When you want to track animal movements on land, there are GPS monitoring systems. But, underwater, if the animal does not rise to the surface like turtles or dolphins, it is difficult to use this technology to retrace their route. It does not work ! So we have to resort to another strategy called acoustic telemetry.
This is why researchers from the‘French Research Institute for eexploitation of the sea (Ifremer) have equipped more than 300 fish, notably bass and pollack as well as around twenty lobsters, with a small transmitter. A small cone one centimeter long which emits an acoustic signal every three seconds for five years and which was implanted under the skin, after capture and anesthesia of these fish. About sixty receivers have also been placed on the seabed, in the Iroise Sea off Finistère, in the English Channel, and researchers will be able to observe the movements of these fish. Indeed: each time a fish passes by a receiver at the bottom of the water, its unique acoustic signal is recorded.
To ensure the sustainable and profitable exploitation of marine species, it is essential to understand how they use marine habitats.
This is the goal of the project #FishIntel which deploys a network of #Telemetry #Acoustic in the Channel to follow them.https://t.co/kAqaoMddQ8— Ifremer (@Ifremer_fr) March 15, 2021
This does not disturb the fish because it is located in a frequency of 69kHz and is therefore not audible for them, nor for that matter for humans, specifies Mathieu Woillez, fisheries researcher, Ifremer, co- project leader.
Here the researchers are interested in the movements of pollack and European bass, because these are species whose stocks and populations have been weakened in recent years. By having better knowledge of their habitat, reproduction or growth areas, it will be easier to protect them, particularly in relation to fishing activity and construction sites for offshore wind turbines.
This research by Ifremer in France is also supplemented by the work of British and Belgian scientists, who have also equipped more than 350 lobsters, bass, pollack, sea bream and bluefin tuna with these same acoustic transmitters. This mesh will therefore make it possible to follow fish over long distances. The first results will be available at the beginning of 2023.