An Odyssey of Thousands of Miles!
The migration of the European eel (pictured above) from their freshwater habitats in Europe to their spawning ground in the Sargasso Sea is one of the unsolved mysteries in animal navigation.
Imagine having to travel thousands of kilometres without a GPS, a compass or a map. Unimaginable! Getting lost is most certain. So how do the European eels (Anguilla anguilla) travel more than 6000 kilometres from their coastal habitats in Europe to their spawning grounds in the Sargasso Sea near the Bahamas every winter?
For years scientists have speculated that the eels may be using the Earth’s magnetic field as a navigational guide for their journey. However, it was not until recently an article published by Durif et al (2013); “Magnetic Compass Orientation in the European Eel,” strongly supported this idea.
To test the ability of eels to orient using a magnetic field, four different experiments were conducted. Experimenters created an artificial magnetic field that had the same magnetic field strength as the Earth’s magnetic field in a test tank. In each experiment, the magnetic North was either set at the geographic North, South, East, or West and then eels were transported from a holding tank into the test tank.
It was found that the eels oriented in a particular direction with respect to the magnetic north for different temperature ranges. At lower temperature (under 12°C), their orientation relative to the magnetic North corresponded to the direction of their displacement from the holding tank while at higher temperatures (12°C–17°C), eels showed bimodal orientation along an axis perpendicular to the axis of their displacement. (Durif et al, 2013). While this experiment provided some insights as to how eels might be navigating their way to their spawning grounds, other observations have been conducted to further study the journey that these eels undertake every winter. Another article,“ The Intricate Mating Migration of the European Eel,” (Brett Israel, 2009) talks about one such observation conducted where satellite tags that recorded location, speed, depth and direction in which the eels swam were placed on the eels to observe their migration patterns.
Durif CMF, Browman HI, Phillips JB, Skiftesvik AB, Vøllestad LA, et al. (2013) Magnetic Compass Orientation in the European Eel (Anguilla anguilla). PLoS ONE 8(3): e59212. doi:10.1371/journal.pone.0059212 URL:
“The Intricate Mating Migration of the European Eel,” by Brett Israel. Discover Magazine, 25 September 2009 URL: http://blogs.discovermagazine.com/80beats/2009/09/25/the-intricate-mating-migration-of-the-european-eel/ (accessed on 4 April 2013)
“European Eel,” by Judith Hartl. Mediacentre.dw.de: Endangered Species. URL: http://mediacenter.dw.de/english/pictures/item/145085/Endangered_plants_and_animals/ (accessed on 4 April 2013)