michi tobler wrote: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)
Joe Middleton wrote: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.
Joe Middleton wrote: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 wrote: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.
Joe Middleton wrote:... also noted that juvenile plecos were being sold in markets in Puerto Barrios.
Juan Artigas wrote: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.
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