and > 60% of the tags injected in the abdomen (P < 0.05). An important observation was that the abdomen site was associated with poor tag retention. For all injected sites, the red and green tags were able to be detected more easily than the yellow tags when observed under both visible and UV lights. Tag readability was lower for the abdomen site than for the other sites (back and caudal vasculature). Thus, VIE tags were easy to apply to marine medaka (< 1 min per fish) and were readily visible when viewed under UV light.

• Journal of Environmental Science International
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• v.29 no.3
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• pp.273-282
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• 2020

Residence time is defined as the time taken for a material in a system to leave the system. The residence time characteristics in shellfish aquaculture determine the dispersion of excretion from aquaculture farms, along with the supply of food by seawater exchange. In this study, we estimated the spatial distribution of average residence time in the shellfish farming area using a particle tracking model. As a result, a relatively short average residence time of about 20 days or less was calculated in most areas, but an average residence time of more than 40 days was calculated in the inner areas. Relatively long average residence times were calculated along the west coast compared to the east coast, with the longest average residence time of more than 50 days in the northwestern areas. It can be inferred that the disturbance of the benthic ecosystem caused by shellfish farms is likely to be large because of the relatively weak dispersion of excrement from shellfish farms located on the west coast, especially in the northwest region. This distribution of average residence time is important for understanding the potential effects of seawater exchange on the environmental sustainability of shellfish farms, along with the seawater circulation characteristics of Jaran Bay.

• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.46 no.2
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• pp.139-147
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• 2010

This study monitored a variety of marine fish communities in artificial reefs unit of the total 5 types (Dice type, Octagonal turtle type, Two-stage tube type, Gazebo type, Tetrapod type) which are located in the marine ranching at Jeju island by scuba diving in May, July, October and December 2009. Underwater photographing was accomplished at total 3 phases (condition of artificial reefs photographing, concentric circle movement photographing and line transect photographing). The preservation condition of artificial reefs facility was very good, and the dominant species were Chromis notatus, Sebastes thompsoni, Oplegnathus fasciatus and Halichoeres poecilopterus. Fish abundance was high in May and June, and low in October and December, 2009. Chromis notatus was dominant at the all types of artificial reefs, Halichoeres poecilopterus for Gazebo type and Tetrapod type of artificial reefs, and Sebastes thompsoni for Dice type, Octagonal turtle type and Two-stage tube type of artificial reefs.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.50 no.5
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• pp.567-575
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• 2017

To understand the geochemical characteristics of Gomso Bay, which features extensive Manila clam, we measured various geochemical parameters, organic matter, and trace metals (Cu, Cd, Pb, Zn, Cr, Hg, As and Fe) of intertidal and subtidal surface sediments in 2011. The surface sediments consisted of sedimentary facies including gravel (0.21%), sand (61.1%), silt (32.1%), and clay (6.5%). The chemical oxygen demand (COD) and acid volatile sulfide (AVS) values in most areas were below sediment quality criteria (COD, $20mg/g{\cdot}dry$; AVS, $0.2mg/g{\cdot}dry$). Trace metals in the surface sediments were below pollution thresholds, except for As (morderately polluted). Sediment quality was evaluated using the trace metal pollution load index (PLI) and ecological risk index (ERI), which showed that sediments were generally not polluted and at low risk; however, values along the outer bay were higher. We expect these results will be valuable for sustainable aquaculture prodution and environmental management in Gomso Bay.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.52 no.5
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• pp.534-538
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• 2019

The distribution and characteristics of spawning beds of the Pacific herring Clupea pallasii, were observed by scuba diving in Jinhae Bay, Korea, with a focus on marine vegetation as adhesive substrates and egg density during the spawning season. In 2017, the fertilized eggs of C. pallasii were mainly found attached to the leaves of algae species Carpopeltis cornea, Gracilaria textorii, and Acrosrium polyneurum at the rocky shore in Wonpo-dong and Jeodo. The mean density of fertilized eggs in C. pallasii spawning beds was $153,776eggs/m^2$ off Wonpo-dong and $856,430eggs/m^2$ off Jeodo, giving an estimated total of $5.345{\times}10^9$ eggs in Wonpo-dong and $3.3074{\times}10^{10}$ eggs in Jeodo. We examined spawning beds with an area of $38,619m^2$ off Wonpo-dong and $34,760m^2$ off Jeodo. The choice of spawning bed may be affected by the composition of marine vegetation, such as the algal diversity of rocky shore environments, which could affect adhesive substrates and egg density during the spawning season. The results of the present study suggest that the spawning season of C. pallasii in Jinhae Bay is in January to mid-February.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.55 no.5
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• pp.598-611
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• 2022

The aim of this study was to investigate the range of influence of aquaculture activities in fish cage farms located on the southern coast of Korea (Farm A and B in Hadong, Farm C in Tongyoung, and Farm D in Geoje) by analyzing the distribution and characteristics of polychaete communities. Farm A and B showed remarkably high aquaculture intensity, and as a result, the polychaete communities near the farms were heavily polluted. However, there was a difference in the polychaete communities at a distance greater than 30 m from farm A and B, which may be due to topographical differences. The effect of the aquaculture activity of Farm C was only observed below the farm, however, the influence of aquaculture activities Farm D was maintained over a relatively long distance. According to the results of this study, the effect of the fish cage culture was mainly influenced by factors related to the production of fish, such as the stocking amount and the amount of food supply. Moreover, the distance at which the influence of aquaculture activity was observed was found to be closely related to the topographical characteristics and flow velocity around the farms.