Administrator’s note: This scientific study tracts the extreme diving (>= 500m) of oceanic manta rays in order to understand the reasons for this behavior.  The study recently appeared in Frontiers in Marine Science.

To read the complete study click here, Deep Diving Behavior in Oceanic Manta Rays…  

From the study:

Deep dives (>= 200m) appear ubiquitous across a wide variety of epipelagic fishes…  The sporadic nature of deep dives in some species raises the question of whether these are simply a version of routine shallow dives or if they serve a fundamentally different purpose. A recent review identified multiple possible explanations for deep diving, including some that have been proposed for shallower vertical movements (e.g., foraging, thermoregulation, surveying the water column) as well as potentially unique functions, such as accessing magnetic gradients for navigation and/or parasite removal). Although deep diving behaviour may have broad ecological significance, since it potentially facilitates energy transfer across trophic levels and connects surface and deep-sea ecosystems, field evidence of the function of deep dives is yet to emerge for many species. 

Potential functions of extreme dives:

Although the precise function of extreme dives remains unclear, their rarity, timing, and characteristics collectively suggest that they are unlikely to be undertaken purely for short-term energetic benefits such as foraging, thermoregulation, predator avoidance, or energy conservation. The most compelling evidence comes from the consistent association between extreme dives (>= 500 m) and subsequent increases in horizontal movement, with rays frequently traveling over 200km in the 72h following extreme dives. This post-dive movement supports the hypothesis that extreme dives serve an informational role, enabling manta rays to gather environmental cues that guide broader-scale movements in offshore habitats. During extreme dives, oceanic manta rays did not prolong bottom time or display foraging-associated behaviours, with these extreme dives comprising ≤3% of recorded days, suggesting minimal direct energetic gain from prey resources.

To know more about Calvin Beale and his work:
 https://www.linkedin.com/in/calvin-beale
 https://www.facebook.com/misoolmantaproject/
 https://www.mantatrust.org/ramp