New paper: Drag from entangling fishing gear
We are pleased to announce a new publication online in Marine Mammal Science: van der Hoop, J. M., Corkeron, P., Kenney, J., Landry, S., Morin, D., Smith, J. and Moore, M. J. (2015), Drag from fishing gear entangling North Atlantic right whales. Marine Mammal Science. doi: 10.1111/mms.12292 The paper is available online: http://onlinelibrary.wiley.com/doi/10.1111/mms.12292/abstract <http://onlinelibrary.wiley.com/doi/10.1111/mms.12292/abstract>A press release can be found here <http://www.whoi.edu/page/preview.do?pid=7545&tid=3622&cid=229369>. Please contact me if you do not otherwise have access to the pdf: jvanderhoop@whoi.edu <mailto:jvanderhoop@whoi.edu> Abstract: Lethal and sublethal fishing gear entanglement is pervasive in North Atlantic right whales (Eubalaena glacialis). Entanglement can lead to direct injury and is likely to incur substantial energetic costs. This study (1) evaluates drag characteristics of entangled right whales, (2) contextualizes gear drag measurements for individual whales, and (3) quantifies the benefits of partial disentanglement. A load cell measured drag forces on 15 sets of fishing gear removed from entangled right whales, a towed satellite telemetry buoy, and 200 m of polypropylene line as it was shortened to 25 m, as they were towed behind a vessel at ~0.77, 1.3, and 2.1 m/s (~1.5, 2.5, and 4 knots) and ~0, 3, and 6 m depth. Mean drag ranges from 8.5 N to 315 N, and can be predicted from the dry weight or length of the gear. Combining gear drag measurements with theoretical estimates of drag on whales’ bodies suggests that on average, entanglement increases drag and propulsive power by 1.47 fold. Reducing trailing line length by 75% can reduce parasitic gear drag by 85%, reinforcing current disentanglement response practices. These drag measurement can be incorporated into disentanglement response, serious injury determination, and evaluation of sublethal effects on population dynamics. Lethal and sublethal fishing gear entanglement is pervasive in North Atlanticright whales (Eubalaena glacialis). Entanglement can lead to direct injury and islikely to incur substantial energetic costs. This study (1) evaluates drag characteris-tics of entangled right whales, (2) contextualizes gear drag measurements for indi-vidual whales, and (3) quantifies the benefits of partial disentanglement. A load cellmeasured drag forces on 15 sets of fishing gear removed from entangled right whales,a towed satellite telemetry buoy, and 200 m of polypropylene line as it was short-ened to 25 m, as they were towed behind a vessel at ~0.77, 1.3, and 2.1 m/s (~1.5,2.5,and4knots)and~0, 3, and 6 m depth. Mean drag ranges from 8.5 N to 315N, and can be predicted from the dry weight or length of the gear. Combining geardrag measurements with theoretical estimates of drag on whales’ bodies suggeststhat on average, entanglement increases drag and propulsive power by 1.47 fold.Reducing trailing line length by 75% can reduce parasitic gear drag by 85%, rein-forcing current disentanglement response practices. These drag measurements can beincorporated into disentanglement response, serious injury determination, and evalu-ation of sublethal effects on population dynamics
participants (1)
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Julie van der Hoop