Bubbles in live-stranded dolphins

Dennison, Sophie; Moore, Michael J.; Fahlman, Andreas; Moore, Kathleen; Sharp, Sarah M.; Harry, Charles T.; Hoppe, Jane M.; Niemeyer, Misty; Lentell, Betty J.; Wells, Randall S.

doi:10.1098/rspb.2011.1754

Cited by 30 publications

(52 citation statements)

References 40 publications

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“…Mesoplodon densirostris) may ascend abruptly to the surface in response to intense anthropogenic sonar signals, causing internal lesions such as gas and fat emboli (Jepson et al 2003, Hildebrand 2004, Fernán-dez et al 2005, Nowacek et al 2007, Dolman et al 2008). This has also been reported in harbor porpoises Phocoena phocoena (Jepson et al 2003), as well as Risso's Grampus griseus and common Delphinus delphis dolphins (Dennison et al 2012). There are no conclusive results showing lethal effects of seismic surveys on cetaceans (Heide-Jørgensen et al 2013) but based on indirect evidence, some authors argue that it could be a possible outcome (Taylor et al 2004).…”

Section: Potential Lethal Effectssupporting

confidence: 69%

Mitigation provisions to be implemented for marine seismic surveying in Latin America: a review based on fish and cetaceans

Acosta¹,

Niño-Rodríguez²,

Yepes³

et al. 2017

Aquat. Biol.

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Population growth and economic development in Latin America has led to an increase in seismic surveying to find new marine hydrocarbon reserves. However, most countries along the Pacific, Atlantic, and Caribbean lack the standards to minimize the impact of seismic exploration on marine organisms. We searched primary and secondary literature in major databases and consulted international authorities and oil companies to provide scientific evidence of the effects of seismic surveying on fish and cetaceans in order to propose minimum guidelines to reduce disturbance to marine organisms in Latin America. The results suggest that seismic surveys can disrupt basic life-cycle activities such as movement, communication, and feeding. Typical outcomes include sub-lethal effects such as escape behavior, habituation, temporary loss of hearing, and changes in vocalization behavior. In order to mitigate these impacts, we propose that oil companies must provide authorities with an environmental impact assessment that includes survey data, array specifications, and acoustic array properties before a hydrocarbon exploration license can be granted. Standard mitigation measures such as exclusion zones, marine mammal observers, and passive acoustic monitoring must be implemented to prevent potential adverse effects. Appropriate legislation and regulations must be designed and implemented, and environmental authorities should be privy to all activities by seismic vessels. Besides relevant regulations and continued monitoring, further investigation must be conducted to evaluate the impact of these activities on marine organisms. The adoption of these proposed minimum guidelines is highly recommended to minimize seismic surveying impact on fish and cetaceans in Latin American countries.

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Section: Potential Lethal Effectssupporting

confidence: 69%

Mitigation provisions to be implemented for marine seismic surveying in Latin America: a review based on fish and cetaceans

Acosta¹,

Niño-Rodríguez²,

Yepes³

et al. 2017

Aquat. Biol.

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“…The presence of gas bubbles in marine mammals stemming from a number of mechanisms has been reported in both live and dead stranded or bycaught animals (Fernández et al 2005, Jepson et al 2005, Moore et al 2009, Bernaldo de Quirós et al 2011, 2012b, 2013b, Dennison et al 2012, Danil et al 2014. Previous studies of marine mammals as well as controlled experimental models have proven that fresh animals (code 2, freshly dead; Geraci & Lounsbury 2005) were free of relevant gas formation by putrefaction (Bernaldo de Quirós et al 2012b, 2013a.…”

Section: Discussionmentioning

confidence: 99%

Discrimination between bycatch and other causes of cetacean and pinniped stranding

Quirós¹,

Hartwick²,

Rotstein³

et al. 2018

Dis. Aquat. Org.

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The challenge of identifying cause of death in discarded bycaught marine mammals stems from a combination of the non-specific nature of the lesions of drowning, the complex physiologic adaptations unique to breath-holding marine mammals, lack of case histories, and the diverse nature of fishing gear. While no pathognomonic lesions are recognized, signs of acute external entanglement, bulging or reddened eyes, recently ingested gastric contents, pulmonary changes, and decompression-associated gas bubbles have been identified in the condition of peracute underwater entrapment (PUE) syndrome in previous studies of marine mammals. We reviewed the gross necropsy and histopathology reports of 36 cetaceans and pinnipeds including 20 directly observed bycaught and 16 live stranded animals that were euthanized between 2005 and 2011 for lesions consistent with PUE. We identified 5 criteria which present at significantly higher rates in bycaught marine mammals: external signs of acute entanglement, red or bulging eyes, recently ingested gastric contents, multi-organ congestion, and disseminated gas bubbles detected grossly during the necropsy and histologically. In contrast, froth in the trachea or primary bronchi, and lung changes (i.e. wet, heavy, froth, edema, congestion, and hemorrhage) were poor indicators of PUE. This is the first study that provides insight into the different published parameters for PUE in bycatch. For regions frequently confronted by stranded marine mammals with non-specific lesions, this could potentially aid in the investigation and quantification of marine fisheries interactions.

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“…However, in the last two decades there have been several atypical mass stranding events, particularly of beaked whales, that have been spatio-temporally associated with the use of naval midfrequency sonar (Frantzis, 1998;Cox et al, 2006); some of these stranded whales exhibited pathologies resembling decompression sickness (Jepson et al, 2003;Fernández et al, 2005). Gas bubbles have also been found in other stranded and by-caught marine mammals (Jepson et al, 2005;Moore et al, 2009;Van Bonn et al, 2011;Dennison et al, 2012). These gas bubbles appear to be dominated by N 2 (Bernaldo de Quirós et al, 2012, 2013, suggesting that deviations from normal diving behaviors may interrupt gas dynamics and cause decompression-related injuries in marine mammals.…”

Section: Introductionmentioning

confidence: 95%

Nitrogen solubility in odontocete blubber and mandibular fats in relation to lipid composition

Lonati

Westgate

Pabst

et al. 2015

Journal of Experimental Biology

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Understanding toothed whale (odontocete) diving gas dynamics is important given the recent atypical mass strandings of odontocetes ( particularly beaked whales) associated with mid-frequency naval sonar. Some stranded whales have exhibited gas emboli ( pathologies resembling decompression sickness) in their specialized intramandibular and extramandibular fat bodies used for echolocation and hearing. These tissues have phylogenetically unique, endogenous lipid profiles with poorly understood biochemical properties. Current diving gas dynamics models assume an Ostwald nitrogen (N 2 ) solubility of 0.07 ml N 2 ml −1 oil in odontocete fats, although solubility in blubber from many odontocetes exceeds this value. The present study examined N 2 solubility in the blubber and mandibular fats of seven species across five families, relating it to lipid composition. Across all species, N 2 solubility increased with wax ester content and was generally higher in mandibular fats (0.083±0.002 ml N 2 ml −1 oil) than in blubber (0.069±0.007 ml N 2 ml −1 oil). This effect was more pronounced in mandibular fats with higher concentrations of shorter, branched fatty acids/alcohols. Mandibular fats of shortfinned pilot whales, Atlantic spotted dolphins and Mesoplodon beaked whales had the highest N 2 solubility values (0.097±0.005, 0.081±0.007 and 0.080±0.003 ml N 2 ml −1 oil, respectively). Pilot and beaked whales may experience high N 2 loads during their relatively deeper dives, although more information is needed about in vivo blood circulation to mandibular fats. Future diving models should incorporate empirically measured N 2 solubility of odontocete mandibular fats to better understand N 2 dynamics and potential pathologies from gas/fat embolism.

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Bubbles in live-stranded dolphins

Cited by 30 publications

References 40 publications

Mitigation provisions to be implemented for marine seismic surveying in Latin America: a review based on fish and cetaceans

Mitigation provisions to be implemented for marine seismic surveying in Latin America: a review based on fish and cetaceans

Discrimination between bycatch and other causes of cetacean and pinniped stranding

Nitrogen solubility in odontocete blubber and mandibular fats in relation to lipid composition

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