Whenever night falls, baby rosefish in Surabaya can always find their way home because they can feel the Earth's magnetic field. New research suggests that the animal's built-in "compass" helps them navigate when they are not guided by the sun and starlight.
Professor Mike Kingsford from the ARC Centre of Excellence for Coral Reef Research at James Cook University in Australia wanted to know why baby rosefish in Surabaya would always be able to find their way home at night. So he worked with colleagues from Germany to study the finger-sized creature.
Professor Kingsford said: "This study is the first clear demonstration that baby reef fish have the magnetic sensing ability to navigate for them at night. Until then, we only knew that adult birds, marine mammals, sharks, and bonefish had this innate sense of direction. ”
The research team collected less than a centimeter-long Surabaya rosefish from a tree island in the Great Barrier Reef. They tested the fish's ability to navigate in complete darkness but with a magnetic field similar to that of corals. As Kingsford explains, the fish generally navigate in a southeasterly direction, but when the team changed the magnetic field 120 degrees clockwise, the fish's swimming direction also changed, and they all turned west and were confident that they were still on track. This suggests that the animal is able to sense magnetic fields and use them to navigate.
Kingsford added: "We learned from previous research that once they approach their target, they begin the homing process, which relies on smells, sounds and signposts to find corals and settle on them. ”
Coral fish, such as the Surabaya rosefish, hatchery is Coral. They then spend days to months in the open sea growing and looking for new corals to use as a place to settle, or returning to their homes. Once they reach a coral somewhere, they stay here for the rest of their lives.
The study tells us that these baby fish have brains, they know they're going there, and they're very strong swimmers. As a result, they can control which coral they live in, rather than just being guided by ocean currents.
Once scientists know this, they will be able to develop a more accurate model of the swim direction of Surabaya rosefish babies and find better ways to protect them.