Whales, sonar and decompression sickness (reply)

Acute and Chronic Gas Bubble Lesions in Cetaceans Stranded in the United Kingdom

“…20 In addition, the acute lesions in 10 beaked whales that mass stranded in the Canary Islands in 2002 are also considered consistent with the theory of bubble formation due to DCS. 12,13,21 The hepatic location and extent of the fibrosed cavitary lesions described in this study are inconsistent with lesions induced by bubble formation in all known causes of gas embolism (including DCS) in human 5,15 and domestic animal pathology. 40 However, cetaceans differ from humans behaviorally (as obligate, repetitive breath-hold divers), physiologically (e.g., profound diving reflex, hypocoagulable blood), 37 and anatomically (e.g., retia mirabilia, large epidural venous spaces and portal veins, portal and diaphragmatic sphincters, lipid predominantly stored as blubber).…”

“…32 In the former study, the Canary Islands' cases consisted of 10 beaked whales that mass stranded coincident with a naval exercise using active sonar, increasing concern that acoustic factors may play a role in bubble formation. 12,13,21 The Canariesstranded beaked whales had acute, systemic lesions consistent with, although not diagnostic of, DCS in humans and experimental animals. 12,13,21 In this study, we describe in detail pathologic findings from the eight UK-stranded cetaceans reported by Jepson et al 21 and additional UK-stranded Risso's dolphin (Grampus griseus) (n ϭ 1) and common dolphin (Delphinus delphis) (n ϭ 1) cases that had acute and chronic lesions associated with gas bubbles in the liver and other parenchymatous organs.…”

“…12,13,21 The Canariesstranded beaked whales had acute, systemic lesions consistent with, although not diagnostic of, DCS in humans and experimental animals. 12,13,21 In this study, we describe in detail pathologic findings from the eight UK-stranded cetaceans reported by Jepson et al 21 and additional UK-stranded Risso's dolphin (Grampus griseus) (n ϭ 1) and common dolphin (Delphinus delphis) (n ϭ 1) cases that had acute and chronic lesions associated with gas bubbles in the liver and other parenchymatous organs. Although the etiology of the gas bubbles remains uncertain, the report demonstrates the first evidence that bubbles can form in vivo in cetaceans and persist through time.…”

Why IUCN Should Replace “Data Deficient” Conservation Status with a Precautionary “Assume Threatened” Status—A Cetacean Case Study

“…But beaked whales are vulnerable to anthropogenic activities, most notably underwater noise such as naval sonar, and there is substantive evidence that naval sonar causes beaked whales to strand en masse (Parsons et al, 2008). Moreover, sonar has been linked to "bends-like" lesions in tissues (Jepson et al, 2003;Fernández et al, 2004Fernández et al, , 2005, injuries that may affect beaked whales disproportionately due to their behavior (Cox et al, 2006) and physiology (Houser et al, 2001;Crum et al, 2005). Beaked whales have even reacted to sonar use in naval exercises over 100 km away (DeRuiter et al, 2013).…”

A note on the unprecedented strandings of 56 deep-diving whales along the UK and Irish coast

“…Unusual stranding events may be associated with anthropogenic noise sources, fisheries interactions, disease, or natural phenomenon, such as earthquakes (see review by Geraci & Lounsbury, 2005). unprecedented cetacean strandingsalthough it has not always been possible to fully investigate these events (Brownell et al, 2004;Freitas, 2004;Fernández et al, 2004;2005a;2005b;Martin et al, 2004;Espinosa et al, 2005;Fernández, 2006;Hohn et al, 2006). In many of these cases a definitive link could not be established, the features are described as 'the "atypical" distribution of strandings involving one or more offshore species, all stranding alive, and without evidence of common infectious or other disease processes' (Hohn et al, 2006).…”