• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.60 no.2
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• pp.170-178
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• 2024

This study aimed to quantitatively analyze the risk using data from 329 safety accidents that occurred in aquaculture fisheries management vessels over the recent five years (2018-2022). For quantitative risk analysis, the Bayesian network proposed by the International Maritime Organization (IMO) was used to analyze the risk level according to the fishing process and cause of safety accidents. Among the work processes, the fishing process was analyzed to have the highest risk, being 12.5 times that of the navigation, 2.7 times that of the maintenance, and 8.8 times that of the loading and unloading. Among the causes of accidents, the hull and working environment showed the highest risk, being 1.7 times that of fishing gear and equipment, 4.7 times that of machinery and equipment, and 9.4 times that of external environment. By quantitatively analyzing the safety accident risks for 64 combinations of these four work processes and four accident causes, this study provided fundamental data to reduce safety accidents occurring in aquaculture fisheries management vessels.

• Journal of Environmental Science International
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• v.16 no.7
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• pp.799-804
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• 2007

Oil spill caused severe effects on the marine fauna and flora due to direct contact of organisms with the oil and even in regions not directly affected by the spill. This study was conducted to understand the effects of the oil spill accidents and the use of dispersant on the red tide of Cochlodinium polykrikoides. Crude oil produced in Kuwait, bunker-C, kerosene and diesel oil, and a chemical dispersant produced in Korea, were added with a series of 10 ppb to 100 ppm in the f/2-Si medium at $20^{\circ}C$ under a photon flux from cool white fluorescent tubes of $100\;mol\;m^{-2}\;s^{-1}$ in a 14: 10 h L:D cycle for the culture of C. polykrikoides. In low concentrations of ${\leq}$ 1 ppm of examined oils no impact on the growth of C. polykrikoides was recorded, while in high concentration of ${\geq}$ 10 ppm, cell density was significantly decreased with the range of 10 to 80% in comparison with the control. The growth of C. polykrikoides after the addition of the dispersant and the mixtures combined with oils and a dispersant of ${\geq}$ 10 ppm appeared to decrease, whereas the growth of C. polykrikoides exposed to ${\leq}$ 100 ppb showed little serious impact. However, almost all the C. polykrikoides cells were died regardless of a dispersant and combined mixtures within a few days after the addition of high concentrations.

• Microbiology and Biotechnology Letters
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• v.49 no.3
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• pp.432-439
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• 2021

Microbial community plays important roles in the culture environment of mud crab Scylla serrata. One of the environmental management efforts for the cultivation of S.serrata is by stabilizing microorganisms involved in nitrogen cycle process. The availability of dissolved inorganic nitrogen in its culture environment under a recirculating system closely relates to the nitrogen cycle, which involves both anaerobic and aerobic bacterial activities. Anaerobically, there are two major nitrogen compound degradation processes, i.e., denitrification and dissimilatory nitrate reduction to ammonium (DNRA). This study aimed to identify denitrifying and DNRA bacteria isolated from the recirculating cultivation of S. serrata. The water samples were collected from anaerobic filters called close filter system, which is anaerobically conditioned with the addition of varying physical filter materials in the recirculating mud crab cultures. The results showed that three denitrifying bacterial isolates and seven DNRA bacterial isolates were successfully identified. The phylogenetic analysis based on 16S rRNA gene of the denitrifying bacteria revealed that HIB_7a had the closest similarity to Stenotrophomonas daejeonensis strain MJ03. Meanwhile, DNRA bacterial isolate of HIB_92 showed a 100% similarity to Bacillus sonorensis strain N3, Bacillus vallismortis strain VITS-17, Bacillus tequlensis strain TY5, Geobacillus sp. strain DB24, Bacillus subtilis strain A1, and Bacillus mojavensis strain SSRAI21. This study provides basic information denitrifying and DNRA bacterial isolates identity which might have the potential to be applied as probiotics in aquaculture systems in order to maintain optimal environmental conditions.

• The Korean Journal of Malacology
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• v.28 no.3
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• pp.277-291
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• 2012

Aquaculture is challenged by a number of constraints with future efforts towards sustainable production. Global climate change has a potential damage to the sustainability by changing environmental surroundings unfavorably. The damaging parameters identified are water temperature, sea level, surface physical energy, precipitation, solar radiation, ocean acidification, and so on. Of them, temperature, mostly temperature elevation, occupies significant concern among marine ecologists and aquaculturists. Ocean acidification particularly draws shellfish aquaculturists' attention as it alters the marine chemistry, shifting the equilibrium towards more dissolved CO2 and hydrogen ions ($H^+$) and thus influencing signaling pathways on shell formation, immune system, and other biological processes. Temperature elevation by climate change is of double-sidedness: it can be an opportunistic parameter besides being a generally known damaging parameter in aquaculture. It can provide better environments for faster and longer growth for aquaculture species. It is also somehow advantageous for alleviation of aquaculture expansion pressure in a given location by opening a gate for new species and aquaculture zone expansion northward in the northern hemisphere, otherwise unavailable due to temperature limit. But in the science of climate change, the ways of influence on aquaculture are complex and ambiguous, and hence are still hard to identify and quantify. At the same time considerable parts of our knowledge on climate change effects on aquaculture are from the estimates from data of fisheries and agriculture. The consequences may be different from what they really are, particularly in the temperature region. In reality, bivalves and tunicates hung or caged in the longline system are often exposed to temperatures higher than those they encounter in nature, locally driving the farmed shellfish into an upper tolerable temperature extreme. We review recent climate change and following environment changes which can be factors or potential factors affecting shellfish aquaculture production in the temperate region.

• Journal of Food Hygiene and Safety
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• v.7 no.2
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• pp.107.2-119
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• 1992

Fish pathology is one of the main scientific bases upon which this expansion in aquaculture has been dependent and requires a wide knowledge of the environmental constraints, the physiology and characteristic of the various pathogens, the responses of the host, and the methods by which they may be controlled. The primary disease and parasite problems in aquaculture animals related to viral, bacteria, fungal and protozoan epizootics. Parasitic nematodes, trematodes and cestodes are commonly found in aquaculture animals, but seldom are they present in concentrations sufficient to cause significant problems, When an epizootic does occur and chemical treatment is indicated, the appropriate chemical must be selected an properly applied. We have antibiotics, sulfa, nitrofuran and other chemicals for treatment of fish diseases, Some may be mixed with the feed during formulation, added to the pellets of feed as a surface coating, given in the form of an injection or used as a bath. Even though a drug or chemical has been officially approved for use in aquaculture, the substance should never be used unless there is a clear need, Some of the reasions for this view are as follows: (1) the constant use of antibiotics can leak to the development of resistant strains of bacteria, (2) biofilter efficiency may be impaired or destroyed by chemicals added to closed recirculating water systems, and(3) the injudicious use of chemical can have a damaging effect on the environment as well as on human.

• The Korean Journal of Malacology
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• v.25 no.2
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• pp.93-96
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• 2009

Unexpected mass mortality has been one of the drawbacks in front of the stable production of Japanese scallop (Patinopecten yessoensis) on the Gangwon coasts of the East Sea. The preliminary data from our routine observation revealed that the mortality appeared to be related to variation of water temperature in the farming site and the degree of the mortality was dependent on scallop strain. The present study performed to verify the preliminary findings exhibited that the mortality was closely related to daily temperature variation rather than monthly variation. Daily temperature variation was particularly damageable to the scallop during the temperature elevation period. Scallops from hatchery seeds (Chinese strain) were more tolerant against the temperature variation over those from wild seeds. The hatchery scallop gain of the temperature tolerance was probably due to their larval experience to higher temperature in the hatchery as well as their maternal genetic acclimation to upper temperature extreme of the Chinese environment which was recently found.

• Proceedings of KOSOMES biannual meeting
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• 2004.11a
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• pp.151-156
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• 2004

In Korea, aquaculture is one of major incomes for fishing households and amounts to $50.6\%$ of total incomes for domestic fishery. The loss of aquaculture farm due to thievery at sea increases every year. In this research, we propose the system model for development of telemonitoring system, which protects aquaculture farms. For the proposed system, general requirements are described. Our system is cost-effective when it is applied to domestic fishing households.

• Fisheries and Aquatic Sciences
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• v.25 no.1
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• pp.40-48
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• 2022

Seahorses, which have been cultivated since the 2000s, are economically very important. Gas bubble disease (GBD) is a significant concern in the cultivation of seahorses; therefore, this study aimed to determine the cause of GBD-induced death in two species of Syngnathidae (Syngnathus schlegeli and Hippocampus haema). Rod-shaped bacteria were observed histopathologically and identified as Vibrio splendidus by conventional and real-time PCR analyses. The lethality of V. splendidus varies depending on the host's immune status, and the disease can be prevented through water quality management or improvement of the breeding environment. In this study, the GBD lesions (gas bubbles) were observed at 12℃, 8.0 mg/L of dissolved oxygen, 30 ppt of salinity, and pH 7.7. In addition, rod-shaped bacteria, infiltration of inflammatory cells, and extensive serous exudate were confirmed in the lesions where gas bubbles were found. PCR analysis was able to detect V. splendidus, possibly a secondary infection of the immunocompromised syngnathid fish. Understanding the risk of immunity control and the correlation between these lesions and causal agents will be of great help to the aquaculture industry and the ornamental fish market.

• The Journal of the Korea institute of electronic communication sciences
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• v.15 no.5
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• pp.959-966
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• 2020

With the growing importance of the fishery industry and the rapid growth of the aquaculture industry, research on smart farms through ICT convergence in the aquaculture field is in progress. To enable monitoring of the growing environment at the farm site, an underwater drone drive unit, an image collection device, an integrated controller for posture stabilization, and a remote control device capable of controlling and controlling drones through real-time underwater images were proposed, and design, development, and tests were conducted. By utilizing underwater drones, it is possible to replace the supply and demand of manpower and high-cost work in the aquaculture industry, and to manage fish farms in a stable manner by reducing the probability of farming deaths.

• Food Science and Biotechnology
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• v.18 no.2
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• pp.533-536
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• 2009

Withdrawal time of erythromycin in the cultured black rockfish (Sebastes schlegeli) was investigated to provide regulatory authority and fishery industry with full information needed to secure food safety of the fish treated with erythromycin. Medication was carried out using the experimental diet containing erythromycin of which concentration was 200 mg/kg diet and its daily dose was about 40 mg/kg body weight. The withdrawal time needed to reduce antibiotic contents around 10.0 mg/kg accumulated during 9 days medication below 0.2 mg/kg was identified about 10 days. The antibiotic with 13.7 mg/kg of fish on the $9^{th}$ days of medication was completely depleted after 30 days from stop of medication.