• Ocean and Polar Research
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• v.23 no.3
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• pp.311-313
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• 2001

Eighteen species of fish were identified by SCUBA diving observations around experimental artificial reefs at Tongyeong marine ranching area between November 1998 and November 1999. The highest species number of 14 was observed in September while the lowest number of 2 was observed in November. Fishes showed three typical behavioral patterns against the experimental artificial reef.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.44 no.4
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• pp.332-338
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• 2011

Two feeding trials were conducted to determine the effects of dietary supplementation with Hizikia fusiformis or Ecklonia cava on the non-specific immune responses of parrot fish Oplegnathus fasciatus. Fish were fed experimental diets to which H. fusiformis or E. cava powder were added to final concentrations of 0, 2, 4 and 6%, respectively. After feeding for two weeks, phagocytic activity was significantly higher in fish fed diets containing H. fusiformis, but not E. cava, than in fish fed the basal diet. Lysozyme activity was significantly increased in the fish fed diets containing 6% H. fusiformis and E. cava. Myeloperoxidase activity was also significantly higher in fish fed diets containing 2 and 4% H. fusiformis, as compared to the basal diet, but not in those fish fed E. cava. These two studies indicate that dietary supplementation with H. fusiformis or E. cava could enhance the innate immune responses of parrot fish during their growth stage.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.53 no.2
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• pp.181-190
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• 2020

This study was conducted to estimate the optimum dietary DHA oil level and replacement level of enzyme treated fish meal (EFM) with sardine fish meal for juvenile Atlantic bluefin tuna Thunnus thynnus. Four diets were used: 1) EFM75 in which 75% EFM and 4% DHA oil were applied, 2) EFM60, with 60% EFM and 15% sardine fish meal, 3) DHA2 with 2% of DHA oil, and 4) SL as a raw fish feed. In a feeding trial, juvenile bluefin tuna (body weight 30.1 g) were randomly stocked into four experimental tanks (69 tones) and fed the experimental diets for 13 days. Fish weight gain was higher in the EFM75 and SL groups than in the DHA2 and EFM60 groups. The feed conversion ratio was lower in the EFM75 and DHA2 groups than in the EFM60 and SL groups. Survival was higher in fish fed the formulated diet groups (EFM75, EFM60 and DHA2) than in fish fed SL. This study clearly indicates that up to 10% dietary sardine fish meal can be used in juvenile T. thynnus diets, with an optimum dietary DHA oil level of approximately 3%.

• The Journal of Fisheries Business Administration
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• v.44 no.3
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• pp.103-109
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• 2013

This paper analyzed that the economic effectiveness of the artificial fish reef project in the Tae-an Marine Ranching. Benefit-cost(B/C) model used to indicate the effects of economic valuation. B/C model is based on the sub-models which are Benefit Cost Ratio(BCR), Net Present Value(NPV) and Internal Ration of Return(IRR). First, the Sum of Incremental Benefit and Cost for total vessel by year in Artificial Fish Reef Area(AFRA) estimated 2,381 million won. And then, using 5.5% discounting rates and the survey data, the sub-models showed economically feasible in the all of analysis and analyzed the results as follows. BCR is 2.66, NPV is 28,014million won, and IRR is 22.78%. In conclusion, these results indicated that the artificial fish reef project in Tae-an Marine Ranching would be increase the income of fishermen as well as fish biomass.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.30 no.6
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• pp.929-935
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• 1997

The total energy of fish movement and the maximum burst swimming speed were estimated and formulated in accordance with body length and water temperature for several species in fisheries by empirical methods and also by using published results. Under the assumption of swimming energy reserve of a fish at the initial rest state, the swimming endurance of fish with different body lengths, swimming speeds and angular velocity was calculated using the relevant equations under similar conditions in tank experiments as well as natural conditions in field. Relative swimming energy efficiency or the transition swimming speed between red and white muscle for energy consumption was represented as a trigonometric function of swimming speed ratio. Therefore, this model does closely approach the actual swimming abilities and their limits especially in relation to the fishing gear operation and allow for the greater vitality of the wild fish in the fields.

• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.50 no.1
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• pp.30-38
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• 2014

Hydro-acoustic survey was carried out to investigate the spatial characteristics of fish distribution near two artificial reefs (AO: large octagonal semi-sphere and AC: combined custom built) having different types in Jeju marine ranching area. The survey system consisted of scientific echo sounder (EK60), DGPS system, and ECDIS (Mecys). Field survey was conducted on August and October 2012 with star survey and line transect survey line method, and species composition was investigated from gill net fishing survey. The acoustic signals from individual fishes and small fish schools were mainly recorded around AO, but large and strong signals from large fish school were mainly detected in the top layer of and the water column near AC. The echogram suggest that the fish aggregation for the two types of AO and AC exist the significant difference in fish species and spatial distribution pattern.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.51 no.1
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• pp.72-78
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• 2018

Fish eggs and larvae were collected in July and November of 2013 and January and May of 2014 to determine seasonal variation in the species composition of ichtyoplankton. Samples were classified based on morphological characteristics. Fish eggs were identified as belonging to five taxa; the most dominant species of fish eggs was Engraulis japonicus (62.05%) followed by Sardinops melanostictus (21.02%) and Leiognathus nuchalis (13.71%). These three species accounted for 96.8% of the total number of fish eggs collected. Larvae of 17 species in six families, and six orders were collected. The most dominant species of fish larvae was E. japonicus (51.79%), followed by L. nuchalis (12.59%) and Omobranchus elegans (12.08%). These three species accounted for 76.46% of the total number of larvae collected. Jinhae Bay was identified as a major spawning and nursery ground for fish species inhabiting in the south coast of Korea, such as E. japonicus, L. nuchalis, S. melanostictus, and Omobranchus elegans. Therefore, management of marine fish resources in the South Sea should necessarily include the ecological management of Jinhae Bay.

• Journal of fish pathology
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• v.29 no.1
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• pp.1-5
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• 2016

Isopods are parasitic crustaceans that pose serious threat to fisheries. Several studies have tried to explore the host-pathogen relationship between marine fishes and isopods. The present study aims to understanding the secondary infections in marine fishes pertaining to isopods. To assess the secondary infection in infected fishes, parasite infested and healthy tissues of fishes were collected. The samples were subjected to standard microbiological procedure to identify the presence of pathogenic bacteria and fungi. Our results showed the branchial region had the higher microbial load of non-sporulating cenocytic fungi in infected fishes. Moreover, fungal strains isolated from the parasitic lesion confirmed that the parasitation and body lesion facilitates the entry of several pathogenic microbes at the damaged host tissue. More over the immune regulation of fish fights back by producing minute cysts, trying to encapsulate the growing fungus. But this may eventually lead to systemic infestation and death of the fish.

• Preventive Nutrition and Food Science
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• v.11 no.2
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• pp.120-126
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• 2006

Fish backbone, a major by-product in the fish processing industry, accounts for about 15% of whole fish weight. In this study, recovery of bioavailable calcium from Alaska pollack (Theragra chalcogramma) backbone by-products using enzymatic hydrolysis was investigated. Finely ground fish backbones were hydrolyzed with two proteolytic enzymes (pepsin and protease) to obtain soluble calcium from the by-products. The pepsin digest had a higher degradation efficiency (88%) than protease. Four different concentrations of the fish backbone calcium (100, 250, 500 and 1000 mg/L) prepared by the pepsin digest were treated with $Na_2HPO_4$ at a concentration gradient (0, 1, 2, 4, 8, 10, 15 and 20 mM) to evaluate their solubility, revealing that solubilities of the fish backbone calcium were superior to those of $CaCl_2$ at all the calcium and $Na_2HPO_4$ concentrations. Among the tested concentrations the highest solubility was found in the pepsin digest containing a calcium concentration of 1000 mg/L. Thus, hydrolyzing with pepsin is an effective mode of recovering bioavailable calcium from Alaska pollack fish backbones.

• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.56 no.2
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• pp.105-113
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• 2020

The fish influx and behavioral properties at a set-net off Goseong, South Korea were investigated using an imaging sonar. As a result, the average influx of fish was 33.9% at day time and 66.1% at night time, respectively, which indicated that a majority of fish entered into a playground in the set-net at night. The fish behavioral properties such as target (fish) length, range, orientation and major-axis angle were examined and compared among survey dates (4, 5, and 6 June 2019) using the statistical analysis tool (analysis of variance, ANOVA). The behavioral properties presented differently sometime of survey dates. This is preparatory study to support fish behavior properties in a set-net. It is expected that more elaborated behavioral information of fishes in the set-net is beneficial for designing and deploying a set-net fishing gear as well as general fish behavior research in the future.