Waters Of South Korea Research Articles

Draft genome sequences of Klebsiella spp. isolated from produce and agricultural water in South Korea.

This report outlines the draft genome sequences of six Klebsiella spp. strains from South Korea's agricultural produce and environments. Genome sizes ranged from 5.25 to 6.21 Mbp with 55.64% to 57.55% GC content. Each strain contained multiple plasmid sequences identified by PlasmidFinder, indicating significant antimicrobial resistance.

Genetic and virulence characteristics of hybrid Shiga toxin-producing and atypical enteropathogenic Escherichia coli strains isolated in South Korea.

The predominant hybrid pathogenic E. coli, enterohemorrhagic E. coli (EHEC), combines characteristics of Shiga toxin-producing E. coli (STEC) and enteropathogenic E. coli (EPEC), contributing to global outbreaks with severe symptoms including fatal consequences. Since EHEC infection was designated as a notifiable disease in 2000 in South Korea, around 2000 cases have been reported, averaging approximately 90 cases annually. In this work, genome-based characteristic analysis and cell-based assay of hybrid STEC/aEPEC strains isolated from livestock feces, animal source foods, and water in South Korea was performed. To identify the virulence and antimicrobial resistance genes, determining the phylogenetic position of hybrid STEC/aEPEC strains isolated in South Korea, a combination of real-time PCR and whole-genome sequencing (WGS) was used. Additionally, to assess the virulence of the hybrid strains and compare them with genomic characterization, we performed a cell cytotoxicity and invasion assays. The hybrid STEC/aEPEC strains harbored stx and eae genes, encoding Shiga toxins and E. coli attachment/effacement related protein of STEC and EPEC, respectively. Furthermore, all hybrid strains harbored plasmid-carried enterohemolysin(ehxCABD), a key virulence factor in prevalent pathogenic E. coli infections, such as diarrheal disease and hemolytic-uremic syndrome (HUS). Genome-wide phylogenetic analysis revealed a close association between all hybrid strains and specific EPEC strains, suggesting the potential acquisition of Stx phages during STEC/aEPEC hybrid formation. Some hybrid strains showed cytotoxic activity against HeLa cells and invasive properties against epithelial cells. Notably, all STEC/aEPEC hybrids with sequence type (ST) 1,034 (n = 11) exhibited higher invasiveness than those with E2348/69. This highlights the importance of investigating potential correlations between STs and virulence characteristics of E. coli hybrid strains. Through genome-based characterization, we confirmed that the hybrid STEC/aEPEC strains are likely EPEC strains that have acquired STEC virulence genes via phage. Furthermore, our results emphasize the potential increased danger to humans posed by hybrid STEC/aEPEC strains isolated in South Korea, containing both stx and eaeA, compared to STEC or EPEC alone.

Evaluation of vertical distribution characteristics of microplastics under 20μm in lake and river waters in South Korea.

Following the alarming reports of microplastic pollution in the marine environment, increased attention has been given to microplastics in other environmental media. Despite the attention, there is limited research available on the depth-distribution of microplastics in freshwater. Specifically, in the case of water sources used for drinking or tap, the height of intake facilities varies, and it is highly likely that there is a correlation between the vertical distribution of microplastics and these water intake structures. Further, because the size of microplastics varies widely in the environment, the commonly used sampling devices are not suitable for selectively extracting microplastics without causing cross-contamination. Thus, we developed a suitable device for microplastics of size 5-20µm and studied microplastic distribution in freshwater at various depths by considering various types of microplastics and aqueous systems. Lake and river, two major water sources, were selected for the study of microplastics distribution in water system. The microplastic distribution characteristics in both water systems showed that polypropylene and polyethylene were the most abundant across all depths because of their production volume. Plastic types with higher density were found only at the lower layers, and polystyrene was found in the upper layers because of the environmental effects on its buoyancy caused pore diameter and surface area. The lake and river had higher microplastic distribution in the lower layer and upper layer, respectively. This was because the flow rate in river was higher than that of lake. The higher flow rate reduced the settling velocity in river. Thus, hydrodynamic stability influences the vertical distribution and concentrations of microplastics in the water systems. These results are expected to be used for understanding the behavioral characteristics of microplastics in water systems and to manage water sources.

Tracing the geographical origin of bottled water collected in South Korea via isotopic and elemental analyses.

The production of bottled water requires a forensic discriminant technique that enables the identification of the brands or accidents caused by intended contaminants. The bottled water poisoning crimes have drawn much attention, and such crimes may recur in the future. The water is colorless and odorless, and thus it is difficult to detect contaminated water through visual observation. Thus, bottled water can be easily exploited for poisoning, and a method for tracing their origin is currently required. In this study, a total of 27 brands of bottled water samples were analyzed to determine stable oxygen isotopes, strontium isotopes, major and trace elements. The geographical origin of the water was traced based on the climatic and geographical characteristics of the location from where water was sourced, which was assumed to be reflected in the bottled water. Furthermore, we investigated whether this method can be applied to identify bottled water products. The results demonstrated that the characteristics of the bottled water, including the oxygen stable isotope ratios, reflect the latitude and altitude of bottled water source in South Korea, from the high-latitude region to the coastal regions. In addition, the results indicated that excellent discrimination was achieved using strontium isotopes to identify source areas with different types of bedrock, complex underlying lithologies, and ocean areas in South Korea. A statistical method based on discriminant analysis was applied to measure trace elements, and the results effectively reflected the characteristics of water-rock interactions (cross-validated classification probability: ≥92%). These data suggest that the geographical characteristics of the source area are well reflected in commercial bottled water in South Korea. The proposed analytical methods can be utilized to trace the geographical origin of different bottled water samples and identify bottled water products used in poisoning crimes.

Analysis of food preference and competition based on stomach contents of fish species inhabiting fresh and brackish waters in South Korea

AbstractWe analysed the stomach contents of fish species inhabiting fresh and brackish waters of South Korea to improve our understanding of feeding preferences and competition among them. The stomach contents of 54 fish species contained 237 genera, 187 families, 84 orders, 37 classes and 25 phyla. Faunal food items included 164 genera, 129 families, 47 orders, 23 classes and 16 phyla. Floral food items were relatively limited, comprising 73 genera, 58 families, 37 orders, 14 classes and nine phyla. The most consumed faunal food item was Chironomidae (Diptera), whereas the most consumed floral food item was Fragilariaceae (Fragilariales). The 54 fish species were classified into six groups using hierarchical and nonmetric multidimensional analysis based on their food preferences: Group 1 (G1) fishes were zooplanktivores; group 2 (G2) fishes mainly consumed Malacostraca, Maxillopoda and other fishes (e.g. Osmeriformes); groups 3 (G3) and 4 (G4) consumed Chlorophyta, Cyanobacteria and Bacillariophyta; and groups 5 (G5) and 6 (G6) consumed macroinvertebrates. Network analysis was used to link fishes with their food items. The highest hub score for food items was for macroinvertebrates, including Diptera (13.9), Ephemeroptera (11.1) and Trichoptera (8.2). Niche breadth analysis represented the diversity of food items among the feeding groups (G1–G6). Food item diversity was high for planktivores (G1 and G3) and omnivores (G4). Conversely, the dietary diversity of carnivores (G2) and insectivores (G5) was limited. Competitive relationships between fishes, as represented by the niche overlap in G5 (insectivores), were higher than those between other groups.

Characteristics and Sources of Selected Halocarbon and Hydrocarbon Volatile Organic Compounds in Surface Water of the Han River Basin

Volatile organic compounds (VOCs) are ubiquitous pollutants in surface water, which is the main source of drinking water in South Korea. We investigated the behavior (concentration, distribution, and environmental risk) of eleven selected VOCs in the surface water of the Han River tributaries using purge-and-trap gas chromatography/mass spectrometry. The average concentration of VOCs was 0.29 ± 0.47 μg/L. Chloroform and trichloroethylene (TCE) were the major pollutants, accounting for approximately 64.2% and 25.6% of the total concentration, respectively, and showing that halocarbons accounted for 94%. Chloroform was positively correlated with TCE and xylenes, and TCE was positively correlated with tetrachloroethylene (PCE). No differences were observed in the temporal average concentrations of total VOCs, but the concentrations differed significantly among sub-watershed areas. The Imjin-Hantan River, Han River mainstream, and Anseong Stream watersheds had a high positive association with TCE, whereas the Bukhan and Namhan River watersheds had a strong positive link with chloroform. The contamination and detection frequency of VOCs were highest in industrial complexes, followed by urban and rural areas. Thus, point source pollution significantly contributed to VOC contamination of these tributaries. Risk quotients for most VOCs were <1, suggesting negligible risk. Considering the relatively high occurrence of VOCs and their potential ecological risks, continuous environmental monitoring and study of environmental impacts based on ecotoxicity studies of domestic aquatic species are warranted.

Bioconcentration and Biotransformation of Pharmaceuticals in Oryzias latipes using Liquid Chromatography-High Resolution Mass Spectrometry (LC-HRMS)

The occurrence of pharmaceuticals in the aquatic environment has been increasing steadily owing to the increasing use of pharmaceuticals in our daily life. This results in increasing challenges of environmental health risk as pharmaceuticals in the surface water can be accumulated and transformed in aquatic organisms. The purpose of this study was to predict the bioconcentration and biotransformation of several pharmaceuticals in Japanese medaka (Oryzias latipes) using a 96 h exposure test. Based on an investigation of the most frequently detected pharmaceuticals in the surface waters in South Korea, 11 target compounds were selected including atenolol, caffeine, carbamazepine, diclofenac, fluoxetine, irbesartan, losartan, mefenamic acid, metoprolol, naproxen, and venlafaxine. A bioconcentration factor of 1.9, 31.3, and 10.7 was expected in fish owing to the accumulation of carbamazepine, fluoxetine, and mefenamic acid, respectively. A total of 12 biotransformation products (BTPs) were tentatively identified via oxidation, hydroxylation, dealkylation, and demethylation reactions. In summary, it is expected that these BTPs represented by molecular structures derived from their parent compounds can be utilized to evaluate the change in toxicity of BTPs compared to that of the parent compounds. Key Words: Pharmaceuticals, Oryzias latipes, Bioconcentration, Biotransformation, LC-HRMS, Suspect screening, Non-target screening

Achromobacter aestuarii sp. nov., Isolated from an Estuary.

A novel strain KS-M25T was isolated from estuary water in South Korea. Strain KS-M25T was Gram-staining-negative, strictly aerobic, motile rods-shaped bacterium and showed oxidase- and catalase-positive reactions. Growth of strain KS-M25T was observed at 10-25°C (optimum, 20°C), at pH 5.5-9.0 (optimum, pH 7.5), and with 0-6.0% (w/v) NaCl (optimum, 1%). Ubiquinone-8 was identified as the sole isoprenoid quinone and the major fatty acids were C16:0, cyclo-C17:0 and sum in feature 3 (comprising C16:1 ω7c and/or C16:1 ω6c). The G+C content values based on genome sequences was 62.3mol%. Phylogenetic analysis based on 16S rRNA gene sequences showed that strain KS-M25T formed a clear cluster within the genus Achromobacter. Strain KS-M25T was most closely related to Achromobacter anxifer LMG 26857T, Achromobacter dolens LMG 26840T, and Achromobacter xylosoxidans NBRC 15126T with 97.8%, 97.8%, and 97.7% 16S rRNA gene sequence similarities, respectively. Based on phenotypic, chemotaxonomic, and phylogenetic analysis, strain KS-M25T represents a novel species of the genes Achromobacter, for which the name Achromobacter aestuarii sp. nov. is proposed. The type strain is KS-M25T (= KACC 21219T = JCM 33329T).

Radon Concentrations in Raw Water and Treated Water Used for Bottled Water in South Korea

Radon concentrations in the raw water and treated water used for 59 brands of bottled water produced in South Korea were analysed. The radon levels in 59 raw water samples ranged from 3.7 to 476.8 Bq/L, with a geometric mean of 49.0 Bq/L. The mean radon levels in raw water samples were high in Jurassic granite aquifers and low in volcanic rock aquifers. However, the maximum radon levels were observed in metamorphic rock aquifers. The concentrations in 55 treated water samples ranged from 0.1 to 239.4 Bq/L, with a geometric mean of 7.7 Bq/L. In treated water, radon levels decreased by 16.0–98.9% (average, 74.9%) due mainly to storage in water tanks and treatment with granular activated carbon (GAC) filters. The radon levels in raw water and treated water samples exceeded the US EPA alternative maximum contaminant level (AMCL) of 148 Bq/L by 16.9% and 1.8%, respectively. Considering the radon reduction rate, it is anticipated that the radon concentrations in bottled water in stores will not exceed 148 Bq/L because it takes about 1–2 weeks for treated water to reach the customer as bottled water.

Two Paradoxostomatidae (Ostracoda) species from South Korea with a key to genera of the family.

Cytherois gajinensissp. nov. is described and Violacytherois sargassicola (Hiruta, 1976) is redescribed. The species have been collected from littoral and interstitial waters in South Korea. They belong to Cytheroisinae, one of the three Paradoxostomatidae subfamilies. Both species are the first taxonomic records of the subfamily in Korea. Taxonomic keys to the living Paradoxostomatidae genera are provided in an attempt to clarify the position of some of the currently included genera as well as a key to East Asian Cytheroisinae species in order to facilitate further biodiversity research in the region.

State and Strategy of Production, Market and Integrated Management of Mineral Water, South Korea

In this study, the state of the production, market, and integrated management of mineral water in South Korea was assessed and a strategy was established to improve the competitiveness of mineral water with respect to foreign brands. Diverse data, including a number of mineral water manufacturers, daily permitted volume, daily production amounts, sales volume, and sales amounts, were used to clarify the state of mineral water and establish a strategy. Real-time data transmitted from the mineral water manufacturers were analyzed and managed in an integrated management system (IMS). Chemical characteristics of mineral water were analyzed to assess water quality and identify problems related to contamination. This study shows that specialization plans according to geological characteristics should be established, rather than focusing on quantitative growth by a low-cost sales method. The establishment of contamination management plans was found to be needed for wells with potential pollution due to sub-surface inflow into the wells. We suggest that an independent editing system of the attribute information needs to be designed based on the analysis and management of the IMS.

How Ångström–Prescott Coefficients Alter the Estimation of Agricultural Water Demand in South Korea

The Food and Agriculture Organization (FAO) Penman–Monteith equation, recognized as the standard method for the estimation of reference crop evapotranspiration (ET0), requires many meteorological inputs. The Ångström–Prescott (A-P) formula containing parameters (i.e., a and b) is recommended to determine global solar radiation, one of the essential meteorological inputs, but may result in a considerable difference in ET0 estimation. This study explored the effects of A-P coefficients not only on the estimation of ET0, but also on the irrigation water requirement (IWR) and design water requirement (DWR) for paddy rice cultivation, which is the largest consumer of agricultural water in South Korea. We compared and analyzed the estimates of ET0, IWR, and DWR using the recommended (a = 0.25 and b = 0.5) and locally calibrated A-P coefficients in 16 locations of South Korea. The estimation of ET0 using the recommended A-P coefficients produced significant overestimation. The overestimation ranged from 3.8% to 14.0% across the 16 locations as compared to the estimates using the locally calibrated A-P coefficients, and the average overestimation was 10.0%. The overestimation of ET0 corresponded to a variation of 1.7% to 7.2% in the overestimation of the mean annual IWR, and the average overestimation of the IWR was 5.1%. On average, the overestimation was slightly reduced to 4.8% in DWR estimation, since the effect of A-P coefficients on the IWR estimation decreased as the IWR increased. This study demonstrates how the use of A-P coefficients can alter the estimation of ET0, IWR, and DWR in South Korea, which underscores the importance of their proper consideration in agricultural water management.

Research on the contamination levels of norovirus in food facilities using groundwater in South Korea, 2015–2016

Norovirus (NoV) is a major pathogenic virus that is responsible for foodborne and waterborne gastroenteritis outbreaks. Groundwater is an important source of drinking water and is used in agriculture and food manufacturing processes. This study investigated norovirus contamination of groundwater treatment systems at 1360 sites in seven metropolitan areas and nine provinces in 2015–2016. Temperature, pH, residual chlorine, and turbidity content were assessed to analyze the water quality. In 2015, six sites were positive for the presence of NoV (0.88%) and in 2016, two sites were positive (0.29%); in total, NoV was detected in 8 of the 1360 sample sites (0.59%) investigated. Identified genotypes of NoV in groundwater included GI.5, 9 and GII.4, 6, 13, 17, and 21. GII.17 was the most prevalent genotype in treated groundwater used in the food industry. This dominance of GII.17 was corroborated by NoV infection outbreak cases and the results of a survey of coastal waters in South Korea in 2014–2015. Although a low detection rate was observed in this study, NoV is a pathogen that can spread extensively. Therefore, it is necessary to periodically monitor levels of norovirus which is responsible for food poisoning in groundwater. This is a first report to reveal epidemic genotype shift of norovirus in groundwater treatment system of food facilities in South Korea. Our results may contribute to the enhancement of public health and sanitary conditions by providing molecular epidemiological information on groundwater NoV.

Fluoride content of bottled water available in South Korea

Objectives The market for bottled water is increasing steadily in South Korea. Bottled water contains several naturally occuring minerals, such as calcium, magnesium, sodium, and fluoride. Fluoride is proven to be effective in preventing dental caries. In South Korea, the maximum permissible concentration of fluoride is 2 ppm for bottled water and 1.5 ppm for tap water. The aim of this study was to investigate the fluoride content of different commercially available brands of bottled water in South Korea, and compare the measured fluoride concentration to the concentration written on the label of each brand of bottled water. Methods Twenty-seven of the 59 different brands of bottled water produced in South Korea were investigated in this study. Three bottles of each brand were purchased from supermarkets, marts, and convenience stores in each region of Korea in August 2016. For each bottled water brand, the fluoride content was measured three times using a fluoride-ion selective electrode (Orion ionplus Fluoride Electrode 9609, Orion Research, USA). The calibration curve was generated using 0.2 and 2 ppm standard solutions, and confirmed using a 1 ppm standard solution. Results The mean fluoride content of the 27 brands of bottled water was 0.374±0.332 mg/L (range=0.040 to 1.172 mg/L). The fluoride content was labeled by the manufacturer, on each of the tested brands of bottled water. In eight brands, the labeled fluoride content differed from the experimental data. The minimum to maximum fluoride content measured from 10 brands showed a variation of 0.3 mg/L or more when compared to the labeled fluoride content. Conclusions This study investigated the fluoride content of various brands of bottled water produced in South Korea and compared the measured fluoride levels with fluoride information on the bottle labels. To ensure that consumers are suitably informed regarding their exposure to fluoride, correct labelling of fluoride content in bottled water is important.

Sphingomonas aquatica sp. nov., isolated from tap water.

A Gram-stain-negative, strictly aerobic, rod-shaped bacterium, designated W1-2-1T, was isolated from tap water in South Korea. The strain was characterized by a polyphasic approach to clarify its taxonomic position. Strain W1-2-1T grew at 18-42 °C and at pH 6.0-10.0 on R2A medium. Phylogenetic analysis based on 16S rRNA gene sequences indicated that the isolate belongs to the genus Sphingomonas and is most closely related to the Sphingomonas oligophenolica JCM 12082T (97.2 % similarity), Sphingomonas asaccharolyticaNBRC 15499T (96.8 %), Sphingomonas desiccabilis CP1DT (96.8 %), Sphingomonas pruniNBRC 15498T (96.8 %), Sphingomonas hankookensis ODN7T (96.4 %) and Sphingomonas yabuuchiae DSM 14562T (95.8 %). Chemotaxonomic data [major ubiquinone - Q10, major polyamine - homospermidine, major fatty acids - summed feature 8 (C18 : 1ω7c/ω6c), C16 : 0 and C14 : 0 2-OH and presence of sphingoglycolipid] supported the affiliation of the strain to the genus Sphingomonas. The G+C content of genomic DNA was 67.1 mol%. However, low level of DNA-DNA relatedness value between strain W1-2-1T and S. oligophenolica JCM 12082T and the results of physiological and biochemical tests allowed genotypic and phenotypic differentiation of strain W1-2-1T from other Sphingomonas species with validly published names. Therefore, the isolate represents a novel species, for which the name Sphingomonas aquatica sp. nov. (type strain W1-2-1T=KACC 18309T=LMG 28596T) is proposed.

The Research Trend and Social Perceptions Related with the Tap Water in South Korea

The Research Trend and Social Perceptions Related with the Tap Water in South Korea

Thalassiella azotovora gen. nov., sp. nov., a New Member of the Family Kineosporiaceae Isolated from Sea Water in South Korea.

A gram-positive, nonmotile, rod-shaped, nonflagellated, aerobic bacterium, designated strain DSD2(T) was isolated from a seawater sample from Sadong wharf, Ulleung-Island, South Korea. Strain DSD2(T) was found to be able to grow at pH ranging from 6 to 11 (optimum 7-8), 0-7% (w/v) NaCl (optimum 0%), at 10-42°C (optimum 37°C). 16S rRNA gene sequence analysis revealed that strain DSD2(T) was 95.8% similar to the type strain of Kineosporia rhamnosa KACC 15195(T), 95.8% similar to Angustibacter aerolatus KACC 15527(T), and 95.5% similar to Kineococcus xinjiangensis KCTC 19474(T) as its closest relatives. A neighbor-joining phylogenetic tree based on the 16S rRNA gene sequence showed that strain DSD2(T) related to Micrococcineae and Kineosporiineae suborder clade. The major polar lipids were phosphoglycolipids and phospholipids. Strain DSD2(T) was found to contain MK-8 (H2) and MK-9 (H4) as the predominant menaquinone and iso-C16:0 as the major fatty acid. The isolate contained meso-diaminopimelic acid (meso-A2pm) with alanine, glutamic acid, and glycine as the diagnostic diamino acid. The DNA G+C content of strain DSD2(T) was 73.2mol%. On the basis of phylogenetic, biochemical, chemotaxonomic, and other physiological characteristics, strain DSD2(T) is assigned to a novel species of a novel genus within the suborder Kineosporiineae and the name Thalassiella azotovora gen nov., sp. nov., is proposed. The type strain is DSD2(T) (=KCTC 39634(T)=JCM 31134(T)).

Bacteriophage application to control the contaminated water with Shigella.

Shigella is one of the most important waterborne and foodborne pathogens around the world. Emergence of antibiotic-resistant Shigella has made the development of alternatives to conventional antibiotics necessary. In this study, a virulent Myoviridae bacteriophage, pSs-1 was isolated from environmental water in South Korea and showed infectivity to S. flexneri as well as S. sonnei strains. One-step growth analysis showed that pSs-1 has a short latent period (25 min) and a large burst size (97 PFU/cell). According to the genomic analysis, pSs-1 contains 164,999 bp of genome with a G + C content of 35.54% and it is considered as a member of the T4-like bacteriophage group. These results showed that pSs-1 may have potential as a biocontrol agent instead of conventional antibiotics for shigellosis.

An assessment of selected hydrochemical parameter trend of the Nakdong River water in South Korea, using time series analyses and PCA.

Time series analyses (autocorrelation, spectral density, and cross-correlation) and principal component analysis (PCA) were used to understand the characteristics of the selected hydrochemical parameters pH, turbidity, alkalinity, Cl, hardness, total dissolved solids (TDS), and metals Fe and Mn in the Nakdong River, South Korea. Autocorrelation and spectral density for pH, alkalinity, hardness, and Cl were very similar to TDS, whereas Fe, Mn, and turbidity showed different trends from TDS. Cross-correlograms of pH, alkalinity, hardness, and Cl versus TDS were very similar to each other. Those of Fe and turbidity represented the opposite relations with other components. Cross-correlation coefficients had the highest values at zero lag, indicating that pH, alkalinity, hardness, and Cl are controlling factors for TDS. On the other hand, Fe and turbidity showed the highest values at 6-month lag and Mn at a month lag. PCA indicated that TDS had very close relation with hardness, pH, and Cl and very small relation with Mn. Turbidity and Fe had relatively opposite relations with TDS. It was concluded that the geostatistical methods were very useful for evaluating the hydrochemical characteristics of the Nakdong River water in South Korea.

Productivity change under the vessel buyback program in Korean fisheries

Korean fisheries are managed mainly by input controls, such as limited licenses, and technical measures such as gear restriction, closed areas, and mesh size regulation. Despite these efforts, stock biomass has declined in the waters of South Korea leading the government to implement a fish restocking plan as well as a vessel buyback program. There has been a debate over the buyback program, its effectiveness and whether it should be for offshore vessels or coastal vessels. To address these concerns, we used a Data Envelopment Analysis method and showed which fisheries are over- or underproductive. To investigate the effectiveness of the buyback program, data were collected for 18 fisheries (nine each of coastal and offshore fisheries) from 1992 to 2012. A distance function approach was used, because the data for this time period consisted of input (number of vessels and tonnage) and output (fish harvest) values, with no corresponding input prices. Since there is a dearth of cost data and questionable market price data in fisheries, the Malmquist index (MI) was calculated to study productivity of the fisheries. Results showed two coastal fishery sectors and one offshore fishery need more intensive management. The Korean government has introduced a fish stock rebuilding plan in parallel with the vessel buyback program. The MI is a useful tool to show how productivity has improved with the two management tools working together.