In 2018, Deep Blue Research Foundation conducted a pioneering expedition to Taiwan focused on one of the ocean’s rarest and least-understood sharks: the megamouth shark (Megachasma pelagios). Since its discovery in 1976, fewer than 300 confirmed sightings of this deep-sea species have been documented worldwide.

Working in close collaboration with local Taiwanese fishers and university researchers, DBRF led the first successful deployment of long-term satellite tracking tags on live megamouth sharks. Because megamouths do not regularly surface, conventional tracking methods are ineffective; instead, our team employed advanced archival tagging technologies that use geomagnetic field data to reconstruct movements and depth behavior across the South China Sea.

During the expedition, we tagged and released a mature female megamouth measuring 21.5 feet (6.6 meters)—significantly larger than any previously recorded individual, fundamentally revising assumptions about the species’ maximum size.

In parallel with the tagging work, DBRF collaborated with regional partners to recover a separate megamouth specimen that entered the local fish market as bycatch. This specimen was transported to the Smithsonian Institution, where DBRF participated in an extensive anatomical dissection alongside international experts in shark morphology. This work is ongoing and represents a major contribution to the limited global knowledge of megamouth anatomy, adding to what is currently the only megamouth specimen held in the United States.

The expedition also yielded another major first: in partnership with Taiwanese researchers, DBRF obtained the first-ever footage of a free-swimming megamouth shark using a remotely operated vehicle (ROV), providing unprecedented observations of natural behavior in the deep sea.

Although megamouth sharks are now legally protected in Taiwan, they continue to be encountered as bycatch by commercial and artisanal fisheries. DBRF aims to return to the region to expand tracking efforts, assess population structure and movement patterns, investigate feeding ecology, and work directly with local communities to better understand encounter rates and develop practical conservation strategies for this extraordinary species.