• Fisheries and Aquatic Sciences
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• v.24 no.11
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• pp.383-389
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• 2021

On the southern coast of South Korea, dark-banded rockfish, sea bass, and red seabream are caught by single-line fishing. In particular, red seabream and sea bass are caught in the Jeollanam-do region using gear with attached fishing hooks, such as longline and single-line gear, with live shrimp as bait. The objective of this study was to compare the catch efficiency of two types of live shrimp (naturally grown Shiba shrimp [Metapenaeus joyneri] and cultured whiteleg shrimp [Litopenaeus vannamei]) used as bait. The investigation included interviews, on-board surveys, and water tank experiments. Interviews were conducted with relevant parties to determine the preference for live shrimp as bait, and the results showed a greater preference for cultured whiteleg shrimp. Further, an on-board survey was conducted to compare catch efficiency between these two types of live shrimp bait for single-line fishing. The on-board investigations were conducted once or twice a month between June and October. In total, the amounts of fish caught using naturally grown Shiba shrimp and cultured whiteleg shrimp were 56 and 52, respectively. Of these, the numbers of sea bass, the primary target fish species, caught using naturally grown Shiba shrimp and cultured whiteleg shrimp were 43 and 40, respectively. Thus, the results showed that there was almost no difference in the number of fish caught based on the bait used. However, according to a water tank experiment, cultured whiteleg shrimp survived longer than naturally grown Shiba shrimp.

• Journal of Environmental Health Sciences
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• v.36 no.6
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• pp.496-501
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• 2010

Fish pathogenic bacteria are a considerable danger of farmed fish and a source of economic loss in the fish farming industry. In this study, $Nanoxil^{(R)}$ was compared to hydrogen peroxide and a silver colloid in terms of disinfection efficacy against E. tarda, V. anguillarum and S. iniae. A bactericidal efficacy test conducted by a broth dilution method was used to determine the lowest effective dilution of the disinfectant following exposure to test bacteria for 30 min at $4^{\circ}C$. $Nanoxil^{(R)}$ and test bacteria were diluted with distilled water (DW), hard water (HW) or an organic matter suspension (OM) according to the treatment condition. Under the OM condition, the bactericidal activity of $Nanoxil^{(R)}$ against E. tarda exhibited a lowered efficacy compared to that under the DW and HW conditions. $Nanoxil^{(R)}$ at 500 fold (dilutions on) under all of the conditions demonstrated a high bactericidal efficacy against S. iniae. As $Nanoxil^{(R)}$ possess bactericidal efficacy against fish pathogenic bacteria such as E. tarda, V. anguillarum and S. iniae, this disinfectant solution can be used to limit the spread of fish bacterial diseases.

• Fisheries and Aquatic Sciences
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• v.7 no.2
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• pp.76-83
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• 2004

To supply fresh and quality quarantined seafood in live seafood specialty restaurants, facilities for short-term culture or holding of live marine fish and shellfish are a necessity. In this study, the performance of a simple recirculating aquarium system for the culture and holding of marine fish was evaluated. The aquarium system consisted of a culture tank, a foam fractionator for solids removal, and a Styrofoam bead filter for nitrification and solids trapping. In the first trial, the aquarium was stocked with a total of 12 kg Korean rockfish, which were fed approximately $0.5\%$ of the total fish body weight daily. During the 2-month culture period, total ammonia nitrogen (TAN) and nitrite nitrogen $(NO_2-N)$ concentrations remained below 1mg/L and 2mg/L, respectively. The chemical oxygen demand (COD) fluctuated between 13.6 and 31.2 mg/L on selected sampling days. The total suspended solids (TSS) removed by the foam fractionator was between 2.7 and 4.6g daily. The Styrofoam bead filter not only reduced TAN and $NO_2-N$ in the culture tank water, but also trapped solids equivalent to 8.3-26.7\% of the weight of feed supplied. In Trial 2, 30kg of live fish were held in the aquarium without feeding for a 24-hour period and the water quality parameters were monitored. TAN and $NO_2-N$ concentrations first increased and then decreased to around 0.3mg/L. These results demonstrate that the recirculating aquarium system is a functional option for the short-term culture or holding of marine fish.

• The Journal of Information Systems
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• v.32 no.4
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• pp.137-147
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• 2023

Purpose The domestic aquaculture industry in South Korea utilizes both formulated feeds and live feeds for the cultivation of fish. While nutrient-rich live feeds, particularly using fry, have been preferred since the past, formulated feeds are gaining attention due to issues related to overfishing and environmental concerns. Formulated feeds are advantageous for storage and supply but require a sustained feeding regimen due to the comparatively slower growth rate compared to live feeds. As the aging population in rural areas leads to a shortage of labor, automated feeding systems are increasingly being adopted in aquaculture facilities. To enhance the efficiency of such systems, it is crucial to quantitatively analyze the behavioral changes in fish based on the presence or absence of feed. Design/methodology/approach In the study, RGB cameras and infrared cameras were used to analyze fish activity according to feeding, and an outline extraction algorithm was applied to analyze the differences resulting from this. Findings Unlike RGB cameras, infrared cameras are more suitable for analyzing underwater fish activity as they convert objects' thermal energy into images. It was observed that Canny, Sobel, and Prewitt filters showed the most distinct identification of fish activity.

• Proceedings of the Korean Society of Developmental Biology Conference
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• 2003.10a
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• pp.22-23
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• 2003

Primordial germ cell (PGC) is the progenitor cell of the germ cell lineage and eventually give rise to gametes that are responsible for creating individual organisms via a fertilization process. This means that PGC is a unique cell that can be converted into individual fish. This advantage of PGCs would make it possible to develop various applications in the field of fish bioengineering. First, PGCs may make it easier to preserve the genetic resources of fish. Cryopreservation of fish eggs or embryos has not been successfully achieved so far. Therefore, the only possible method to preserve genetic resources of fishes is to raise fish as live individuals. If PGCs isolated from various fishes could be cryopresewed, these cells could be converted into live fishes via germ-line chimera production. This is particularly useful for preserving genetic materials of endangered species. Even if the species of interest were to become extinct, it could be recovered by the transplantation of cryopreserved PGCs into the embryos of a closely related species. Another application of this technology is in what could be termed "surrogate broodstock technology". (중략)

• Korean Journal of Fisheries and Aquatic Sciences
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• v.51 no.3
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• pp.238-247
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• 2018

This study investigated survival rates and physiological responses in Pacific abalone (Haliotis discus hannai) to 18 days of containment in live fish containers ($8^{\circ}C$, 34 psu). The investigation was divided into three periods: before, during, and recovery after transportation. The overall survival rate was greater than 99%. Glucose, aspartate aminotransferase (AST) and alanine aminotransferase (ALT) rose immediately on the first day of containment, but then gradually returned to normal levels. $NH_3$ continued to rise after the first day, but during the recovery period it decreased to a level not significantly different from that of the control group. $Na^+$ and osmolality did not show any abnormal changes. After recovery, superoxide dismutase (SOD) was not significantly different from control. Abalone in the experimental group had lower glutathione reductase (GR) than control. The hyalinocyte ratio fell immediately after confinement, but then gradually increased until it reached a normal level. The ratios of apoptotic and necrotic cells indicated no specific variations in hemocyte viability. Histological changes in the epidermal layer and muscle layer of the foot were not significantly different from those seen in the control group. The experimental data obtained in this study suggest that live fish containers may be used for transport of Pacific abalone without significantly impacting their physiology or survival rates.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.51 no.4
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• pp.411-419
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• 2018

This study investigated the survival rates and physiological responses of Korean rockfish, Sebastes schlegeli, in live fish containers ($8^{\circ}C$, 33 psu) for 18 days. The survival rate was 99% and 97% in the control and experimental groups, respectively. Hematocrit and hemoglobin did not differ significantly between the control and experimental groups. Glucose and cortisol rose immediately on the first day of containment, but both gradually normalized. Aspartate aminotransferase and alanine aminotransferase did not differ significantly between the two groups after recovery. $NH_3$ continued to rise after the first day, but decreased to a level not significantly different from that of the control group during the recovery period. Plasma ions and osmolality did not change abnormally. The hemocyte population was not significantly different from that of the control. The ratios of apoptotic and necrotic cells indicated no specific variation in hemocyte viability. The histological changes in the skin and gills were not significantly different from those seen in the control. The experimental data obtained in this study suggest that live fish containers may be used to transport Korean rockfish without significantly affecting their physiology or survival.

• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.52 no.1
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• pp.36-41
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• 2016

Changes in target strength (TS) values of sandfish when sandfish was alive and dead were investigated using ex-situ at 120 kHz. TS values measured by tilt angles with -50~+50 degrees showed ranges from -71.0 to -53.3 dB for live sandfish, -63.1~-46.3 dB for thawed sandfish, and -70.0~-50.4 dB after 24 hours from thawed, respectively. It was shown that while TS values were similar between the case of live and the case of after 24 hours from thawed, mean TS values were higher by approximately 5 dB in the case of immediate thawed sandfish. It was also seen that TS values were similar between the case of thawed sandfish and the case of after 21 hours from live. The results showed that TS values of live sandfish were different from those of frozen sandfish. It implies that when estimating TS of frozen fish, the influx of bubbles and changes of body should be considered.

• Journal of fish pathology
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• v.19 no.1
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• pp.83-86
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• 2006

Effect of iron on the extracellular proteolytic activity of live Uronema marium was determined by fluorescence polarization (FP) method. Supplementation of 0.5 and 5.0 μM iron significantly increased caseinolytic activity of live U. marinum. In contrast, supplementation of 50 μM iron showed no significant differences in FP values compared to the control. The present result suggests that iron in cultured water or skin tissue of olive flounder may influence on the penetration and establishment of U. marinum, correlating with modulation of extracellular protease activity of the ciliates.

• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.50 no.4
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• pp.427-434
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• 2014

Although ex situ target strength (TS) measurements using dual- and split-beam systems have become the primary approach of estimating fish abundance, theoretical model estimation is a powerful tool for verifying the measurements, as well as for providing values when making direct measurements is difficult. TS values for 20 samples of live bambooleaf wrasse (Pseudolabrus japonicus) whose target length (TL) ranged between 13.7 and 21.3 cm were estimated theoretically using the Kirchhoff-ray mode model, and the TS values for 18 live fish samples were additionally measured at ${\sim}0^{\circ}$ tilt angle to the swimming aspect using a tethered method at a frequency of 120 kHz to verify the theoretical values. The digitizing intervals used to extract the fish body and swim bladder morphology in the X-ray photographs significantly affected the calculated TS patterns, but variations based on the speed of sound and density ratio values for the general range of fish flesh were relatively small (within 1 dB). Close agreement was observed between the measured and theoretical TS values, and the correlation between the average TS and body length of the fish could be calculated accurately as <$TS_{120kHz}$>= 20logTL (cm) -71.6 using the theoretical method.