Why Carp Facing North-South?

The carp swimming in a bucket at the Czech's traditional markets apparently not arbitrary swimming. They tend to steer their body facing north-south. The scientists suspect this fish are used to determine the orientation of the geomagnetic field, perhaps even help navigate them when swimming.

An example of a photo of carps
 analyzed in the study. (Picture
from: http://www.livescience.com/)

To conduct their study, the team took the picture of carp that are sold in 25 markets in Prague at the Bohemia region in December 2011. The fish was the main course for Christmas celebrations in the country so often found on the market in December.

The team of scientists led by Hynek Burda from the University of Life Sciences in Prague, Czech Republic, it took 817 photos and documented more than 14 thousand fish. The analysis showed that the number of fish, lined up according to a north-south axis far more than that leads to the east-west axis (with a ratio of 1:44). In the narrow barrel, the fish can not see the instructions orientation, such as wind, temperature, light, water, water flow, noise, and vibration. The Czech team's findings show that the carp was relying geomagnetic clues to march.

The tendency towards a particular magnetic orientation has also been documented in many types of animals, ranging from cockroaches, water lizards to cattle and migratory birds. But scientists say the significance of this internal compass remains a puzzle, although it does play a role in synchronization.

Graphic demonstration of the measuring of carps bearings. (Picture from: http://phys.org/)

"The tendency of certain magnetic faces the possibility of supporting the spontaneous formation of groups, movements in the same direction," said Burda and colleagues in a report published on December 5, 2012 of PLoS ONE open access journal. "It may be important to synchronize the movement, including when to swim away from predators and prevent collisions." *** [ EKA | FROM VARIOUS SOURCES |PLOS ONE | LIVESCIENCE | KORAN TEMPO 4082]
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