Effects of the Net Contrast of a Model Codend on the Escapement of Juvenile Red Seabream Pagrus major
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Visual stimuli of nets, which affect fishing selectivity, vary by twine diameter, color, and material under different light conditions and visual geometries. In this study, two cylindrical model codends of two mesh sizes, 28 and 43 mm, were made of high-contrast, dark brown polyethylene (PE) netting twine and low contrast, light-blue polyamid (PA) monofilament twine. Each model codend was filled with juvenile seabream and set in the water channel of a light-blue circular tank under a flow speed 0.8 m/s for 30 min. Light conditions were set to relatively bright, dim, and dark. The resulting retention rates of juvenile seabream were 15-35% lower for the low-contrast codend with PA monofilament than for the high contrast PE twine netting under bright and dim light conditions, while no difference was observed under dark conditions. The effects of mesh size and netting contrast on the retention rate were dependent on the light level, while the retention rate due to netting contrast was independent of mesh size. Therefore, low-contrast nets in the codend could help to reduce juvenile bycatch by disturbing the orderly optomotor response.
Abstract
Visual stimuli of nets, which affect fishing selectivity, vary by twine diameter, color, and material under different light conditions and visual geometries. In this study, two cylindrical model codends of two mesh sizes, 28 and 43 mm, were made of high-contrast, dark brown polyethylene (PE) netting twine and low contrast, light-blue polyamid (PA) monofilament twine. Each model codend was filled with juvenile seabream and set in the water channel of a light-blue circular tank under a flow speed 0.8 m/s for 30 min. Light conditions were set to relatively bright, dim, and dark. The resulting retention rates of juvenile seabream were 15-35% lower for the low-contrast codend with PA monofilament than for the high contrast PE twine netting under bright and dim light conditions, while no difference was observed under dark conditions. The effects of mesh size and netting contrast on the retention rate were dependent on the light level, while the retention rate due to netting contrast was independent of mesh size. Therefore, low-contrast nets in the codend could help to reduce juvenile bycatch by disturbing the orderly optomotor response.
참고문헌 (28)
- Arnolds GP, "Rheotropism in fishes", Biol Rev Camb Philos Soc, 49, pp.515~576 (1974)
- Broadhurst MK, "Square-mesh codend circumference and selectivity", ICES J Mar Sci, 66, pp.566~572 (2009)
- Broadhurst MK, "Effects of twine diameter and mesh size in the body of prawn trawls on bycatch in Gulf St.Vincent,Australia", Fish Bull, 98, pp.463~473 (2000)
- Chopin F, "The development of international guidelines on bycatch management and reduction of discards", ICES CM, M(01) (2009)
- Cui G, "Light level thresholds for visual reaction of mackerel,Scomber scombrus L.,to coloured monofilament nylon gillnet materials", Fish Res, 10, pp.255~263 (1991)
- Glass CW, "Comparison of the reactions of fish to a trawl gear,at high and low light intensities", Fish Res, 7, pp.249~266 (1989)
- Graham KJ, "Effects of codend circumference and twine diameter on selection in south-eastern Australian fish trawls", Fish Res, 95, pp.341~349 (2009)
- Graham N, "Review of technological advances for the study of fish behaviour in relation to demersal fishing trawls", ICES J Mar Sci, 61, pp.1036~1043 (2004)
- Gray CA, "Use of transparent netting to improve size selectivity and reduce bycatch in fish seine nets", Fish Res, 45, pp.155~166 (2000)
- Jones EG, "The influence of towing speed and fish density on the behaviour of haddock in a trawl cod-end", Fish Res, 94, pp.166~174 (2008)
- Kim YH, "Modelling on contrast threshold and minimum resolvable angle of fish vision", Bull Korean Soc Fish Technol, 34, pp.43~51 (1998)
- 김용해, "Effects on the Escapement of Juvenile Bastard Halibut Paralichthys olivaceus of Actively Stimulating Devices Inside a Model Cod End", Fisheries and Aquatic Sciences, 14(1), pp.62~69 (2011), 한국수산과학회
- Kim YH, "Modelling the visual stimulus of towed fishing gear", Fish Res, 34, pp.165~177 (1998)
- Kim YH, "Optomotor response and erratic response: quantitative analysis of fish reaction to towed fishing gears", Fish Res, 60, pp.455~470 (2003)
- Kim YH, "An actively stimulating net panel and rope array inside a model cod-end to increase juvenile red seabream escapement", FISHERIES RESEARCH, 106(0), pp.71~75 (2010), ELSEVIER SCIENCE BV
- Kim YH, "Herding and escaping responses of juvenile roundfish to square mesh window in a trawl cod end", FISHERIES SCIENCE, 74(1), pp.1~7 (2008), BLACKWELL PUBLISHING
- Lowry N, "The effect of twine thickness on cod-end selectivity of trawls for haddock in the North Sea", Fish Res, 26, pp.353~363 (1996)
- Olla BL, "Effects of simulated trawling on sablefish and walleye pollock:the role of light intensity,net velocity and towing duration", J Fish Biol, 50, pp.1181~1194 (1997)
- O’Neill FG, "The effect of varying cod-end circumference,inserting a ‘flexi-grid’ or inserting a Bacoma type panel on the selectivity of North Sea haddock and saithe", Fish Res, 94, pp.175~183 (2008)
- Özbilgin H, "Comparison of the selectivities of double and single codends", Fish Res, 63, pp.143~147 (2003)
- Ryer CH, "Avoidance of an approaching net by juvenile walleye pollock Theragra chalcogramma in the laboratory:the influence of light intensity", Fish Res, 45, pp.195~199 (2000)
- Sala A, "The influence of twine thickness on the size selectivity of polyamide codends in a Mediterranean bottom trawl", Fish Res, 83, pp.192~203 (2007)
- Shiobara Y, "Developmental changes in the visual acuity of red sea bream Pagrus major", Fish Sci, 64, pp.944~947 (1998)
- Tokaç A, "Effect of PA and PE material on codend selectivity in Turkish bottom trawl", Fish Res, 67, pp.317~327 (2004)
- Videler JJ, "Fish Swimming", pp.113~206 (1993), Chapman & Hall
- Walsh SJ, "Behavioural reactions of demersal fish to bottom trawls at various light conditions. In: Fish Behaviour in Relation to Fishing Operations. ICES Marine Science Symposia, Vol. 196", pp.68~76 (1993), ICES Mar Sci Symp
- Wardle CS, "Fish behaviour and fishing gear.In:The Behaviour of Teleost Fishes", pp.609~644 (1993), Chapman & Hall
- Zar JH, "Biostatistical Analysis", pp.163~305 (1984), Prentice Hall