• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.43 no.4
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• pp.310-319
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• 2007

To investigate the catches of squid jigging fishery, a series of fishing experiments was conducted in the high seas of the Northwest Pacific($40^{\circ}-43^{\circ}N$, $150^{\circ}-155^{\circ}E$) during the period of 1 August to 22 October 2005 by commercial fishing vessel. The number of 142 test fishing was carried out in the Northwest Pacific during 83days. The total catch were 47,524kg as 4 squid species and CPUE was $8.9kg/line{\cdot}day$. CPUE showed high values in the frontal zone during the survey. Main squid species caught from the experimental fishing were the neon flying squid, Ommastrephes bartrami(96.8%) and the boreopacific gonate squid, Gonatopsis borealis(3.2%). Dorsal mantle length of the neon flying squid were increased by the time and increasing of the hook size. Loss rate of the neon flying squid in the water showed the highest values in 28.2% compare to the others. And the loss rate of the front roller and in the air were 1.1% and 1.0%, respectively.

• Journal of Aquaculture
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• v.22 no.1
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• pp.92-99
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• 2009

Population dynamics and sexual maturity of Neomysis japonica (Ishikawa and Oshima, 1951) were investigated from a shrimp farm in Tae-an, Korea. N. japonica was collected monthly at the shrimp farm belonging to the Marine and Fisheries Research Institute, the Soonchunhyang University from October 2002 to September 2003. The proportion of female was higher than that of male. The mean carapace length of male (2.42 mm) was larger than that of female (2.31 mm). Brood size increased with increasing female body size. The size of N. japonica at 50% sexual maturity was approximately 4.4 mm. N. japonica females grew faster and reached larger size than males. The mortality rate (z) calculated by length-converted catch curves was $3.46\;yr^{-1}$. The annual recruitment pattern of N. japonica had two major peaks. Log-transformed total length was significantly related with log-transformed carapace length.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.54 no.6
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• pp.1023-1029
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• 2021

The Japanese common squid Todarodes pacificus is one of the fish species within the total allowable catch (TAC) system which requires further investigation. In this study, the acoustic survey method was used to analyze the distribution of the Japanese common squid Todarodes pacificus across all the seas of South Korea. The sea area within Korea was investigated using the research vessels 20, 21, and 22 of the National Institute of Fisheries Science. The acoustic surveys were carried out from July to September 2019 and February to May 2020. The acoustic systems used in the survey had frequencies of 38 kHz and 120 kHz (EK60, EK80, Simrad, Norway) of the split-beam scientific echosounder. The results showed that, in spring, 277 m²/nmi² was the highest in the east sea area, and the same in the summer season 880 m²/nmi² was the highest in the east sea area. In autumn, the highest nautical area scattering coefficient (NASC) value was observed in the coastal portion of the south sea, and in winter, the NASC values were generally low in all the sea area.

• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.58 no.3
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• pp.199-204
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• 2022

The Pacific giant octopus (Enteroctopus dofleini) is one of the most important species in the East Sea fishery of Korea. The annual production of Pacific giant octopus in 2021 was 3,880 metric ton between Gangwon province and Gyeongsangbuk province. Most of the fishing gears for the octopus fishery were based on behavioral properties such as thigmotaxis and chemotaxis. Wooden octopus box is also one of the fishing gears, which is application of thigmotaxis for the octopus capture in fishing industry. In this study, the tank experiments were designed to examine the behaviour and the effect of surface roughness to the infiltration of the octopus quantitatively. Three different types of octopus boxes were used for the experiments with different surface roughness on the average of 701.6 ㎛, 141.7 ㎛ and 2.09 ㎛ for each gear. 22 trials were conducted from June to September 2021. The normality of the experiments was tested using Shapiro-Wilk normality test (p-value < 0.05). The significance of results was conducted by Kruskal-Wallis rank sum test (Chi-squarded = 21, Degree of freedom = 3, p-value < 0.05). The use of wooden octopus box with rough surface was found to enhance the catch efficiency and observe infiltration behaviour of the octopus frequently.

• Fisheries and Aquatic Sciences
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• v.27 no.4
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• pp.256-264
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• 2024

Small pelagic fish populations have long been exploited by various fishing gears in the Natuna Sea, and since the 1970s, purse seine exploitation has expanded to offshore fishing grounds. Various small pelagic fish species are exploited from these waters including spotted sardinella (Amblygaster sirm). This research was conducted for 22 months, from March 2019 to December 2020. The fish sample was taken from the purse seine fleet's catch in the fisheries management area (FMA) 711 Natuna Sea and Karimata Strait, which was brought to Pemangkat fishing port in the West Kalimantan Province, Indonesia. This paper aims to determine the exploitation status of spotted sardinella in the Natuna Sea as a recommendation material for management policies. The methods used in this analysis are estimated age, cohort, population parameters, and spawning potential ratio of spotted sardinella. The results show three primary cohorts of spotted sardinella in the Natuna Sea, with ages ranging from 9 months to 3.1 years and a maximum attainable age (longevity) of 4.3 years. The asymptotic value (L_∞) is 21.79 cmFL in length, with a growth rate (K) of 0.65 per year. The natural mortality rate (M) was 1.19, the total mortality rate (Z) was 2.19, and the fishing mortality rate (F) was 0.99. The exploitation rate (E) was 0.45 and the stock status was still in a sustainable condition. Therefore, the sardinella fisheries can be developed using a precautionary approach and focus on the ecosystem sustainability of FMA 711.

• Clinical and Experimental Pediatrics
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• v.52 no.9
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• pp.984-990
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• 2009

Purpose : Being small for gestational age (SGA) is a risk factor of short stature in children. Genetic background such as mid-parental height (MPH) is known to influence growth of children born SGA. We studied the relationship between growth of children born SGA and MPH and studied the effects of insulin-like growth factor (IGF-I) and insulin-like growth factor binding protein 3 (IGFBP-3) on postnatal growth in children born SGA according to MPH. Methods : Forty-nine neonates born SGA were included in this study. We defined corrected height standard deviation score (cHtSDS) by modified height SDS (HtSDS) based on their MPH. We categorized subjects into group 1 consisting of children with cHtSDS ${\geq}0$ (n=35) and group 2 consisting of children with cHtSDS <0 (n=14), and compared IGF-I and IGFBP-3 between the two groups. Results : The HtSDSs and cHtSDSs in groups 1 and 2 were $0.06{\pm}1.05$ vs. $-0.95{\pm}0.85$ (P=0.000) and $0.78{\pm}0.93$ vs. $-0.46{\pm}0.67$ (P=0.000), respectively. IGF-I SDS was higher in group 1 than in group 2 ($2.82{\pm}3.69$ vs. $0.23{\pm}2.42$, P=0.012). Total cHtSDS ($0.42{\pm}1.03$) was significantly higher than HtSDS ($-0.22{\pm}1.10$) (P=0.000). Conclusion : Our results show that cHtSDS differs significantly from HtSDS. Growth assessment by standardized growth curve does not uniformly show effects of genetic factors. A more accurate assessment of growth uses a personalized corrected growth curve that considers the genetic factor measured by MPH.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.19 no.5
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• pp.423-435
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• 1986

As the first part of the studies on utilization of polyunsaturated lipids in red muscled fishes like sardine (Sardinops melanosticta) and mackerel (Scomber japonicus), lipid distribution in body sections, whole body, meat, viscera, skin, and head, lipids, polar and nonpolar, and fatty acid composition of the oils obtained from these body sections, and seasonal variations in fatty acid composition, particularly in the content of polyenoic acids, EPA and DHA, were determined, The content of total lipids was ranged $22.2\%\;to\;27.2\%$ in case of sardine without broad difference between body sections, while in case of mackerel $36.7\%\;to\;38.8\%$ unevenly in skin and head. The lipids of both fish were composed of more than $80\%$ of non-polar lipid and there was not much differences in the fatty acid composition between the lipids, polar and non-polar. The major fatty acids of the lipids were $C_{14:0},\;C_{16:0},\;C_{18:0},\;C_{16:1},\;C_{18:1},\;C_{20:1},\;C_{20:4},\;C_{20:5},\;and\;C_{22:6}$, and these acids, $C_{18:1},\;C_{16:0},\;C_{22:6},\;C_{18:0},\;C_{20:5},\;C_{14:0},\;C_{16:1}$, were in high quantity in order. Seasonal variation in fatty acid composition of sardine oil did not show any great variety between sections. There was a tendency in general that saturated and monoenoic acids began to decrease in winter and showed the minimum in April; hereafter get to increase again, while polyenoic acids showed the maximum in April. Both $C_{20:5}\;and\;C_{22:6}$ acids were high in the season of April to July. Variation in fatty acid content was in a width of $8\%$ for saturated, $5\%$ for monoenoic, and $12\%$ for polyenoic acid. $C_{20:5}\;and\;C_{22:6}$ acid were varied in $9.4\%\;and\;9.8\%$, respectively. In case of mackerel oil, seasonal variation tended same as in sardine oil except the fact that the saturated and monoenoic acid decreased to the minimum in the term of April to July in which the polyenoic acid content was also higher marking $27.3\%\;to\;36.1\%$ in average. Fatty acid variation was in a range of $6.3\%$ for saturated, $8.3\%$ for monoenoic, and $13.8\%$ for polyenoic acid but variation of $C_{20:5}\;and\;C_{22:6}$ acid was 4, $3\%$ and 3, $4\%$ respectively. When fresh sardine was stored for 10 days at $5^{\circ}C$, oxidation was rapidly initialed and consequently resulted in fast loss of $C_{20:5}\;and\;C_{22:6}$ acids. It is concluded from the results that the catch of sardine and mackerel in the season of April to June would be adequate for the preparation of polyunsaturated lipid condenced oil in regard to sectional lipid distribution and its variation in seasons.

• Journal of Environmental Science International
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• v.22 no.3
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• pp.259-267
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• 2013

In this study, non-point source(NPS) contribution was investigated based on flow rates and water qualities of streams into the lake during rainfall events. Event mean concentration(EMC) and the pollution loads were calculated to establish a database for NPS control measurement in the survey area, and so on. The runoff characteristics of NPS were investigated and estimated on the basis of the ratio of an agricultural to forest area in the stream of sub-catch basin during rainfall events. Non-point source pollution loads were also calculated to establish a database for NPS control measure in the upstream lake Chinyang. At a rainfall event, BOD concentrations rise sharply at the early peak time of runoff, however, peaks of TSS concentration were observed at the similar time of peak flow. This was a phenomenon shown at the watersheds caused by forest and geological types. The discharged EMC range was 2.9-4.8 mg/L in terms of BOD. The discharged EMC range was 6.2-8.2 mg/L in terms of SS. The discharged EMCs of T-N and T-P were 1.4-2.5 mg/L and 0.059-0.233 mg/L, respectively. Total BOD loading rate through the 3 tributaries to the lake Chinyang was 1,136 kg/d during dry weather. The upper watershed area of the Nam-river dam in this study was divided into 14 catchment basins based on the Korean guideline for total maximum daily load(TMDL) of water quality pollutants. The higher the agricultural land-use ratio, the more NPS loading rate discharged, but the more occupied a forest area, the lower more NPS loading rate discharged. In an agricultural land-use area more than 20%, the increase of NPS loadings might be dramatically diffused by increasing the integrated complex-use like vinyl-house facilities and fertilizer use etc. according to the effective land-use utilization. The NPS loading rates were BOD 0.3 $kg/ha{\cdot}day$, SS 0.21 $kg/ha{\cdot}day$, TN 0.02 $kg/ha{\cdot}day$, TP 0.005 $kg/ha{\cdot}day$ under less than 10% agricultural land-use. In agricultural land-use of 20%-50%, these values were investigated in the range of 0.32 $kg/ha{\cdot}day$-0.73 $kg/ha{\cdot}day$ for BOD, 0.92 $kg/ha{\cdot}day$-3.32 $kg/ha{\cdot}day$ for SS, 0.70 $kg/ha{\cdot}day$-0.90 $kg/ha{\cdot}day$ TN, 0.03 $kg/ha{\cdot}day$-0.044 $kg/ha{\cdot}day$ for TP.

• Korean Journal of Ecology and Environment
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• v.41 no.3
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• pp.301-310
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• 2008

This study was to analyze characteristics of fish compositions and longitudinal distribution, based on trophic and tolerance guild at 22 sampling sites of Yeongsan River watershed during 2003$\sim$2006, and also to compare before and after the estuary dam construction. The collected fishes, based on catch per unit effort (CPUE), were 44 species in the watershed and dominant fishes were Zacco platypus, Acheilognathus macropeterus, Zacco temminckii and Carassius auratus. According to comparative analysis of fish in the non polluted sites (NPS) vs. polluted sites (PS), the number of species and individuals was lower by 70% in the PS than the NPS, indicating ecological degradations by chemical pollutions or/and habitat modifications. The relative abundance of sensitive and insectivore species decreased as the stream order increases, while tolerant and omnivore species increased with the stream order. In this survey, largemouth bass (Micropterus salmoides), which is a top-carnivore and exotic species, may influence trophic guild system throughout active predations on endemic species, resulting in modifications of ecological functions. The construction of estuary dam on Yeongsan River in 1981 resulted in wider lacustrine zone and desalinated through limitation of seawater input. These physical changes have caused increases of lentic dwelling species and limited fish migrations (i.e., eel). Overall, fish fauna and composition analyses showed that the number of species and individuals in this water body may be reduced due to inputs of pollutants from the watershed, habitat modifications, and increases of exotic species (largemouth bass). For these reasons, effective lake management strategies are required for the ecosystem conservation.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.12 no.4
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• pp.201-207
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• 1979

The stow net now used in the Yellow Sea, are traditional bag net with the opening held by a lighter upper and a weighted lower beams standing against the current. Such bag net anchored at the bottom are known in many countries, particularly in the estuaries of large rivers, but more rarely in sea fisheries, because they are too much affected by the weather, moreover a permanent strong current is necessary. Some scientists intended to improve this fishing gear, using the shearing devices instead of a lighter upper and a weighted lower beams in order to widen mouth of the stow net however they are unsuccessful. One-fortieth scale model net of the stow net was tested in a circular water tank with an effective volume of $5.67m\times1.76m\times1.00m$ of observing the configuration and tension of the net. Experiments were carried out under the various combination including water velocity, spherical floats and elevating floats with the shearing hoods instead of the upper beam. We found those devices offered a very low resistance per net area to current compared with the spherical floats or upper beam, and had a fairly good shearing power at any velocity and direction of the current. The total resistance (R) of the model net to which shearing hoods and floats are attached can be induced by the following formula under the condition of 0.25m/sec to 0.5m/sec, $$R(kg)=3.11V^{1.54}$$ The height (h) of the improved model net (m-B) is higher than traditional model net(m-A) with upper and lower beams, m-A: h(cm)=89.22-2.42(V-15). $V\geqq15,\;cm/sec$ m-B: h(cm)=89.20-0.78V (V:cm/sec) The catch efficiency of improved model net is 1.5 times traditional model net.