Acoustic Trauma and Hearing Loss in Cetaceans

While the concern about the effects on man-made noise in the marine environment is increasing in the light of recent evidence of the negative impact of anthropogenic sound sources on marine mammals, there is an urgent need to define and quantify the added average power spectrum and spatio-temporal variability of acoustic pollution from different sources and identify the resulting short, medium or long-term changes and effects in the marine organisms. Because most cetaceans rely on sounds to orientate and look for food, the analysis of the acoustic pollution related lesions in the cetacean inner ear structures against non-anthropogenic lesions and associated general pathological findings could certainly be a way to assess the correlation level between known acoustic sources and acoustic trauma to further control the introduction of noise in the ocean.

The LAB is routinely analysing inner ear structures from stranded cetaceans and improving assessment methods. Specimens are examined for gross pathology, especially signs of human interactions inducing trauma, and body condition. Samples are collected for the histopathological, microbiological, toxicological and parasitological analysis as well as for electronmicroscopy, CT and MRI studies.

The ouput of this research module, in addition to detect acoustic induced lesions in individual cetaceans, is being modelled and integrated into the LAB simulations aiming at determining the sound production, propagation and reception mechanisms and the pathological effects of anthropogenic noise on these processes.