Report: cetaceans and noise pollution

Cetaceans are marine mammals that heavily rely on sound communication, and noise pollution caused by maritime traffic, seismic surveys, sonar, oil and gas exploitation, and offshore wind farms unfortunately causes serious harm to whales, dolphins, and other marine mammals. 

Noise can be classified as:

• Impulsive noise or “impact noise,” such as that produced by oil explorations, seismic and oceanographic surveys, the use of airguns, or sonar. This is a high-frequency sound of short duration that may or may not repeat over time. 

• Continuous noise, like that produced by maritime traffic, is a low-frequency sound that persists over time (from a few minutes to several hours). 

• The acoustic sources used by humans vary greatly over time and space and can be grouped into the following main categories: 

• Maritime traffic 

• Seismic surveys 

• Sonar 

• Oil and gas exploitation 

• Offshore wind farms

Effects of Noise on Cetaceans

Exposure to noise can produce a wide range of effects on marine mammals, from forced abandonment of an area to hearing loss as a result of acoustic trauma, depending on the duration and intensity of the exposure. 

The effects of noise pollution can be distinguished as: 

• Primary effects (immediate or delayed): Barotrauma affecting animals close to the sound sources, embolisms caused by rapid ascent to the surface, or even certain death. 

• Secondary effects: Various types of injuries, including auditory damage, which can have long-term implications for the survival of the species. 

• Tertiary or behavioural effects: Impacts on species that use the noise-affected area for crucial activities such as reproduction, feeding, and migratory routes.

Conservation Depends on Us

The conservation of cetaceans in the world’s seas depends on a number of important factors, including humanity’s ability and willingness to reduce noise pollution, starting with the development of legislation, which is currently lacking. 

Key actions include: 

• Implementing comprehensive national-scale monitoring programs to update the conservation status of cetacean species, fill knowledge gaps about the species, and identify critical areas for cetaceans in Italian waters. 

• Deepening knowledge about the acoustic behaviour of different cetacean species, the acoustic impacts of maritime traffic, seismic surveys, military exercises, offshore wind farm construction, and appropriate mitigation measures. 

• Raising public awareness about the importance of these species for the marine ecosystem, also involving society in citizen science programs aimed at filling knowledge gaps.