Risk versus reward: Interactions, depredation rates, and bycatch mitigation of dolphins in demersal fish trawls
Access Status
Authors
Date
2018Type
Metadata
Show full item recordCitation
Source Title
ISSN
School
Collection
Abstract
© 2018, Canadian Science Publishing. All rights reserved. An improved understanding of interaction dynamics between dolphins and trawlers is essential for improving bycatch mitigation strategies. In-situ observations using video at increasing distances from the net opening during 50 commercial fish trawls, recorded 5908 common bottlenose dolphin (Tursiops truncatus (Montagu, 1821)) interactions and provided details on their duration, depredation rates, and behaviours. Dolphin interactions with trawls were very common (98% of day-trawls, 118 ± 16 interactions per trawl), with durations and prey consumption positively correlated with the distances ventured into the net. Acoustic deterrents (pingers) had no effect on interaction numbers or durations. Based on in-situ observations, the factors that contribute toward dolphin bycatch in demersal fish trawls were likely associated with (i) risky dolphin behaviour (i.e., entering net during hauling, residing deep within trawl for extended periods or social aggression) and (or) (ii) instability of fishing gear resulting in entrapment. Given the high level of dolphin attendance during most day-trawls, mitigation strategies that focus on improving and monitoring the stability of trawl gear would be more effective than current acoustic deterrent devices aimed at modifying dolphin behaviour.
Related items
Showing items related by title, author, creator and subject.
-
Wakefield, Corey; Hesp, S.; Blight, S.; Molony, B.; Newman, Stephen; Hall, N. (2018)© 2018 Concerns regarding quantifying fishing impacts on rarely-encountered bycatch species in a demersal fish trawl fishery in north-western Australia have raised issues with, 1) uncertainty associated with extrapolated ...
-
Sterling, David John (2005)Management of prawn trawling fisheries is a difficult task due to the competing interests of strongly motivated stakeholders and interest groups. This occurs because prawn trawling operations are technically complex, ...
-
Amoroso, R.; Pitcher, C.; Rijnsdorp, A.; McConnaughey, R.; Parma, A.; Suuronen, P.; Eigaard, O.; Bastardie, F.; Hintzen, N.; Althaus, F.; Baird, S.; Black, J.; Buhl-Mortensen, L.; Campbell, A.; Catarino, R.; Collie, J.; Cowan, J.; Durholtz, D.; Engstrom, N.; Fairweather, T.; Fock, H.; Ford, R.; Gálvez, P.; Gerritsen, H.; Góngora, M.; González, J.; Hiddink, J.; Hughes, K.; Intelmann, S.; Jenkins, C.; Jonsson, P.; Kainge, P.; Kangas, M.; Kathena, J.; Kavadas, S.; Leslie, R.; Lewise, S.; Lundy, M.; Makin, D.; Martin, J.; Mazor, T.; Gonzalez-Mirelis, G.; Newman, Stephen; Papadopoulou, N.; Posen, P.; Rochester, W.; Russok, T.; Salal, A.; Semmens, J.; Silvan, C.; Tsoloso, A.; Vanelslander, B.; Wakefield, Corey; Wood, B.; Hilborn, R.; Kaiser, M.; Jennings, S. (2018)© 2018 National Academy of Sciences. All rights reserved. Bottom trawlers land around 19 million tons of fish and invertebrates annually, almost one-quarter of wild marine landings. The extent of bottom trawling footprint ...