• 수산해양기술연구
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• 제49권4호
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• pp.360-367
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• 2013

The mesh selectivity of the gillnet for Pacific herring (Clupea pallasii) was examined in field experiments with four different mesh sizes (63, 69, 75 and 81mm) from June to July, 2013 in the coastal areas of Imwon in Gangwon province. The fishing performance tests were conducted with a commercial Pacific herring gillnet and a biodegradable gillnet for Pacific herring together selectivity tests. The filed tests were carried out the total 11 times. The master curve of selectivity was estimated by the extended Kitahara's method. In the results, the catch number of Pacific herring was 9,409 (2,203kg) and occupied 84.2% in total catches weight. The optimal mesh size for 50% retention on first maturity size (female, 250mm) of Pacific herring was estimated as 64.5mm by master selectivity curves. The fishing performance of the biodegradable gillnet was showed to be equivalent with commercial gill for Pacific herring.

• 한국수산과학회지
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• 제30권6호
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• pp.916-922
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• 1997

This paper attempted to estimate mesh selectivity of gill nets for neon flying squid in the north Pacific Ocean. The 11 linear regressions, (P<0.05) were obtained using the data on catch ratios derived from mesh size combinations between two slightly different mesh sizes of 12 kinds of research gillnet (namely 33, 37, 42, 48, 55, 63, 72. 76, 86, 96, 105 and 115 mm in stretched mesh size). There was an increase in the optimum length with the increase in mesh size but standard deviation showed somewhat increase with the increase in the mesh size. The selectivity curves were well fitted to the length frequency distributions obtained from samples for the mesh sizes from 48 mm through 86 mm. For the mesh sizes of 33, 37 and 42 mm the DML (Dorsal Mantle Length) compositions were distributed towards the right hand-limb of the curves. The DML distributions from the 96 mm and larger meshes showed a trend towards the left hand-limb of the curves. The selectivity curves for different mesh sizes indicate that large mesh sizes catch a greater size range of squid, and the gill net fishery in the north Pacific Ocean captures effectively neon flying squid within the range of $9\~43cm$ DML.

• 수산해양기술연구
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• 제49권4호
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• pp.352-359
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• 2013

To estimate the mesh selectivity of gillnet for ocellate spot skate (Okamejei kenojei), the field tests were carried out 12 times with six different mesh sizes (121.2mm, 137.7mm, 151.5mm, 168.3mm, 178.2mm, 189.4mm) in the coastal waters of Taean, Chungcheongnamdo of Korea, 2010~2011. In the field tests, the total number of species was 31, and that of catch was 1,410 and the total weight was 618,006g. The number and weight of ocellate spot skate which is main target in this study were 1,004 and 434,592g, respectively. The catch in number of ocellate spot skate occupied about 71.2% in total catch. The others of catch species were marbled sole (8.4%), sea raven (4.4%), japanese swimming crab (4.2%) and flatfish (4.1%) and so on. The range of body disk width (DW) of ocellate spot skates which were caught in this study was 15.2~35cm and the mode was 27~29cm. The estimation equation of mesh selectivity using the extended Kitahara's method was expressed as s $(R)=s(DW/m)={\exp}\{(-0.56R^3-1.80R^2+12.96R-9.99)-4.26\}$. The optimum value of DW/m for 1.0 of retention probability in this estimation equation was estimated 1.899 and DW/m was estimated to be 1.194, 1.314, 1.395, 1.461 and 1.520 when the retention probability were 0.1, 0.2, 0.3, 0.4 and 0.5, respectively. When applied to the retention probability of 0.5, the optimum mesh size was estimated to be 177.0mm on first maturity disk width 26.9cm of ocellate spot skate.