• Journal of the Korean Society of Marine Environment & Safety
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• v.18 no.2
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• pp.95-100
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• 2012

This study was determined to analysis marine environmental and phytoplankton monitoring in Wando coastal waters in August during the period of 2009-2010 and provided the basic environmental data against Southwest Sea of Korea. In August, 2009, the distribution of water temperature and salinity showed an unique characteristics for all of stations, which was associated with a long duration of rainfall after July, 2009 and a lack of sunshine. In the lower of August, 2010, the stratification of water temperature and salinity was shown, which was caused by an intensive sunshine after the middle of August, 2010. Gangjin Bay and Gogeundo waters showed a highly different water temperature and transparency. It is thought that two regions have a distinct water mass and characteristics. In dissolved oxygen and oxygen saturation were higher according to higher water depth regardless of stations. In August, 2009, different dominant species occurred that Gangjin Bay showed a higher cell density of diatom, but Gonyaulax polygramma played an important role in dominant species in Gogeundo waters. It is associated with the introduction red tide water of G. polygramma occurring to southern coastal water in August, 2009. In August, 2010, diatom was extremely higher cell density compared with that of dinoflagellate that regarded as adaptive microrganism against higher quantity of suspended solid in Wando waters. Although Wando has a record of Cochlodinium red tide, this species may be difficult to grow and persist. Dominant species, diatom, play an important role in food organism for shellfish and forming a ecological lineage.

• The Sea:JOURNAL OF THE KOREAN SOCIETY OF OCEANOGRAPHY
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• v.20 no.1
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• pp.36-42
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• 2015

To determine the predation rate of threadsail filefish, we conducted feeding experiment of threadsail filefish, Stephanolepis cirrhifer on different life stages (medusae, ephyrae, and polyps) of Aurelia aurita s.l. in the laboratory. All size groups of threadsail filefish actively preyed on moon jellyfish Aurelia aurita s.l. and predation rate was proportional to the wet weight of threadsail filefish. Average wet weight 0.5, 1, 2.2 g of threadsail filefish preyed on average $0.77{\pm}0.51g\;fish^{-1}h^{-1}$ of medusae. Average wet weight 150 and 344 g of threadsail filefish preyed on $9.26{\pm}1.61$ and $15.89{\pm}3.67g\;fish^{-1}h^{-1}$ of medusae respectively. In ephyrae and polyps, average wet weight 3.7 g of juvenile of threadsail filefish preyed on 100 ephyrae within 10 minutes and average wet weight 2.2 g of juvenile of threadsail filefish preyed on $5.73{\pm}0.59$ polyps $g^{-1}$ of fish $h^{-1}$. Whereas adults of threadsail filefish did not prey on polyps. In feeding preference experiments to elucidate whether threadsail filefish prey on moon jellyfish in the sea, adults of threadsail filefish preyed on mostly oysters (ca. 60%) and polychaetes (ca. 80%). Medusae were consumed only 2% of total. However, juvenile of threadsail filefish preyed on ephyrae and polyps as well as mysid shrimps. Besides, polyps were consistently consumed during the experiment. Although juvenile of threadsail filefish consumed all kinds of prey, they ceased feeding at temperatures below $11^{\circ}C$, which suggests that possibility of predation on ephyrae may be very low in the sea because ephyrae are released at low temperatures below $11^{\circ}C$ from March to April. Whereas polyps are inhabitable in all seasons in Korean coastal waters, juvenile of threadsail filefish may prey on polyps in the sea. These results suggest that removing moon jellyfish at polyp stage by using juvenile of threadsail filefish is the most effective way for extermination of moon jellyfish.

• Journal of Life Science
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• v.23 no.9
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• pp.1088-1095
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• 2013

The swimming crab, Portunus trituberculatus, inhabits seafloor habitats containing sand or pebbles and is widely distributed throughout the world. The present study investigated genetic polymorphisms of 10 microsatellites in 281 samples of P. trituberculatus collected from four locations along the coastal water of the Korean side of the Yellow Sea (Yeonggwang, Taean, Sorea, and Yeonpyeong-do Island). The number of alleles per locus ranged from 50 to 129, with a mean of 69.5. The observed and expected hetrozygosity varied from 0.111 to 1.000 and from 0.609 to 0.979, respectively. The inbreeding coefficients (Fis) varied among the loci from -0.0207 to 0.8175. The genetic differentiation (Fst) was less than 0.05 (range 0.0020-0.0124). Therefore, the four groups of P. trituberculatus appeared to exhibit little genetic differentiation. The lack of differentiation was confirmed in a phylogenetic tree constructed by the unweighted pair group method with the arithmetic average (UPGMA). The hypervariation between the populations and the lack of genetic differentiation may reflect active gene flow among the Yellow Sea populations and the absence of geographical boundaries. The highly polymorphic microsatellite loci will be useful for molecular and phylogenetic studies, as well as stock management, of swimming crab, which is an important fishery resource.

• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.43 no.2
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• pp.101-115
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• 2007

The pound net fishery is very important one in Korean coastal fishery and it need to grasp the characteristics of the net affected by many factors. It is considered that the structure and the shape of the pound net can be changed by the direction and speed of current, wave height, depth and conditions of sea bed. However, most of all, the speed of current and wave height influence more upon the pound net than any other factors to deform and flutter. In this study, author carried out the experiments with a model of double one-side pound net made by the similarity law as 1:100 scales at a real experimental area, and additionally the model net experiments were conducted in the circulating water channel in Pukyong National University. The author analyzed the data of transformation of shape and tension of the model pound net to recognize the characteristics of the current and wave acting on it. Regardless of the direction of flow affecting on the fish court net or bag net, the deformed angle and depth to the side panel and bottom of box nets becomes bigger as the wave gets higher and the period of wave is faster. The tension in both upward or downward tends to be changed by the speed of wave. Those value of changes occurred similarly in either fish court net or bag net. Generally, when bag net is located at upward of flow, the value of tension was bigger 10% than any other location or nets. Regardless of the setting direction, the tension of the pound net is increased in proportion to flow speed, wave height and period of wave, and it becomes bigger about 15-30% at upward to flow than downward. Where the flow is upward in the court net, the tension in the wave increased to 37% compared to the one in the flow only in the condition of flow of 0.1-0.3m/s. Where the flow is upward in the bag net, the tension in the wave increased to 52% in the flow of 0.1m/s, and the tension increased to 48% in the flow of 0.2-0.3m/s.

• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.36 no.3
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• pp.166-174
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• 2000

Anchovy, EngrauEis japonica scoop nets are used in the coastal of Southern and Cheju of Korea. Especially in the Cheju, the fishing gear of scoop nets consists of upper boom, lower boom, pressing stick and bag net. They are operated by fishing boats of 6 to 10 ton class and 8 persons on board. The booms are controlled by side drum, and the net and pressing stick are hauled by only human power in operating. Therefore this fishery needs to large labor and heavy human power and has much risk. Three kinds of hydraulic winding device which controls two booms was designed and manufactured to reduce heavy labor force of scoop nets, and trial in the sea was carried out to test their performances using the commercial fishing boats of 6 ton class. The proper capacity of hydraulic pump and motor were determined by model test of boom 1/5 scale. The results obtained are as follows, 1. Tension of boom which is being drawn was the strongest and 187.5kgf when the boom's end is in the depth of 4m under the water. 2. The hydraulic motor of the fittest kind of winder has the least leakage per time than the other kinds. 3. In the best type of several winder devices, when the pressure difference was fixed $130kg/^2$ for the safe fishery, the winding velocity of boom line was 2m/sec, is faster 0.48/sec than traditional fishing method and this winder can catch the anchovy of 1.6 tonnage. 4. As a result, the crew were decreased from 8 to 6 and the problem of heavy human power and risk on fishing operation were solved by using the this winder.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.8 no.8
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• pp.1620-1625
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• 2004

To advance fisheries, we set developmental directions of fishery information by grasping present situations and analyzing maritime & fisheries issues. We promote various policies through effective systematical information data bases, based on both control and utilization of oceanic resources. For these puposes, it is imperative that we set up fisheries communication networks. There are satellite assisted informational networks to assist fishing vessels with their marine based movements. However, there's no hope for poorly equipped fishermen to adopt this network because of extravagant network call charges. So we think that using existing SSB communication system is the best plan. We organize fishery communication network by HF SSB communication which doesn't have operational costs. We build wireless transmitting and receiving stations that are basic systems of informnation, and equip wireless data communication systems by the use of wireless communication network protocols in coastal stations. It is necessary that a fish boat has a terminal device for wireless data communication. In this research we can conclude that if we transmit the location of a fishing boat in-real time through GPS channels then we propose that some methods be formulated to able terminal devices on fishing boats to collect various types of information, such as meteorological and oceanic conditions.

• Korean Journal of Environmental Biology
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• v.37 no.2
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• pp.119-128
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• 2019

The morphological characteristics of the bloom-forming dinoflagellate Akashiwo sanguinea isolated from Jangmok Harbour, Geoje in Korea was examined using light and scanning electron microscope (SEM), and its large subunit (LSU) rDNA was sequenced. Additionally, investigation was done on the effects of temperature and salinity on the growth of A. sanguinea. The cells were dorso-ventrally compressed up to 54.7-70.3 ㎛ long and 31.5-48.5 ㎛ wide. The epicone was conical while the hypocone was separated into two lobes. The nucleus was positioned at the center of the cell. The yellow-brown chloroplasts radiated close to the cell center. SEM observation indicated that A. sanguinea has an e-shaped apical groove. Molecular phylogeny based on LSU rDNA gene sequences revealed that the A. sanguinea strains isolated from Jangmok Harbor were classified in the clade of ribotype A. The maximum growth rate (0.50 day^-1) was observed at 20℃ and 20 psu, while the maximum cell density (1,372 cells mL^-1) was observed at 25℃ and 30 psu. This indicates that the blooms of A. sanguinea ribotype A in Korean coastal area are affected by water temperature, rather than the salinity.

• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.38 no.4
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• pp.293-299
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• 2002

The anchovy scoop net fishery is one of the important in the South sea and coastal of Jeju of Korea. They are using incandescent lamp as a fishing lamp at night to gather anchovy shoals in the water surface. Fishing lamp (AC 100 V 500 W$\times$2~3 or AC 100 V 1 ㎾$\times$1) was installed at 1 m ahead of the prow and 1.5 m height from the water surface. The fishing lamp let anchovy shoals rise to the water surface and are attracted to bag net. On this study, the distribution of submarine illumination of 1㎾ and 2 ㎾ incandescent lamp were analyzed and discussed to investigate the ability of fishing lamp which can gather anchovy shoals effectively. The submarine illumination of incandescent lamp showed peak in wave length 690 nm. The relationship between submarine illumination (L) and water depth (Z) of 1 ㎾ and 2 ㎾ incandescent lamp in vertical light is 1 ㎾ : L = 3851. 9 $e^{-1.4587Z}$ $R^2$=0.9952 2 ㎾ : L= 8211.9 $e^{-1.2852Z}$ $R^2$=0.9977 The submarine illumination of 2 ㎾ incandescent lamp of 0～4 m layers appeared to be 3 to 4 times higher than 1 ㎾ incandescent lamp, and in more deep layers than 6 m appeared to be equal value of each lamp. The light of incandescent lamp (1 ㎾) pass through much better into vertical direction than horizontal, and submarine illumination of 20 m layers was 1.0 l$\chi$. Therefore, fishing lamp power is thought that 1 ㎾ incandescent lamp is more efficient than 2 ㎾ to gather anchovy shoals in depth of 15~20 m to water surface.

• The Journal of Fisheries Business Administration
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• v.30 no.2
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• pp.1-23
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• 1999

In the Northeast Asian region fisheries agreements of the past regarding high seas as an agreement area were transformed or new agreements were introduced in order to conform to the EEZ regime. However, the existing joint regulatory zone which “open” status is somewhat similar to the high sea not only disappear, but also two new systems were established. To begin with, parties of the agreement claimed their EEZs to be from the territorial sea baselines to the extent set forth, problem of the fishery access of the other party under the agreement is to be solved on the principle of reciprocity and on recognizing of the catch results achieved in the past. In regards to the overlapping zones like neutral zone of the East Sea of Korea(Sea of Japan) and neutral zone to the south of the Cheju Island, provisional measures zones in the Yellow Sea and in the East China Sea, and transitional zone of the Yellow Sea special fisheries management systems reflecting the legal character of the zone involved are applied. Moreover, as fisheries agreements defining open sea as an agreement zone are not able to conform to the EEZ regime, so new fisheries agreements must be taken out from old systems and conceptions, and must be understood and enforced from the new point view. Therefore, countermeasures needed to do so should be developed, and their basic structure is as follows. Firstly, the basic concept of the EEZ regime requires that the coastal states have sovereign rights on their sea zones' natural resources and bear responsibilities appropriate to their allowed jurisdiction. Each Northeast Asian state should adjust the structure of fishing industries and employ advanced fisheries management system, and should make efforts toward such issues of the state policy as increasing fishery resources and preserving ocean environment. Secondly, measures should be developed to solve the international fisheries disputes which are to occur under enforcement of the new fisheries agreements system. In regards to the acts of violation the fisheries laws in the foreign EEZ the principle of jail sentence prohibition is established by the UN Convention on the Law of the Sea, and every fisheries agreement reflects this principle. Therefore, the present question is to consider concrete measures to enable the easy release of the seamen, who violated fisheries laws slightly and well-intently, through establishment and management of the guarantee fund needed to make collateral reasonable. Thirdly, Korean-Russian and Russian-Japanese fisheries relations were formed on the basis of the EEZ regime, since 1992 and 1977 respectively, and are expected to maintain mutually beneficial cooperative character. As for Korean-Chinese-Japanese fisheries relations, the operational problems of overlapping zones, and problem of the permits for EEZ mutual access should be solved on the basis of the principle of reciprocity and equity rather than unilaterally from any side.

• 한국해양학회지
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• v.1
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• pp.37-48
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• 1971

Observations of water temperature, salinity, pH and transparency of the Ko-ri sea area were made between May 1969 and April 1970. A seasonal thermocline was well defined in August, strongly isolating the warm serface water(19-22$^{\circ}C$) from the cold bottom water (14-17.5$^{\circ}C$) introducing from the open sea. In February the coldest isothermal water (11$^{\circ}C$) occurred. In the warm months(May- September), the salinity patterns show great variations with the coastal run-off During the cold months(December-April) the highest isohaline water (35 ) occurred. Annual ranges of surface and bottom pH values were 7.8-8.4(averaging 8.27) and 7.9-8.4(averaging 8.26), respectively. The transparency was greatest (6.0-7.0m) during winter and spring months and least (1.2-2.5m) during summer months.