Seems like “Finding Nemo” should have been more like “The Lost Boys” or “The Outsiders”. Right after birth, baby clownfish stray from home and scientists are playing truancy officers using the distance they travel as an indicator of the effects of reef management.
In reality, the little fry don’t run away, they float away and can travel anywhere from 10 to 13 kilometers over the course of two weeks until their transparent newborn bodies develop their colors and they need to settle on a reef and find their new homes. It’s also known that butterfly fish can travel even farther up to 64 kilometers.
Now researchers are recommending using these distances in marine conservation efforts. Instead of just working on one specific area as a sanctuary, planning should involve ensuring there are other reef areas within those distances to ensure fish populations stabilize and even grow.
“Patches of reef habitat are frequently isolated from each other by deeper water that forms a barrier to adult movement,” noted the research team in Nature Ecology and Evolution. “and so larval dispersal is likely to be a critical process in the persistence of many reef fish populations over demographic and evolutionary timescales.”
This team of international researchers tracked the dispersal of thousands of clown and butterfly fish larvae on coral reefs off New Britain Island in Papua New Guinea. The research involved extensive field sampling at eight sites in Kempe Bay on the north coast of New Britain Island in 2009 and 2014, collecting thousands of fish and then using their DNA fingerprints to match juveniles with potential parents (and thus point of origin). An estimated 90% of Clownfish juveniles settled within 43 km of their parents in 2009, compared with 31 km in 2011.
The research team included scientists from Australia’s Great Barrier Reef Marine Park Authority, James Cook University, University of Queensland and University of Melbourne, as well as the Woods Hole Oceanographic Institution in Massachusetts, the King Abdullah University of Science and Technology in Saudi Arabia and the Insular Research Centre and Environment Observatory in French Polynesia.