• Journal of the Korea Concrete Institute
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• v.25 no.1
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• pp.115-123
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• 2013

The steel industry, a representative industry that significantly consumes raw materials and energy, produces steel as well as a large amount of by-product steel slag through the production process. The vast habitat foundation of marine life has been destroyed due to recent reckless marine development and environment pollution, resulting in intensification of the decline of marine resources, and a solution to this issue is imperative. In order to propose a method to recycle large amounts of by-product slag into a material that can serve as an alternative to natural aggregate, the engineering properties and applicability for each mixing factor of environment friendly porous concrete as a material for the composition of marine ranches were evaluated in this study. The test results for percentage of voids per mixing ratio revealed that the margin of error for all conditions was within 2.5%. The compressive strength test results showed that the most outstanding environmental friendly porous concrete can be manufactured when mixing 30% slag aggregate and 10% specially treated granular fertilizer for the optimum volume fraction. As concrete for marine applications, the best seawater resistance was obtained with mixing conditions for high compression strength. An assessment of the ability to provide a marine life habitat foundation of environmentally friendly porous concrete showed that a greater percentage of voids facilitated implantation and inhabitation of marine life, and the mixing of specially treated granular fertilizer led to active initial implantation and activation of inhabitation. The evaluation of harmfulness to marine life depending on the mixture of slag aggregate and specially treated granular fertilizer revealed that the stability of fish is secured.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.15 no.3
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• pp.233-240
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• 1982

Some environmental parameters on the shell-fish farms in Deukryang and Gamagyang Bays during summer in 1981 were determined to find an eutrophication level for the conservation of the farm. Chlorophyll-a content in the seawater in the Deukryang Bay in September was $1.0{\sim}5.0{\mu}g/l$ with an average of $2.5{\mu}g/l$ In the superficial bottom muds, contents of COD were 5-10 mg/g, ignition loss $5-9\%$, phaeophytin pigment $2{\sim}5{\mu}g/g$, and sulfide 0.1-0.3 mg/g dry mud in both bays. High contents of both organic matters and sulfide were found in the innermost area of the Deukryang Bay and in the north western part of the Gamagyang Bay. All quantities including chlorphyll-a in the water are little less than or similar to those of Hansan-Geoje Bay, one of the most productive shellfish farms in the southern coastal waters in Korea . Eutrophication on both water and bottom mud was under way like other shellfish farms but pollution indices on the bottom mud calculated from the data of CODs and phaeophytin pigments shelved 6-11, which is much lower than those of Jinhae Bay and of the Hansan-Geoje Bay. This means that the bottom muds are in an early stage of eutrophication, unlike the Jinhae and Hansan-Geoje Bays though the water, similar to the other bays, shows a middle stage of eutrophication.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.44 no.5
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• pp.464-469
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• 2011

Residues of ampicillin and amoxicillin in the muscles of olive flounder Paralichthys olivaceus were investigated after oral doses of 20 mg/kg body weight/day of ampicillin and 40 mg/kg body weight/day of amoxicillin in a first examination and 40 mg/kg body weight/day of ampicillin and 80 mg/kg body weight/day of amoxicillin in a second examination for 5-6 days. The ranges of seawater temperatures in the $1^{st}$ and $2^{nd}$ examinations were $13.4-15.6^{\circ}C$ and $16.8-21.4^{\circ}C$, respectively. Ampicillin and amoxicillin concentrations were analyzed by high performance liquid chromatography (HPLC). The average recovery rates of ampicillin and amoxicillin in fish samples ranged from 84.8-95.2% and 100.8-103.8%, respectively. Residual concentrations in the olive flounder peaked on the $5^{th}$ day, with average concentrations of 0.075 mg/kg and 0.311 mg/kg in the $1^{st}$ examination, and 0.098 mg/kg and 0.630 mg/kg in the $2^{nd}$ examination for ampicillin and amoxicillin, respectively, with maximum concentrations in muscle. In the $1^{st}$ examination, ampicillin concentrations in olive flounder after withdrawals of 1 and 3 days were 0.041 mg/kg and 0.023 mg/kg, respectively, and amoxicillin concentrations after withdrawals of 1 day and 10 days were 0.172 mg/kg and 0.023 mg/kg, respectively. In the $2^{nd}$ examination, the ampicillin concentrations in olive flounder after withdrawals of 1 and 3 days were 0.041 mg/kg and 0.023 mg/kg, respectively, and amoxicillin concentration after withdrawals of 1 day and 10 days were 0.172 mg/kg and 0.023 mg/kg, respectively. We suggest that the recommended withdrawal periods should be 3 days for ampicillin and 10 days for amoxicillin in the olive flounder.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.32 no.2A
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• pp.123-130
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• 2012

A cooling system is indispensable for the fossil and nuclear power plants which produce electricity by rotating the turbines with hot steam. A cycle of the typical cooling system includes pumping of seawater at the intake pump house, exchange of heat at the condenser, and discharge of hot water to the sea. The cooling type of the nuclear power plants in Korea recently evolves from the conventional surface intake/discharge systems to the submerged intake/discharge systems that minimize effectively an intake temperature rise of the existing plants and that are beneficial to the marine environment by reducing the high temperature region with an intensive dilution due to a high velocity jet and density differential at the mixing zone. It is highly anticipated that the future nuclear power plants in Korea will accommodate the submerged cooling system in credit of supplying the lower temperature water in the summer season. This study investigates the approach flow patterns at the velocity caps and discharge flow patterns from diffusers using the 3-D computational fluid dynamics code of $FLOW-3D^{(R)}$. The approach flow test has been conducted at the velocity caps with and without a cap. The discharge flow from the diffuser was simulated for the single-port diffuser and multi-ports diffuser. The flow characteristics to the velocity cap with a cap demonstrate that fish entrainment can significantly be minimized on account of the low vertical flow component around the cap. The flow pattern around the diffuser is well agreed with the schematic diagram by Jirka and Harleman.

• Journal of the Korean Society for Marine Environment & Energy
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• v.15 no.1
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• pp.30-37
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• 2012

This paper assessed environmental impact of tidal power plant construction in the western sea of Korea, and diagnosed problems of the related assessment. We also proposed key assessment items (scoping) and system improvement for environmental impact assessment (EIA). The establishment of a broad consensus of the appropriateness and a clear purpose for business is an important aspect of the aptness of using the waters, and the aggressive collecting of opinions of the stakeholder and institutions will have to be fulfilled. In addition, we presented the following scoping plan in order to minimize the negative effects of the marine ecosystem and the conflict between the people who work in the fishing industry which result due to the construction of the tidal power plants. (1) the change in seawater exchange rates and the aspect of erosion/sedimentation which result from the change in the velocity of running fluid, (2) the destruction of spawns/habitats of fish due to the damage of tidal flats, (3) fishery resources, impacts of fishing grounds, and the spread of suspended sediments, etc. will have to be applied to the key assessment items(scoping). In addition, every citizen will have work hard for an establishment of an active plan which achieves the harmony and balance of environmental preservation and for the policy to be applied through changing their consciousness of environmental preservation.

• Fisheries and Aquatic Sciences
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• v.21 no.9
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• pp.26.1-26.8
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• 2018

Inclusion effect of soybean meal (SBM) and fermented SBM (FSM) in extruded pellet for juvenile abalone (Haliotis discus) was compared in abalone farm. Dietary inclusion effect of the combined macroalgae (MA) (Undaria pinnatifida and Hizikia fusiforme) and a single Saccharina japonica on abalone was also compared. Three thousand six hundred juvenile abalone were purchased from a private hatchery and acclimated to the experimental conditions for 2 weeks. Six 5-ton flow-through raceway tanks were used, and abalone were randomly distributed into tanks (n = 600 per tank). Three experimental diets were prepared in duplicate. Fish meal, FSM, corn gluten meal, and shrimp meal and wheat flour and dextrin were used as the protein and carbohydrate sources, respectively, in the FSM diet. MA was also included in the FSM diet. FSM and MA in the FSM diet were substituted with SBM at the expense of wheat flour and S. japonica, referred to as the SBM and SJ diets. The experimental diets were pelletized by an extruded pelleter. Water stability of nutrients in the experimental diets was monitored at 12, 24, and 48 h after seawater immersion. The experimental diets were fed to abalone once a day to satiation with a little leftover for 120 days. The retained crude protein and lipid and ash content of the extruded pellets were changed over all period of time. Weight gain and specific growth rate (SGR) of abalone fed the SBM diet were greater than those of abalone fed the FSM and SJ diets. Weight gain and SGR of abalone fed the SJ diet were also greater than those of abalone fed the FSM diet. The longest shell length, widest shell width, highest shell height, and greatest soft body weight were obtained in abalone fed the SBM diet, followed by the SJ and FSM diets. Proximates of the soft body of abalone were not different among the experimental diets. In conclusion, SBM was a superior protein source to FSM in extruded pellet for growth performance of abalone. Dietary inclusion of a single S. japonica was superior to the combined inclusion of U. pinnatifida and H. fusiforme in the production of abalone.

• Journal of Fisheries and Marine Sciences Education
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• v.26 no.1
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• pp.72-80
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• 2014

Oxygen consumption (OC) of male black porgy Acanthopagrus schlegelii reared in freshwater (BFW) and seawater (BSW) during the reproductive period was $165.4{\pm}11.0$, $77.6{\pm}8.0$ mg $O_2/kg/h$ at $15^{\circ}C$, $186.2{\pm}13.1$, $133.4{\pm}6.7$ mg $O_2/kg/h$ at $20^{\circ}C$ and $267.9{\pm}19.1$, $198.6{\pm}8.3$ mg $O_2/kg/h$ at $25^{\circ}C$, respectively. During the non-reproductive period, it was shown as $174.0{\pm}7.0$, $85.6{\pm}5.5$ mg $O_2/kg/h$ at $15^{\circ}C$, $200.6{\pm}11.1$, $119.2{\pm}8.7$ mg $O_2/kg/h$ at $20^{\circ}C$ and $271.1{\pm}7.5$, $194.7{\pm}16.7$ mg $O_2/kg/h$ at $25^{\circ}C$, respectively. Thus, OC of BFW was higher than BSW both for non-reproductive and reproductive period. Also, OC increased in proportion to the rise in water temperature, and there was no difference of OC between BFW and BSW at each water temperature during the reproductive or non-reproductive period. OC of BFW and BSW showed clear circadian rhythms on photic conditions of reproductive and non-reproductive period, and the fish consumed more oxygen during the dark phase than for the light phase. In particular, OC of BFW during the reproductive period increased more sharply compared to non-reproductive period when the increase of water temperature was accompanied by the shift from dark to light phase. This implies that they react to the light more sensitively for reproductive period than for non-reproductive period.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.33 no.5
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• pp.408-412
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• 2000

The juvenile Bobiids, Faronirobius gymnauchen, were reared for 40 days under $0{\~}33.6{\%_{\circ}}$ salinity conditions to examine the effects of various salinity on its survival, growth and oxygen consumption rates, Survival rate was significantly declined below $6.7{\%_{\circ}}$ salinity, and daily growth rate was also reduced below $10.1{\%{\circ}}$. Body length and weight of gobiids reared below $10.1{\%_{\circ}}$ were smaller than those of gobiids reared above $20.2{\%_{\circ}}$. Oxygen consumption rate in the salinity conditions ${\leq}13.4{\%_{\circ}}$ was significantly reduced with decreasing salinity than that in natural seawater ($33.6{\%_{\circ}}$), This study revealed that low salinity reduced survival, growth and oxygen consumption rates of the juvenile gobiids suggesting potential influence on the natural mortality of F gymnauchen in the coastal areas.

• Journal of Microbiology and Biotechnology
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• v.27 no.9
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• pp.1593-1601
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• 2017

Vibrio species are generally recognized as pathogens predominant in seafood along coastal areas. The food industry has sought to develop efficient microbial detection methods. Owing to the limits of conventional methods, this study aimed to establish a rapid identification method for Vibrio isolated from Korea, based on matrix-assisted laser-desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS). Four different preparation procedures were compared to determine the appropriate means to pretreat Vibrio species, using 17 isolates and five reference strains. Extended direct transfer and full formic acid extraction methods using bacterial colonies on agar plates revealed very low identification rates. Formic acid and trifluoroacetic acid (TFA) extractions using bacterial broth cultures were also performed. All Vibrio isolates and reference strains prepared by TFA extraction were successfully identified to the species level (17/22, 77.3%) and to the genus level (5/22, 22.7%). Thus, TFA extraction was considered the most appropriate method to pretreat Vibrio species for MALDI-TOF MS. The remaining 33 isolates and two reference strains were prepared by TFA extraction and analyzed by MALDI-TOF MS. Overall, 50 isolates were identified to the species level (40/50, 80%) and to the genus level (10/50, 20%). All isolates were identified as 43 V. alginolyticus, six V. parahaemolyticus, and one V. vulnificus species. V. alginolyticus and V. parahaemolyticus were isolated from fish offal (87.5% and 12.5%, respectively), seawater (91.3%, 8.7%), and shellfish (62.5%, 37.5%), whereas V. alginolyticus and V. vulnificus were isolated from sediment (90.9% and 9.1%, respectively). This study established a reliable system of MALDI-TOF MS preparation and analysis for Vibrio identification.

• Journal of Life Science
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• v.26 no.2
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• pp.164-173
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• 2016

Isotocin (IT), a nonapeptide homolog of oxytocin in mammals, has been suggested to be involved in physiological processes including social behaviors, stress responses, and osmoregulation in teleost fish. To study its structure and function, the gene encoding the IT precursor was cloned from the genomic DNA and brain cDNA of the cinnamon clownfish, Amphiprion melanopus. The IT precursor gene consists of three exons separated by two introns, and encodes an open reading frame of 156 amino acid (aa) residues, comprising a putative signal peptide of 19 aa, a mature IT protein of 9 aa, a proteolytic processing site of 3 aa, and 125 aa of neurophysin. Tissue-specific analysis of the IT precursor transcript indicated its expression in the brain and gonads of A. melanopus. To examine its osmoregulatory effects, the salinity of the seawater (34 ppt) used for rearing A. melanopus was lowered to 15 ppt. Histological analysis of the gills indicated the apparent disappearance of an apical crypt on the surface of the gill lamella of A. melanopus, as pavement cells covered the surface upon acclimation to the lower salinity. The level of Na⁺/K^+-ATPase activity in the gills was increased during the initial stage of acclimation, followed by a decrease to its normal level, suggesting its involvement in osmoregulation and homeostasis. The only slight increase in the level of IT precursor transcript in the A. melanopus brain upon low-salinity acclimation suggested that IT played a minor role, if any, in the process of osmoregulation.