• Korean Journal of Ecology and Environment
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• v.40 no.2
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• pp.327-336
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• 2007

This study assessed ecological health using a multi-metric fish model from 15 sites in the headwater watershed of southern Han River during June${\sim}$August 1999 and then compared the health with conventional community diversity index to figure out differences between health and diversity index. For the analysis, we adopted 10 metric IBI model for regional applications. During this survey, total number of species sampled were 24 (6 families) and varied depending on magnitude of ecological disturbance and stream order. In the mountainous streams, mean proportion of sensitive and insectivore species was composed of 91% and 56%, respectively, indicating a potential healthy conditions. However, tolerant species with 66% and omnivore species with 76% were sampled from the 2nd order stream, which was shown deterioration in the physical habitat quality. In the overall watershed, mean IBI value was 38, judging as "fair" condition by the health criteria. Values of Individual IBI were closely associated with stream order and this pattern was similar to other mountainous streams showing low chemical pollutions and disturbance. Our comparison between IBI and diversity index over the stream order showed a distinct difference; Shannon-Weaver diversity index overestimated the actual community conditions and the variation range in the 2nd order stream was greater in the diversity index. Overall data suggest that the multi-metric approach may to a useful tool for stream ecosystem management and the conventional diversity index may not effective unless the stream order is considered for the stream evaluation.

• Korean Journal of Ecology and Environment
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• v.39 no.3 s.117
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• pp.310-319
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• 2006

The objective of study was to evaluate ecological health from seven sampling locations of Yoogu Stream, one of the tributaries of Guem River, July and September 2005. The research approach was based on the Index of Biological Integrity (IBI) using fish assemblage and Qualitative Habitat Evaluation Index (QHEI) using fish assemblage. The models of IBI and QHEI were modified as 10 metric model and 11 metric model, respectively, for the regional applications. In Yoogu Stream, value of IBI were averaged 29.5 (n=7) which is judged as a 'fair condition'. The IBI model scores, at the site 3 and 7, were estimated as 23 and 24, indicating a 'poor${\sim}$fair condition' while, site 5 was estimated as 28, 'fair condition'. The remaining sites were between 31 and 34, indicating 'fair${\sim}$good condition'. According to the analysis of QHEI, the average was estimated as 136, 'fair${\sim}$good condition'. Spatial variation the QHEI were evident; site 1 and site 4 were 186 and 120 respectively, indicating an 'excellent and fair${\sim}$good conditions'. Site 3 was 69, fair condition while the other sites were 128${\sim}$156, good condition.

• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.31 no.1
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• pp.74-83
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• 1995

To estimate the parameters of a mathematical model of fishes' swimming behavior, the behavior in a experimental water tank was observed and analyzed using the video monitoring system. The tank was equipped with vertical circulation system, and measured $3,500L\;{\times}\;1,500B\;{\times}\;1,000H\;mm$ at flow channel and $1,200L\;{\times}\;900B\;{\times}\;500H\;mm$ at observational part. Rainbow trout, salmo gairdnerii were used as experimental fishes. Their swimming behavior in the tank was observed by the monitoring system, and the positions of every individual were checked at 0.5 second intervals by the image processing of recorded pictures for 5 minutes. The mean swimming speed calculated from the time series data of positions of every individual ranged from 2.5BL cm/sec to 2.9BL cm/sec at the stagnated flow. The mean swimming speed of 10 individuals in a school increased according to the flow speed. The mean swimming depth ranged from 17 cm to 38 cm even though it changed irregularly at the stagnated flow and gradually became stable according to the increase of flow speed. In the present study, the mean distance of individuals from wall of the tank varied from 17.6cm to 21.4cm. The mean distance between the nearest individual varied from 0.4BL cm to 0.7BL cm when 10 individuals in a school were observed. The mean dimension of fish schools became enlarged in all directions according to increase in the number of individuals, and as flow speed increased the horizontal dimension of fish schools expanded while their vertical dimension decreased.

• Nutritional Sciences
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• v.1 no.1
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• pp.42-50
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• 1998

In this study, we evaluated the dietary fatty-acid pattern and serum fatty-acid composition of middle school students (total, 355 ; male, 182 ; female, 173), who are vulnerable to excessive and unbalanced food intakes such as fatty acids and energy. In serum lipid levels, total Chol (p<0.05) and HDL-Chol (p<0.001) levels of female students were significantly higher than those of mal, students. The average fat intake was 23-26 energy % which falls in with the current recommendation level (15-25%) for adults. Although the average P/M/S ratio of dietary fat was 1.1/1.2/1.0 which approaches the recommended ratio, the average range of $\omega$6/$\omega$3 fatty acid ratio of dietary fat was found to be 12.0-16.5, which is higher than the presently recommended range of 4 -10. Some of the very high values found in this study were partly explained by the fact that the range of individual variation of $\omega$6/$\omega$3 ratios was very large. Mean daily intake of Chol was 357-361 mg. The n3 fatty acid intake of middle school students was higher in the LFHM (high fish low meat) group than in the LFHM (low fish high meat) group. EPA and DHA intakes appeared to be significantly higher (p<0.01) in the HFLM group than in the LFHM group as expected. Dietary total $\omega$3 fatty acids (p<0.05) and EPA (p<0.01) were also negatively associated with serum AA($\omega$6) levels. Interestingly, energy intakes and dietary SEAs such as 12 : 0 (p<0.05), 14 : 0 (p<0.01) and 16 : 0 (p<0.05) were negatively associated with serum AA ($\omega$6) levels. To lower the $\omega$6/$\omega$3 ratio of dietary fatty acids for children, frequent consumption of $\omega$3 series fatty-acid rich foods such as soy bean, bean products and fish is recommended. Detailed guidelines should be developed in recommending balanced food intake and qualitative fat intake for Korean adolescents taking heterogeneous groups into consideration. In accurately evaluating fatty acid intake, it is also necessary to have the fatty acid composition data of all foods consumed in each country.

• Fisheries and Aquatic Sciences
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• v.3 no.1
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• pp.37-43
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• 2000

We used a mammalian GnRH antagonist, $[Ac-3,4-dehydro-Pro^1,\;D-p-F-Phe^2,\;D-Trp^{3.6}]$-GnRH, to examine the details of the salmon type gonadotropin-releasing hormone (sGnRH) and GnRH agonist analog $(Des-Gly^{10}$[d-Ala^6]-ethylamide GnRH; GnRHa) functions in the control of maturational gonadotropin (GTH II) secretion, in precocious male rainbow trout, in both in vivo and in vitro experiments. In the in vivo study, plasma GTH II levels increased by sGnRH or GnRHa treatment, but the response was more rapid and stronger in the GnRHa treatment group. The increase in GTH II was significantly suppressed by the GnRH antagonist, while the antagonist had no effect on basal GTH II levels in both groups. The GnRH antagonist showed stronger suppression of GTH II levels in the sGnRH treatment fish than in the GnRHa treatment fish. In addition, plasma androgenic steroid hormones (testosterone and 11-ketotestosterone) increased by the sGnRH or GnRHa treatment. The GnRH antagonist significantly inhibited the increases in plasma androgenic steroid hormone levels stimulated by the sGnRH or GnRHa, while the antagonist had no effect on basal androgenic steroid hormone levels in both groups. In the in vitro study, treatment with sGnRH or GnRHa increased GTH II release from the cultured dispersed pituitary cells, but the response was stronger in the GnRHa treatment group. The increase in GTH II release by GnRH was suppressed by adding the GnRH antagonist, dose­dependently. On the other hand, basal release of GTH II did not decrease by the GnRH antagonist treatment in both groups. These results suggest that the GnRH antagonist, $[Ac-3,4-dehydro-Pro^1,\;D-p-F-Phe^2,\;D-Trp^{3.6}]-GnRH$, used in this study is effective in blocking the action of GnRH-induced GTH II release from the pituitary gland both in vivo and in vitro.

• Microbiology and Biotechnology Letters
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• v.34 no.3
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• pp.257-264
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• 2006

An aerobic submerged membrane bioreactor (MBR) treating ammonium wastewater was studied in respect of nitrification characteristics and distribution of nitrification bacteria over a period of 350 days. MBR was fed with ammonium concentration of 500-1000 mg $NH_4-N/L$ at a nitrogen load of $1-2kg\;N/m^3{\cdot}d$. Overall ammonium oxidation rate increased with dissolved oxygen (DO) concentration, temperature, and sludge retention time (SRT). Under a higher concentration of free ammonia ($NH_3-N$) due to the decrease of ammonium oxidation rate, the nitrite ratio ($NO_2-N/NO_x-N$) in the effluent increased. The sudden collapse of nitrification efficiency accompanied by sludge foaming and the increase of sludge volume index (SVI) was observed unexpectedly during the operation. At the later stage of operation, additional carbon source was fed to the MBR and resulted in twice higher value of SVI and the decrease of ammonium oxidation rate. In fluorescence in situ hybridization (FISH) analysis, genus Nitrosomonas which is specifically hybridized with probe NSM156 was initially the dominant ammonia oxidizing bacteria and the amount of Nitrosospira gradually increased. Nitrospira was the dominant nitrite oxidizing bacteria during whole operational period. Significant amount of Nitrobacter was also detected which might due to the high concentration of nitrite maintained in the reactor.

• Korean Journal of Ecology and Environment
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• v.41 no.2
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• pp.228-236
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• 2008

The purpose of this study was to evaluate fish metric attributes using a model of Lentic Ecosystem Health Assessment (LEHA) and apply the model to the dataset sampled from six sites of Namyang Reservoir during October 2005$\sim$May 2006. The model was composed of 11 metries and the metric attributes were made of physical, chemical and biological parameters. Trophic composition's metrics showed that tolerant species ($M_3$, 80%) and omnivore species ($M_4$, 92%) dominated the fish fauna, indicating a biological degradation in the aquatic ecosystem. The metric of $M_7$, relative proportions of exotic species, also showed greater than 8% of the total, indicating a ecological disturbance. The average value of LEHA model was 24.3 (n= 12) in the reservoir, indicating a "poor condition" by the criteria of An and Han (2007). Spatial variation based on the model values was low (range: $21{\sim}26$), and temporal variation occurred due to a monsoon rainfall. Electrical conductivity (EC) and tropic state index of chlorophyll-$\alpha$ [TSI(CHL)] was greater in the premonsoon than the postmonsoon.

• Korean Journal of Ichthyology
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• v.32 no.3
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• pp.160-165
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• 2020

Seasonal fluctuation in abundance and species composition of fish in coastal waters off Samcheonpo were investigated using seasonal samples collected by a beam trawl in 2019 to compare the variation of species composition and dominant species with previous studies. A total of 6,518 fish were sampled and classified into 44 species, 30 families, and 6 orders. The dominant species were Nuchequula nuchalis (1,542 individuals, 23.7%), Platycephalus indicus (529 individuals, 8.1%), Thryssa kammalensis (437 individuals, 6.7%), Argyrosomus argentatus (403 individuals, 6.2%), and Acanthogobius flavimanus (354 individuals, 5.4%). The highest number of individuals was found in July (2,385 individuals), while the lowest number of individuals was found in January (925 individuals). The diversity index was the highest in April (H'=2.733) and the lowest in July (H'=2.546).

• Journal of Life Science
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• v.19 no.2
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• pp.256-263
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• 2009

The lactate dehydrogenase (EC 1.1.1.27, LDH) $A_4$ isozyme in skeletal muscle of mandrin fish (Siniperca scherzeri) was successfully purified by affinity chromatography and ultrafiltration. The molecular weight of the purified LDH $A_4$ isozyme was 140.4 kDa and its isoelectric point (pI) was 7.0. Optimal pH for enzymatic reaction was 7.5. ${K_m}^{PYR}$ and $V_{max}$ value of the purified LDH $A_4$ isozyme were $4.86{\times}10^{-5}$ M and 13.31 mM/min using pyruvate as a substrate, respectively. These kinetic properties of the purified LDH $A_4$ isozyme supported the fact that the mandrin fish was a warm-adapted species. The antibody against the purified LDH $A_4$ isozyme may be used in the metabolic physiological studies of ectothermic vertebrates and in the diagnosis of several human diseases.

• Fisheries and Aquatic Sciences
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• v.20 no.4
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• pp.6.1-6.8
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• 2017

The objective of this research was to study the effect of astaxanthin (AST) on growth performance and antioxidant capacity in golden pompano (Trachinotus ovatus) both in vivo and in vitro. In the in vivo study, two diets were formulated with or without astaxanthin supplementation (D1 and D2; 0 and 200 mg/kg) to feed fish for 6 weeks. In the in vitro study, cells from hepatopancreas of golden pompano were isolated and four treatments with or without astaxanthin and $H_2O_2$ supplementation were applied (control group: without both astaxanthin and $H_2O_2$ treated; $H_2O_2$ group: just with $H_2O_2$ treated; $H_2O_2$ + AST group: with both astaxanthin and $H_2O_2$treated; AST group: just with AST treated). Results of the in vivo study showed that weight gain (WG) and special growth rate (SGR) significantly increased with astaxanthin supplemented (P < 0.05). Feed conversion ratio (FCR) of fish fed D2 diet was significantly lower than that of fish fed D1 diet (P < 0.05). Hepatic total antioxidant capacity (T-AOC) and the reduced glutathione (GSH) of golden pompano fed D2 diet were significant higher than those of fish fed D1 diet (P < 0.05). Superoxide dismutase (SOD) was significantly declined as astaxanthin was supplemented (P < 0.05). Results of the in vitro study showed that the cell viability of $H_2O_2$ group was 52.37% compared to the control group, and it was significantly elevated to 84.18% by astaxanthin supplementation ($H_2O_2$ + AST group) (P < 0.05). The total antioxidant capacity (T-AOC) and the reduced glutathione (GSH) of cell were significant decreased by oxidative stress from $H_2O_2$ (P < 0.05), but it could be raised by astaxanthin supplementation ($H_2O_2$ vs $H_2O_2$ + AST), and the malondialdehyde (MDA) was significant higher in $H_2O_2$ group (P < 0.05) and astaxanthin supplementation could alleviate the cells from lipid peroxidation injury. In conclusion, dietary astaxanthin supplementation can improve the growth performance of golden pompano. Moreover, astaxanthin can improve the golden pompano hepatic antioxidant capacity both in vivo and in vitro study by eliminating the reactive oxygen species.