Re: NANFA-L-- Florida Flag fish in pond without aeration

dlmcneely-in-lunet.edu
Wed, 18 May 2005 09:46:18 -0500

this is a good effort-in-obtaining survival data, and it does suggest a
lower limit somewhere around 40 F. However, the fish that ".... were
fine .... " may have been suffering cold stress without it being
visually evident. Fish suffering cold stress, as we know, are more
susceptible to infections than fish living-in-healthy temps. To be
more nearly definitive, a controlled experiment with a series of tanks
at a series of temperatures, and determination of an LT-50, would be
better. In such an experiment, a population of fish is divided into
several experimental groups, with each group exposed to a particular
temperature over a measured period of time, usually 24 hours. Prior to
the experiment, each group is acclimated to the same constant (and
suitable) temperature for a period, usually 14 days. The number alive
in each temperature-in-the termination of the experiment is counted,
and plotted on a graph against temperature. Then the temperature-in-
which 50% would have survived according to the graph is reported as the
LT-50. Of course, the final result will differ depending on
acclimation temperature, and that is something that should be
considered in evaluating the result reported above, too. Fish in the
same cold room but in Ohio might go to a lower temperature before
giving up the ghost than would those in a cold room in Georgia.

But this data point is interesting, since water temps in S. Florida
never reach as low as reported here.

Dave

David L. McNeely, Ph.D., Professor of Biology
Langston University; P.O. Box 1500
Langston, OK 73050; email: dlmcneely-in-lunet.edu
telephone: (405) 466-6025; fax: 405) 466-3307
home page http://www.lunet.edu/mcneely/index.htm

"Where are we going?" "I don't know, are we there yet?"

----- Original Message -----
From: EELReprah-in-aol.com
Date: Wednesday, May 18, 2005 8:47 am
Subject: Re: NANFA-L-- Florida Flag fish in pond without aeration

>
> In a message dated 5/17/05 11:34:25 PM,
> njz-in-clevelandmetroparks.com writes:
>
> << Does anyone know how low of temperatures that they can endure?
>
> >>
>
> I think so. I ran an experiment this past winter. I had several I
> left in an
> outdoor pond because I couldn't catch all of them. I brought some
> into the
> basement and some others into my "cool room" (an unheated storage
> area). I could
> not find any in the pond this Spring. The ones in the heated
> basement did
> fine. Those in the "cool room" did fine down to 40 degrees. When
> it dropped to 37
> degrees in late January they died overnight.
>
> Lee Harper
> Media, PA
> /------------------------------------------------------------------
> -----
> / This is the discussion list of the North American Native Fishes
> / Association (NANFA). Comments made on this list do not necessarily
> / reflect the beliefs or goals of NANFA. For more information
> about NANFA,
> / visit http://www.nanfa.org Please make sure all posts to nanfa-l are
> / consistent with the guidelines as per
> / http://www.nanfa.org/guidelines.shtml To subscribe, unsubscribe,
> or get
> / help, visit the NANFA email list home page and archive at
> / http://www.nanfa.org/email.shtml
>
>
/-----------------------------------------------------------------------
/ This is the discussion list of the North American Native Fishes
/ Association (NANFA). Comments made on this list do not necessarily
/ reflect the beliefs or goals of NANFA. For more information about NANFA,
/ visit http://www.nanfa.org Please make sure all posts to nanfa-l are
/ consistent with the guidelines as per
/ http://www.nanfa.org/guidelines.shtml To subscribe, unsubscribe, or get
/ help, visit the NANFA email list home page and archive at
/ http://www.nanfa.org/email.shtml