• Korean Journal of Fisheries and Aquatic Sciences
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• v.35 no.1
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• pp.27-34
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• 2002

The performances of fish culture were evaluated in the integrated recirculating aquaculture system consisting of a double drain type rearing tank ($2.5 m^3$), a sedimentation tank, a floating bead filter, a foam separator and a rotating biological contactor. A system was stocked with nile tilapia at an initial rearing densities of $5\%$ (A), $5\%$ (B) and $7\%$ (C) oyer 30 days. Feed coefficient was 1.62, 1,79 and 1.80 and average daily growth rate was $0.452\%$, 0.u5% and $0.423\%$, respectively. The level of TAN was maintained below $1 g/m^3$ for $5\%$ of initial rearing density and $2-4 g/m^3$ for $7\%$. The dissolved oxygen level ($2-4 g/m^3$) was not optimum but should not be inhibitory to fish growth. The total suspended solid was completely removed during overall experimental period.

• Journal of Aquaculture
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• v.16 no.2
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• pp.88-93
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• 2003

Diets containing 3000 kcal/kg at the crude protein (CP) level of 40% (Diet 1) and 4000 kcal/kg at the CP level of 50% (Diet 2) were fed to the juvenile rockfish, Sebastes schlegeli (35.6 g) at 3-4% body weight for a period of 28 days. Diet 2 promoted significantly higher growth and feed efficiency than Diet 1. Oxygen uptake increased with increasing body weight. The oxygen uptake-body weight relationship of diets 1 and 2 were best expressed by y=0.3218 $e^{0.0592x}$ (R=0.8494) and y=0.3612 $e^{0.0532x}$ ($R^2$=0.8805), respectively. Assimilation efficiency (AE), gross growth efficiency ( $K_1$) and net growth efficiency ( $K_2$) of the fish fed on Diet 2 were 73.8, 16.0 and 22.6%, respec- tively. Fish fed on Diet 2 showed significantly higher AE, $K_1$ and $K_2$ than those fed on Diet 1. Hence Diet 2 con- taining 4000 kcal/ kg with crude protein of 50% is recommended for the Korean rockfish.kfish.

• Journal of fish pathology
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• v.19 no.1
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• pp.65-72
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• 2006

Nervous necrosis virus (NNV) that causes severe mortality during seed production of red drum (Sciaenops ocellatus) is known to be vertically transmitted from infected spawners. This study was conducted to produce NNV free seeds by testing spawners for NNV infection and using virus free eggs for seed production. RT-PCR analysis of 40 spawners showed 18 positives and 22 negatives. NNV was not detected from eggs obtained from the negative spawners but was detected from those obtained from the positives. NNV was not detected from culturing seawater in tanks and Chlorella spp., Brachionus plicatilis., and Brine shrimp those were provided as live feed. The survival rates of fry from NNV positive and negative spawners were 80% and 85%, respectively by two weeks after hatching. The mortality increased from 25days after hatching and the final survival rate of seeds from NNV positive and negative spawners were 0% and 18.3%, respectively on 41 days after hatching. These results suggested that virus free red drum seeds can be obtained by using virus-free spawners.

• Korean Journal of Ichthyology
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• v.8 no.2
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• pp.16-22
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• 1996

Age and growth of Epinephelus akaara were determined using samples collected from the south western sea of Korea. Thin - sectioned otoliths showed relatively well defined annuli when examined under dark - field microscope. Because the fish do not feed at the temperature under $10^{\circ}C$, the annuli in otoliths are considered to be formed during the period between December and April. Considering that the peak spawning season is July, the first annulus must have been formed in 0.5 year after birth. The oldest fish examined was 9 years old, and the largest one was 47cm. The body length(L, cm) was linearly related to the otolith radius (R, ${\mu}m$) : L= - 2.84+7.01 R. Back-calculated lengths for each age using the relationship between body and otolith size were well adjusted to the Von Bertalanffy growth curve : $L_t$=55.5[1-exp{-0.162(t+0.128)}]. Using relationship between length and weight ($W_t$=0.00608$L^{3.21}$), growth in weight was expressed by Wt=2409(1-exp{-0.162(t+0.128)}]$^{3.21}$.

• Journal of Environmental Science International
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• v.23 no.10
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• pp.1703-1718
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• 2014

An eco-friendly integrated multi-trophic aquaculture (IMTA) farming technique was developed with the goal of resolving eutrophication by excess feed and feces as fish-farming by-products. A variety of seaweed species were tried to remove inorganic nutrients produced by fish farming. However, there have been few trials to use Sargassum fulvellum in an IMTA system, a species with a relatively wide distribution across regions with various habitat conditions, great nutrient removal efficiency and importance for human food source and industrial purposes. In this regard, our study tried to examine feasibility of using S. fulvellum in an IMTA system by analyzing growth characteristics of the species in an IMTA system comprising of rockfish (Sebastes shlegeli), sea cucumber (Stichopus japonocus) and the tried S. fulvellum (October 2011 - November 2012). We also monitored environment conditions around the system including current speed, water temperature and inorganic nutrient level as they may affect growth of S. fulvellum. S. fulvellum in the IMTA system, which were $15.72{\pm}5.67mm$ long at the start of the experiment in October 2011, grew to a maximum of $1093{\pm}271.13mm$ by May 2012. In September, seaweed growth was reduced to a minimum of $280{\pm}70.43mm$ in length. Then, S. fulvellum began to grow again reaching $325{\pm}196.19mm$ by November 2012. Wet weight of the seaweed was $4.01{\pm}1.89g$ at the start of the experiment and reached a maximum of $109.26{\pm}34.23g$ in May. The weight gradually declined to a low of $15.12{\pm}8.40g$ in September 2012. Weight began to increase once more, rising to $39.27{\pm}21.69g$ by November. During the experiment, the average velocity at the surface and the bottom was 6.5 cm/s and 3.4 cm/s, respectively. The water temperature ranged $5.0-23.5^{\circ}C$, which was considered suitable for growing S. fulvellum. Results of the study indicated no significant differences in inorganic nutrients between pre- and post-IMTA installation. It was thus concluded that S. fulvellum can be a suitable seaweed species to be used in an IMTA system.

• Journal of Aquaculture
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• v.22 no.1
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• pp.1-4
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• 2009

A 10-week feeding trial was conducted to investigate the effects of feeding rate on growth and body composition of adult flounder during the summer season. Three replicated groups of the fish (initial mean weight of $535{\pm}4.1\;g$) were hand-fed a extruded diet twice a day at the different feeding rates of satiation (100%), 90%, 80% and 70% of satiation for 10 weeks. Mean Water temperature was $19.2{\pm}2.8^{\circ}C$ during the feeding trial. Weight gain and condition factor increased significantly with increase in daily feeding rate (P<0.05), but there was no significant difference in weight gain of fish fed the diet between 100% and 90% of satiation. Survival and feed efficiency were not significantly different among all groups. Proximate composition of dorsal muscle was not significantly affected by feeding rate. Based on the results of this study, optimum feeding rate for growth and condition factor of adult flounder (535-928 g) seemed to be 90% of satiation.

• Journal of the Korean Society of Food Science and Nutrition
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• v.30 no.6
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• pp.1278-1282
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• 2001

Effect of the egg yolks from laying hens intubated, p.o., astaxanthin (designated AEY) on the catabolic response overcome of mice was examined. Female ICR mice (6~7 weeks of age) were adapted in a temperature- and humidity-controlled house for one week and randomly divided into 5 groups (6 mice/cage/treatment). Mice were intubated p.o., AEY (5, 10 and 15 mg), control egg yolk (CEY, 10 mg), or fish oil (5 mg) dissolved in 0.2 mL phosphate buffered saline (PBS) every two days for 14 days. At day 15, the 0.1 mL of lipopolysaccharide solution (LPS, 30$\mu\textrm{g}$/0.1 mL 10 mM HEPES) was injected through tail vein, and then, the body weight of mouse and the amount of feed intake were measured over a period of 72 hours. Control group mice were received only PBS and LPS. AEY treatment suppressed the loss of mice body weight in a dose-response manner. Twenty four hours post LPS injection, the reduced body weight per mouse of AEY 5, AEY 10, and AEY 15 mg treatment groups was 3.70, 3.54, and 3.25 g, respectively. Body weight suppression effect of AEY treatment was greater than that of CEY, but less than fish oil. AEY treatment did not alter thymus weight, but increased the weight of spleen or liver. These results indicate that AEY suppressed the loss of body weight by LPS via any function of the spleen and/or liver.

• Journal of Sensor Science and Technology
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• v.30 no.3
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• pp.154-164
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• 2021

In this study, the IoT sensor technology required for improving the survival rate and high-density productivity of individual shrimp in smart shrimp farming (which involves the usage of recirculating aquaculture systems and biofloc technology) was analyzed. The principles and performances of domestic and overseas water quality monitoring IoT sensors were compared. Furthermore, the drawbacks of existing aquaculture monitoring technologies and the countermeasures for future aquaculture monitoring technologies were examined. In particular, for farming white-legged shrimp, an IoT sensor was employed to collect measurement indicators for managing the water quality environment in real-time, and the IoT sensor-based real-time monitoring technology was then analyzed for implementing the optimal farming environment. The results obtained from this study can potentially contribute to the realization of an autonomous farming platform that can improve the survival rate and productivity of shrimp, achieve feed reduction, improve the water quality environment, and save energy.

• Journal of fish pathology
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• v.35 no.1
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• pp.103-111
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• 2022

This study has been performed to investigate the potential effects of by-product discarded after probiotics production (BPPP) on growth performance, immune gene expression, innate-immunity status, and disease resistance of carp, Cyprinus carpio. For 3 weeks, carp were fed four diets containing different levels of BPPP at 0, 0.1, 0.2 and 0.5% per kg of normal diet. Every 7 days of feeding, immune-related gene expression, serum lysozyme activity and ACH₅₀ were analyzed. Growth rates and challenge test with E. tarda were conducted after 3 weeks of BPPP feeding. Both lysozyme activity and ACH₅₀ were significantly (p<0.05) increased in all BPPP supplemented groups compared to the control at every 7 day for 3 weeks of feeding trial. The gene expression of pro-inflammatory cytokines, IL-1β and TNF-α was significantly (p<0.05) up-regulated until 21 days of feeding in all groups except for 0.2% group on day 7 post feeding. The anti-inflammatory cytokine IL-10 gene expression was only significantly (p<0.05) increased in 0.1% group on day 7 and decreased (p<0.05) on day 14 in all BPPP supplemented groups. On day 21, the IL-10 gene expression was augmented (p<0.05) in all groups. SOD gene expression was significantly (p<0.05) increased compared to the control on day 14 and 21 post feeding, whereas no significant difference was observed on day 7. In challenging test, 0.2%, 0.1%, 0.5% and control group showed 80%, 70%, 60% and 40% of survival rate, respectively. Feed conversion rate was only improved in 0.5% group. In conclusion, the present study indicates that dietary BPPP suplementation improved growth performance, innate immune response and bactericidal activity in carp.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.44 no.4
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• pp.359-365
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• 2011

This study was conducted to investigate the production, elver stocking, rearing facilities and rearing method of eel culture to determine aquaculture management conditions for optimal rearing of eel Anguilla japonica. The production of eel culture was evaluated by the proportion of eels from the main inland fin fish species production in Korea. Elver stocking was assessed by the elver stocking densities of pond and recirculation culture. Rearing facilities were investigated according to the rearing tank size proportion of the pond and recirculation culture. We selected sample farms by region and by size. We visited sample farms and recorded the number of elvers stock for pond area, size of tanks, feed and feed quantity, and the size and number of harvest eels. The production capacity of Jeollanam-do and Jeollabuk-do were 71.9% and 21.3% respectively. This production quantity represented 93.2% of the total Korean eel production quantity. In Jeollanam-do, there are 236 eel farms, 202 pond farms, and 34 recirculation aquaculture facilities. The elvers' first density data by each aquaculture method revealed that elvers' first density varied more in recirculation system farms, as compared to pond aquaculture. In intensive pond farms, the elvers' first density decreased as the size of farm increased. There was a correlation between the size of tank(x) and the facility of a water wheel for dissolved oxygen in pond culture systems(y=0.022x-0.494; $R^2$=0.860). Another strong correlation was found between the weight of eel(x) and eel density(y) in pond culture systems(y=283.5x-0.27; $R^2$=0.992). Finally, there was a strong correlation between the length of eel(x) and the weight of eel(y) in intensive pond culture(y=0.0005x-3.2783; $R^2$=0.9775). The final survival rate did not differ significantly among pond sizes and culture types.