Scientists have captured the first footage of a fish walking backward on the seafloor. A team led by Han Tian of Sun Yat-sen University recorded the behavior of Scalicus engyceros in the South China Sea at a depth of approximately 350 meters using a remotely operated underwater vehicle. This member of the Triglidae family, which is generally found in the western Pacific Ocean and was described in 1872, was known to walk on the seafloor; the new footage shows that it can also move sideways and backward by using its thick, rigid fins.
Researchers observed two more fish from the same family at depths of 350 to 500 meters. The rake-like appendages on the animals’ snouts are thought to help them “smell” prey, while their laterally extended pectoral fins are believed to provide balance. S. engyceros, which has two large eyes, did not react to the vehicle but turned toward the light and moved away. This suggests that the species may not live in darkness for extended periods or may occasionally move into shallower waters. The study was published in Ocean-Land-Atmosphere Research. The researchers said the findings would contribute to understanding the adaptations of deep-sea creatures.
Why it matters
The findings show that movement on the seafloor is not based solely on forward motion and that some fish adapt to their surroundings by using their stiff fins in different directions. This opens up a new area of observation for research examining how deep-sea creatures move and how they adapt to living conditions on the seafloor. The roles of the snout appendages in finding prey and of the pectoral fins in maintaining balance have not yet been conclusively established; the function of these structures remains an open question. The fish’s response to light also requires further research into whether its habitat is limited to deep waters and whether it occasionally moves into shallower waters.