title: Compositional discrimination of decompression and decomposition gas bubbles in bycaught seals and dolphins.
abstract: Gas bubbles in marine mammals entangled and drowned in gillnets have been previously described by computed tomography, gross examination and histopathology. The absence of bacteria or autolytic changes in the tissues of those animals suggested that the gas was produced peri- or post-mortem by a fast decompression, probably by quickly hauling animals entangled in the net at depth to the surface. Gas composition analysis and gas scoring are two new diagnostic tools available to distinguish gas embolisms from putrefaction gases. With this goal, these methods have been successfully applied to pathological studies of marine mammals. In this study, we characterized the flux and composition of the gas bubbles from bycaught marine mammals in anchored sink gillnets and bottom otter trawls. We compared these data with marine mammals stranded on Cape Cod, MA, USA. Fresh animals or with moderate decomposition (decomposition scores of 2 and 3) were prioritized. Results showed that bycaught animals presented with significantly higher gas scores than stranded animals. Gas composition analyses indicate that gas was formed by decompression, confirming the decompression hypothesis.
authors.affiliation: Woods Hole Oceanographic Institution, Biology Department, Woods Hole, Massachusetts, United States of America.
authors.forename: Yara
authors.initials: Y
authors.lastname: Bernaldo de Quirós
authors.affiliation: Woods Hole Oceanographic Institution, Marine Chemistry and Geochemistry Department, Woods Hole, Massachusetts , United States of America.
authors.forename: Jeffrey S
authors.initials: JS
authors.lastname: Seewald
authors.affiliation: Woods Hole Oceanographic Institution, Marine Chemistry and Geochemistry Department, Woods Hole, Massachusetts , United States of America.
authors.forename: Sean P
authors.initials: SP
authors.lastname: Sylva
authors.affiliation: Integrated Statistics, Woods Hole, Massachusetts, United States of America ; NOAA NMFS Northeast Fisheries, Woods Hole, Massachusetts, United States of America.
authors.forename: Bill
authors.initials: B
authors.lastname: Greer
authors.affiliation: International Fund for Animal Welfare, Yarmouth Port, Massachusetts, United States of America.
authors.forename: Misty
authors.initials: M
authors.lastname: Niemeyer
authors.affiliation: Woods Hole Oceanographic Institution, Biology Department, Woods Hole, Massachusetts, United States of America ; University of Connecticut, Department of Pathobiology and Veterinary Science, Storrs, Connecticut, United States of America.
authors.forename: Andrea L
authors.initials: AL
authors.lastname: Bogomolni
authors.affiliation: Woods Hole Oceanographic Institution, Biology Department, Woods Hole, Massachusetts, United States of America.
authors.forename: Michael J
authors.initials: MJ
authors.lastname: Moore
mesh_terms: D000818:Animals; D010872:Caniformia / Q000378:metabolism*; D003664:Decompression; D004289:Dolphins / Q000378:metabolism*; D005740:Gases / Q000737:chemistry* / Q000378:metabolism*; D011180:Postmortem Changes
chemical_list: D005740:Gases