Collecting the Chorro de Chorrera River

[duanes]

Yesterday, Danial Atencio, his son Jacob, and I decided to return to the Chorro de Chorrera, a part of the Rio Caimito and Chagres drainage system, slightly west of the Panama Canal to collect.
The river cascades from the highlands in a series of picturesque waterfalls, and eventually flows into the Pacific.
Back in June of 2023 (the last time, we visited), we purposely came back empty handed, the fish we did catch (in my view) were too large to keep, they were very large chupa piedras `(Ancistrus chagresi).
With almost every cast, at least one large pleco was pulled up.

Didn¨t take long to figure out thia day wasn´t going to work for collecting here.



Moving on, we found the Rio Cacoa de Capira, a small stream a few miles down the road,and spent about 2 hours netting there.


We landed 2 juvie Andonoacara cichlids, a Roeboides tetra, and a one fresh water shrimp.


Some days you eat the bar, some days, it eats you.

 

[cockroach]

Are those Roeboides quite common there?

 

[duanes]

Although not as common as Astyanax I have found them spread throughout central and eastern Panama so far, and according to the handbook I use, Freshwater of Fishes of Cost Rica, are found found as far norrth as Mexico.

Similar to the way Andinoacara cichlids have transcended geographic boundaries, both east and west and into Costa Rica.

It´s interesting (to me at least) that ¨some cichlids¨ seem restricted by severly by geographic boundaries,
while the tetras, and Andinoacara are not.
An example would be Darienheros, which I have not found west of the Mamoni river, to the edge of the Darien.
Yet Andinoacara cichlids, the Roedoides tetras abound everywhere.

 

[cockroach]

First of all, you have been to the edge of the Darien. Fish exploration on the wild side!

That is an interesting observation.
Does the water chemistry change that much that the fish must "turn back"? Any rapids or cascades that less agile fish may not be able to traverse?
have you ever seen the breeding habits of the Darienheros? Is it specialized or in a niche way/habitat?
The Andinoacara sound more like Mozambique Tilapia in being ecological generalists.

 

[duanes]

Tilapines have always interested me, the way they are able to to transcend any water type by evolving into adaptive forms that coincide with any habitat.
The Acolapia of soda Lake Natron, that is more alkaline and more saline than the ocean, and has water temps in the 90´F (mid 30s C)

To Iranocichla hormuzensis migrating far north to desert areas in Iran,
to the certain Tilapines that have developed enhanced hemoglobin to cope with hydrogen sulfide burps of certain volcananic lakes, like the Tilapines in Lake Barumbi mbo, and Lake Bermin. Obvious from the orange color.


I don't know if Andinoacara are quite that adoptive, but I have found them at high elevations, in cool, water only a few inches deep, in pH 8.2 water, and large warm water rivers, like the Rio Chagres that gets saline inundations, via the Panama Canal locks (wher pH often hovers above 9) .

Whereas their almost indistinguishable cousin A pulcher (the blue Acara), lives in the acidic, low pH waters of northern S America, and Trinidad.
In my aquarium, A coeruleopunctatus (the Panamanian Acara), will place eggs on a portable leaf, which it can move at the slightest threat of danger.


I have yet to witness the breeding behaviour of Darienheros.