• Korean Journal of Ichthyology
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• v.12 no.3
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• pp.166-172
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• 2000

Growth of Ammodytes personatus was investigated based on the specimens collected in the costal waters of Shinsudo, Sacheon from March 20 to December 14, 1988. Age determination based on otolith. The rings in the otolith were used as the basis for age annulus. The time of ring formation was estimated to one time per year in May far 1st ring group and March for 2nd ring group. The spawning season peaked in December. It takes approximately 16 months for the first ring and 11 months for the second ring to form in the otolith. The opaque zone was formed and marked over summer at 1st ring group and spawning mark at 2nd ring group. The relationship between the total length(TL) and otolith radius(R), and body weight(BW) were represented respectively as follows: TL=29.17+182.9R, BW=$4.9{\times}10^{-8}TL^{3.9587}$. Von Bertalanffy growth model is $TL_t$ = 177.273 ($1_e^{-0.040(t+7.332)}$), Robertson growth model is $TL_t=\frac{150.275}{1+2.085e^{-0.099t}}$ and Gompertz growth model is $TL_t=157.551e^{-1.214exp(-0.069t)}$.

• Korean Journal of Agricultural Science
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• v.44 no.2
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• pp.211-220
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• 2017

We conducted this study to determine the recommended application rate of fertilizer for Houttuynia cordata Thunb cultivation. The effects of various application levels of N, $P_2O_5$, and $K_2O$ fertilizers on the growth of this plant were investigated and the associated changes in soil properties were evaluated in the field. Soil pH at harvest time of Houttuynia cordata Thunb did not differ from that before fertilization, whereas EC tended to decrease during cultivation. The soil organic matter (SOM) and available phosphorus increased after treatment, and the amount of applied fertilizer ($P_2O_5$) and available phosphorus were proportional. The nitrogen absorption amount increased in N 100% treatment, but decreased in N 150% treatment. The phosphorus absorption amount rose with the fertilizer treatment concentration until $P_2O_5$ 150% treatment. The amount of absorbed potassium decreased in treatments with $K_2O$ 150% and $K_2O$ 200%. The plant length was the longest in N 100%, $P_2O_5$ 150%, and $K_2O$ 200%. The stem diameter was estimated to be 3.46 - 3.67 mm in N 100 - 200% treatment, 3.55 - 3.67 mm in $P_2O_5$ 100 - 150%, and 3.79 mm in $K_2O$ 200%. The number of tillers did not differ amongst fertilization treatments. The fresh weight was summed to be 3.67 ton/10 a in N 100% treatment, 3.79 Mg/10 a in $P_2O_5$ 150%, and 3.83 Mg/10 a in $K_2O$ 150%. Thus, the relationship between the fertilizer amount and yields of the plant showed that the most economical quantity of fertilizers should be 10.2 N kg/10 a, 5.5 $P_2O_5$ kg/10 a, and 8.2 $K_2O$ kg/10 a for Houttuynia Cordata Thunb.

• Korean Journal of Soil Science and Fertilizer
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• v.20 no.3
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• pp.269-274
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• 1987

A laboratory experiment was conducted to find out the effect of inoculation with plant growth of associative $N_2$-fixing bacteria on the combination of eight different rice seedling with seven different associative $N_2$-fixing bacteria in which were isolated and identified from grasses and rice in saline and reclaimed saline paddy soil. Those were examined in N-free axenic culture medium. The result of this experiment exemplified the contribution of associative $N_2$-fixing bacteria to their host plant were varied much by the combination of rice cultivars and bacterial strains. Acetylene reduction ($N_2$-fixation) activity seems to be more variable with respect to the combination of rice cultivars and bacterial strains. The relationship between acetylene reduction activity and rice performance such as dry matter weight, plant height, root length, and number of root were statistically insignificant. However, in comparision with the control, the dry matter yield of Annapuruna was increased by inoculation of all the seven bacteria strains. Among the seven rice cultivars, the average acetylene reducing activity was the highest in Annapuruna, and Shingwang, and the lowest in IR-8 inoculated with Pseudomonas sp H8. Among the seven bacterial strains the highest acetylene reducing activity was obtained by the combination of Shingwang with Pseudomonas sp H8.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.27 no.1
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• pp.59-68
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• 1994

The effects of silt and clay, water temperature and salinity on the metabolic activities: rates of respiration, filtration and nitrogen excretion in the clam, Mactra veneriformis, were investigated in ranges of $0{\sim}250ppm,\;15{\sim}25^{\circ}C\;and\;10{\sim}30\%0$ respectively. The weight specific respiration rate decreased with shell length and significantly declined at lower temperatures and lower salinity levels. Average respiration rates, filtration rates and ammonia excretion rates of the clam groups declined as water temperature was lowered. The respiration rate(R) and the filtration rate(F) decreased as the concentration of silt and clay(C) increased, the relationships between the two parameters were expressed as a regression line, R=a+b LogC and LogF=a+b LogC, respectively. On the rearing experiment treated with 50ppm of silt and clay, the relationship between the accumulative mortality(M) and the elapsed day(T) was $M=0.0186T^{2.7965}$, and the median lethal time was calculated at 16.8 days. From the rearing experiment, both rate of respiration and ammonia nitrogen excretion of experimental groups and control groups decreased with elapsed days, the rates of experimental groups, especially declined more compared with those of the control groups.

• Korean Journal of Soil Science and Fertilizer
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• v.38 no.4
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• pp.218-221
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• 2005

The present study was investigated in the Chittagong hill forest of Bangladesh to assess the feasibility of ginger cultivation under multipurpose forest and fruit tree species. There were three treatments such as i) ginger grown under open field condition, ie. full sunlight (T1), ii) ginger grown under Gamar tree (spacing of $90{\times}90cm$ (T2) and iii) ginger grown under guava tree (spacing $180{\times}180cm$) tree (T3). The experiment was laid out in randomized block design (RBD) and each treatment was replicated three times. From data it was observed that some morphological parameters of ginger such as plant height, number of leaves per plant, leaf length and leaf breadth were higher in the treatments T2 and T3 as compared to the treatment T1. A positive and linear relationship was observed between the weight of rhizome and yield of ginger which caused the highest yield of ginger ($23.63Mg\;ha^{-1}$) under guava tree species at partial shaded condition in the T3 treatment ($180{\times}180cm$), whereas the lowest yield ($15.64Mg\;ha^{-1}$) was recorded in the T2 treatment when ginger was cultivated under Gamar tree species at closer spacing ($90{\times}90cm$). Therefore, it was revealed that partial shaded condition favoured the optimum growth and yield of ginger, whereas the dense shade from intensively planted tree species badly affected the dry matter production and yield of ginger.

• Korean Journal of Ecology and Environment
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• v.48 no.2
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• pp.77-85
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• 2015

Siniperca scherzeri is major target species for restocking and restoration project as it is one of the economic species in South Korea. In this study, to investigate their ecological characteristics movement pattern and habitat characteristic of S. scherzeri were analyzed using radio telemetry. Three specimens released during spawning season, moved more than 10 km toward upstream from the release site. Whereas the remains released after spawning season, settled within 400 m of their release site except two specimens (Ss 11, 3.2 km; Ss, 15, 1.4 km). One of possible reason of upstream movement during spawning season is reproduction. The conditions of their settlement area is similar with reference conditions of their spawning ground. S. scherzeri were mainly detected near the edge of the water, and it may related with the facts that rocks are mainly located at the edge of the water and S. scherzeri prefers rocks for their shelter. AMD (Accumulated movement distance) positively related with body weight and condition factor K, but no significant relationship was identified with gender and total length. Daily movement boundary of S. scherzeri was $214.94m^2{\sim}3,257.19m^2$, and their movement was restricted near the edge of the water. The results of this study could be useful to restocking and restoration.

• Journal of Korean Society of Forest Science
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• v.90 no.1
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• pp.124-132
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• 2001

This study was conducted to reveal the relationship between physiological characteristics and growth by family for open-pollinated progeny stand of Korean white pine in Gapyung site. Average growth performance of total 25 families for 18 years old progeny stand in this study site showed 5.9m in mean height, 8.9cm in mean DBH, $12.0m^2$ in basal area per hectare and $46.5m^3$ in volume per hectare, respectively. By the analysis result of growth performance for all 25 families, family No. 20 showed the most excellent growth and middle in family No. 10. On the other hand, family No. 3 represented the worst growth among the 25 families. The change of seasonal photosynthesis rate by increasing luminous intensity was the same tendency as the growth pattern of all 25 families and showed the same results in all four seasons. In the seasonal analysis, the photosynthesis rate was increased as the season has changed from winter to summer. Chlorophyll contents was also increased from winter to summer. Especially, family No. 20 which is the best in growth performance has more chlorophyll contents than the others. In addition, family No. 20 was also better than other families in the weight of assimilation tissue(g), length of needle(cm), width of needle(cm), and number of Stoma. However, in water utilization rate, family No. 3 which is the worst in the growth performance showed the best result that is reverse tendency compared with the photosynthesis rate. The changes of water utilization rate represented to be increased as the season has changed from winter to summer.

• Korean Journal of Ichthyology
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• v.35 no.1
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• pp.50-56
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• 2023

This study is the first to report the biometric information between the length and weight relationships (LWR) and seasonal body condition factors (K) of Sebastes zonatus Chen & Barsukov, 1976 and Thamnaconus modestus (Günther, 1877) inhabiting the waters off Ulleung-do and Dokdo. The LWRs in spring and summer, and all seasons combined were highly correlated (r²>0.959), and the regression slopes of LWRs were significantly different between the spring and summer in both species. The body conditions of the two fish were significantly higher during the spring than during the summer, reflecting their fatness in relation to spawning. The results from this study contribute to the understanding of the biology of S. zonatus and T. modestus and provide useful data for the development of conservation and management plans for these species.

• The Sea:JOURNAL OF THE KOREAN SOCIETY OF OCEANOGRAPHY
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• v.12 no.2
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• pp.81-85
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• 2007

Early growth of chum salmon was investigated in terms of rearing pond condition. The number of fingerling showed big differences by rearing pond $1,003,000{\sim}1,865,000$. The fork length of fingerlings ranged from $3.20{\sim}3.78cm$ and body weight ranged $0.34{\sim}0.49g$. Daily temperature of rearing water in January to March was $6{\sim}8^{\circ}C$, which is inadequate for salmon growth. pH was $6.0{\sim}6.3$ in early and mid February, 6.5 in late February and $6.5{\sim}7.0$ in March. Dissolved oxygen concentration was lowest from 8 a.m. to 6 p.m. and increased after 6 p.m. The maximum value was seen from 9 p.m. to 6 a.m. The mortality of fingerlings was 5 times higher in the daytime than at night because of dissolved oxygen. Growth of fingerlings was affected by daily ration, concentration of dissolved oxygen and rearing temperature.

• Journal of Life Science
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• v.34 no.2
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• pp.122-127
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• 2024

This study investigated the reproductive ecology and spawning of Hoplobrotula armata on the coast of Jejudo Island. Samples were collected from February to December 2019 and February to December 2020, with a total of 2,634 samples. The results of the investigation showed that total length (TL) ranged from 22.0 cm to 68.8 cm, and the body weight (BW) ranged from 66.5 g to 3,553.9 g. According to the development process of gonads and the gonadosomatic index (GSI), the spawning period of H. armata was from July to October. The relationship between TL and BW was BW = 0.0024TL^3.3278 in females and BW = 0.0035TL^3.2162 in males. The sex ratios of surveyed female to male H. armata was 1:0.71, with more females. At 50%, 75%, and 97.5%, the group maturities of H. armata were as follows: Females, 39.9 cm, 42.7 cm, and 49.4 cm; males, 37.6 cm, 40.4 cm, and 46.9 cm, respectively. According to monthly GSI and gametocyte (ovarian, testis) development stage observations of H. armata on the coast of Jejudo Island, they spawn once a year and are presumed to be summer spawners.