• Journal of Navigation and Port Research
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• v.46 no.1
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• pp.1-10
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• 2022

This study aims to investigate changes in the demand for ship officers in response to changes in the shipping industry environment in which Maritime Autonomous Surface Ships (MASS) emerge according to the application of the fourth industrial revolution technology to ships, and it looks into changes in the skill of ship officer. It also analyzes and proposes a plan for nurturing ship officers accordingly. As a result of the degree of recognition and AHP analysis, this study suggests that a new training system is required because the current training and education system may cover the job competencies of emergency response, caution and danger navigation, general sailing, cargo handling, seaworthiness maintenance, emergency response, and ship maintenance and management, but tasks such as remote control, monitoring diagnosis, device management capability, and big data analysis require competency for unmanned and shore-based control. By evaluating the importance of change factors in the duties of ship officers in Maritime Autonomous Surface Ships, this study provides information on ship officer educational institutions' response strategies for nurturing ship officers and prioritization of resource allocation, etc. The importance of these factors was compared and evaluated to suggest changes in the duties of ship officers and methods of nurturing ship officers according to the introduction of Maritime Autonomous Surface Ships. It is expected that the findings of this study will be meaningful as it systematically derives the duties and competency factors of ship officers of Maritime Autonomous Surface Ships from a practical point of view and analyzed the perception level of each relevant expert to diagnose expert-level responses to the introduction of Maritime Autonomous Surface Ships.

• Journal of Marine Life Science
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• v.1 no.2
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• pp.95-108
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• 2016

This study was performed to investigate the community structure of macrobenthic assemblages in the Environmental Conservation area, Korea. Benthic animals were collected by van Veen grab sampler at spring (May) and summer (August) 2009. The total species number and mean density were 195 species 5.6 m^-2 and 667 individuals m^-2, respectively. Polychaetes were the most dominant faunal group in species (96 species) and abundance (431 individuals m^-2). The major dominant species were the polychaetes Lumbrineris longifolia (76±224 individuals m^-2), Mediomastus californiensis (42±117 individuals m^-2), Tharyx sp.3 (26±110 individuals m^-2), the bivalvia Theora fragilis (54±78 individuals m^-2) and the amphipod Eriopisella schellensis (70±146 individuals m^-2). Based on the cluster and nMDS ordination analysis, macrobenthic communities were divided into three faunal groups. The first group was characterized by high abundance of the polychaeta Sternaspis scutata and the amphipod Ampelisca cyclops iyoensis, which is located by most stations of Hampyeong Bay and St. 4 of Deungnyang Bay. The second group was numerically dominated by the polychaeta Capitella capitata at St. 4 and St. 5 in Gamak Bay where was most pollutant area. Finally, the third group was dominated by the polychaetes Heteromastus filiformis, Tharyx sp.3 and the amphipod Sinocorophium sinensis. Therefore, geochemical characteristics such as the bay shape and pollution gradient may be important factors controlling of the macrobenthic community structure in Environment Conservation Area.

• Journal of fish pathology
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• v.36 no.2
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• pp.263-275
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• 2023

Chum salmon (Oncorhynchus keta) is a species which returns to Korea for spawning and was produced as seed production at the Fisheries Resources Agency located in Uljin-gun, Gyeongsangbuk-do to preserve the species. However, farmed chum salmon showed symptoms of bacterial infection. Therefore, in this study, bacteria were isolated to identify the causative agent from chum salmon in October 2021. The isolated bacteria were identified based on the sequences of 16S rDNA, rpoD (RNA polymerase sigma factor σ⁷⁰), and vapA (A-layer) genes. Also, salinity-growth curve, biochemical characterization, antibiotic susceptibility test, and pathogenicity analysis were performed in four strains. As a result, four isolated strains were identified as Aeromonas salmonicida subsp. salmonicida. Additionally, the bacterial strains showed a decrease in growth as the salt concentration increased in the medium. All of the isolated strains exhibited γ-hemolysis, and the same biochemical properties. In the antimicrobial susceptibility test, all strains showed an inhibition zone of 40 to 44 mm for oxolinic acid, flumequine, and florfenicol. Pathogenic factors were assessed by RT-PCR at the mRNA level, and found that the four strains expresses the outer membrane ring of T3SS (ascV), inner membrane ring of T3SS (ascC), vapA, enterotoxin (act), and lipase (lip) genes which are well known to significantly contribute to the pathogenicity of A. salmonicida. The results of this study can be used as basic data to prevent A. salmonicida subsp. salmonicida occurring in sea-chum salmon in the future.

• Journal of Navigation and Port Research
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• v.48 no.3
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• pp.232-238
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• 2024

This study examines the effectiveness of Gamcheon Port's leading lights in reflecting the characteristics of ship traffic entering the port. The leading light of Gamcheon Port was proposed and installed in 1996 during the basic design process of supplementing the port's route signs for the entry and exit of 4,000 TEU container ships. Since then, it has been improved to accommodate the entry of 50,000 DWT general cargo ships and to reflect the crane height of Hanjin Pier, as a result of a review study conducted by the Busan Regional Maritime Affairs and Fisheries Administration to improve the still temperature of Gamcheon Port by relocating existing outer facilities. However, an analysis of the current characteristics of maritime traffic at Gamcheon Port reveals that maritime traffic congestion is smooth and the proportion of small and medium-sized ships under 10,000 tons is higher than that of large ships, resulting in decreased efficiency of the leading lights to respond to the entry of large ships. Nevertheless, considering the increasing CAGR of the entry ratio of ships of 30,000 tons or more by 8.45%, preparations for the anticipated increase in the proportion of large ships entering the port in the future are necessary, and it is preferable to maintain the function of the leading lights rather than demolishing the entrance to Gamcheon Port. The narrow nature of the Gamcheon Port route poses a higher risk of collision when ships entering and exiting encounter each other, which can burden the navigator. Therefore, instead of maintaining the function of the leading lights, it is possible to relocate the conduction light to reduce maintenance burden and install a direction light in its place. When installing the direction light, it is worth considering using Double Sector Lights instead of the currently installed Single Sector Lights at nearby Busan Bukhang Port, as the former can improve user satisfaction by providing a clearer middle line and reducing difficulties in distinguishing between points.

• The Sea:JOURNAL OF THE KOREAN SOCIETY OF OCEANOGRAPHY
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• v.17 no.4
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• pp.292-302
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• 2012

This paper reviews comparison analysis of current and latest application for stock identification methods of Todarodes pacificus, and the pros and cons of each method and consideration of how to compensate for each other. Todarodes pacificus which migrates wide areas in western North Pacific is important fishery resource ecologically and commercially. Todarodes pacificus is also considered as 'biological indicator' of ocean environmental changes. And changes in its short and long term catch and distribution area occur along with environmental changes. For example, while the catch of pollack, a cold water fish, has dramatically decreased until today after the climate regime shift in 1987/1988, the catch of Todarodes pacificus has been dramatically increased. Regarding the decrease in pollack catch, overfishing and climate changes were considered as the main causes, but there has been no definite reason until today. One of the reasons why there is no definite answer is related with no proper analysis about ecological and environmental aspects based on stock identification. Subpopulation is a group sharing the same gene pool through sexual reproduction process within limited boundaries having similar ecological characteristics. Each individual with same stock might be affected by different environment in temporal and spatial during the process of spawning, recruitment and then reproduction. Thereby, accurate stock analysis about the species can play an efficient alternative to comply with effective resource management and rapid changes. Four main stock analysis were applied to Todarodes pacificus: Morphologic Method, Ecological Method, Tagging Method, Genetic Method. Ecological method is studies for analysis of differences in spawning grounds by analysing the individual ecological change, distribution, migration status, parasitic state of parasite, kinds of parasite and parasite infection rate etc. Currently the method has been studying lively can identify the group in the similar environment. However It is difficult to know to identify the same genetic group in each other. Tagging Method is direct method. It can analyse cohort's migration, distribution and location of spawning, but it is very difficult to recapture tagged squids and hard to tag juveniles. Genetic method, which is for useful fishery resource stock analysis has provided the basic information regarding resource management study. Genetic method for stock analysis is determined according to markers' sensitivity and need to select high multiform of genetic markers. For stock identification, isozyme multiform has been used for genetic markers. Recently there is increase in use of makers with high range variability among DNA sequencing like mitochondria, microsatellite. Even the current morphologic method, tagging method and ecological method played important rolls through finding Todarodes pacificus' life cycle, migration route and changes in spawning grounds, it is still difficult to analyze the stock of Todarodes pacificus as those are distributed in difference seas. Lately, by taking advantages of each stock analysis method, more complicated method is being applied. If based on such analysis and genetic method for improvement are played, there will be much advance in management system for the resource fluctuation of Todarodes pacificus.

• Journal of the Korean Society of Food Science and Nutrition
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• v.26 no.2
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• pp.270-284
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• 1997

Effects of dietary carotenoids were investigated on the metaboβsm and body pigmentation of rainbow trout(Salmo gairdneri), masu salmon(Oncorhynchus macrostomos), eel(Anguilla japonica), rock fish(Sebastes inermis) and black rock fish(Sebastes schlegeli). Three weeks later after depletion, these fishes were fed diet supplemented with ${\beta}-carotene$, lutein, canthaxanthin', astaxanthin or ${\beta}-apo-8'-carotenal$ for 4 to 5 weeks, respectively. Carotenoids distributed to and changed in integument were analyzed. In the integument of rainbow trout. zeaxanthin, ${\beta}-carotene$ and canthaxanthin were found to be the major carotenoids, while lutein, isocryptoxanthin and salmoxanthin were the minor carotenoids. In the integument of masu salmon, zeaxanthin was found to be the major carotenoids, while triol, lutein, tunaxanthin, ${\beta}-carotene$, ${\beta}-cryptoxanthin$ and canthaxanthin were the minor carotenoids. In the integument of eel, ${\beta}-carotene$ was found to be the major carotenoids, while lutein, zeaxanthin and ${\beta}-cryptoxanthin$ were the minor carotenoids. In the integument of rock fish, zeaxanthin, ${\beta}-carotene$, tunaxanthin$(A{\sim}C)$ and lutein were found to be the major carotenoids, while ${\beta}-cryptoxanthin$, ${\alpha}-cryptoxanthin$ and astaxanthin were the minor carotenoids. Likely in the integument of black rock fish, ${\beta}-carotene$, astaxanthin and zeaxanthin were found to be the major carotenoids, whereas ${\alpha}-cryptoxanthin$, ${\beta}-cryptoxanthin$, lutein and canthaxanthin were the minor contributor. The efficacy of body pigmentation by the accumulation of carotenoids in the integument of rainbow trout and masu salmon were the most effectively shown in the canthaxanthin group and of eel, rock fish and black rock fish were the most effectively shown in the lutein group. Based on these results in the integument of each fish, dietary carotenoids were presumably biotransformed via oxidative and reductive pathways. In the rainbow trout, ${\beta}-carotene$ was oxidized to astaxanthin via successively isocryptoxanthin, echinenone and canthaxanthin. Lutein was oxidized to canthaxanthin. Canthaxanthin was reduced to ${\beta}-carotene$ via isozeaxanthin, and astaxanthin was reduced to zeaxanthin via triol. In the masu salmon, ${\beta}-carotene$ was oxidized to zeaxanthin. Lutein was reduced to zeaxanthin via tunaxanthin. Canthaxanthin was reduced to zeaxanthin via ${\beta}-carotene$. and astaxanthin was reduced to zeaxanthin via triol. In the eel, ${\beta}-carotene$ and lutein were directly deposited but canthaxanthin was reduced to ${\beta}-carotene$, and cholesterol lowering effect by Meju supplementation might be resulted from the modulation of fecal axanthin, astaxanthin and ${\beta}-apo-8'-carotenal$ were oxidized and reduced to tunaxanthin via zeaxanthin. In the black roch fish, ${\beta}-carotene$ was oxidized to ${\beta}-cryptoxanthin$. Lutein was reduced to ${\beta}-carotene$ via ${\alpha}-cryptoxanthin$. Canthaxanthin was reduced to ${\alpha}-cryptoxanthin$ via successively ${\beta}-cryptoxanthin$ and zeaxanthin. Astaxanthin converted to tunaxanthin via isocryptoxanthin and zeaxanthin, and ${\beta}-apo-8'-carotenal$ was reduced to ${\alpha}-cryptoxanthin$ via ${\beta}-cryptoxanthin$ and zeaxanthin.

• Journal of the Korean Society of Food Science and Nutrition
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• v.18 no.1
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• pp.71-92
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• 1989

The seasonal variations of environmental sea water, arid carotenoid and lipid composition of reddish muscle tissue of arkshell, Anadara broughtonii in Chungmu and $Y{\check{o}}su-area$ were investigated. In the sea water, pH value, salinity, electrical conductivity of Chungmu and $Y{\check{o}}su-area$ were similar tendency, but water temperature in annual average at Chungmu-area was about $2^{\circ}C$ higher than that of $Y{\check{o}}su-area$. The concentration of nitrite-nitrogen, ammonia-nitrogen, phosphate-phosphours at Chungmu-area were slightly higher than those at $Y{\check{o}}su-area$. Meanwhile the concentration of silicate-silicious at $Y{\check{o}}su-area$ was about 2 times higher than that of Chungmu-area. The bacterial density of the sea water was ranged from 3.6 to 93/100ml for coliform and 3.0 to 15/100ml for fecal colifrom at Chungmu-area, but the coliform was ranged 7.3 to 150/100ml and the fecal coliform was ranged 3.6 to 20/100ml at $Y{\check{o}}su-area$. Among the coliform, 8.9% Escherichia coli, 33.9% Citrobacter freundii, 41.1% Enterobacter aerogenes groups were classified and 16.1% was not identified. In the hemoglobin content of reddish muscle tissue of arkshell, one from Chungmu-area was ranged from 1.1 to 2.5 g /dl and one from $Y{\check{o}}su-area$ was ranged from 1.7 to 4.4 g /dl. In total carotenoid content, 0.80 to 1.28mg/100 g muscle was in Chungmu-area and 0.45 to 0.99mg/100 g muscle was in $Y{\check{o}}su-area$. Among the carotenoid compositions, pectenolone content was 63.0% in annual average from Chungmu area and 59.6% from $Y{\check{o}}su-area$, 6.5% from Chungmu area and 18.9% from $Y{\check{o}}su-area$ in ${\beta}-carotene$, 9.9% from Chungmu-area and 9.1% from Yosu-area in pectenoxanthin, 11.2% from Chungmu-area and 5.2% from $Y{\check{o}}su-area$ in diatoxanthin monoester were observed. In the seasonal variation for the major carotenoids, the content of pectenolone was continuously incresedbefore spawning period and showed the maximum in July, but decresed after spawning period. Diatoxanthin monoester was gradually incresed during all growing period from March to next January. And ${\beta}-carotene$ was decresed before spawning period and showed the maximum in July but incresed after spawning period. The major fatty acids of total lipid and fractionated lipid classes from total lipid namely neutral-, glyco- and phospholipid were $C_{16:0},\;C_{18:1},\;C_{22:6},\;C_{20:2},\;C_{18:2},\;C_{20:5}\;and\;C_{18:3}$ acid in the muscle tissue of arkshell. The content of neutral lipid showed about 2 times higher than polar lipid in the muscle tissue of arkshell from both Chungmu and, $Y{\check{o}}su-area$. The content of total and neutral lipid was decresed during spawning period. In the seasonal variation for fatty acid compositions, the content of polyenenoic acid in total and neutral lipid was decresed and saturated acid was incresed. On contrary, polyenoic acid in glyco and phospholipid was incresed and saturated acid was decresed during spawning period from July to September. The sterol composition in total lipid were mainly consisted of cholesterol, campesterol, brassicasterol and ${\beta}-sitosterol$. Especially, the rate of content in cholesterol showed decrese during spawning period butcampesterol showed increse from March to November.

• Korean Journal of Agricultural and Forest Meteorology
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• v.24 no.3
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• pp.133-144
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• 2022

This study was conducted to investigate the cultivation period, adaptive genetic resources, growth and development patterns, and water consumption for rice cultivation in the desert environment of United Arab Emirates (UAE). R esearch on rice cultivation in the desert environment is expected to contribute to resolving food shortages caused by climate change and water scarcity. It was found that the optimal cultivation period of rice was from late November to late April of the following year during which the low temperature occurred at the vegetative growth stage of rice in the UAE. Asemi and FL478 were selected to be candidate cultivars for temperature and day-length conditions in the desert areas as a result of pre-testing genetic resources under reclaimed soil and artificial meteorological conditions. In the desert environment in the UAE, FL478 died before harvest due to the etiolation and poor growth in the early stage of growth. In contrast, Asemi overcame the etiolation in the early stage of growth, which allowed for harvest. The vegetative growth phases of Asemi were from early December to early March of the following year whereas its reproductive growth and ripening phases were from early March to late March and from late March to late April, respectively. The yield of milled rice for Asemi was 763kg/10a in the UAE, which was about 41.8% higher than that in Korea. Such an outcome was likely due to the abundant solar radiation during the reproductive growth and grain filling periods. On the other hand, water consumption during the cultivation period in the UAE was 2,619 ton/10a, which was about three times higher than that in Korea. These results suggest that irrigation technology and development of cultivation methods would be needed to minimize water consumption, which would make it economically viable to grow rice in the UAE. In addition, select on of genetic resources for the UAE desert environments such as minimum etiolation in the early stages of growth would be merited further studies, which would promote stable rice cultivation in the arid conditions.

• Journal of Wetlands Research
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• v.25 no.1
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• pp.35-47
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• 2023

Korean facility horticulture and hydroponic cultivation methods increase, requiring the management of waste water generated. In this study, the amount of fertilizer contained in the discharged waste liquid was determined. By evaluating this as a price, it was suggested to reduce water treatment costs and recycle fertilizer components. It was evaluated based on the results of major water quality analysis of waste liquid by crop, such as tomatoes, paprika, cucumbers, and strawberries, and in the case of P component, it was analyzed by converting it to the amount of phosphoric acid (P₂O₅). The amount of nitrogen (N) can be calculated by discharging 1,145.90kg·ha^-1 of tomatoes, 920.43kg·ha^-1 of paprika, 804.16kg·ha^-1 of cucumbers, 405.83kg·ha^-1 of strawberries, and the fertilizer content of P₂O₅ is 830.65kg·ha^-1 of paprika, 622.32kg·ha^-1 of tomatoes, 477.67kg·ha^-1 of cucumbers. In addition, trace elements such as potassium (K), calcium (Ca), magnesium (Mg), iron (Fe), and manganese (Mn) were also analyzed to be emitted. The price per kg of each item calculated by averaging the price of fertilizer sold on the market can be evaluated as KRW, N 860.7, P 2,378.2, K 2,121.7, Ca 981.2, Mg 1,036.3, Fe 126,076.9, Mn 62,322.1, Zn 15,825.0, Cu 31,362.0, B 4,238.0, Mo 149,041.7. The annual fertilizer loss amount for each crop was calculated by comprehensively considering the price per kg calculated based on the market price of fertilizer, the concentration of waste by crop analyzed earlier, and the average annual emission of hydroponic cultivation. As a result of the analysis, the average of the four hydroponic crops was 5,475,361.1 won in fertilizer ingredients, with tomatoes valued at 6,995,622.3 won, paprika valued at 7,384,923.8 won, cucumbers valued at 5,091,607.9 won, and strawberries valued at 2,429,290.6 won. It was expected that if hydroponic drainage is managed through self-treatment or threshing before discharge rather than by leaking it into a river and treating it as a pollutant, it can be a valuable reusable fertilizer ingredient along with reducing water treatment costs.

• Journal of fish pathology
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• v.1 no.1
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• pp.5-30
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• 1988

This is a comprehensive study for considering the effective treatment and control program of bacterial disease occurring in common carp, israel carp, color carp, crucian carp, eel and tilapia by clarifying the causes, mechanism of infection and onset and the diagnostic criteria. As a first step, the authors investigated the external views, gross and histopathologic findings of diseased fish using 450 infected fishes obtained from various farmer of Korea. This infection was characterized by hyperemia, hemorrhage and swelling of body surface and fins, congestion of liver, spleen, kidney, inflammation of intestine, hemorrhagic inflammation of various tissues, and necrosis and ulcer of various tissues were accompanied in serious cases. Bacteriologically, Aeromonas hydrophila and Edwardsiella tarda were isoiated from these fishes. Particularly in the regular check on 222 eels, 177 strains were isolated as 29.94% of Aeromonas hydrophila, 48.58% of Edwardsiella tarda and 21.47% of Flexibacter columnaris. Hexibacter columnaris was isolated from corroded gill of eels. The identical disease was occurred by innoculating the isolated Aeromonas hydrophila and Edwardsiella tarda and the identical strains were isolated from infected experimental fishes. The eels which were diagnosed Aeromonas disease from Kwangju, Pusan accompanied hemorrhage, swelling of body surface and fins, inflammation of stomach and intestine containing mucous fluids mixed with the pathogens. Color carp and crucian carp which were innoculated with the isolated 5 strins of Aeromomas hydrorphil died within 3 or 4 days accompanying with the characteristics of Aeromonas disease. Edward disease was characterized by abscesses of body surface, pus formation with concentration on phagocytes. The size of absecsses increased with progression elf disease. There were also various abscesses at internal organ and white nodules appeared in kidney. Histologically, various progressive granuloma were examined without inflammation of intestine. Columnaris disease of eels showed no hemorrhage except slight white body color. In autopsy, most of internal organs appeared normal and there were no septic odors. The only character was corrosion of gills. In order to treat these bacterial diseases, infected fishes must bathe in 20ppm chloramphenicol or kanamycin solution for 1 hour. Besides, medication program in oral ingestion of 75mg/kg chloramphenicol per day continuing for 5 to 7 days. After injecting the formalin treated Aermonas hydrophila antigen into carp, relatively high agglutination titer showed between 3 weeks and 6 weeks. Though this titer decreased from that time, it was continued for 18 weeks. In the case of injecting the formalin treated Edwardsiella tarda antigen into tilapia, the titer also increased. But tilapia which were immersed in the suspension fluid of the formalin treated Edwardsiella tarda showed no increase of the titer.