Blubber thickness in right whales Eubalaena glacialis and Eubalaena australis related with reproduction, life history status and prey abundance

Miller, Colin; Reeb, Desray; Best, Peter B.; Knowlton, Amy R.; Brown, Moira W.; Moore, Michael J.

doi:10.3354/meps09174

Cited by 116 publications

(202 citation statements)

References 60 publications

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“…Energetic demands on individual right whales are not uniform across the population and can be influenced by both natural and anthropogenic processes. The high energetic costs of reproduction have been well documented for large whales (Lockyer 1986, Perryman & Lynn 2002, including right whales (Miller et al 2011, Fortune et al 2013, and previous visual health assessment analyses have documented decreases in body condition during lactation, as well as increases in condition just prior to pregnancy (Pettis et al 2004). Age−length curves for known-age right whales derived from necropsy and photogrammetric measurements indicate that rapid growth occurs from 0 to 4 yr, with the most dramatic growth occurring in the first 12 mo after birth (Moore et al 2004, Fortune et al 2012, suggesting an elevated energetic demand for this demographic group.…”

Section: Introductionmentioning

confidence: 99%

“…Age−length curves for known-age right whales derived from necropsy and photogrammetric measurements indicate that rapid growth occurs from 0 to 4 yr, with the most dramatic growth occurring in the first 12 mo after birth (Moore et al 2004, Fortune et al 2012, suggesting an elevated energetic demand for this demographic group. 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.…”

Section: Introductionmentioning

confidence: 99%

“…Body condition, a metric used to estimate relative energetic reserves, has been correlated with survival and reproductive success of both terrestrial (Young 1976, Schulte-Hostedde et al 2001) and marine mam -mals (Lockyer 1986, 1993, Pitcher et al 1998, Hall et al 2001, Pettis et al 2004, Rolland et al 2007b, Miller et al 2011 and is often used to assess and monitor the overall health of animal populations (Beck et al 1993, Gerhart et al 1996, Pitcher et al 1998, Bradford et al 2012, Williams et al 2013. In large whale species, energetic reserves are stored in, and mobilized from, the blubber layer, visceral tissues, and muscles (Lockyer et al 1985, Aguilar & Borrell 1990, Niaess et al 1998, and thus characteristics of these tissues, including thickness and chemical composition, are considered to be primary indicators of overall body condition (Lockyer et al 1985, Miller et al 2011.…”

Section: Introductionmentioning

confidence: 99%

“…Standard means of assessing the body condition of marine mammals, including live capture or direct post mortem measurements (Lockyer et al 1985, Beck et al 1993, Nilssen et al 2001, Koopman et al 2002, Wells et al 2004) are inappropriate for tracking individual and population-wide health in rare, free-ranging large whale species. The development and application of several new methods, such as ultrasonic measurement of blubber thickness (Moore et al 2001, Angell 2005, Miller et al 2011, vertical aerial photogrammetric measurements of length and width (Perryman & Lynn 2002) and visual assessments of body contours (Pettis et al 2004, Bradford et al 2012) have allowed researchers to document correlations between changes in body condition and periods of known energetic stress and recovery in large whale species, including right whales (Perryman & Lynn 2002, Pettis et al 2004, Rolland et al 2007b, Miller et al 2011, Bradford et al 2012.…”

Section: Introductionmentioning

confidence: 99%

“…In large whale species, energetic reserves are stored in, and mobilized from, the blubber layer, visceral tissues, and muscles (Lockyer et al 1985, Aguilar & Borrell 1990, Niaess et al 1998, and thus characteristics of these tissues, including thickness and chemical composition, are considered to be primary indicators of overall body condition (Lockyer et al 1985, Miller et al 2011. Standard means of assessing the body condition of marine mammals, including live capture or direct post mortem measurements (Lockyer et al 1985, Beck et al 1993, Nilssen et al 2001, Koopman et al 2002, Wells et al 2004) are inappropriate for tracking individual and population-wide health in rare, free-ranging large whale species.…”

Section: Introductionmentioning

confidence: 99%

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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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Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 3 more Smart Citations

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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View full text Add to dashboard Cite

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Bio‐energetic modeling of medium‐sized cetaceans shows high sensitivity to disturbance in seasons of low resource supply

Hin

Harwood

Roos

2019

Ecological Applications

108

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Understanding the full scope of human impact on wildlife populations requires a framework to assess the population‐level repercussions of nonlethal disturbance. The Population Consequences of Disturbance (PCoD) framework provides such an approach, by linking the effects of disturbance on the behavior and physiology of individuals to their population‐level consequences. Bio‐energetic models have been used as implementations of PCoD, as these integrate the behavioral and physiological state of an individual with the state of the environment, to mediate between disturbance and biological significant changes in vital rates (survival, growth, and reproduction). To assess which levels of disturbance lead to adverse effects on population growth rate requires a bio‐energetic model that covers the complete life cycle of the organism under study. In a density‐independent setting, the expected lifetime reproductive output of a single female can then be used to predict the level of disturbance that leads to population decline. Here, we present such a model for a medium‐sized cetacean, the long‐finned pilot whale ( Globicephala melas ). Disturbance is modeled as a yearly recurrent period of no resource feeding for the pilot whale female and her calf. Short periods of disturbance lead to the pre‐weaned death of the first one or more calves of the young female. Higher disturbance levels also affect survival of calves produced later in the life of the female, in addition to degrading female survival. The level of disturbance that leads to a negative population growth rate strongly depends on the available resources in the environment. This has important repercussion for the timing of disturbance if resource availability fluctuates seasonally. The model predicts that pilot whales can tolerate on average three times longer periods of disturbance in seasons of high resource availability, compared to disturbance happening when resources are low. Although our model is specifically parameterized for pilot whales, it provides useful insights into the general consequences of nonlethal disturbance. If appropriate data on life history and energetics are available, it can be used to provide management advice for specific species or populations.

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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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Blubber thickness in right whales Eubalaena glacialis and Eubalaena australis related with reproduction, life history status and prey abundance

Cited by 116 publications

References 60 publications

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

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

Bio‐energetic modeling of medium‐sized cetaceans shows high sensitivity to disturbance in seasons of low resource supply

Entanglement is a costly life‐history stage in large whales

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