By Vanesa Reyes
WDC welcomes the news from the Philippines regarding the ban of oil exploration activities in the Tañon Strait. The area is host to 14 species of whales and dolphins (some resident with others transiting through), coral reefs, colourful fish, whale sharks and dugongs as well as many other marine species. Designated in 1998 it is the largest marine protected area in the country.
A few days ago an important ruling from the Supreme Court of the Philippines declared a project for oil exploration, development, and exploitation of petroleum in this protected area unconstitutional, thereby protecting many species from several potential impacts.
The project failed to accomplish the legal steps for its implementation and importantly, wasn’t subjected to an environmental impact assessment which would have provided decision-makers with a robust scientific background to assess the implications of such developments within the marine environment. This is a landmark decision and we hope it sets a positive precedent for future determinations regarding regulation of anthropogenic activities within (and without) marine protected areas.
Over the last few decades, an increase in ocean noise due to human activities has become a major concern among the scientific community and conservationists because of the many potential impacts it may pose to marine organisms, especially marine mammals. Cetaceans have evolved to exploit the extremely efficient sound propagation through the oceans where light attenuates within the first meters of depth. Most of them rely on sounds for almost every aspect of their lives: communication, mating, foraging, navigation, etc. This is why whales, dolphins and porpoises are expected to be especially vulnerable to increases in levels of background noise in the oceans.
In the particular case of seismic surveys for oil and gas exploration the sound-producing elements used are called air-gun arrays, which are towed behind ships. These air-guns release air under high pressure producing high intensity, low frequency sounds that can be heard hundreds or even thousands of kilometers away from the source, impacting several species in many ways that are still not fully understood. These high levels of noise can prevent cetaceans from hearing sounds that help them to communicate with conspecifics, find prey and avoid predators. Loud noises can make animals alter their behaviour such as displacement from an area or changes in their vocalizations with long-term implications; cetaceans can also suffer physical damage in their hearing system or other body tissues that may even cause the death of the individual.
In recent years, based on recommendations related to noise exposure thresholds for marine mammals provided by the scientific community, many international conventions have formulated guidelines to mitigate the negative effects of anthropogenic noise on cetaceans. These guidelines promote the development and use of best available quieting technologies, acoustic modelling to assess risks and the undertaking of activities in lower‐risk areas excluding areas where species may be exposed to the impact of noise. The gradual increase of source levels so that animals have the opportunity to escape dangerous areas and visual and acoustic monitoring of cetaceans before and during the activity is also recommended.
WDC actively participates in many of these international fora and continues to focus on ocean noise related issues with the aim of ensuring that oceans can be a quieter place, with reduced human noise and more natural marine life sounds, where every whale and dolphin can be safe and free.