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[Killietalk] RE: Killietalk Digest, Vol 18, Issue 13
Brian, et. al.,
Check the following reference
http://www.cpc.ncep.noaa.gov/products/global_monitoring/precipitation/sesa_1y
rprec.html
It sort of backs up some of what Brian is saying. When we were in Uruguay
this past summer (their winter) it was inconsistent with respect to age of
fish. Along the southeast and eastern coast, by the end of July most of the
fish were full grown and many were pst their prime. As you traveled to the
north and west, in general (liberally used here), the fish were less mature;
however, there were places where water levels had already receded. Our hosts
also explained that rainfall is normally consistent. Brian, what you might
think about is the rate of (pan) evaporation. Even though you are looking in
winter at much drier air, you need kinetic energy to bring about vapor escape
(which summer heating supplies). Another point here is loss of water through
plant transpiration. Obviously if plants are dormant in the winter, you
don't have this process taking place to any great degree.
There is another link to temperatures on a yearly basis but they have changed
the site and I cannot find it quickly.
Dave Koran
Date: Fri, 07 Jan 2005 10:56:28 -0600
From: "Brian R. Watters" <bwatters at sasktel_net>
Subject: RE: [Killietalk] Cool water killis
To: killifish discussion list <killietalk at aka_org>
Martin,
As the "man on the spot" you would know the situation best. When do the
annual pools start to fill in your area and when do the fishes first start
to appear ?
I ask this because the rainfall data for Beunos Aires is as follows:
Jan 93.0 mm
Feb 81.3
Mar 116.9
Apr 89.9
May 76.6
Jun 63.7
Jul 59.1
Aug 65.0
Sep 78.3
Oct 96.6
Nov 88.8
Dec 95.9
There is really not much variation through the year (the distinction between
"wet" and "dry" seasons seems to become more distinct and one goes inland).
However, I do see an obvious relatively low rainfall period during
June-September which corresponds mainly with your winter. The "rainy season"
seems to be from about November to March (during your summer), suggesting
that the annual fishes would start to appear in the pools around
June-August. It would take some time for the water table to rise and form
surface pools, or to noticeably increase the area of the existing pools, and
that might only become obvious late in the rainy season for your area, i.e.
March-April (and, therefore, late in the summer). Is this correct ?
Please understand that I am not disputing what you say - I am merely trying
to understand how these things work in your part of the world.
___________________________________________
Brian R. Watters
University of Regina
Regina, Sask. S4S 0A2, Canada
Ph: (306) 584-9161 (home); (306) 585-4663 (work)
Fax: (306) 585-5433
E-mail: bwatters at sasktel_net
> -----Original Message-----
> From: killietalk-bounces+bwatters=sasktel_net at aka.org
> [mailto:killietalk-bounces+bwatters=sasktel_net at aka.org]On Behalf Of
> Martin Fourcade
> Sent: Friday, January 07, 2005 10:18 AM
> To: killietalk at aka_org
> Subject: [Killietalk] Cool water killis
>
>
> Hi fellows
>
>
> About dry pools on summer:
>
> Well, I guess the Austrolebias pools are dry in
> summer.
> I live in Maschwitz, 47 km to Buenos AIres city(on
> north) and the most clasical biotopes are dry now.
> In some oportunities, the pools dont dry 100%, but the
> water level down a lot and all the fishes die(killis)
> for salt concentrations, hot or some predator, like
> birds and anphibians.
>
> In some oportunities, as Brian says, rains season
> fills the pool agains, with river ups, and the pools
> are "visited" for others fishes, like tetras,
> ciclids,hoplias and livebearers, but they only have a
> small chance to survive, the heat usually dry the pool
> again, in few days.
>
> About the question: all the Austrolebias and
> Megalebias can support cold waters.
> We have find some killis in very cold waters, 2oC in
> Ezeiza is a good example, Megalebias elongatus and
> Austrolebias bellottii.
>
> Pterolebias bokermanni(former longipinnis) can be
> breeded in a 13oc -20 oc without problems.
> Rivulus punctatus can survive under 13oC.
> I has test this one,with a tank outside my house in
> the end of winter(October and September) and they
> supported without problems low weeks temperatures.
>
> All the Austrolebias and Megalebias, love the cold
> waters:-)
>
> Regards
>
> Martin
>
>
>
>
>
>
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