Tailoring codend mesh size to improve the size selectivity of undifferentiated trawl species

2014 ◽  
Vol 21 (6) ◽  
pp. 503-508 ◽  
Author(s):  
D. E. Hunt ◽  
D. L. Maynard ◽  
T. F. Gaston
Keyword(s):  
2006 ◽  
Vol 72 (3) ◽  
pp. 414-423 ◽  
Author(s):  
KOJI SAIURA ◽  
KEISUKE MORI ◽  
TADASHI TOKAI

1992 ◽  
Vol 49 (10) ◽  
pp. 2104-2117 ◽  
Author(s):  
Petri Suuronen ◽  
Russell B. Millar

A twin codend trawl was fished in the northern Baltic to study the size selectivity of square mesh and diamond mesh codends of 36-mm nominal mesh size. For each codend, 15 hauls were completed with a small mesh (20 mm) codend deployed on the other side of the trawl. The relative size of the catches in the two sides of the trawl varied considerably from haul to haul (the separator section was not operating properly) and selection curves were estimated from each individual haul using a method that incorporated the differences in catching efficiency of the two sides. The length of 50% retention decreased with increased catch for both the diamond and square mesh codends, although in neither case was this relationship statistically significant. Selection curves fitted to the combined haul data were asymmetric. The square mesh codend retained significantly less small herring than the diamond mesh codend, and for larger herring the two codends had similar selectivity. In both codends, most escapes occurred at the front of the catch bulge, from the upper side of the codend. At high catch rates, mesh blockage was observed for several metres ahead of the catch bulge during the later part of the tow.


2014 ◽  
Vol 94 (7) ◽  
pp. 1539-1544
Author(s):  
Ferhat Kalaycı ◽  
Tuncay Yeşılçıçek

The size selectivity of traditional gillnets for whiting, (Merlangius merlangus euxinus) was investigated in the eastern Black Sea between June 2010 and June 2011. Experimental fishing operations were carried out by using gillnets of 16, 17, 18, 20 and 22 mm mesh size. A total of 2038 specimens belonging to 16 different fish species were caught during the experiment. The Share Each Length's Catch Total method was used to fit gillnet selectivity curves. Gillnet selectivity was best described by a bi-modal selectivity curve. The modal catch sizes were estimated as 14.81, 15.74, 16.66, 18.51 and 20.37 cm for 16, 17, 18, 20 and 22 mm mesh sizes, respectively. Modal lengths and spread values increased with increasing mesh size. The majority of fish (71.8%) caught by 16 mm mesh size were less than the length at first sexual maturity.


Author(s):  
L Z Li ◽  
J H Tang ◽  
Y Xiong ◽  
H L Huang ◽  
L Wu ◽  
...  

2010 ◽  
Vol 35 (2) ◽  
pp. 39-46 ◽  
Author(s):  
Barbara Grace Hutubessy ◽  
Augy Syahilatua

The gillnets' performance for capturing flying fish was obtained from the selectivity parameters of each mesh size. Gillnet selectivity parameters for flying fish were estimated using multi-panel drift gillnets with four different mesh sizes in southern Ambon Island. The black-spot flying fish Cheilopogon suttoni reached peak selectivity at 20.34 cm for mesh size of 1.25", 24.37 cm (1.5") and 28.47 cm (1.75"). Peak selectivity occurred at 22.16 cm for the 1,25" mesh size in the yellow-spot flying fish Cheilopogon abei, with the maximum size selectivity at 31.61cm for the 1.75" mesh. The optimum size for the black-plain flying fish Hirundichthys oxycephalus was 18.67 cm for the 1.25" mesh size, and 22.37 cm for 1.50" mesh size. Selectivity was highest at 26.12 cm for the 1.75" mesh size. Gillnet used in this study was constructed specifically for targeting flying fish suggesting that information on mesh selectivity examined here should has direct applicability to local flying fish fishery.


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