Is there any sound repelent/attractant to help rescuing a Beluga who got lost in a river far from the sea?

Question

I've seen in the news that a live Beluga whale has been identified in a French river (Seine, very busy and polluted, >150 km from the sea), which is particularly rare as no Beluga has been seen around main-land France sea for the last 70 years (ref):

"Marine conservation group Seyya Shepherd France [...] said the whale is likely to need food and help to guide it back toward its natural ocean habitat. “It's condemned to die if it stays in the Seine,” Lamya Essemlali, the group's president, told TF1." The Seine river is very busy and polluted.

Wikipedia says that:

belugas are among the most vocal cetaceans. They use their vocalisations for echolocation, during mating and for communication. They possess a large repertoire, emitting up to 11 different sounds, such as cackles, whistles, trills and squawks.

Wikipedia again also mentions that:

In the summer, they occupy estuaries and the waters of the continental shelf, and, on occasion, they even swim up the rivers. A number of incidents have been reported where groups or individuals have been found hundreds or even thousands of kilometres from the ocean.

Assuming human help would be helpful, is there any previous case of use of sound repellent/attractant to "guide" a Beluga from the river up to the sea? Or would it be just useless in this case?

Answer 1

I do not know of an example with a beluga, but there are two contrasting examples with humpbacks.

As a child growing up in the San Francisco Bay Area in California, Humphrey the Humpback whale was quite famous! He ventured up the delta that flows into the San Francisco bay twice(!) and sounds were used (and said to have helped) to get him back out to sea.

At first, they tried to use killer whale sounds or loud banging sounds to scare him back towards the ocean but that did not work. But, when they played sounds of humpbacks towards the ocean, that did help!

The Wikipedia article gives a bit of basic info and links to several news articles.

More recently in 2007, a female humpback and her calf ("Delta and Dawn") did the same thing - went up the Sacramento River all the way to fresh water - and went even further than Humphrey. There is a scientific article about the approaches used for the mother-calf pair and in this case playbacks did not seem to cause a response/help.

Gulland, Frances MD, et al. "Health assessment, antibiotic treatment, and behavioral responses to herding efforts of a cow-calf pair of humpback whales (Megaptera novaeangliae) in the Sacramento River Delta, California." Aquatic Mammals 34.2 (2008): 182.

Answer 2

My free Android app DC Dolphin Communicator could be helpful in such situations. One could interact acoustically with the individual and exchange whistles. Maybe one could figure out what the individual is up to, somewhat, and try to protect it. Also government agencies need to protect the individual around the clock. Experts like Dr Vergara could be of assistance.

DC is a proof of concept app to chat with whistle-using cetaceans using underwater whistles. The human user emits whistles by typing their names, and the beluga user emits whistles their natural ways and the app tries to match these with whistles it has in memory, and if there is no match then it gives a name to the whistle, such as x125, and stores it, in real time. The newly acquired whistles can be emitted by the human user.

It has its limitations and it could be improved but it could be used today to interact with any whistle-using cetaceans, and belugas are great whistle users. One would need an inexpensive tablet with a hydrophone for input and a projector transducer (or underwater speaker) for output, with a splitter cable in the audio port of the tablet.

Over a series of trials and errors, a team may be able to notice patterns with associated behavior and come to some hypotheses about whistles and intents, and such hypothesis can be tested in subsequent interactions.

The above describes ad hoc experiments which are different from controlled experimental designs. Because the main goal here is to protect the individual, to learn enough to try to protect it, in a timely manner. The goal is not to publish a peer-reviewed paper.

In a situation such as those with individuals near people that can act dangerously, much care must be taken to keep people at a safe distance. Many cetaceans in such situations have been hurt or killed by people, intentionally or by accident. A few weeks ago, the orca that came in the same river died in a few weeks and it had been shot in the head. The cause of death was not clear.

Someone interested in a more academic setting for using DC, one could learn from Dr Denise Herzing's experience with a somewhat similar device a few years ago, with free Stenella frontalis. Btw, the license for DC forbids its use with individuals in captivity in a commercial or military installation, even if the usage is scientific research (I am thinking of amending the license to allow medical usage).

The app contains details on how to use it. The app's page on Google Play has some too. The documents in gitlab has some.

https://play.google.com/store/apps/details?id=sm.app.dc