Background: Mass strandings of sperm whales (Physeter macrocephalus) remain peculiar and rather unexplained events,which rarely occur in the Mediterranean Sea. Solar cycles and related changes in the geomagnetic field, variations in watertemperature and weather conditions, coast geographical features and human activities have been proposed as possiblecauses. In December 2009, a pod of seven male sperm whales stranded along the Adriatic coast of Southern Italy. This is thesixth instance from 1555 in this basin.Methodology/Principal Findings: Complete necropsies were performed on three whales whose bodies were in goodcondition, carrying out on sampled tissues histopathology, virology, bacteriology, parasitology, and screening of veinslooking for gas emboli. Furthermore, samples for age determination, genetic studies, gastric content evaluation, stableisotopes and toxicology were taken from all the seven specimens. The animals were part of the same group anddetermined by genetic and photo-identification to be part of the Mediterranean population. Causes of death did notinclude biological agents, or the ‘‘gas and fat embolic syndrome’’, associated with direct sonar exposure. Environmentalpollutant tissue concentrations were relatively high, in particular organochlorinated xenobiotics. Gastric content andmorphologic tissue examinations showed a prolonged starvation, which likely caused, at its turn, the mobilization oflipophilic contaminants from the adipose tissue. Chemical compounds subsequently entered the blood circulation and mayhave impaired immune and nervous functions.Conclusions/Significance: A multi-factorial cause underlying this sperm whales’ mass stranding is proposed herein basedupon the results of postmortem investigations as well as of the detailed analyses of the geographical and historicalbackground. The seven sperm whales took the same ‘‘wrong way’’ into the Adriatic Sea, a potentially dangerous trap forMediterranean sperm whales. Seismic surveys should be also regarded as potential co-factors, even if no evidence of directimpact has been detected.
|Numero di pagine||17|
|Stato di pubblicazione||Published - 2011|