Jepson Paul D.

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Jepson
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Paul D.
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Criteria and case definitions for serious injury and death of pinnipeds and cetaceans caused by anthropogenic trauma

2013-04-11 , Moore, Michael J. , van der Hoop, Julie , Barco, Susan G. , Costidis, Alexander M. , Gulland, Frances M. , Jepson, Paul D. , Moore, Kathleen M. T. , Raverty, Stephen A. , McLellan, William A.

Post-mortem examination of dead and live stranded beach-cast pinnipeds and cetaceans for determination of a cause of death provides valuable information for the management, mitigation and prosecution of unintentional and sometimes malicious human impacts, such as vessel collision, fishing gear entanglement and gunshot. Delayed discovery, inaccessibility, logistics, human safety concerns, and weather make these events challenging. Over the past 3 decades, in response to public concern and federal and state or provincial regulations mandating such investigations to inform mitigation efforts, there has been an increasing effort to objectively and systematically investigate these strandings from a diagnostic and forensic perspective. This Theme Section provides basic investigative methods, and case definitions for each of the more commonly recognized case presentations of human interactions in pinnipeds and cetaceans. Wild animals are often adversely affected by factors such as parasitism, anthropogenic contaminants, biotoxins, subclinical microbial infections and competing habitat uses, such as prey depletion and elevated background and episodic noise. Understanding the potential contribution of these subclinical factors in predisposing or contributing to a particular case of trauma of human origin is hampered, especially where putrefaction is significant and resources as well as expertise are limited. These case criteria descriptions attempt to acknowledge those confounding factors to enable an appreciation of the significance of the observed human-derived trauma in that broader context where possible.

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Decompression sickness (‘the bends’) in sea turtles

2014-10-16 , Garcia-Parraga, Daniel , Crespo-Picazo, J. L. , Bernaldo de Quiros, Yara , Cervera, V. , Marti-Bonmati, L. , Diaz-Delgado, J. , Arbelo, Manuel , Moore, Michael J. , Jepson, Paul D. , Fernandez, Antonio

Decompression sickness (DCS), as clinically diagnosed by reversal of symptoms with recompression, has never been reported in aquatic breath-hold diving vertebrates despite the occurrence of tissue gas tensions sufficient for bubble formation and injury in terrestrial animals. Similarly to diving mammals, sea turtles manage gas exchange and decompression through anatomical, physiological, and behavioral adaptations. In the former group, DCS-like lesions have been observed on necropsies following behavioral disturbance such as high-powered acoustic sources (e.g. active sonar) and in bycaught animals. In sea turtles, in spite of abundant literature on diving physiology and bycatch interference, this is the first report of DCS-like symptoms and lesions. We diagnosed a clinico-pathological condition consistent with DCS in 29 gas-embolized loggerhead sea turtles Caretta caretta from a sample of 67. Fifty-nine were recovered alive and 8 had recently died following bycatch in trawls and gillnets of local fisheries from the east coast of Spain. Gas embolization and distribution in vital organs were evaluated through conventional radiography, computed tomography, and ultrasound. Additionally, positive response following repressurization was clinically observed in 2 live affected turtles. Gas embolism was also observed postmortem in carcasses and tissues as described in cetaceans and human divers. Compositional gas analysis of intravascular bubbles was consistent with DCS. Definitive diagnosis of DCS in sea turtles opens a new era for research in sea turtle diving physiology, conservation, and bycatch impact mitigation, as well as for comparative studies in other air-breathing marine vertebrates and human divers.

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Deadly diving? Physiological and behavioural management of decompression stress in diving mammals

2011-12-21 , Hooker, Sascha K. , Fahlman, Andreas , Moore, Michael J. , Aguilar De Soto, Natacha , Bernaldo de Quiros, Yara , Brubakk, A. O. , Costa, Daniel P. , Costidis, Alexander M. , Dennison, Sophie , Falke, K. J. , Fernandez, Antonio , Ferrigno, Massimo , Fitz-Clarke, J. R. , Garner, Michael M. , Houser, Dorian S. , Jepson, Paul D. , Ketten, Darlene R. , Kvadsheim, P. H. , Madsen, Peter T. , Pollock, N. W. , Rotstein, David S. , Rowles, Teresa K. , Simmons, S. E. , Van Bonn, William , Weathersby, P. K. , Weise, Michael , Williams, Terrie M. , Tyack, Peter L.

Decompression sickness (DCS; ‘the bends’) is a disease associated with gas uptake at pressure. The basic pathology and cause are relatively well known to human divers. Breath-hold diving marine mammals were thought to be relatively immune to DCS owing to multiple anatomical, physiological and behavioural adaptations that reduce nitrogen gas (N2) loading during dives. However, recent observations have shown that gas bubbles may form and tissue injury may occur in marine mammals under certain circumstances. Gas kinetic models based on measured time-depth profiles further suggest the potential occurrence of high blood and tissue N2 tensions. We review evidence for gas-bubble incidence in marine mammal tissues and discuss the theory behind gas loading and bubble formation. We suggest that diving mammals vary their physiological responses according to multiple stressors, and that the perspective on marine mammal diving physiology should change from simply minimizing N2 loading to management of the N2 load. This suggests several avenues for further study, ranging from the effects of gas bubbles at molecular, cellular and organ function levels, to comparative studies relating the presence/absence of gas bubbles to diving behaviour. Technological advances in imaging and remote instrumentation are likely to advance this field in coming years.

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