"Simple" question re:fish & currents

unknown at dl.ac.uk unknown at dl.ac.uk
Tue Jan 4 09:14:00 EST 1994


[I don't have the original text, but apparently a question was asked about
the tendency of fish to face upstream.]
I'm not an icthyologist per se, but I am a fisherman, and in streams fish
face almost exclusively upstream, which is *not* necessarily into the
current, where eddies occur.  Another reason for facing upstream is that
food is often carried in the current, and they can see items, and determine
whether or not the item is edible, as it approaches them.  Fish will often
station themselves at the edge of an eddie, where the current is practically
stalled, since this requires less work, and then face upstream to watch for
food in the adjacent (faster) downstream flow.

Positions near to the inlet to a pool (charaacterized by the fastest flow) are
prime, since any food entering the pool appears their first.  Waiting further
from this source would allow other fish 1st chances at entering food.  I
suspect that it is this desire to be near the inlet, and potential source of
food, that is causing the aquarium fish to approach the flow as close as
possible.

Yours,
Paul
schlosser at beta.ciit.org



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