An independent scientific review panel has concluded that the mass stranding of approximately 100 melon-headed whales in the Loza Lagoon system in northwest Madagascar in 2008 was primarily triggered by acoustic stimuli – more specifically – a multi-beam echo-sounder system operated by a survey vessel contracted by ExxonMobil Exploration and Production (Northern Madagascar) Limited.
In response to the event, The Wildlife Conservation Society (WCS) has led an international stranding team to help return live whales from the lagoon system to the open sea, and to conduct necropsies on dead whales to determine the cause of death.
According to the final report, this is the first known marine mammal mass stranding event of this nature to be closely associated with high-frequency mapping sonar systems. Based on these findings, there is cause for concern over the impact of noise on marine mammals as these high-frequency mapping sonar systems are used by various stakeholders, including the hydrocarbon industry, military, and research vessels used by other industries.
The report concluded: “The potential for behavioral responses and indirect injury or mortality from the use of similar MBES [multi-beam echo-sounder systems] should be considered in future environmental assessments, operational planning and regulatory decisions.”
The WCS and the International Fund for Animal Welfare (IFAW) welcomed the report and praised all those involved in the process, including governments, NGOs and industry.
“WCS and IFAW support these conclusions that add to a mounting body of evidence of the potential impacts of anthropogenic noise on marine mammals,” said Dr Howard Rosenbaum, director of the Ocean Giants Program for WCS.
“Implications go well beyond the hydrocarbon industry, as these sonar systems are widely used aboard military and research vessels for generating more precise bathymetry (underwater mapping). We now hope that these results will be used by industry, regulatory authorities, and others to minimize risks and to better protect marine life, especially marine mammal species that are particularly sensitive to increasing ocean noise from human activities.”