• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.39 no.2
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• pp.143-151
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• 2003

A series of fishing experiments was carried out in the waters off the east coast of Korea from January, 2002 to March, 2003, using gill nets of different mesh sizes (m = 180, 210, 240, 270, and 300 ㎜) to determine the size selectivity of gill net for male snow crab Chionoecetes opilio. The maximum carapace length (RL) of each male snow crab caught in the fishing experiment was measured. The master curve of mesh selectivity was estimated by applying the extended Kitahara's method. Two kinds of functional models, quadratic function and cubic function were used to express logarithmic selectivity curve and were fitted to the data using the method of least squares. The obtained results were summarized as follows; 1. The cubic function of asymmetry was chosen to determine the selectivity curve of gill net for male snow crab from the model deviance comparison. 2. The result of size selectivity showed that the catch number of small male crab was getting decreased according to the increase of mesh size. 3. The optimum value (RL/m) was 0.549 and the RL/m was estimated to be 0.281, 0.296, and 0.356 when the retention probability were 0.2, 0.25 and 0.5, respectively.

• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.39 no.3
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• pp.174-180
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• 2003

This study investigated the size selectivity of the round traps for greenling (Hexagrammos otakii) in the western sea of Korea. The selection curve for the greenling from the experiments on Oct. 2000 and Ar. 2001 was fitted by Kitahara's method to a polynomial equation and two parameter logistic selection curve. The selectio curve of the latter was more reasonable than that of the former. The equation of selectivity curve obtained using a logistic function with least square method was , s(R)=1/1+exp(-1.1169R+6.4565), where R=1/m, and 1 and m are total length and mesh size, respectively. The size selectivity curve showed that the current regulated mesh size(35mm) in case of the round trap was close to the L50 (37.0mm) of the selection curve for the biological minimum length (21.4cm) of the greenling.

• Journal of Fisheries and Marine Sciences Education
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• v.9 no.1
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• pp.71-82
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• 1997

The squid fishery from the East China Sea has increased in importance in recent years, for management of resources were carried out selection experments using diamond and square mesh cod-end with enclosing small mesh cover net by trouser net method during 1991-1994 year. Mesh selection studies on Short-finned squid and Long-finned squid divided from catches by trial experiments. The results that square mesh cod-end retained proportionally fewer small and undersized Short-finned squid and Long-finned squid, square mesh cod-end were greater selection factor and 50% selection length than diamond mesh cod-end.

• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.40 no.3
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• pp.169-175
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• 2004

In order to examine the mesh selectivity and optimum mesh size of gill nets for croaker, Milichthys miiuy, the field experiments were carried out during Aug. 10 to 14, 2002 and Aug. 10 to 17, 2003 at the caostal area of Imja-Do, Shinan, Jeonnam province. The experimental fishing gears were used in two set of gill nets, which one set was consisted of 12 sheets of gill nets, and each set was connected alternatively 4 different sheets that were 129mm, 135mm, 144mm and 150mm in mesh size. The analysis of mesh selectivity curve was done by Kitahara's method. The results obtained are summerized as follows : 1. The total number of catch by the experimental fishing of gill nets for croaker was 719, and it was consisted of 526 croakers (73.1%), 168 blue crabs (23.4%), 17 harvest fishes (2.4%) and 8 other fishes (1.1%). 2. The value of maximum 1/m on the mesh selectivity curve was estimated at 6.91. 3. The value of 1/m on the 50% selection range was estimated at 5.62${\sim}$80.3, and the selection width was 2.41. 4. The optimum mesh size of gill nets for croaker was estimated 142mm, and the 50% selection range of total length of croaker was 798${\sim}$1,140mm.

• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.41 no.1
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• pp.27-34
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• 2005

This study was conducted to examine the mesh selecivity and optimum mesh size of spring frame trap for conger eel. Conger myriaster. It was carried out on 25th Sep. 2002 at the coastal sea of Nung-po, Geojedo. The experimental fishing gear was used in five kinds of different mesh size spring frame trap that were 15mm, 20mm, 25mm, 30mm and 35mm, and one plastic pot as control fishing gear that was 6.7mm hole diameter. The mesh size 15mm, 20mm are the current gears, 25mm, 30mm are used in experiment, and 35mm is the legal mesh. These were made 50 traps, respectively. The mesh selectivity curve was analysed by the Kitahara's method(1968) and the optimum mesh size was estimated by relationship between the total length and diameter of conger eel and by the mesh selectivity master curve. The results obtained are summarized follows : 1. The total number of catch by the trap for conger eel was 835, it was consisted of 537 conger eel(64.4), 225 crabs(2639%) and 73 others(8.7%). 2. The value of maximum 1/m on the mesh selectivity curve was estimated at about 23.9. 3. The optimum mesh size of spring frame trap for conger eel was estimated 34.0mm in 50% selection range of the mesh selectivity master curve.

• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.40 no.3
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• pp.176-181
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• 2004

In order to examine the mesh selectivity and optimum mesh size of trap nets for purple shell, Rapane venosa, the field experiments were carried out during Jun. 27 to 29, 2003 at the coastal area of Mal-Do, Kunsan, Jeonbuk province. The experimental fishing gears were used in two set of trap nets, which one set was consisted of 210 trap nets that were coverd with 35mm, 50mm and 65mm in mesh size. The analysis of mesh selectivity curve was done by Kitahara's method. The results obtained are summerized as follows : 1. The total number of catch by the experimental fishing of trap nets for purple shell was 1,682, and it was consisted of 1,268 purple shells (75.4%), 225 Glossaulax reiniana (13.4%), 113 green lings (6.7%) and 76 other fishes (4.5%). 2. The value of maximum 1/m on the mesh selectivity curve was estimated at 1.79. 3. The value of 1/m on the 50% selection range was estimated at 1.24${\sim}$2.72, and the selection width was 1.48.. 4. The optimum mesh size of trap nets for purple shell based on the catch prohibition shell height(50mm) was estimated 40.3mm, and the 50% selection range of shell height of purple shell was 50.0${\sim}$109.6mm.

• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.40 no.1
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• pp.86-94
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• 2004

This study was conducted to mesh selectivity of Beam trawl for shrimps fishing experiment in the coastal waters around Geomundo, South sea of Korea, during from Oct. to Nov. 2002. The selectivity parameters of big head shrimp (Solenocera melantho) have been studied on the covered con-end method. with mesh of 8, 38, 51 and 61 mm. Selection curves and selection parameters were calculated by using a logistic function S=1/(1+exp-(aCL+b)). The mesh selection master curves were estimated by S=1/(1+exp$^{({\alpha}(CL/M)+{\beta}}$), and the optimum mesh size were calculated with (L/M)50 of master curve. Optimum mesh size and selectivity master curves for the southern rough shrimp (Yrachysalambria curvirostris) and smoothshell shrimp (Parapenaeopsis tenella) optimum mesh size and selectivity master curves were estimated by big head shrimp master curves. The results obtained are summarized as follows : Selection parameters '${\alpha}$' and '${\beta}$' of the master curve for big head shrimp were 8.84 and -5.89, and The selection factor of the master curve (L/M)$_{50}$ was 0.67. The optimum mesh size of minimum length for sexual maturity for big head shrimp was 30.7 mm. Estimated (L/M)$_{50}$ for southern rough shrimp and smoothshell shrimp by using the master curve of big head shrimp was 0.73 and the optimum mesh sizes were 25.5 mm for southern rough shrimp and 16.9 mm for smoothshell shrimp, respectively.

• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.40 no.4
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• pp.247-254
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• 2004

The mesh selectivity of the drum net fish trap for elkhorn sculpin(Alcichthys alcicornis) in the estern sea of Korea was described. The selection curve for the elkhorn sculpin caught from the experiments between June 2003 and December 2003 was by SELECT(Share Each Length Class's Catch Total)model and by Kitahaa's method to a polynomial equation and two parameter logistic selection curve. The selection curve by SELECT model showed to be equal probability of entrance of the elkhorn sculpin in the large(55mm) and small(20mm) mesh traps by minimum AIC (Akaike Information Criteria). The equation of selectivity curve obtained by Kitahara's method using a logistic function with least square method was $s(R)\;=\;\frac{1}{1+exp(-0.3545R+2.141)$, where R=1/m, and/and m are total length and mesh size, respectively. The mesh selectivity curve showed that the current regulated mesh size(35mm) for the trap was corresponded to 21.4cm in the $L_{50}$of the selection curve for the elkhorn sculpin.

• Proceedings of the Korean Society of Fisheries Technology Conference
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• 2005.05a
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• pp.33-35
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• 2005

• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.36 no.2
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• pp.89-95
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• 2000

Test fishing was carried out to examine the selectivity of the mesh size in trammel net for tonguefish (Cynoglossidae spp.) from May to August, 1999 and a total of 30 times of test fishing have been done in the coastal waters around Dolsando, Yosu, South Chunra province, Korea. A gill net and a trammel net which were composed of three different mesh sizes (70.5mm, 86.6mm and 101mm) were used for the experiment. The selectivity curve of mesh size was estimated by Kitahara's method for Robust tonguefish (Cynoglossus robustus). The results obtained are summarized as follows ; 1. Catching efficiency of the trammel net (70.5mm-sized-lint main net) was 39.0% and it was 2.5 times higher than 15.8% for the gill net. 2. The optimum l/m value of the trammel net was 3.51 and it was 0.13 higher than 3.38 for the gill net. 3. The selectivity of trammel net was similar to that of the gill net for low length-class. However, the selectivity of trammel net was not good compared with that of the gill net for high length-class. The 50% selectivity was 1.33 for the trammel net and 0.83 for the gill net. According to the experimental results, fishing efficiency of the trammel net was better than that of the gill net for tonguefish (Cynoglossidae spp.) and it was known that catch length for targeted species could be selected by controlling the mesh size.