Sticking to the bodies of sharks and other larger marine life is a well-known specialty of remora fishes (Echeneidae) and their super-powered suction disks on their heads. But a new study has now fully documented the “suckerfish” in hitchhiking action below the ocean’s surface, uncovering a much more refined skillset that the fish uses for navigating intense hydrodynamics that come with trying to ride aboard a 100-ft. blue whale (Balaenoptera musculus).
In a study published Oct. 28 in the Journal of Experimental Biology, an international team of researchers studying the unique fluid environments of blue whales traveling off the coast of Palos Verdes and San Diego, CA has reported capturing the first-ever continuous recording of remora behavior on a host organism, using advanced biosensing tags with video recording capabilities.
The study shows the secrets behind the remora fish’s success in hitchhiking aboard baleen whales more than 30 times their size to safely traverse the ocean—they select the most flow-optimal regions on the whale’s body to stick to, such as behind the whale’s blowhole, where drag resistance for the fish is reduced by as much as 84%. The team’s findings also show that remoras can freely move around to feed and socialize on their ride even as their whale host hits burst speeds of more than 5 meters per second, by utilizing previously unknown surfing and skimming behaviors along special low-drag traveling lanes that exist just off the surface of the whale’s body.
Researchers say the study represents the highest-resolution whole-body fluid dynamic analysis of whales to date, the insights from which could potentially be used as a basis to better understand the behavior, energy use and overall ecological health of the species, as well as improve tagging and tracking of whales and other migratory animals in future studies.
“Whales are like their own floating island, basically like their own little ecosystems. …To get a look into the flow environment of blue whales within a millimeter resolution through this study is extremely exciting,” said Brooke Flammang, assistant professor of biology at New Jersey Institute of Technology and the study’s corresponding author. “Through lucky coincidence, our recordings captured how remoras interact in this environment and are able to use the distinct flow dynamics of these whales to their advantage. It is incredible because we’ve really known next to nothing about how remoras behave on their hosts in the wild over any prolonged period of time.”
Until now, scientists studying the symbiotic relationships between remoras and their hosts in their natural ocean habitat have predominantly relied on still images and anecdotal evidence, leaving much of how they go about their renown sticking behavior beneath the surface a mystery.
In their recent investigation, the researchers employed multi-sensor biologging tags with