Fisheries and Aquatic Sciences

The Korean Society of Fisheries and Aquatic Science (한국수산과학회)
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Shaking Motion Characteristics of a Cod-end Caused by an Attached Circular Canvas during Tank Experiments and Sea Trials

  • Kim, Yonghae (Institute of Marine Industry, Department of Marine Production Technology, College of Marine Science, Gyeongsang National University)
  • Received : 2013.06.04
  • Accepted : 2013.07.26
  • Published : 2013.09.30
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Abstract

A shaking motion could be used to improve fish escapement from a cod-end net by creating a sieving effect over the swept volume or by disturbing the optomotor response of the fish. In this study, a perpendicular shaking motion was generated in a towed cod-end net by a circular canvas attached to the end of the codend, which formed a biased cap-like shape. This concept was tested by using a model in a flow tank and by towing a prototype cod-end during sea trials. For the model tests, the amplitude of the shaking motion was $0.6{\pm}0.1$ times the rear diameter of the cod-end, and the period of the shaking motion was $2.6{\pm}0.1$ s at a flow velocity of 0.6 or 0.8 m/s. In the sea trials, the amplitude was $0.5{\pm}0.2$ times the rear diameter of the cod-end, and the period of the shaking motion was $7{\pm}4$ s at towing speeds of 1.2 or 1.7 m/s. Thus, the shaking amplitude during the sea trials was equal to or less than that observed in the tank tests, and the shaking period was twice as long. The shaking motion described by the amplitude and period could be an effective means to stimulate fish escapement from cod-end during fishing operations considering the response of the fish.

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References

  1. Broadhurst MK, Kennelly SJ and Eayrs S. 1999. Flow-related effects in prawn-trawl codends: potential for increasing the escape of unwanted fish through square-mesh panels. Fish Bull 97, 1-8.
  2. Grimaldo E, Sistiaga M and Larsen RB. 2008. Evaluation of codends with sorting grids, exit windows, and diamond meshes: size selection and fish behaviour. Fish Res 91, 271-280. http://dx.doi.org/10.1016/j.fishres.2007.12.003.
  3. Jones EG, Summerbell K and O'Neill FG. 2008. The influence of towing speed and fish density on the behaviour of haddock in a trawl cod-end. Fish Res 94, 166-174. http://dx.doi.org/10.1016/j.fishres.2008.06.010.
  4. Kim YH. 2010. Performance of an active stimulating device using a rope kite or array in the cod-end to reduce juvenile by-catch. Fish Aquat Sci 13, 182-189. http://dx.doi.org/10.5657/fas.2010.13.2.182.
  5. Kim YH. 2011. Effects on the escapement of juvenile bastard halibut Paralichthys olivaceus of actively stimulating devices inside a model cod end. Fish Aquat Sci 14, 62-69. http://dx.doi.org/10.5657/fas.2011.14.1.062.
  6. Kim YH. 2012. Analysis of turbulence and tilt by in-situ measurements inside the codend of a shrimp beam trawl. Ocean Eng 53, 6-15. http://dx.doi.org/10.1016/j.oceaneng.2012.06.014.
  7. Kim YH. 2013. Analysis of the turbulent flow and tilt in the codend of a bottom trawl during fishing operations. Ocean Eng 64, 100-108. http://dx.doi.org/10.1016/j.oceaneng.2013.02.019.
  8. Kim YH and Jang CY. 2005. Swimming characteristics of the black porgy Acanthopagrus schlegeli in the towing cod-end of a trawl. Fish Aquat Sci 8, 177-181. http://dx.doi.org/10.5657/fas.2005.8.3.177.
  9. Kim YH and Wardle CS. 1998. Modelling the visual stimulus of towed fishing gear. Fish Res 34, 165-177. http://dx.doi.org/10.1016/S0165-7836(97)00089-1.
  10. Kim YH and Whang DS. 2010. An actively stimulating net panel and rope array inside a model cod-end to increase juvenile red seabream escapement. Fish Res 106, 71-75. http://dx.doi.org/10.1016/j.fishres.2010.07.005.
  11. Kim YH, Wardle CS and An YS. 2008. Herding and escaping responses of juvenile roundfish to square mesh window in a trawl cod end. Fish Sci 74, 1-7. http://dx.doi.org/10.1111/j.1444-2906.2007.01490.x.
  12. Liao JC. 2007. A review of fish swimming mechanics and behaviour in altered flows. Philos Trans R Soc B 362, 1973-1993. http://dx.doi.org/10.1098/rstb.2007.2082.
  13. Macbeth WG, Broadhurst MK, Millar RB and Smith SDA. 2005. Increasing codend mesh openings: an appropriate strategy for improving the selectivity of penaeid fishing gears in an Australian estuary? Mar Freshw Res 56, 889-900. http://dx.doi.org/10.1071/MF04256.
  14. Narasimha R, Kumar SR, Prabhu A and Kailas SV. 2007. Turbulent flux events in a nearly neutral atmospheric boundary layer. Philos Trans R Soc A 365, 841-858. http://dx.doi.org/10.1098/rsta.2006.1949.
  15. O'Neill FG, McKay SJ, Ward JN, Strickland A, Kynoch RJ and Zuur AF. 2003. An investigation of the relationship between sea state induced vessel motion and cod-end selection. Fish Res 60, 107-130. http://dx.doi.org/10.1016/S0165-7836(02)00056-5.
  16. Pichot G, Germain G and Priour D. 2009. On the experimental study of the flow around a fishing net. Eur J Mech B/Fluids 28, 103-116. http://dx.doi.org/10.1016/j.euromechflu.2008.02.002.
  17. Tauti M. 1934. A relation between experiments on model and full scale of net. Nippon Suisan Gakk 3, 171-177. http://dx.doi.org/10.2331/suisan.3.171.
  18. Torrence C and Compo GP. 1998. A practical guide to wavelet analysis. Bull Am Meteorol Soc 79, 61-78. http://dx.doi.org/10.1175/1520-0477(1998)079<0061:APGTWA>2.0.CO;2.
  19. Webb PW and Cotel AJ. 2010. Turbulence: Does vorticity affect the structure and shape of body and fin propulsors? Integr Comp Biol 50, 1155-1166. http://dx.doi.org/10.1093/icb/icq020.
  20. World Council of Fisheries Societies. 2012. 6th World Fisheries Congress Final Programme and Abstracts [Internet]. World Fisheries Congress, Edinburgh, http://www.6thwfc2012.com.
  21. Ziembo Z. 1993. Turbulent mixing of water flow within trawl walls and method of calculating component force of reaction, parallel to direction of motion. Biul Morsk Inst Ryback 130, 61-73.

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