du bruit de petites embarcations

"experimental playback OF recordings of small watercraft"

--------------------------------------------------
Note added at 18 hrs (2016-12-13 09:26:14 GMT)
--------------------------------------------------

on "n'écoute" pas les enregistrements, on les diffuse à l'intention des lamantins pour évaluer l'impact des bruits de l'activité humaine sur les animaux.

"Chapter 5. Characterizing Manatee Responses to Playbacks of Approaching Vessels
5.1 Abstract
One of the most pressing concerns associated with the endangered Florida
manatee is mortality and serious injury due to collisions with watercraft. Watercraft
collisions are the leading identified cause of manatee mortality, resulting in 25 to
greater than 30% of deaths each year. The primary management tools aimed at
reducing manatee mortality have been establishing zones where boat speed is
regulated and limiting boat access in certain areas. The successful establishment and
management of boat speed regulatory zones and manatee sanctuaries depends upon the acquisition of data assessing behavior patterns, habitat-use patterns, and identification of environmental characteristics influencing manatee behavior and habitat selection.
Detailed information on manatee distribution, behavior patterns, and habitat-use
during non-winter months is sparse compared to the amount of knowledge and number
of studies at winter aggregation sites. Acoustic playback experiments
to assess the behavioral responses of manatees to watercraft approaches in shallow-
water environments during the non-winter season. Playback stimuli were constructed
to simulate a vessel approach to approximately 10m in seagrass habitats. Stimulus
categories were 1) silent control, 2) approach with outboard at idle speed, 3) planing
outboard approach, and 4) fast personal watercraft approach. Analyses of swim speed, changes in behavioral state, and respiration rate indicate that the animals respond differentially to the playback categories. "
Miksis-Olds, 2006: Manatee Response to Environmental Noise
http://montereybay.noaa.gov/resourcepro/resmanissues/mpwc/mi...