[Cyprinodontiformes] Translation : Resultados da prospecção ao lago este fim-de-semana

[www.viviparos.com]

Dear friend Peter,

Here is the translation you have asked :

Dear Friends, 

It’s time to share with you my survey effort on the garden fishpond last
weekend.
It seams that we can count with new exceptional species quite well adapted
to our local climate, besides a few nice surprises.
Allow me also to affirm myself in harmony with Paulo Alves, according to
who, “ any fish who manage to live to tell the tale after 2008/2009 winter
in outdoors facilities, is no doubt skilled to stay alive during any winter
at all in this country “.
This way, it was imperative to complete, as soon as possible, an exhaustive
assessment on the fish resident’s dynamic of the garden fishpond, taking in
consideration the extreme low temperatures of last January, in particular
during a certain period of time.
The survey operation took place last Monday, the February 23rd.
The idea was to drain out all the water and capture as many fish as
possible, filling it up afterwards and replacing fish and plants back again.
Air temperature recorded between 0:00 and 24:00 that day was 7ºC ( 44,6ºF )
and 19ºC ( 66,2ºF ).
Water temperature recorded was 14ºC ( 57,2ºF ) at 6:00 and 15ºC ( 59ºF ) at
18:00.
On the photos enclosed you can see some of species listed next.

Complete list of captured fish :
  
Carassius auratus ( unintentional introduction )
Cyprinus carpio ( Koy )
Cyprinodon alvarezi ( El Potosi )
Heterandria formosa
Oryzias latipes
Skiffia multipunctata
Xenotoca eiseni 

The fallowing species have fail to spot :

Ameca splendens
Aphanius mento ( Elbistan )
Fundulus cingulatus 


In conclusion :

The complete absence of Aphanius mento as well as Fundulus cingulatus was a
colossal surprise. These fish are surprisingly resistant to cold.
The Fundulus cingulatus founder colony introduced last October 2008, was in
fact the same lineage of those raised by Alberto Gil. Such fish are
completely acclimated to our winter in a Northern and colder region of this
country. They are cultivated for some years in smaller outdoors fishponds
all year round.
The somewhat small size of the individuals released on the fishpond, could
have turn them in a fairly easy meal for predators ?
Well… who knows, but if that was the case all Heterandria formosa had long
vanish too.
Even present in a rather small number ( only 23 captured ), the presence of
the “ Least Killifish “ was no doubt the most unexpected good news. The
ancestors of these little fellows were left there for so long, that on my
previous message about this subject, last January 26th, the species was not
even listed. 
Another interesting surprise was Xenotoca eiseni. The survivors were all
young adults and fry. The older fish ( and larger ones ) have all vanish.
Xenotoca eiseni was regarded ( in theory ) as less resistant to low
temperatures than Ameca splendens, so it was a dramatic shock to loose
several hundred fish of all ages belonging to this last species this season,
as they have overcome very well in other years, like in 2007/2008 winter.
Our esteemed colleague Martin R. Tversted, have written on his article “ Low
Temperatures and Cyprinodonts “, that both species can withstand as low as a
limit of 10ºC ( 50ºF ), but the good news is that these Xenotoca eiseni were
able to cope with 5 days below 8ºC ( 46,4ºF ) and overcome the lowest limit
of ever according to my records - 5,4ºC ( 41,72ºF ) – as you can see down
below on this text.
With reference to Martin’s own experience, another admirable surprise was
Skiffia multipunctata, staying alive rather close to the mentioned lower
limits of 7ºC ( 44,6ºF ).
This time it was even possible to capture again the “ old “ female I’ve
mentioned earlier, as you can see in one of the pictures enclosed.
This exceptional fish was the third generation born in my own tanks, and was
capable to prevail over the preceding 3 winters outdoors on this same
fishpond.
Such longevity title holder is the remaining of my earliest colony, spread
by friends when I was forced to give up from all my tanks in Lisbon. Thanks
to her skills, this fish had managed to escape from my attempt to capture
all of her kind on the above mentioned process of giving up fish keeping in
Lisbon.
After this experience, it becomes my “ most wanted “ species in order to
keep some Goodeids on the fishpond for the upcoming.
This was also a nice opportunity to get rid of a few Goldfish ( Carassius
auratus ) introduced with eggs on aquatic plants and a individual escapee
last time I had the opportunity to perform a maintenance procedure on the
fishpond. This species was eradicated this time in order to reduce egg
predation on the other egg layers as well as to decrease resources
competition with other species.
It was also noteworthy the admirable amount of Red Cherry shrimps captured (
Neocaridina denticulata sinensis ), including rape females with lots of
yellowish eggs, besides a remarkable number of very small fry.
Among a considerable quantity of unidentified invertebrate species, a Green
frog or Common frog ( Rana perezi ) tadpole, almost certainly born last
reproduction season, has captured, but no other ones or even frog postures
was still present this year.
Another amphibian species found was the Iberian Painted Frog ( Discoglossus
galganoi ), but merely two animals were spotted.
For the first time this winter an aquatic plant was vanish.
The so called Java moss ( Vesicularia dubyana ? ou Taxiphyllum barbieri ? )
here referenced this way, because it is possibly another species like the
one from Taiwan ( Taxiphyllum alternans ), because the real Vesicularia
dubyana would never support our winter season at all.
There was no more missing plant species so the complete list of flora is
this one :

Elodea canadensis
Egeria densa
Lagarosiphon major
Myriophyllum spicatum
Potamogeton nudosus
Potamogeton pectinatus 


In conclusion, I’ll simply replicate a few passages of my late message on
the subject of this winter low temperatures, sent to the list last January
26th :

Although daily water temperature records at the fishpond have come in to an
end 3 years ago, during extraordinarily extreme weather conditions ( cold or
warm ) I continue to check the thermometer in order to maintain an inventory
for additional reference.

On the extraordinary frozen days during this last January the records of
temperature at the fishpond surface ( 15 cm depth ) are those listed next :

05-01-2009 > 12,3ºC ( 54,14ºF )
06-01-2009 > 10,1ºC ( 50,18ºF )
07-01-2009 > 9,6ºC ( 49,28ºF )
08-01-2009 > 9,2ºC ( 48,56ºF )
09-01-2009 > 7,2ºC ( 44,96ºF )
10-01-2009 > 7,1ºC ( 44,78ºF )
11-01-2009 > 6,4ºC ( 43,51ºF )
12-01-2009 > 5,2ºC ( 41,36ºF )
13-01-2009 > 6,7ºC ( 44,06ºF )
14-01-2009 > 8,3ºC ( 46,94ºF )
15-01-2009 > 10,2ºC ( 50,36ºF )


The coldest day was 9-1-2009, with air temperatures ranging from -1,6ºC (
29,12ºF ) to 5,2ºC ( 41,36ºF ).
If you take a look at my preceding records in
http://www.viviparos.com/Biologia/Lake.htm, please verify that such intense
cold periods are not common at all.
There are two other intense wintry periods moderately comparable to this one
between 1985 and 2006.
If you explore January 1992 and January 2005 data, than you will found the
last cold uttermost periods and the previous lowest temperature record of
5,5ºC ( 41,9ºF ). 
January 2009 unique distinguishing is the fact that, besides a new minimum
extreme, the lowest value did not took place on the coldest day but 3 days
later.
It seams obvious that there was an apparent delay effect as well as a clear
tendency to low down caused by a long period of air freezing.
For future reference we kept also the coldest November of ever ( 2008 ) and
a “ gelid “ January ( 2009 ) with a new low temperature limit, since first
records were registered back in 1985.