[MARMAM] Short review of whale carcass behavior

Michael Moore mmoore at whoi.edu
Thu May 21 06:58:11 PDT 2020

Please see the Open Access paper Moore MJ, Mitchell GH, Rowles TK, Early 
G (2020) Dead Cetacean? Beach, Bloat, Float, Sink. Frontiers in Marine 


Abstract: Variably buoyant, dead Cetacea may float, or sink and later 
bloat to refloat if ambient temperature and pressure allow sufficient 
decomposition gas formation and expansion. Mortality can result from 
acute or chronic disease, fishery entanglement, vessel collision, 
noxious noises, or toxicant spills. Investigators often face the 
daunting task of elucidating a complex series of events, in reverse 
order, from when and where an animal is found, and to diagnose the cause 
of death. Various scenarios are possible: an animal could die at sea 
remaining there or floating ashore, or strand on a beach alive, where it 
dies and, if cast high enough, remain beached to be scavenged or 
decompose. An animal that rests low on a beach may refloat again, 
through increased buoyancy from decomposition gas and favorable tides, 
currents, and wind. Here we review the factors responsible for the 
different outcomes, and how to recognize the provenance of a cetacean 
mortality found beached, or floating at sea. In conclusion, only some 
carcasses strand, or remain floating. Negatively buoyant animals that 
die at depth, or on the surface, and sink, may never surface, even after 
decomposition gas accumulation, as in cold, deep waters gas may fail to 
adequately reduce the density of a carcass, precluding it from returning 
to the surface.

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