• Journal of Aquaculture
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• v.12 no.3
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• pp.213-220
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• 1999

This study was performed to investigate the effects of water temperature and stocking density and rotifer density on the mass production of larval red marbled rockfish, Sebastiscus tertius. Total length of the marbled rockfish larva grown in $23^{\circ}C$ of water temperature were 10.80mm, which was the best, while those grown in $29^{\circ}C$ of water temperature were 6.28mm, which was the lowest. The survival rates of red marbled rockfish larvae grown in $20^{\circ}C$ and $23^{\circ}C$ were 24.0% and 18.5%, respectively. However, the survival rate of red marbled rockfish larvae grown in $26^{\circ}C$ was $7^{\circ}C$ and no larvae survived in $29^{\circ}C$. The total length of red marvled rockfish larva stocked at the density of 5 and 10 larvaper liter of water were high, which were 11.52 mm and 11.22 mm, respectively, but those stocked at the density of 30 larva per liter of water were 7.55mm, which was the lowest. The survival rate of red marbled rockfish larva stocked at the density of 2.5 larva per liter of water was 52.0%, which was the best, but the lowest, 18.0% for the red marbled rockfish larva stocked at the density of 30 larva per liter. There was a trend toward decrease in survival rate of red marbled rockfish larva as their stocking density increased. The survival rates of red marbled rockfish larva fed rotifers at the density of 10 and 5 individuals per ml were high, 48.5% and 48.0%, and their total lengths were 11.92 and 11.89mm, respectively, which grew relatively fast. The survival rate and the total length of red marbled rockfish larva fed rotifers at the density of 30 individuals per ml were the lowest, which were 8.40mm and 21.5%, respectively. Also, red marbled rockfish larva fed rotifers at the density of more than 20 individuals per ml achieved poor survival and growth. These results indicated that the proper conditions for the mass production of larval red marbled rockfish were $23^{\circ}C$ of water temperature, fish larva stocking density of 5 to 10 larva per liter of water and rotifers density of 5 to 10 individuals per ml as live feed.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.49 no.3
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• pp.351-358
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• 2016

The aim of this study was to verify the performance of Teleaulax amphioxeia as prey for Brachionus plicatilis and for the larvae of the bivalves (Pacific oyster Crassostrea gigas and Manila clam Ruditapes philippinarum) to select the best of five T. amphioxeia strains. The five strains of T. amphioxeia were collected from the coasts of Korea, purecultured and then fed to the rotifer and bivalve larvae. The density and fecundity rate of the rotifer fed on strain 01 were the highest. The instantaneous growth rate of the rotifer fed strain 08-2 was the highest. The maximum density and fecundity rate of the rotifer fed strain 08-2 were significantly higher than those fed Chlorella ellipsoidea, while instantaneous growth rate showed the opposite pattern. Survival rates of the Manila clam larvae fed each strain of Teleaulax showed no significant difference between strains. Survival rates of the Pacific oyster fed Teleaulax were significantly higher than those fed Chaetoceros sp., but lower than those fed I. galbana. This study indicates that strain 08-2 showed better growth for B. plicatilis and better survival for the bivalve larvae than did the other strains, and that T. amphioxeia can also be used as a prey organism for rotifers or bivalve larvae.

• Journal of Aquaculture
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• v.12 no.3
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• pp.185-191
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• 1999

A genetic analysis for survival in fry and juvenile stages of masu salmon was described. Data from two year-classes of masu salmon were analyzed to estimate the heritability for survival during the fresh water-rearing period. The overall survival for each year-class during 8 months of freshwater rearing were 17.8 and 11.6%, respectively. Whirling disease virus (WDV) was the main cause of death in all year-classes. Survival data obtained for offspring of 42 sires and 60 dams of masu salmon (two year classes of data) was analyzed. Average survival rates in the observation period ranged 2-87% for 1994; 0-98% for 1995, repectively. In both year-classes, heritabilities for survival derived from the sire components of variance were low(0.13-0.18), except one. Heritabilities derived from the dam components of variance ranged 0.14-0.61, including non-additive genetic and /or common enviromental effects. Correlations between survival in two long-term periods were all positive and medium to high in magnitude(0.345-0.918). Correlations between survival in non-succeeding periods were, in general, low and insignificant. Correlation between long-term survival and growth rate was found in masu salmon. The corresponding correlation in masu salmon was not significantly different from zero. Correlations between sire survival and body weight, length and condition factor of slaughter were not significant, but varied.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.29 no.5
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• pp.567-577
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• 1996

This study is to estimate population ecological parameters, including growth parameters, survival rates, instantaneous coefficients of natural and fishing mortalities, and age at first capture, as well as growth rates at age of the hairtail, Trichiurus lepturus Linne in Korean waters. For describing the growth of the hairtail, three growth models were fitted, and the von Bertalanffy growth model was adopted for the purpose of the further stock assessment work. The von Bertalanffy growth parameters estimated from a nonlinear regression using EXCEL Solver were $L_\infty=46.01cm$, K=0.3868, and $t_0=-0.3220$. Annual survival rate (S) of the hairtail was estimated to be 0.277 (variance=0.00035) and the instantaneous coefficient of natural mortality (M) was estimated to be 0.441/year. Instantaneous coefficient of fishing mortality (F) for the recent years was calculated as 0.843/year, implying an impact from fishing about two times greater than that of natural mortality. The age at first capture $(t_c)$ was estimated to be 0.787 years, which is much younger age than $50\%$ mature age. Finally, the growth rates at age were estimated.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.48 no.4
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• pp.466-473
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• 2015

The juvenile red variant of the sea cucumber Stichopus japonicus is distributed worldwide. It is a valuable food source in Korea, China, and Japan. Major issues in farming the juvenile red variant sea cucumber include growth rates and disease resistance. In recent years, studies have focused on feed additives to enhance immune system and health. In this study, we used a common diet (CD), a nutritional diet (ND; mixed nutritional supplements), and an immunity diet (ID; mixed probiotics, spirulina, and levan) and compared the growth rates and immunity of juvenile red variant sea cucumbers fed the experimental diets for 12 weeks. The growth and survival rates in the ID group were significantly increased (P>0.05). This suggests that the feed additives positively influenced immunity and growth in the ID group. However, the immune activity was exhibit a stabilizing effect, and further investigation of immune effects is required.

• The Korean Journal of Malacology
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• v.17 no.2
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• pp.79-84
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• 2001

In order to obtain the basic information for seedling production of the scallop, Patinopecten yessoensis, the egg development and larva growth were investigated at different conditions such as water temperature, salinity and phytoplankton. Eggs were demersal isolated eggs, which averaged 77.3${\pm}$2.7$\mu\textrm{m}$ in diameter after spawning. The fertilized eggs developed to D-shaped larva of shell length 117.5${\pm}$3.8$\mu\textrm{m}$ after 60 hours at 15$^{\circ}C$. The range of water temperature and salinity during egg development were 10-20$^{\circ}C$ and 28-34 ppt, respectively. The time of egg development was shorter with higher water temperature. After 10 days of spawning, D-shaped larva reached 160 $\mu\textrm{m}$ in shell length, and after 25 days became full-grown larva 250 $\mu\textrm{m}$ in shell length, in which could be observed eye spots. The relative growth formula between shell length (SL) and shell height (SH) was SH = 1.0425SL-27.731 (r$^2$= 0.9749) during the entire larva period. In regard to water temperature, growth and survival rates of larvae were good at 16$^{\circ}C$. Lower growth and survival rates were observed at 12$^{\circ}C$ and 20$^{\circ}C$ than that at 16$^{\circ}C$. When larvae were fed mixed phytoplankters, such as isochrysis galbana, Pavlova lutheri and Chaetoceros calcitrans, their growth and survival rates were the highest among groups.

• Journal of Ecology and Environment
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• v.32 no.2
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• pp.87-96
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• 2009

Pinus thunbergii plantations in Pohang-si, Gyeongsangbuk-do, Korea, are of low ecological quality, with arrested succession and a high proportion of ruderal species. To improve the quality of the habitat, we created canopy gaps ($\sim42\;m^2$) and monitored changes in abiotic (light availability, canopy openness) and biotic (survival and growth of seedlings and understory communities) variables in 2007 and 2008 in plots that had received one of five types of treatment: cutting of canopy trees and removal of the understory (CU), cutting of canopy trees only (C), girdling of canopy trees and removal of the understory (GU), girdling of canopy trees (G) or control. Each treatment was applied to three replicate plots. Abiotic variables did not significantly differ among treatments. Survival rates of target species were slightly lower in the CU, G and control conditions. Based on logistic regression analysis, the only significant growth factor affecting survival was height growth. Positive effects of seedling height and leaf area growth on survival were also detected, but did not reach statistical significance. In treatment G, gradual improvement of overstory conditions and mitigation of competition by limitation of disturbance to the understory community were likely to have promoted seedling growth. There were no significant effects of gap treatments on changes in species abundance (cover and richness) and composition of understory between the study years. This result implies that the small gaps created in our study may be below the threshold size to affect understory growth. However, the results of this study are based on a short-term investigation of only two years. Long-term research is strongly recommended to clarify the effects of gap treatment on plant communities in afforested areas.

• Childhood Kidney Diseases
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• v.21 no.2
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• pp.69-74
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• 2017

Purpose: Kidney transplantation (KT) is an ideal treatment for pediatric patients with end-stage renal disease (ESRD). We report the clinical outcomes of pediatric ESRD patients who underwent KT in a single regional center. Methods: We retrospectively investigated the medical records of 60 pediatric patients who were diagnosed with ESRD and underwent KT in our hospital between January 1985 and June 2016. Results: A total of 60 children and adolescents (40 male, 20 female; mean age, $13.86{\pm}4.26$ years) were included in this study. Six patients (10.0%) underwent KT immediately after receiving the diagnosis of ESRD, while the others underwent KT after dialysis treatment (mean period of dialysis, $368.7{\pm}4,41.8$ days). The mean donor age (50 living-related [83.3%], 10 deceased [16.7%]) was $40.0{\pm}12.85$ years and the male:female ratio was 1.07:1. The most common cause of ESRD was chronic glomerulonephritis. The overall survival rates at 1, 3, and 5 years after KT were 98%, 98%, and 96%, respectively, while the graft survival rates at 1, 3, and 5 years were 93%, 86%, and 68%, respectively. Children who underwent KT before 10 years of age had better monthly growth rates than those who underwent KT later than 10 years of age. Conclusions: KT is performed less frequently in children than in adults, but causes of ESRD vary and clinical outcomes after KT greatly affect the growth and development of pediatric patients. Therefore, further analysis and monitoring of clinical progression after KT in pediatric ESRD patients are necessary.

• Journal of Aquaculture
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• v.9 no.4
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• pp.311-320
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• 1996

In order to compare the growth and survival rates of grey mullet (Mugil cephalus) juveniles in different salinities, the fish reared in seawater (SW) abruptly were transferred to each experimental rearing water of $0\%SW\;(0\%_{\circ}),\;25\%SW\;(7.7\%_{\circ}),\;50\%SW\;(16.1\%_{\circ})$ and $100\%SW (32.8\%_{\circ})$. Growth rates in total length and body weight of fish in $25\%$ SW, $50\%$ SW and $75\%$ SW were greater than that in $0\%$ SW (P<0,05). Decreased salinity appeared to have an acute, but appetite depressive effect in short term in the experimental groups. Survival rate was low in $0\%$ SW (P<0.05), although those were more than $81\%$ in all salinities. There were no differences in thickness of epidermis and dermis layers in fish skin among the all experimental groups at the end of experiment. But the thickness of lipid layer in $0\%$ SW fish showed the significant differences to those in $50\%$ SW and $100\%$ SW (P<0.05). With decreased salinities, oxygen consumption was found to be decresed in the other experimental groups compared to the group in $100\%$ SW. The levels of lethal dissolved oxygen in $0\%$ SW to $100\%$ SW were 1.18, 0.30, 0,28 and 0.31 ppm, respectively.

• Journal of the Korean Society of Environmental Restoration Technology
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• v.18 no.3
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• pp.79-95
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• 2015

To suggest ecological management plans for invasion of Salix gracilistyla, stepwise environmental sieve of seed dispersal, germination, seedling and juvenile stages were investigated. About 84% of total seeds were released between May 6 and 10. Germination rates significantly declined with decrease of light intensity from 100% to 30% and 0% (p<.001), but above 60% of seeds germinated in all treatments. Difference of germination rates with 0 and 2cm water level was not significant (p = .571). With increase of elapsed time after seed dispersal, germination rates significantly decreased (p<.001), and seed viability was lost within 16 days. Considering both germination rate of seed and survival rate of seedling, survival rate of all dispersed seeds was only 5% when 8 days passed after seed dispersal. All 22-day-old seedlings (height: 1cm) died under flooding of twice level as its height. With decrease of light intensity from 100% to 30%, survival rates of seedling decreased from 90% to 33% (p<.001). In the case of 45-day-old juvenile (height: 20cm), survival rate was 70% under the water level same as its height. There was significant interactive effect of water level and light intensity on the growth of juvenile (height: p<.001, dry weight: p<.01), and survival rate of juvenile was 10% under +20cm-water level and 30%-light intensity condition. The following management plans for invasion of S. gracilistyla are recommended from these results. (1) Dry condition should be maintained at fringe of wetlands for about two weeks at seed dispersal and germination stage (early May~mid May). (2) Water level should be raised to about 5cm at fringe of wetlands for about two weeks at seedling stage (mid May~early June). (3) Water level should be raised to over 20cm at fringe of wetlands for a long time at juvenile stage. Planting trees for shading can raise management effectiveness (mid June~). (4) As water level manipulating is performed as fast as possible for controlling seedling and juvenile, management become easier and more effective.