In a new study, scientists have turned their attention to the question of how glass eel larvae in the Sargasso Sea find their way to European coastlines to start their adult lives in the coastal estuaries there.
The life of the glass eel (Anguilla anguilla) is an epic one (and considering its tiny size, the description is an understatement). After hatching in the Sargasso Sea, they travel thousands of kilometres across the Atlantic Ocean. Somewhere between the Canary Islands and northern Norway, they leave the Gulf Stream and swim towards the coast. Some remain in the coastal area, while others move inland into lakes there.
The question that scientists have is how the glass eels instinctively know when to leave the Gulf Stream and which direction to head for.
A new study by the University of Miami (UM)’s Rosenstiel School of Marine and Atmospheric Science in collaboration with the Norwegian Institute of Marine Research's Austevoll Research Station sheds some light on this. Its findings were recently published in the Science Advances journal.
The research team discovered that the glass eels can sense the earth’s magnetic field and then use it to orient themselves towards the coast.
“It is incredible that these small transparent glass eels can detect the earth's magnetic field,” said lead author and UM Rosenstiel School Ph.D. student Alessandro Cresci. “It is also the first observation of glass eels keeping a compass as they swim in shelf waters, and that alone is an exciting discovery.”
“This study is an important addition to our understanding of the mechanisms of eel migration and also to that of other species, if it turns out that their magnetic orientation is similarly controlled by a biological clock,” said senior author UM Rosenstiel School Professor Claire Paris.