WASHINGTON (AFP) - In the movie "Finding Nemo," a baby clownfish swims across the ocean to find his way home after getting lost - his father in hot pursuit. In reality, the babies actually do make such long journeys to survive, researchers have found.
In their first days of life, clownfish larvae can swim up to 400 kilometres in order to find a home, said the study out on Wednesday in the journal PLOS ONE.
"That's an epic journey for these little dudes," said co-author Stephen Simpson from the University of Exeter. "When they make it back to the reef, they're only a few millimetres long and they have only a few days to make it there so they must be using ocean currents to assist their migration."
Indeed, researchers studying the fish off the waters of Oman saw that there were just two coral reef systems along the coast, separated by 400 kilometres of ocean.
Divers collected tissue samples from almost 400 clownfish, by taking a small fin clip for DNA analysis before releasing the fish again. They used DNA fingerprinting to identify fish that were migrating from one population to another, and found that six percent of the fish sampled had made this long journey.
"In order to persist, fish must be migrating between these two populations," Simpson said.
Researchers said that much like in the 2003 Disney movie, clownfish live most of their adult lives in anemone. They also rely heavily on ocean currents to take them from place to place.
Most of the migrant fish travelled from north to south, corresponding with the dominant ocean currents in the region that are driven by the winter monsoon. But unlike in the movie, their travels only take place when the fish are tiny.
Researchers said the findings will help establish marine protected areas and has added to scientists' understanding of how fish adapt to their environment.