Behavioral impacts of disentanglement of a right whale under sedation and the energetic cost of entanglement

Hoop, Julie van der; Moore, Michael J.; Fahlman, Andreas; Bocconcelli, Alessandro; George, Clay; Jackson, Katharine; Miller, Colin; Morin, David; Pitchford, Thomas D.; Rowles, Teresa K.; Smith, Jamison; Zoodsma, Barb

doi:10.1111/mms.12042

Cited by 47 publications

(76 citation statements)

References 46 publications

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“…Further, the additional drag from trailing fishing gear can exacerbate energy expenditure and prevent efficient foraging. Van der Hoop et al (2013) placed a Dtag on an entangled Northern right whale and found slower diving ascents and descents, as well as shallower dives during entanglement than for whales that were not entangled [18]. Modeling the drag force of gear attached to the entangled right whale also showed that whales entangled in fishing gear experience a greater energetic demand [18].…”

Section: Group Compositionmentioning

confidence: 99%

“…Van der Hoop et al (2013) placed a Dtag on an entangled Northern right whale and found slower diving ascents and descents, as well as shallower dives during entanglement than for whales that were not entangled [18]. Modeling the drag force of gear attached to the entangled right whale also showed that whales entangled in fishing gear experience a greater energetic demand [18]. Further, there appears to be a critical duration period in which the duration of additional drag due to entanglement can be a predictor of survival [19].…”

Section: Group Compositionmentioning

confidence: 99%

“…In addition to ingestion, entanglement in fishing gear can also result in death [16]. Studies of entanglement are usually based on necropsies or scarring [10] [16], but there are a few that have examined the impact of entanglement on cetacean behavior [17] [15] [18]. Virtually no studies have detailed behavioral changes based on observations of individuals before, during, and after entanglement.…”

Section: Introductionmentioning

confidence: 99%

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Behavioral responses to fishing line entanglement of a juvenile bottlenose dolphin in Shark Bay, Australia

Miketa

Krzyszczyk

Mann

2017

Matters

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Entanglement in marine debris has become a serious matter for marine fauna, yet most data come from deceased animals. Here we studied a non-lethal entanglement event involving a female juvenile bottlenose dolphin (Tursiops aduncus), known as EDE, in Shark Bay, Western Australia who has been monitored and observed since birth as part of a long-term study. We compared her behavior before, during, and after entanglement. During entanglement, EDE markedly decreased time spent foraging, and increased time spent traveling. In contrast to before and after entanglement, EDE was mostly alone during entanglement, which may compound the negative impacts in a social species. During entanglement, erratic behaviors including leaps and fast swims were frequent. After entanglement, her activity budget and associations were similar to the period before entanglement. This study marks a rare opportunity to systematically examine the effects of entanglement on dolphin behavior and has implications for other highly social marine species.

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Section: Group Compositionmentioning

confidence: 99%

Section: Group Compositionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Behavioral responses to fishing line entanglement of a juvenile bottlenose dolphin in Shark Bay, Australia

Miketa

Krzyszczyk

Mann

2017

Matters

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“…Additionally, ultrasonic measurements showed increased blubber thickness in older juveniles (8 yr) compared to younger juveniles (1 to 2 yr) (Miller et al 2011). Anthropogenic impacts, including entanglement in fishing gear, may impede foraging ability, increase energy draw due to disruption of the hydrostatic oral seal (Lambertsen et al 2005, Cassoff et al 2011, or increase drag forces created by the entangling gear , Cassoff et al 2011, van der Hoop et al 2014. Although each of these factors creates energetic demands, the degree to which they alter body condition as well as the speed at which changes can be visually detected have not been characterized.…”

Section: Introductionmentioning

confidence: 99%

“…The North Atlantic right whale Eubalaena glacialis remains one of the most endangered large whales in the world, despite a myriad of agency and institutional recovery efforts (van der Hoop et al 2013). High levels of anthropogenic-related mortality as well as variable annual reproductive rates in E. glacialis have led to population growth that is lower (~2.6%) than their southern right whale E. australis counterparts (~7.5%) and other large baleen whale species in the western North Atlantic (Best et al 2001, Waring et al 2015.…”

Section: Introductionmentioning

confidence: 99%

Body condition changes arising from natural factors and fishing gear entanglements in North Atlantic right whales Eubalaena glacialis

Pettis¹,

Rolland²,

Hamilton³

et al. 2017

Endang. Species. Res.

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Body condition has been correlated with survival and reproductive success in both terrestrial and marine mammals, including North Atlantic right whales Eubalaena glacialis. We used photographs of individually identified right whales to assess visual changes in body condition in reproductive females, adult males, juveniles, and entangled whales. Images from sightings of individual whales were grouped sequentially by habitat region, and each group of images was assigned a body condition score of good, fair, or poor based on the dorsal profile posterior to the blowholes. Temporally consecutive groups of images (n = 1496) of 340 individual whales were compared to investigate the frequency, direction, and minimum timeframe between changes in body condition. Changes in body condition scores of right whales were significantly influenced by group category. Lactating females and severely entangled right whales were more likely to exhibit declining body condition than other groups. Resting females were significantly more likely to improve in condition than other groups but exhibited the longest timeframe for improving condition. Young juveniles were less likely to improve in condition compared to adult males, but remained in compromised condition less frequently than older juveniles and adult males. The shortest timeframes between changing body condition scores were 11 d for declining condition and 12 d for improving condition. This study demonstrates that photographic analysis can detect rapid body condition changes and identifies groups of right whales that are particularly vulnerable to declining condition and delayed recovery from energetically taxing events.

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Entanglement is a costly life‐history stage in large whales

Hoop

Corkeron

Moore

2016

Ecology and Evolution

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Individuals store energy to balance deficits in natural cycles; however, unnatural events can also lead to unbalanced energy budgets. Entanglement in fishing gear is one example of an unnatural but relatively common circumstance that imposes energetic demands of a similar order of magnitude and duration of life‐history events such as migration and pregnancy in large whales. We present two complementary bioenergetic approaches to estimate the energy associated with entanglement in North Atlantic right whales, and compare these estimates to the natural energetic life history of individual whales. Differences in measured blubber thicknesses and estimated blubber volumes between normal and entangled, emaciated whales indicate between 7.4 × 1010 J and 1.2 × 1011 J of energy are consumed during the course to death of a lethal entanglement. Increased thrust power requirements to overcome drag forces suggest that when entangled, whales require 3.95 × 109 to 4.08 × 1010 J more energy to swim. Individuals who died from their entanglements performed significantly more work (energy expenditure × time) than those that survived; entanglement duration is therefore critical in determining whales’ survival. Significant sublethal energetic impacts also occur, especially in reproductive females. Drag from fishing gear contributes up to 8% of the 4‐year female reproductive energy budget, delaying time of energetic equilibrium (to restore energy lost by a particular entanglement) for reproduction by months to years. In certain populations, chronic entanglement in fishing gear can be viewed as a costly unnatural life‐history stage, rather than a rare or short‐term incident.

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Behavioral impacts of disentanglement of a right whale under sedation and the energetic cost of entanglement

Cited by 47 publications

References 46 publications

Behavioral responses to fishing line entanglement of a juvenile bottlenose dolphin in Shark Bay, Australia

Behavioral responses to fishing line entanglement of a juvenile bottlenose dolphin in Shark Bay, Australia

Body condition changes arising from natural factors and fishing gear entanglements in North Atlantic right whales Eubalaena glacialis

Entanglement is a costly life‐history stage in large whales

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