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

A Fernández

doi:10.4172/2155-9910.1000107

Abstract

In July 2004, four Ziphius cavirostris stranded in the Canary Islands several days after an international naval exercises were conducted north of the Canary Islands. During the maneuvers high intensity mid-frequency sonar was used. Three of the animals were fully necropsied. Abundant fresh non-digestive aliment was found in all stomachs. Hemorrhages were a constant finding in several organs. Although “in vivo” gas embolism could not be established due to decomposition, systemic fat embolism was diagnosed in all three beaked whales. Epidemiological and pathological findings were highly consistent with an “atypical” beaked whale mass stranding that was temporally and spatially associated with sonar. This was the last atypical mass stranding in the Canary Islands once an antisonar moratorium was established around the islands, following the EU parliament recommendation and Spanish government resolution in 2004.

Highlights

The possibility that exposure to sonar stimuli could lead to the stranding of cetaceans is an issue of environmental concern because of cetacean stranding and deaths temporally and geographically coincident with naval sonar operations [1,2]
Some common epidemiologic factors in this type of mass stranding were: (1) the oceanographic features were characteristic of steep-slope regions; (2) the species involved were predominantly Beaked whales (BWs); and (3) these events were temporally associated with naval maneuvers that employed high intensity, low- or mid frequency range sonar signals [3,5]
We report the last beaked whale mass stranding occurred in the Canary Islands in July 2004, associated with naval exercises and antisubmarine sonar activities before an anti-sonar moratorium was recommended by European Union parliament and established around the islands by the Spanish and Canary Islands governments in 2004 [10,11]

Summary

Introduction

The possibility that exposure to sonar stimuli could lead to the stranding of cetaceans is an issue of environmental concern because of cetacean stranding and deaths temporally and geographically coincident with naval sonar operations [1,2]. Some common epidemiologic factors in this type of mass stranding were: (1) the oceanographic features were characteristic of steep-slope regions; (2) the species involved were predominantly BWs; and (3) these events were temporally associated with naval maneuvers that employed high intensity, low- or mid frequency range sonar signals [3,5]. A detailed pathological study revealed unusual ‘‘bubble’’ lesions and fat emboli in most of the necropsied beaked whales. 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]

Methods

Results

Conclusion