New research begins on the ocean sunfish, Mola mola, in Galapagos

A new collaboration between world expert Dr. Tierney Thys ( and Migramar researchers based in Galapagos highlights the importance of key sites for the ocean sunfish Mola mola.

Thanks to the permission of the Galapagos National Park Service, world experts Dr. Tierney Thys and Dr. Kevin Weng joined forces with Migramar researchers Dr. Alex Hearn (UC Davis) and Cesar Penaherrera (Charles Darwin Foundation) to undertake the first ever study in the Eastern Tropical Pacific of the world’s heaviest fish – the ocean sunfish, Mola mola. Sunfish are seen regularly at only one location in the Galapagos Marine Reserve – Punta Vicente Roca, at the northern tip of Isabela Island. This site has become an attraction for tourists, yet little is known about the spatial dynamics of molas in the Reserve.

A pilot study undertaken in September 2011 aims to gather information about the site fidelity of molas around this point. We placed ultrasonic tags on five individuals, and deployed underwater listening stations at the site. This will feed into the regional array of listening stations deployed from Mexico to Ecuador, so that visits by the molas to these other sites can also be detected. In addition, we placed two fastloc GPS tags, which are providing us with near real-time positions of the tagged fish.

While diving at the site, the research team saw evidence of cleaning behavior by the reef fish in the vicinity. Have you been diving or snorkelling at Punta Vicente Roca? If you have any photos of cleaning behavior, we’d love to see them. Please send them to and let us know where and when they were taken.