Bio-Sonar Functionality of Stranded Cetaceans: A Complementary Clinical Procedure
IAAAM Archive
Michel André1; Eric Delory1; Alexander Supin2; Cees Kamminga3; Eduard Degollada4; Josep María Alonso5
1Marine Mammal Conservation Research Unit, School of Veterinary Medicine, University of Las Palmas de Gran Canaria, Trasmontaña, Arucas, Spain; 2Institute of Evolutionary Morphology and Ecology, Russian Academy of Science; 3Information Theory Group, Technological University of Delft, The Netherlands; 4Veterinary School of Medicine, Autonomous University of Barcelona, Spain; 5North Western Spain Marine Animals Stranding Network, CEMMA, Instituto de Investigaciones Marinas, CSIC, Spain


The odontocete bio-sonar processes constitute a primary information exchange mechanism for communication, food location and orientation in the marine habitat. In a healthy organism, the hearing system characteristics are directly and evolutively related with the habitat use, thus further characterises a cetacean species. Both the species related frequency resolving power and the hearing frequency sensitivity, HFS (i.e., hearing threshold) can be studied with electrophysiological methods, through the analysis of evoked potentials (EP) from the head surface.

The analysis of the hearing frequency sensitivity is of particular interest in the case of a rehabilitated cetacean in order to assess the physiological and/or pathological status of the auditory system, estimate the bio-sonar performance and evaluate the survival probability of the animal after release.

A female striped dolphin, Stenella coreuleoalba, stranded alive in August 2001 on the West Mediterranean Coast (Alicante, Spain). After a 16 week rehabilitation period, HFS-EP analysis as well as experiments to stimulate the production of sonar click trains were conducted prior to the release. Although these experiments represent the first attempt to record EP responses from this species with the consecutive lack of reference about the striped dolphin audiogram (overcome by analogies with odontocete species for which audiograms are available), a severe hearing loss appeared in response to the whole frequency spectrum tested as well as a total absence of sonar click production. These results illustrate that, despite the vital parameters and the nutritional state of the animal were correct during the whole rehabilitation process, this dolphin would have very little chance to survive if released.

Therefore, we recommend the introduction of EP measurements as a complementary clinical procedure and a necessary analysis in any cetacean rehabilitation process since it represents an objective parameter to assess the functionality of the cetacean most critical sensory systems.

Speaker Information
(click the speaker's name to view other papers and abstracts submitted by this speaker)

Michel André

MAIN : Recovery, Rehabilitation : Bio-Sonar Functionality
Powered By VIN