A 2008 whale mass stranding in Madagascar linked to sonar mapping for the first time

An alien environment for a deep diving species. Photographer: Tim Collins

In 2008, approximately 100 melon-headed whales stranded in the Loza Lagoon system in Madagascar. The response effort was multi-faceted and included local people, government officials, conservation organisations and marine mammal experts. A significant amount of information was collected and, several years later, the International Whaling Commission facilitated a review of the circumstances of the stranding in conjunction with the US Marine Mammal Commission, the US National Oceanic and Atmospheric Administration, the US Bureau of Ocean Energy Management, ExxonMobil Exploration and Production (Northern Madagascar) Ltd, the International Fund for Animal Welfare, the Wildlife Conservation Society and the Government of Madagascar. An independent scientific review panel (ISRP) of five experts was invited to conduct a formal examination of the available facts.

Capturing a whale in a mangrove channel. Photographer: Yvette Razafindrakoto

The ISRP concluded that the mass stranding was primarily triggered by acoustic stimuli, more specifically, a multi-­beam echosounder system operated by a survey vessel contracted by ExxonMobil Exploration and Production (Northern Madagascar) Limited. 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.

Initial strandings at Antsohihy were the subjects of huge fascination, and were brought into town for inspection by the local government veterinarian. Photographer: Unknown local resident

Links to the report, which became available on 25th September 2013 and the associated material considered by them can be found at http://iwc.int/2008-mass-stranding-in-madagascar

Click Here for the full press release issued by WCS and IFAW.