Ork cannot be heard

2004/06/01 Elhuyar Zientzia Iturria: Elhuyar aldizkaria

• Ingurumena

Orcas have to make ‘screams’ or ‘chants’ longer and longer to communicate, to face the hum of ships. The noise pollution generated by the continuous increase in maritime traffic has caused the behavior change of these animals.

The orcas of the western coastal waters of the United States live in an increasingly noisy environment, so they have had to adapt the communication between them.

Researchers studying orcas have observed a significant change in the sounds produced by these animals. An investigation has compared the recordings of the cries from the 1970s to the present, and has seen how since 1990 these cries have elongated a lot. In addition, the longest cries occur when there are boats around.

In addition to the growing presence of merchant ships, the number of tourists visiting the orcas has multiplied by five in the last ten years. To the hum generated by its engines must be added the strong sonars of the army.