Methodology for in situ gas sampling, transport and laboratory analysis of gases from stranded cetaceans

Abstract

Gas-bubble lesions were described in cetaceans stranded in spatio-temporal concordance with naval exercises using high-powered sonars. A behaviourally induced decompression sickness-like disease was proposed as a plausible causal mechanism, although these findings remain scientifically controversial. Investigations into the constituents of the gas bubbles in suspected gas embolism cases are highly desirable. We have found that vacuum tubes, insulin syringes and an aspirometer are reliable tools for in situ gas sampling, storage and transportation without appreciable loss of gas and without compromising the accuracy of the analysis. Gas analysis is conducted by gas chromatography in the laboratory. This methodology was successfully applied to a mass stranding of sperm whales, to a beaked whale stranded in spatial and temporal association with military exercises and to a cetacean chronic gas embolism case. Results from the freshest animals confirmed that bubbles were relatively free of gases associated with putrefaction and consisted predominantly of nitrogen.

Retrospective Study of Traumatic Intra-Interspecific Interactions in Stranded Cetaceans, Canary Islands

“…Gross and histologically, both animals presented generalized round to oval intravascular spaces consistent with gas bubbles. Gas analysis of both animals confirmed a systemic decompression sickness (45,46).…”

Decompression vs. Decomposition: Distribution, Amount, and Gas Composition of Bubbles in Stranded Marine Mammals

“…Dissection, gas sampling and analysis were performed following procedures described by Bernaldo de Quirós et al (2011). A total of 429 samples were recovered and analyzed from the studied animals, 208 (48%) of which belong to deep diving animals.…”

Last “Atypical” Beaked Whales Mass Stranding in the Canary Islands(July, 2004)

“…From the pathological point of view, the high amount of "gas bubble" found in the three necropsied whales could not be considered as an evidence of "gas embolism" since all three animals showed an advanced postmortem autolysis and no gas analysis methodology was then available as it is now [9]. However, the evidence of fat emboli in these beaked whales together with the fact that all three died at sea, are highly suggestive that fat emboli was not due to trauma during stranding but was triggered and developed at sea and probably contributing to the whales relatively rapid death.…”

“…These findings constituted a new pathological entity in marine mammals consistent with decompression sickness in human divers [6,7] and was most likely due to a severe changes in the dive behavior of these deep divers [3,[6][7][8]. Epidemiological features, pathological studies, gas analysis and naval exercises information are considered the main diagnostic parameters to approach a diagnosis of this type of atypical mass stranding [3,4,7,9].…”