title: Sometimes sperm whales (Physeter macrocephalus) cannot find their way back to the high seas: a multidisciplinary study on a mass stranding.
abstract: 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 water temperature and weather conditions, coast geographical features and human activities have been proposed as possible causes. In December 2009, a pod of seven male sperm whales stranded along the Adriatic coast of Southern Italy. This is the sixth instance from 1555 in this basin.
  
  
  RESULTS
  Complete necropsies were performed on three whales whose bodies were in good condition, carrying out on sampled tissues histopathology, virology, bacteriology, parasitology, and screening of veins looking for gas emboli. Furthermore, samples for age determination, genetic studies, gastric content evaluation, stable isotopes and toxicology were taken from all the seven specimens. The animals were part of the same group and determined by genetic and photo-identification to be part of the Mediterranean population. Causes of death did not include biological agents, or the "gas and fat embolic syndrome", associated with direct sonar exposure. Environmental pollutant tissue concentrations were relatively high, in particular organochlorinated xenobiotics. Gastric content and morphologic tissue examinations showed a prolonged starvation, which likely caused, at its turn, the mobilization of lipophilic contaminants from the adipose tissue. Chemical compounds subsequently entered the blood circulation and may have impaired immune and nervous functions.
  
  
  CONCLUSIONS
  A multi-factorial cause underlying this sperm whales' mass stranding is proposed herein based upon the results of postmortem investigations as well as of the detailed analyses of the geographical and historical background. The seven sperm whales took the same "wrong way" into the Adriatic Sea, a potentially dangerous trap for Mediterranean sperm whales. Seismic surveys should be also regarded as potential co-factors, even if no evidence of direct impact has been detected.
authors.affiliation: Department of Public Health, Comparative Pathology and Veterinary Hygiene, University of Padua, Legnaro, Italy. sandro.mazzariol@unipd.it
authors.forename: Sandro
authors.initials: S
authors.lastname: Mazzariol
authors.forename: Giovanni
authors.initials: G
authors.lastname: Di Guardo
authors.forename: Antonio
authors.initials: A
authors.lastname: Petrella
authors.forename: Letizia
authors.initials: L
authors.lastname: Marsili
authors.forename: Cristina M
authors.initials: CM
authors.lastname: Fossi
authors.forename: Claudio
authors.initials: C
authors.lastname: Leonzio
authors.forename: Nicola
authors.initials: N
authors.lastname: Zizzo
authors.forename: Salvatrice
authors.initials: S
authors.lastname: Vizzini
authors.forename: Stefania
authors.initials: S
authors.lastname: Gaspari
authors.forename: Gianni
authors.initials: G
authors.lastname: Pavan
authors.forename: Michela
authors.initials: M
authors.lastname: Podestà
authors.forename: Fulvio
authors.initials: F
authors.lastname: Garibaldi
authors.forename: Margherita
authors.initials: M
authors.lastname: Ferrante
authors.forename: Chiara
authors.initials: C
authors.lastname: Copat
authors.forename: Donato
authors.initials: D
authors.lastname: Traversa
authors.forename: Federica
authors.initials: F
authors.lastname: Marcer
authors.forename: Sabina
authors.initials: S
authors.lastname: Airoldi
authors.forename: Alexandros
authors.initials: A
authors.lastname: Frantzis
authors.forename: Yara De Bernaldo
authors.initials: Yde B
authors.lastname: Quirós
authors.forename: Bruno
authors.initials: B
authors.lastname: Cozzi
authors.forename: Antonio
authors.initials: A
authors.lastname: Fernández
mesh_terms: D000273:Adipose Tissue / Q000737:chemistry / Q000378:metabolism; D000818:Animals; D001522:Behavior, Animal / Q000502:physiology*; D004785:Environmental Pollutants / Q000737:chemistry / Q000378:metabolism; D005843:Geography; D006801:Humans; D007558:Italy; D008297:Male; D008522:Mediterranean Sea; D019216:Metals, Heavy / Q000737:chemistry / Q000378:metabolism; D008685:Meteorological Concepts; D009949:Orientation / Q000502:physiology*; D050661:Sperm Whale / Q000033:anatomy & histology / Q000502:physiology*
chemical_list: D004785:Environmental Pollutants; D019216:Metals, Heavy