Mexico 2007 and 2008

[michi tobler]

Hi Dan, sure. I have stocks both at home and on campus. I'm currently in Switzerland but will be back in June. Just drop me an email and stop by.

Hook'em horns (I'm sorry... have a UT past...)

Cheers, m

[dandempsey]

Outstanding! (aside from the UT comment)

I'm a cichlid guy but those live bearers are now becoming an interest. Great fish.

[michi tobler]

Hi Paulo,

I just stumbled over the PDF of the work I mentioned above. As already mentioned, I could not agree more with the authors regarding the status of P. kykesis.

http://globiz.sachsen.de/snsd/publikati ... 45-154.pdf

Cheers, m

[Paulo José Alves]

Hi Michi

Thank you for giving me access to the Poecilia paper. It would be a simpler world for us amateur fish breeders if all ichthyologists agreed in what concerns taxonomy and the correct name for a certain fish.
I take this oportunity to ask you to confirm if the big sailfin species we´re talking about was living in freshwater. Being so that would make her the only sailfin species that lives predominantly, or exclusevely in freshwater. Aparently P. velifera and P. latipinna need in most cases, or allways, some salt in the water.

[Ken Davis]

I've collected a lot of P. latipinna in pure fresh water in both Georgia and Florida, very far inland from the coast, they are smaller bodied and have smaller dorsal fins, but do just fine in pure fresh water. Ken

[michi tobler]

Hi Jose,

yes, to my knowledge P. petenensis is the only sailfin species that occurs outside of coastal areas in pure freshwater. You will find many populations of P. latipinna nowadays that occur outside of coastal plains but these populations are not natural. Both P. latipinna and P. verlifera naturally occur in coastal water with varying salinity. Regarding to P. latipinna, there should be quite some information here: http://faculty-staff.ou.edu/S/Ingo.B.Sc ... etal02.pdf

Cheers, m

[Ken Davis]

I agree they have been seeded into many area and the biggest, best looking fish do come from 100% to nearly so salt water, biggest male P. latipenna I have ever caught were in the ocean around mangroves.

[Paulo José Alves]

Thanks Michi and Ken
Yes I´m aware of the existence of freshwater P. latipinna and once I even had a few from Texas but they did not survive in freshwater. I read that they can replace salt by calcium if the first does not exist in the water but the matter is not very clear.
The variability in this genus does no facilitate things and intermediate characteristics even less. The big sailfin Poecilia that Michi caught are very probably the same species that years ago was considered by some french to be freshwater P. velifera when they were in that area catching fish. The existence of P. mexicana with the tail´s outer area red, like in Michi´s picture, is something new to me, I thought that it had to be yellow., but we are allways learning.

[Marco Arroyo]

Hi Michi, great to hear from you again, and thanks a lot for sharing the spectacular photos you show to us from your trip to the land of Tequila, greetings

[Joe Middleton]

Michi: from where did you catch the loricariid cat? I've heard throught the proverbial grapevine that the fish was introduced into a reservoir that feeds the Usamacinta, hence its later occurrence in the Rio Chacamax (as noted previously by Dan Woodland, herein). I am wondering how far the fish has distributed by now, and, if you have seen its impacts in other biotopes/areas.

[michi tobler]

Hi Joe,

we collected them in various rivers of the Grijalva drainage (Rios Tacotalpa, Puyacatengo, El Azufre etc.). So these fish definitely occur outside of the Usumacinta drainage. Whether there were multiple introductions or the species spread from one spot, I don't know... but there deinitely on the way to conquer southern Mexico. The locals call them peces de diabolo (sorry if I misspelled that). I think that is for a good reason;o)

Cheers, m

[Joe Middleton]

Hi Joe,

we collected them in various rivers of the Grijalva drainage (Rios Tacotalpa, Puyacatengo, El Azufre etc.). So these fish definitely occur outside of the Usumacinta drainage. Whether there were multiple introductions or the species spread from one spot, I don't know... but there deinitely on the way to conquer southern Mexico. The locals call them peces de diabolo (sorry if I misspelled that). I think that is for a good reason;o)

Cheers, m

Well, their recorded presence in the Rio Grijalva doesn't surprise me. It's likely that they managed to swim down the mouth of the Usamacinta and then across the swampy headlands to the Grijalva (some maps show the Grijalva as a tributary of the Usamacinta). Along the way one can readily expect them to wipe out a lot fish due to competing food sources alone. Particularly threatened, I expect, would be any of the small-spawn, rheophilus species like coeruleus, lentiginosus, irregularis, or any of the Thorichthys species. I would not be surprised to find them in the Rio de la Pasion or Rio Candelaria by now, and that means all of the habitats of western Guatemala share a similar fate as that of southern Mexico's.

If the government can be blamed for introducing them as algae control, so be it. Blame won't help here. I just hope that they don't start a largescale tilapia introduction plan to supplant the locals' diet with protein after these monsters decimate the endemic cichlid populations.

[Juan Artigas]

Along the way one can readily expect them to wipe out a lot fish due to competing food sources alone. Particularly threatened, I expect, would be any of the small-spawn, rheophilus species like coeruleus, lentiginosus, irregularis, or any of the Thorichthys species. I would not be surprised to find them in the Rio de la Pasion or Rio Candelaria by now, and that means all of the habitats of western Guatemala share a similar fate as that of southern Mexico's.

Fortunately, Thorichthys and rheophilus like T. coeruleus and T. lentiginosus are invertebrate feeders so are not directly (but indirectly are) competed by Plecostomus. I am not sure about Rio Candelaria, which is not part of the Grijalva-Usumacinta system, but in Rio de la Pasión sooner or later Plecostomus could be found. It just amazes me how we humans are incredibly fast messing up the entire planet. I wonder what follows.

If the government can be blamed for introducing them as algae control, so be it. Blame won't help here. I just hope that they don't start a largescale tilapia introduction plan to supplant the locals' diet with protein after these monsters decimate the endemic cichlid populations.

Joe do you have any data about this?

[Raf.fr]

There are also thousands of these plekos in the "Presa del infernillo" in the Balsas river basin.

They are not appreciated, not because of there impact on the ecosystem but because they get into the nets of fishermen and ruined them!

[Joe Middleton]

Fortunately, Thorichthys and rheophilus like T. coeruleus and T. lentiginosus are invertebrate feeders so are not directly (but indirectly are) competed by Plecostomus. I am not sure about Rio Candelaria, which is not part of the Grijalva-Usumacinta system, but in Rio de la Pasión sooner or later Plecostomus could be found. It just amazes me how we humans are incredibly fast messing up the entire planet. I wonder what follows.

As far as these fish are concerned, I was more worried about their ability to defend their fry.

As far as the data on the reservoir introduction, I think the word came from one of my travelling companions secondhand. I can try to find out more information. Douglas Hutchings, a "man in the field" of sorts, also noted that juvenile plecos were being sold in markets in Puerto Barrios. He asked about their origin and the store owner gleefully stated that they were from Chiapas.

[michi tobler]

... also noted that juvenile plecos were being sold in markets in Puerto Barrios.

That is something I can absolutely confirm. I saw Plecos - as well as many other aquarium fish - being sold in some small towns in southern Mexico. So, it is not a big surprise where they actually came from...

Cheers, m

[Juan Artigas]

Puerto Barrios is actually in northern Guatemala. According to Dr. Salvador Contreras Balderas from the University of Nuevo León (Specialist in exotic fish in México), Guatemala is where the original introduction took place, which is not difficult to believe if you consider the great invasion of Rio Chacamax in such a small amount of time. In less than six months thousands of adults (over 60 cm as reported) plecos had invaded the river where I had previously been in March 2005 and seen none. Rio Chacamax is directly connected to the Usumacinta 60 km down the Chacamax river. The Usumacinta is as close as 50 km. east from Nututum in straight line.

[Dan Woodland]

Here is a video I shot last spring in Nututun near Palenque, Rio Chacamax.

http://www.youtube.com/watch?v=5bK5wg2tZ0U

Dan

[Joe Middleton]

Puerto Barrios is actually in northern Guatemala. According to Dr. Salvador Contreras Balderas from the University of Nuevo León (Specialist in exotic fish in México), Guatemala is where the original introduction took place, which is not difficult to believe if you consider the great invasion of Rio Chacamax in such a small amount of time. In less than six months thousands of adults (over 60 cm as reported) plecos had invaded the river where I had previously been in March 2005 and seen none. Rio Chacamax is directly connected to the Usumacinta 60 km down the Chacamax river. The Usumacinta is as close as 50 km. east from Nututum in straight line.

Puerto Barrios is not in northern Guatemala. It is in eastern Guatemala, almost in the center of the country, wedged in the thin strip of land between Belize and Honduras.

Also, wouldn't the plecos have made the migration through the swampy headlands, to the Laguna de Terminos (some maps show a connection directly from the Usamacinta) and around the periphery in to the Rio Candelaria? It's only a matter of time, methiks.

[Juan Artigas]

You are quite right Joe, I offer an apology for my careless assertion, I don't know why I tend to ignore the Petén as an area of Guatemala. Puerto Barrios is in Guatemala and not in Mexico anyways, which complies with the point of my statement.

Guatemala an Puerto Barrios

guatemala.jpg (33.4 KiB) Viewed 1874 times

As for the hypothesis of Plecos jumping over the low areas between Rio Usumacinta and Ro Candelaria I hardly think this would happen in the short term personally, as even in the remote case the gap would be closed by a flooding connecting Usumacinta and Laguna de Terminos directly, Laguna de Terminos is salty and I am not sure Plecos would enjoy that. In any case, Rio Candelaria is not part of the Usumacinta drainage. I predict there will be people introducing Plecos in the Candelaria river (for any given reason) before this can happen.

I also want to add that aquarium fish are sold in towns in southern Mexico for many years now, I remember visiting aquarium stores in Campeche 26 years ago, and that hasn't necessary result in an inflow of exotics in rivers. Even if they happened, I assume natural systems (especially those as complex as the Usumacinta, I understand that was probably not true in Cuatro Cienegas Churince pond) have certain resistant to such introductions. I believe the Pleco colonization in the Usumacinta river is the result of a large scale accident or introduction, and not the result of an irresponsible or/and ignorant hobbyist doing it.

In any case, we seem to be doomed...