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Oriented swimming at an angle to light in a schooling characid, Moenkhausia dichrowa Kner
Author(s) -
Levin L. E.,
Belmonte P.
Publication year - 1988
Publication title -
journal of fish biology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.672
H-Index - 115
eISSN - 1095-8649
pISSN - 0022-1112
DOI - 10.1111/j.1095-8649.1988.tb05350.x
Subject(s) - biology , fish <actinopterygii> , constant (computer programming) , channel (broadcasting) , visual angle , orientation (vector space) , shoaling and schooling , optics , geometry , physics , ecology , fishery , mathematics , telecommunications , computer science , programming language
Two groups each of approximately 100 Moenkhausia dichroua , a schooling characid, showed a long–lasting, constant–oriented swimming when placed in a light–centred circular channel. This apparatus consists of a 1–m diameter circular channel illuminated by either a central or a peripheral light system, so that the light angle is constant all around the channel. With the central light at a fixed angle, fish swam for several months in one direction and reversed direction at a certain date. When the light angle was increased by 10° every other day between 0° (horizontal) and 90° (vertical), swimming direction was reversed at a particular angle in each experiment. This response to artificial light suggests that this small schooling fish uses the sun as an orientation clue in its seasonal migrations.