How do whales react to the sound of ships?

When the whales begin to peek off the shores of Madryn, in Chubut, thousands of tourists arrive to the city to observe them first person. However, it is not only the whales that occupy the coastal waters. Humans also develop tourist and commercial activities in them. So in the use of that common space, they can generate potential conflicts between humans and whales.

How does population growth affect the city's ecosystem?

From 1970 and to date, it is estimated thatthe population of the city of Puerto Madryn increased fourteen times. This growth is reflected in increased number of activities carried out around the sea.

Daily they navigate the area, commercial vessels, fishing vessels, mineralers, container ships, among others. And there are also sports boats and small size that may or may not be related to a commercial activity such as diving boats, semi-rigid private boats, non-motor boats such as sailing boats, kayaks and windsurfing boards. “This human population increase coincides with a growth in the number of whales visiting the area. I counted about 200 in 2019 for a single day inside the Bay,” describes Belén Argüelles, a postdoctoral fellow from the Center for the Study of Marine Systems.

On the marine and environmental survey

To observe this interaction that occurs between these animals and the different classes of vessels, a study was conducted that seeks to evaluate the probability of risk of colliding with each other.

“ There are three possible reactions of the whale to the presence of a ship. Stay neutral. That is, it does not change its behavior. Reacts positively: stops doing what you're doing and approaches the boat. Or, however, react negatively: stop doing what you are doing and move away. In Puerto Pirámides, for example, where there are concentrated vessels that carry out sighting, we were able to verify that, if the boats have the engine turned off, the animal is coming. On the contrary, if you turn it on, it will move away. That is to say that the sound of the boat, modifies the behavior of whales,” says Argüelles.

In the waters near the port of Madryn, where the noise of the ships is constant because there are more boats, the results were other. The researcher confirmed that most whales do not react to the sounds of engines in this Chubutense city. “We think they're so used to the sound inside the bay that they assimilated it and feel no danger . They have assimilated sound as something peculiar to the marine ecosystem,” he explains.

Fieldwork and some revelations

For conducting this study, researchers collected information by recording the quantity of vessels and whales. They generated a zoning of the area, generating a virtual map of possible interactions between whales and boats. In addition to evaluate the movement and behavior of animals, developed the Raspiwhale. This device has a microprocessor that allows you to record different variables and film the whale under the water.

“ This monitoring allowed us to describe a cooperative feeding behavior that was not registered. We were able to observe a group of at least forty Adult whales arranged in pairs, swimming in the form of a circle. East behavior, in which different strategies of