• Journal of Ocean Engineering and Technology
• /
• v.33 no.6
• /
• pp.648-656
• /
• 2019

The ecological changes in the ocean due to the drastic global warming require that action be taken to sustain the productivity of fisheries. Proper ocean facilities could help prevent the loss of the expenditures made on marine aquaculture and reduce the related compensation for various ocean conditions. The aim of this study was to develop a floating ocean wave-breaker using an eco-friendly concrete and conducting a site survey, a structural analysis, and a test of towing the tank. As a result, the wave at the fish farm would be reduced. The results of the holding power of anchors and the capability of moving the floating structures were considered in the design of the wave-breaker. The analyses of the material properties of concrete and the steel structures, as well as the CAPEX and OPEX analyses of the manufacturing and operation processes confirmed the superiority of the floating concrete wave-breaker. In particular, this study demonstrated that the concrete floating breakwater can protect the fish farm against typhoons and reverse-waves, thereby reducing losses of the fish.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
• /
• v.29 no.1
• /
• pp.285-290
• /
• 2005

Until now, korean aquaculture industry has been grown largely from a quantitative viewpoint. However, an increase of quantity has caused lots of problems producing a derived effect recently. Nearly 82% of korean aquaculture farms had been installed mainly at inshore of the southern sea and also sewage, factory wastes, high density of fishcage at the limited area and autoinfection have deteriorated inshore fisheries. The offshore have been on the rise for the solution to these problems since it has clear seawater reduces the environmental pollution with much current. As a matter of fact, the existing inshore fishcage facilities have trouble advancing to the offshore due to the rough environmental conditons such as a high sea, strong currents etc.; therefore, it is necessary to develop a new cultivating equipment fit the open sea conditons. In this research, the theoretical study and experimental analysis have been carried out for the fishcage design of the structure which is able to use at the open sea.

• ALGAE
• /
• v.37 no.2
• /
• pp.85-103
• /
• 2022

Korea is one of the most advanced countries in kelp aquaculture. The brown algae, Undaria pinnatifida and Saccharina japonica are major aquaculture species and have been principally utilized for human food and abalone feed in Korea. This review discusses the diversity, population structure and genomics of kelps. In addition, we have introduced new cultivar development efforts considering climate change, and potential carbon sequestration of kelp aquaculture in Korea. U. pinnatifida showed high diversity within the natural populations but reduced genetic diversity in cultivars. However, very few studies of S. japonica have been conducted in terms of population structure. Since studies on cultivar development began in early 2000s, five U. pinnatifida and one S. japonica varieties have been registered to the International Union for the Protection of New Varieties of Plants (UPOV). To meet the demands for seaweed biomass in various industries, more cultivars should be developed with specific traits to meet application demands. Additionally, cultivation technologies should be diversified, such as integrated multi-trophic aquaculture (IMTA) and offshore aquaculture, to achieve environmental and economic sustainability. These kelps are anticipated to be important sources of blue carbon in Korea.

• ALGAE
• /
• v.26 no.1
• /
• pp.41-50
• /
• 2011

Yellow Sea surface sediment samples collected on October 15-31, 2003 were analyzed using the palynological process to investigate the spatial distribution of dinoflagellate resting cysts. The sampling areas comprised four latitudinal transects, the northernmost of which was located off the Shandong Peninsula, China and the southernmost off Jeju Island, Korea. Each transect line was composed of six to nine stations, spanning the distance between the Chinese and Korean coasts. Twenty-five different types of dinoflagellate cysts were identified. Gonyaulax scrippsae, Alexandrium spp. (ellipsoidal type), and G. spinifera were the most dominant at all stations surveyed. Dinoflagellate cysts belonging to the Gonyaulacales comprised over 50% of all cysts collected. The latitudinal distribution trend showed that cyst concentrations along the two middle transects were much higher than those along the two northern and southern transects. Cyst concentrations in the offshore central areas reached their highest values within each transect and gradually decreased toward the Chinese and Korean coasts. Overall, cyst concentrations were markedly elevated in the offshore central Yellow Sea areas and gradually decreased outward in all four directions. This concentric cyst distribution pattern was consistent with the hydrographic features of the Yellow Sea, such as circular current systems, sedimentary properties, and water depth.

• Proceedings of the Korean Aquaculture Society Conference
• /
• 2003.10a
• /
• pp.128-128
• /
• 2003

The annually outbreak of paralytic shellfish poisoning (PSP) were caused by toxic dinolagellate A. tamarense and A. catenella in Korea. The purpose of this study were to investigate the distribution of PSP-causative organisms, A. tamarense and A. catenella and their species classification. Sediment (Saemangeum, the south open sea) and water samples (southeastern coast) were sampled to establish clonal isolates in 2003. After isolation and purification, strains were cultured under $17^{\circ}C$, f/2 media, 14:10=L:D cycle. PST analysis and species identification were performed by HPLC-FD method and specific DNA probe, respectively. Thirty-ons strains were isolated from the Saemangeum reclamation, southeastern coast including Jinhae Bay and south open sea. PSTs were detected in all cultured strains. In eight strains from south offshore, major toxin components are GTX5, C1/2 and minors are GTX3/4, dcGTX3, neoSTX. Sixteen strains from south coastal area have GTX1/4, neoSTX, C1/2 as major toxin components and GTX2/3 as minors. Seven strains from the Saemangeum reclamation have GTX5, C1/2 as major toxin components and GTX1/2/3/4 as minors. Thus, among eight south offshore isolates, four A. tamarense have more toxic (38.31~l19.16 fmol.$cell^{-1}$) than A. catenella (3.78~13.13 fmol.$cell^{-1}$). With the previous results of different toxin composition, toxin components and toxin contents, .it is toxin profile that could used to diagnosis of regional toxic population and geographical distribution of both A. tamarense and A. catenella and their toxigenic strains.

• Journal of Fisheries and Marine Sciences Education
• /
• v.28 no.5
• /
• pp.1444-1458
• /
• 2016

The expansion of high-density aquaculture in the limited waters has caused a wide variety of problems. The problems include environmental problems nearby aquaculture sites, growth rate of aquatic organisms, quality decline of farmed fish and price fall in the market. The phenomenon of aquaculture industry happens in not only inshore but also offshore. Therefore, the fisheries authorities have been changing their policy paradigms from mass production to sustainable production based on ecosystem. Other countries, however, focusing on relieving poverty and providing protein from fish production have not recognized the degree of seriousness. When it comes to enhancing the problems, National Institute of Fisheries Science has been developing the technology of Integrated Multi-Trophic Aquaculture (IMTA) to reduce and to prevent contaminants from fish and aquaculture sites, remained feed from fish farming process. In long-terms of view, the system is one of the most sustainable fishery production methods based on ecosystem. As integration of nutrient feed system from aquatic organisms is firmly established, the earlier mentioned problems will be diminished gradually. In term of the substantiality, this study was conducted. The research on management system for IMTA also has been incorporated. This study also investigated the features and current status of IMTA and demonstrated the developed management system and direction for the future advancement.

• Korean Journal of Remote Sensing
• /
• v.39 no.6_1
• /
• pp.1401-1411
• /
• 2023

In the face of escalating utilization of the marine spatial domain, conflicts have emerged among stakeholders, necessitating effective management strategies beyond conventional government permits and regulations. Particularly within the domain of aquaculture, operational oversight relies on a localized licensing system, posing challenges in accurately assessing the prevailing circumstances. This research employs synthetic aperture radar (SAR) imagery as a tool to monitor coastal aquaculture fish farms, aimed at enhancing insights into management protocols. Leveraging Sentinel-1A imagery and time series SAR data integration, a superimposition technique is utilized, facilitating noise reduction while retaining crucial information regarding smaller-scale facilities, such as fish farms. Through analysis of VH polarization data, a detection overall accuracy of approximately 88% for coastal fish farms was achieved. The findings of this study offer potential applications in the continuous monitoring of aquaculture farms in correspondence with seasonal variations in aquaculture yields, thereby proposing frameworks for the establishment of effective management cycles for marine space utilization.

• Journal of Ocean Engineering and Technology
• /
• v.10 no.1
• /
• pp.92-99
• /
• 1996

Longline type aquaculture facilities are being used for scallpop culture in 30 m of water 2.5 km off the coast of Joomoonjin, Kangwon-do. In this paper, the facilities are modeled by the cabele-buoy-weight system, subject to the nonlinear behaviors of the mooring lines and the effects of current. Its static configuration is shown as a solution of 3-D nonlinear static equation and Runge-Kutta $4^{th}$ method is employed.

• Journal of the Korean Society of Fisheries and Ocean Technology
• /
• v.49 no.4
• /
• pp.395-403
• /
• 2013

Fishing efficiency of the squid jigging vessel using the LED and metal halide fishing lamp combination was analyzed to reduce the cost for fishing operation utilizing the fishing light system for high degree of efficiency in the squid jigging fishery (one of the representative coastal and offshore fisheries in Korea). This study aims to improve the nature of existing LED lamps and to develop fan-shaped LED lights having 180W of power and ${\pm}45^{\circ}$ angle of light intensity distribution. The marine experiment for making a comparison of their fishing efficiency was tested by a 9.77 tons fishing vessel from Oct. through Dec. 2012. As a result, experimental fishing vessel showed slightly higher fishing efficiency than the average of metal halide lamp-equipped vessel and 20% energy savings. This means that the combination of LED and metal halide lamps would provide an efficient way to lower energy consumption while maintaining fishing efficiency.

• Journal of the Korean Society of Fisheries and Ocean Technology
• /
• v.53 no.3
• /
• pp.266-275
• /
• 2017

The maximum sustained yield (MSY) of shellfish caught through dredge fishery was 7,250 to 7,490 MT from 1990 to 1999, which was not affected by the construction of the Saemangeum Dike. The MSY from 2000 to 2016, under the influence of the dike, was 1,716 to 1,776 MT when the total annual fish catch was 1,000 MT or more, and 289 to 336 MT when it was less than 1,000 MT. The construction of the Saemangeum Dike led to a decrease in the catch volume of the offshore dredge fishery in Jeollabuk-do, to 4.2 to 23.7% of that before its construction. The allowable biological catch (ABC) was estimated to be 313 to 1,532 MT per year, which was about 72.3 to 94.3% less than before the construction of Saemangeum Dike. Currently, the dredge fishery in Jeollabuk-do relies on comb pen shells. For fishery management, the catch per vessel should be set at 51.0 MT/year or less, and the number of fishing vessels should be reduced to 22 as quickly as possible. Besides, in the long term, the number of current fishing vessels should be reduced to less than half in consideration of the comb pen shell collecting period in Jeollabuk-do.