Calculating Hanging Ratio for gill nets - Definition and Explanation

Explanation of how to calculate hanging ratio (E) for gill nets and how differing levels of net flexibility, tension and mesh shape impacts and relates to size and species selectivity, catching efficiency and bycatch.
Examples given include the cod fishery in northern Norway, size selectivity of blue ling and the sole fishery around The Gambia.
Image Sources:
Gabis, G., Kelpsaite, L., Parkins, C. and K. Castro. 2012. Effect of Hanging Ratio on the Catch of Red Sole (Cynoglossus senegalensis), Black Sole (Synaptura cadenati) and Catfish (Arius spp) in The Gambian Bottom Set Gillnet Fishery , CRC, URI, 16 pps.
Music Sources:
Creative minds, bensound.com
Juliush, pixabay.com

[@nm12349]

This channel just gets better and better. Bravo!

[@zshakthy]

hi, i'm from Indonesia. thanx for the explanation

[@oceans_explained]

Glad I could help!

[@tenenteoliveira3149]

make a video whow to ring a net ,if possible .

[@oceans_explained]

Thanks for the request - happy to tailor it to specific deployment methods/target species

[@vladnet4748]

0:50 is not right picture.
E=0,7 for central image
E 0,3(or0,5) for image on the left
And image on the right the net hanging on E= 0,9
))

[@oceans_explained]

Hi! Thanks for your comment - hanging ratio is calculated by the length of the headrope divided by the stretched length of the mesh, using the same units for both. In this example, I have kept the length of the headrope as '1 meter' for all three examples. Therefore for the first image, dividing 1 meter by 1.4 meters gives a hanging ratio of 0.7 (unitless). This is repeated for all three examples, so 1/2 is 0.5 and 1/3 is 0.3...

[@vladnet4748]

@@oceans_explained коэффициент вы определяете правильно. Но ваши изображения не соответствуют значению коэффициента,
При E=0,7 (0,71) форма ячейки стремится к квадрату, всё по теореме Пифагора. Этому соответствует изображение в центре.
При E=0 сеть не имеет длины. При E=1 сеть не имеет высоты.

[@olafs_vetra]

​@@vladnet4748Mozhno s vami svezatsja po emailu?