Two day collecting trip to the Anavilhanas confirmed

[dw1305]

Hi all,

The "high" pH is unusual for this area, and very interesting. & The water was so High the igarapes have almost all disappeared in the Amazon.

I think these may be linked, the large amount of rain water would have both diluted the humic acids and tannic substances in the water, and possibly increased the oxygen saturation and CO2 out-gassing due to the faster water flow.

Less CO2, more O2 and a dilution of organic acids would all tend to increase pH.

cheers Darrel

 

[Hudson Ensz]

Yes that is true though it is hard to imagine the entire rio negro changing PH by 1% JK. I have always found the Rio negro to be slightly higher then the Igarapés at almost any time of year.

 

[Hudson Ensz]

Great photos and really interesting to read. You build a wish to travel!

Yeah I did some revisions for my blog post, my original plan was to make three writups but that didn't pan out and I basically copied to my blog (I did improve the grammar and repeated photos though). I am still working on the Full travel report if the ACA or some other nonprofit organization wants it.
Thanks a lot Melanchromis!

 

[dw1305]

Hi all,

Yes that is true though it is hard to imagine the entire rio negro changing PH by 1

It is most likely to be an inaccurate measurement, but I think that it is possible that the pH will be higher during periods of high flow when turbulence will add oxygen and out-gas CO2. The reason for this is that pH is a ratio, and doesn't tell you anything about the amount of H+ ion acceptors (bases) and H+ ion donors (acids).

Both weak acids and salts in solution contribute to the TDS, if you have "water" (technically nearly all "water" is a dilute solution, pure H2O is an electrical insulator and doesn't conduct electricity) with a very low TDS (like these waters, figures in "Spawning areas, dispersion and microhabitats of fish larvae in the Anavilhanas Ecological Station, rio Negro, Amazonas State, Brazil" <http://www.scielo.br/scielo.php?pid=S1679-62252008000400003&script=sci_arttext&tlng=pt>), you know that you have a small reservoir of acids and bases, and that any small change in their amounts will alter the H+ ion acceptors: H+ ion donors ratio, and therefore the pH.

More here:
<http://www.apistogramma.com/forum/showthread.php?11708>

You can substitute any salt or dilute acid for NaCl and HSO4 in this graph.


Even though pH values are often quoted, pH isn't a very meaningful measurement when you are around pH7 (= equal numbers of acids and bases, 10-7 H+ ion conc.) or when you have very low conductivity water.

This is the balance for highly buffered alkaline water, where the pH will be stable.
,
and this is the situation for Rio Negro type water,

where the pH may vary.

Normally the large "tannin and humic acid content" will depress pH, but if a larger volume of water dilutes this, and CO2 is out-gassed, pH will rise.

cheers Darrel

 

[rafael]

Amazing reportage, thanks for sharing Hudson. Your A. paucisquamis male is very very beautiful, enjoy it.

 

[Hudson Ensz]

Thank you Dw, I had to read it a few times but I think I got it!
Thanks a lot Rafael.
Here are a few more photos Mike, can you tell if it is the true A. pertensis for sure or do you need better pictures?

 

[Mike Wise]

I don't see any of these fish being A. pertensis. They are all members of the agassizii-lineage. Note the metallic blue blotch at the corner of the mouth, which is diagnostic for this lineage. All appear to be A. paucisquamis, except the next-to-last photo. The fish in this photo could be any of several agassizii- or bitaenata-group species; just not enough visible diagnostic features showing.

 

[Hudson Ensz]

I didnt post any pictures of the A. pertensis yesterday, I jumped to the conclusion that second to the last foto was of an A. gibbiceps, do you think it is something else?
Here are pictures of what I think is a True Apistogramma pertensis

 

[Mike Wise]

Yes, your pertensis fish look like the true, holotype, form of A. pertensis. The other fish could be A. gibbicep, but like I said, "not enough visible diagnostic features showing".

 

[Hudson Ensz]

Thats OK, anyway I am in Boa Vista, I havent fished at all but I did pass two creeks on ther road going to caracarai about 10 km from boa vista, I will do everything to visit them, it seems to be a bit harder then I expected but I will work on it.

 

[Hudson Ensz]

I am posting most every day on my blog, visit for the latest news... passionate4pikes.wordpress.com

 

[Hudson Ensz]

Caught my first apistos of the trip, more collecting tomorow

 

[Hudson Ensz]

Sorry to post yet again but pictures are up on my blog. I caught a fish wich may be A. wapisana but I havent seen very good pictures of them and... well I cant correctly identify apistos to save my life. If anyone has trouble accessing my site, tell me... I cant even go on.

 

[Mike Wise]

Hudson, I see that you are using a 'rapiche' net. Did you make it yourself? In Peru they use seign nets. In tight quarters, I think the Brazilian rapiche would be a better choice.

 

[Hudson Ensz]

Yes I make them myself, to be 100 percent honest I got the basic idea from Heiko Bleher in one of his articles for TFH. I use PVC pipes and window screen actually and I have never seen another one like it, I am looking for better designs but so far it works pretty good other then breaking a lot.
I fished a lot yesterday but the water was so incredibly muddy that all of the fish are completely washed out but they didnt survive in the bag. For ID purposes my pictures wouldnt help anything I think, no bars, barely any spots, barely distinguishable spangling... In Boa vista the igarapes are dry. Today I will fish in the Rio Caumé and tomorow the type locality of A. rorimae (sp). I have caught two species of apistos so far, rupununis and the other unidentified species.

 

[Hudson Ensz]

A sign of things to come..