Last week, a new study revealed Chilean devil rays to be some of the oceans' deepest-divers, often taking dives deeper than a mile under the water's surface. The rays' physiology hinted at this discovery, since they do have a retia mirabilia—an organ found in other deep-divers like great white sharks. Following the study's findings, Oceana in Europe's Angela Pauly took a close look at the Chilean devil ray. This blog first appeared on Oceana in Europe's blog.
A few days ago, the Internet was abuzz with news about the Chilean devil ray’s ability to reach previously unknown depths. What a perfect excuse to introduce this species to our readers!
Despite its intimidating name, this mostly solitary creature (though it can be found in groups) is harmless to humans and feeds on small fish and plankton. It can grow to reach 13 feet across and weigh up to 770 pounds!
Because these rays are so often spotted in warmer surface waters, scientists were baffled by the results of a tagging study, which indicated that these rays are capable of descending to depths of over 6,000 feet—at speeds of up to 19 feet per second. It isn’t certain what they are doing for two to three hours in the frigid depths, but the assumption is that they are foraging for fish to feed on.
The tagging for this study took place in Portugal’s Azores islands, where devil rays are known to congregate in the summer. In fact, though its name implies it is located in Chilean waters (which is true), the Chilean devil ray can also be found in other areas of the Pacific Ocean as well as in the Atlantic and Indian Oceans.
Unfortunately, according to the Woods Hole Oceanographic Institution, devil rays are under increased pressure from fishing – particularly from gillnet fleets. They are used for their gill filter plates, which are highly valued, as well as for their meat, cartilage (used as a filler in shark fin soup) and skin.
These mysterious creatures – which have a unique ability to handle warm and near freezing temperatures - still have so much to teach us about their biology and ecology. As with many species and habitats in our vast oceans, there isn’t enough information available about them. Hopefully, this news will spur more studies to ensure their healthy future in marine ecosystems.
Our expedition photographers and videographers have yet to spot one, but we’ve spent a lot of time documenting Portugal’s Gorringe Bank, located between the Azores and the Straight of Gibraltar. If you’d like to take a look at some of the incredible photographs we have of species and habitats in this biological hotspot in the Atlantic, take a look at our albums here and here.