Live
carp floating in tubs at traditional Czech Christmas markets like to align
their bodies north-south, researchers say. The finding suggests the fish use
the geomagnetic field to orient themselves and possibly even navigate through
freshwater.
For
their study, a team of scientists photographed common carp being sold out of
containers at 25 holiday markets in Prague and elsewhere in Bohemia in December
2011. In total, they collected 817 pictures and documented more than 14,000
fish.
An
analysis showed that fish lining up close to the north-south axis significantly
outnumbered those floating over the east-west axis by a ratio of 1.44. In such
cramped quarters, the fish lack orientation clues like wind, temperature,
light, water flow, noise and vibrations. As such, the researchers say their
findings suggest that carp rely primarily on geomagnetic cues to align
themselves.
Posts
