• Korean Journal of Fisheries and Aquatic Sciences
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• v.47 no.6
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• pp.945-959
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• 2014

This study was conducted to provide basic data for optimal fisheries management through the accurate understanding the catches, fishing level, species composition, distribution characteristics and fisheries status of trammel net in Gangwon Province. As the results of trammel net survey, Pisces were collected 77 species, 1,983.0 kg, Crustacea 9 species, 569.0 kg, Cephalopoda 5 species, 75.3 kg, Gastropoda 12 species, 16.5 kg in the coastal waters of Sokcho and Pisces 55 species, 3,681.5 kg, Crustacea 6 species, 2,229.8 kg, Gastropoda 10 species, 72.8 kg, Cephalopoda 4 species, 10.1 kg in the coastal waters of Donghae, respectively. The catches of important species with season and depths showed that the main target species is Pleuronectidae spp. at all depth and Aptocyclus ventricosus at <100 m in Sokcho, Liparis spp. and Dasycottus setiger at 200-500 m in Donghae, respectively. The mean total length (cm) of Gadus macrocephalus and Aptocyclus ventricosus didn't appear significant difference, but the mean total length of Pleuronectidae spp., Liparis spp. and D. setiger in Donghae is bigger than in Sokcho. From the cluster and MDS analysis based on Bray-Curtis similarity matrix of fourth root transformed, catches data of dominant species in the coastal waters of Sokcho and Donghae was divided into three different groups of the demersal organisms community in 12 survey of Donghae (Group A) and Jul., Oct.-Dec. survey of Sokcho (Group B) and Jan.-Jun. and Aug.-Sep. survey of Sokcho (Group C).

• Korean Journal of Fisheries and Aquatic Sciences
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• v.31 no.5
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• pp.739-748
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• 1998

Demersal fishery resources were collected by an otter trawl in May, August and November 1996 at 9 stations off Youngkwang. And they were compared with the data obtained by a stow net, Of 73 species identified, assemblages were consisted of $63.0\%$ in fish, $14\%$ in shrimps, $14\%$ in crabs, $5\%$ in cephalopods and $3\%$ in gastropods. Johnius grypotus, Palaemon gravieri, Crangon hakodatei, Cynoglossus joyneri, Collichthys niveatus predominated in abundance, consisting of $64.4\%$ in the number of individuals. Catch by an otter trawl consisted mainly of demersal fishery resources, while catch by a stow net consisted mainly of pelagic fishery resources.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.49 no.6
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• pp.849-855
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• 2016

The community composition and distribution of fish species in the middle of the Yellow Sea were investigated in summer from 2008 to 2014. A total of 72 demersal fish species from 46 families and 17 orders were collected. The most common species were Larimichthys polyactis, Engraulis japonicus, and Chaeturichthys hexane, which accounted for 72.0% of the total number of individuals while Liparis tanakai, Larimichthys polyactis, and Lophius litulon accounted for 67.8% of the total biomass. A cluster analysis based on the Bray-Curtis similarity revealed that the fish community fell into three groups, according to latitude. Principal Component Analysis (PCA) and correlation analysis showed that variation in bottom water temperature could act as an indicator of variation in community structure and abundance of the dominant species. Characteristics of fish communities, such as the number of species, the total number of individuals ($/km^2$), and biomass ($/km^2$), were highly correlated with bottom water temperature and depth.

• Journal of Korean Society of Coastal and Ocean Engineers
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• v.30 no.3
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• pp.95-102
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• 2018

As a recent technical approach, a high-speed planing hull was tried to realize a friction reducing system by simultaneously actuating the triple streamlined step hull form in association with optimum speed of 35 knot planing for fishing boat. In this approach, the streamlined step hull form with triple structure of type was attached under the bottom of high-speed planing hull, while a friction resistance is reduced in the process of running at the speed of 35 knot. In addition, this research was to make a performance test as to the manufactured product and acquire the purposed values and the development items. Actually, after manufacturing the desired prototype of high-speed planing hull, the significant items, fuel efficiency (second) and amount of fuel consumption (degree) including maximum speed (knot) were estimated for a performance test. And tensile strength (MPa) and bend strength (MPa) as to the completed prototype like a high speed planing hull were also acquired during the test.

• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.46 no.2
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• pp.103-114
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• 2010

For an effective management of fisheries resources, we need fisheries informations necessary for the establishment of reasonable fishing effort and TAC distribution. To study the present state of by-catch and discard of gill-net fishery in the East Sea, we carried out fishing research using trammel nets in the coastal sea of Susan-port (Yangyang), Jangho-port (Samcheok) and Hupo-port (Uljin). As a result, a total of catch of Susan was 259,172g and that of Hopo was 577,638g. Thus Catch of Susan was 1.49 times more than that of Hupo considering the number of used fishing gear. And catch of Janho was 7.4 times more than that of Susan considering the number of experiment. Two methods of by-catch analysis in this study were used, one method is standardizing of listed species catching possible in fishing license, another method is regarding catch species under 1% of total catch as by-catch. As a result of by-catch analysis of two method, by-catch rate of Susan was 6.55% and 5.87% respectively, that of Hupo was 44.70% and 5.24% and that of Jangho was 0.96% and 2.31%. Discard rate of fish in Susan, Hupo and Jangho were 1.59%, 3.42%, 2.23% respectively.

• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.50 no.3
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• pp.368-377
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• 2014

Small yellow croaker is one of the important stocks in Korean waters. In this study, we conducted sea trials to estimate optimum height of a drift gill net for effective fishing of small yellow croaker. In the trial using existing net which has 9.2m in height, there was 22 species (1,180 fishes, 99.9kg) caught. The catch (in individuals) of small yellow croaker, especially larger fishes (over 22cm in FL), was higher as part of net height is higher, while the number of species bycaught and the catch of those species were higher as part of net height is lower. In the trial using extension net which has 18.4m in height, there was 27 species (2,030 fishes, 151.7kg). It showed same pattern with existing net in the section I to III, however, in the section IV which is over 13.8m of net height, the catch sharply decreased. The number of species bycaught and the catch of those species using extension net were also same as results using existing net. It showed that section III (9.2-13.8m) where is upper-middle part of the net has caught most of catch and large fishes having over 22cm in length. Through these results, it is judged that the setting depth of the net where is 4.6-13.8m above the sea bottom is the best to reduce bycatch and catch much more large size fishes, and the catch per net is proportional to filtering area of net. Therefore the Fisheries Resource Management Act (the clause 1, article 10) on the amount of usage for offshore drift gill net need to be considered not only length of a net but also net height.

• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.54 no.4
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• pp.279-286
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• 2018

The objective of this study was to quantitatively evaluate the influence of the netting hanging ratio on fishing performance of gillnet. A total of six tests was carried out using three kinds of gillnets with different horizontal hanging ratios (0.3, 0.5 and 0.7) on the basis commercial gillnet of mesh size of 60 mm used in Yeosu Dolsan. As a result of the test fishing operation, catches of the net with hanging ratio 0.3 and the shortest float length was 1.34 times larger than the net with hanging ratio 0.7. The caught species in experimental testes was lager in the net with hanging ratio 0.3 than the net with hanging ratio 0.7. The catch rate per unit area (CPUE) is on the silver croaker with the largest catches in tests as follows. The net with hanging ratio 0.3 net was $89.45g/m^2$, hanging ratio 0.5 net was $41.63g/m^2$, and hanging ratio 0.7 net was $24.50g/m^2$. The net with hanging ratio 0.3 (float line length of 45 m) exhibited the largest CPUE value.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.55 no.5
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• pp.751-757
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• 2022

To develop a trap to prevent the catch of juvenile rockfish Sebastes inermis and bycatch, we compared the fishing characteristics of four traps with different mesh sizes (35 mm and 50 mm) and flapper connecting lines (FCL) (3 lines and 4 lines).The number of rockfish caught in trap 1 (35 mm, 4 FCL) was 200, and juvenile rockfish (15 cm or less) accounted for 49.0%. The number of rockfish caught in trap 2 (35 mm, 3 FCL) was 185, and juvenile rockfish accounted for 58.9%. The number of rockfish caught in trap 3 (50 mm, 4 FCL) was 82, and juvenile rockfish accounted for 4.9%. The number of rockfish caught in trap 4 (50 mm, 3 FCL) was 68, and juvenile rockfish accounted for 22.1%. The total catch (bycatch rate) in trap 1, trap 2, trap 3 and trap 4 was 565 (64.6%), 637(71.0%), 260 (68.5%) and 276 (75.4%), respectively. The catch per unit effort (CPUE) for juvenile rockfish in trap 1, trap 2, trap 3 and trap 4 was 0.8, 0.9, 0.0, and 0.1 individuals/trap, respectively. The CPUE of bycatch in trap 1, trap 2, trap 3 and trap 4 was 2.9, 3.6, 1.4 and 1.7 individuals/trap, respectively.

• Korean Journal of Ecology and Environment
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• v.43 no.1
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• pp.82-90
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• 2010

The ecological characteristics of the Korean Aucha perch, Coreoperca herzi, were determined in order to estimate stock of the mid-upper system of the Seomjin River. The age was determined by counting the otolith annuli. The oldest fish observed in this study was 5 years old. Relationships between body length (BL) and body weight (BW) were $BW=0.0195BL^{3.08}$ ($R^2=0.966$) (p<0.01). Relationships between the otolith radius (R) and body length (BL) were BL=3.882R+1.66 ($R^2=0.944$). The von Bertalanffy growth parameters estimated from a non-linear regression method were $L_{\infty}=19.68\;cm$, $W_{\infty}=188.64\;g$, $K=0.17\;year^{-1}$ and $t_0=-1.46$ year. Therefore, growth in length of the fish was expressed by the von Bertalanffy's growth equation as $L_t=19.68$ ($1-e^{-0.17(t+1.46)}$) ($R^2=0.997$). The annual survival rate (S) was estimated to be $0.666\;year^{-1}$. The instantaneous coefficient of natural mortality (M) of estimated from the Zhang and Megrey method was $0.346\;year^{-1}$, and instantaneous coefficient of fishing mortality (F) was calculated $0.061\;year^{-1}$. From the estimates of survival rate (S), the instantaneous coefficient of total mortality(Z) was estimated to be $0.407\;year^{-1}$.

• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.26 no.1
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• pp.34-44
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• 1990

This paper describe on the target strengths for the dorsal and the side aspects of swimbladdered fishes, Mullet Mugil cephalus, Flounder Pleuronichthys cornutus and Rock trout Hexagrammos otakii two frequencies of 50KHz and 200KHz in the experimental water tank in order to improve the biomass estimation by the scientific fish finder. The results obtained are as follows: 1. The average of maximum target strength normalized by squared total length in cm unit are almost ranging from -70.9 dB to -66.8 dB regardless of species or frequencies. 2. The average of maximum target strength normalized by two-thirds squared body weight in g unit are almost ranging from -57.1 dB to -54.1 dB regardless of species or frequencies. 3. In comparison with target strength for 50KHz and 200KHz the former is more strong than the latter.