A review of flatfish behavior relative to trawls

Ryer, Clifford H.

doi:10.1016/j.fishres.2007.10.005

Cited by 98 publications

(69 citation statements)

References 88 publications

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“…Novel stimuli often trigger avoidance, a tactic to avoid predation (Ryer 2008). Among the 7 species examined, reactions ranged from strong avoidance to no reaction whatsoever.…”

Section: Discussionmentioning

confidence: 99%

“…Both species use cryptic coloration as camouflage and remain motionless on the sediment or amongst rocks to ambush prey. For flatfishes, this detection minimization strategy predisposes them towards remaining motionless until a trawl, or predator, gets extremely close; typically a distance of <1 m (Ryer 2008). Similarly, in areas where spearfishing is prohibited, lingcod resting on the bottom are easily approached (M. Spencer pers.…”

Section: Discussionmentioning

confidence: 99%

“…For trawls, survey bias can be attributed to avoidance and/or escape behavior (Ryer 2008), which may be influenced by ambient illumination and water temperature (Woodhead 1964a,b, Ryer & Barnett 2006. Effort has been directed towards correcting trawl catch data to obtain accurate abundance estimates (e.g.…”

Section: Introductionmentioning

confidence: 99%

“…In the ecological literature, this has been applied in the context of predator-prey interactions, and has been used to examine factors such as perception of predator size and prey-reactive distances (Domenici 2002, Paglianti & Domenici 2006. As a UV approaches, the lights from the vehicle will appear to loom to a fish, and as with trawls (Ryer 2008), may be interpreted by the fish as a threat, resulting in avoidance behavior. Alternatively, under some conditions fish are attracted to underwater lights.…”

Section: Introductionmentioning

confidence: 99%

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Effects of simulated underwater vehicle lighting on fish behavior

Ryer

Stoner²,

Iseri³

et al. 2009

Mar. Ecol. Prog. Ser.

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Little is known regarding bias attributable to fish behavior for visual transects conducted using underwater vehicles (UVs). Experiments were conducted under 2 ambient illuminations to assess the behavioral responses of 7 north Pacific Ocean groundfish species to a light stimulus that simulated the approach of a UV. Species included sablefish Anoplopoma fimbria, Pacific halibut Hippoglossus stenolepis, lingcod Ophiodon elongatus and 4 species in the genus Sebastes: blue rockfish S. mystinus, black rockfish S. melanops, copper rockfish S. caurinus and quillback rockfish S. maliger. Movement, as well as general activity, varied greatly between species. The most active species, sablefish, became agitated and moved away from the looming light source, while the least active species, Pacific halibut and lingcod, typically remained stationary. Of the 4 rockfish species, 2 demonstrated a strong response to ambient light level. Black rockfish and blue rockfish moved away from the looming light source, but avoidance was delayed under high ambient light. Bias probably differs among species, being greatest for those that are highly active and mobile, like sablefish. Further, ambient light may modulate bias, such that researchers need to be cautious about comparing results for surveys conducted at different depths and/or times of day. KEY WORDS: Fish behavior · Light response · Survey bias · Gear avoidance · ROV · Submersible Resale or republication not permitted without written consent of the publisherMar Ecol Prog Ser 391: [97][98][99][100][101][102][103][104][105][106] 2009 Due to the efficiency of sound propagation in water, fish will probably first detect the sound generated by an approaching UV. Most fish have hearing in the range of 300 to 1000 Hz (Popper 2003), and both electric and hydraulic thrusters probably emit sound in this frequency range. Gadids and herring respond to approaching surface vessels with both diving and horizontal movements (Vabø et al. 2002, Handegard et al. 2003, Handegard & Thøstheim 2005. Similarly, fish may elicit avoidance behavior in response to the noise generated by trawl warps and doors (Handegard & Thøstheim 2005).Artificial lighting also constitutes a major stimulus likely to influence fish; nearly all UVs use lights for video and still photography. As an object or light approaches, the projected image on the observer's retina expands, a process referred to as visual looming (Schiff et al. 1962), which frequently triggers avoidance behaviors in animals. In the ecological literature, this has been applied in the context of predator-prey interactions, and has been used to examine factors such as perception of predator size and prey-reactive distances (Domenici 2002, Paglianti & Domenici 2006. As a UV approaches, the lights from the vehicle will appear to loom to a fish, and as with trawls (Ryer 2008), may be interpreted by the fish as a threat, resulting in avoidance behavior. Alternatively, under some conditions fish are attracted to underwater lights. We frequently use dr...

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“…Novel stimuli often trigger avoidance, a tactic to avoid predation (Ryer 2008). Among the 7 species examined, reactions ranged from strong avoidance to no reaction whatsoever.…”

Section: Discussionmentioning

confidence: 99%

Section: Discussionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Effects of simulated underwater vehicle lighting on fish behavior

Ryer

Stoner²,

Iseri³

et al. 2009

Mar. Ecol. Prog. Ser.

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“…The size of the caught fish has mostly been controlled by mesh size and mesh opening, such as hanging ratio, including square mesh or grid interval as modification of the fishing gear (Chopin and Suuronen, 2009). Numerous studies have been carried out on bycatch reduction devices (BRDs) according to gear type, locality, species focused on selectivity, separating unwanted species, and preventing the catch of specific animals (Matsushita, 2000;Ryer, 2008;Ingólfsson, 2011). As a result, bycatch reduction by BRD has gained importance, and some countries have adopted BRDs as compulsory regulation for specific gear and species.…”

Section: Introductionmentioning

confidence: 99%

Effects on bycatch reduction in a shaking cod end generated by canvas in a shrimp beam trawl

Kim¹,

Whang²

2014

Journal of the Korean society of Fisheries Technology

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An active stimulating device, such as a fluttering net or canvas attached to the end of a cod end generating a shaking motion, could help to encourage the escape of juvenile fish positioned passively near the net. Field fishing trials using a shrimp beam trawl were carried out to examine the effect on the reduction of juvenile fish or other discard catch by generating a shaking movement of the cod end using an unbiased cap-like round canvas. The mean period of the shaking motion with the round canvas was -14 s, and the mean amplitude was 0.4 m as measured by peak event analysis and the global wavelet method. The bycatch of juvenile fish in 14 trials decreased by -30% and by -25% using a steady cod end for the total bycatch using a shaking cod end in the shrimp beam trawl, while the marketing catch was similar between steady and shaking cod ends. There was no difference in the body size of the shrimp or fish and species composition between the steady and shaking cod ends. Above results demonstrate a new method for bycatch reduction using an active stimulating device, although more detailed studies are needed.

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