Re: NANFA-- Spawning in high water

Jay DeLong (thirdwind_at_att.net)
Sun, 27 May 2001 12:51:56 -0700

<x-flowed>

><< A lot of minnows or darters would be surprisingly
> unaffected, because the hydrology along benthic surfaces may not be as
> altered as we would think. >>
>
>Bruce:
>
>Could you expand on this? I have always wondered how fish stay in an area
>when there is excessive water flow.

Fish associated with the stream's substrate experience little flow relative
to what's going on higher in the water column. This is due to several
factors:
- what's called a "boundary layer", where the friction of the water on the
actual substrate reduces wayer velocity there, creating calmer conditions
- the morphology some benthic fishes have evolved, such as sculpins, with
their streamlined upper bodies which the water passes over and actually
pushes the fish closer to the substrate.
- protection offered by the substrate itself, such as from boulders and
such too large to be moved by water.

--
Jay DeLong
Olympia, WA

/----------------------------------------------------------------------------- /"Unless stated otherwise, comments made on this list do not necessarily / reflect the beliefs or goals of the North American Native Fishes / Association" / This is the discussion list of the North American Native Fishes Association / nanfa_at_aquaria.net. To subscribe, unsubscribe, or get help, send the word / subscribe, unsubscribe, or help in the body (not subject) of an email to / nanfa-request_at_aquaria.net. For a digest version, send the command to / nanfa-digest-request_at_aquaria.net instead. / For more information about NANFA, visit our web page, http://www.nanfa.org </x-flowed>