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2010 Expedition to the Upper Ventuari, Venezuela

Overview

Since 2004, when I first discovered the highly distinctive fish fauna that exists above Salto Tencua (the first waterfall and barrier to navigation on the Ventuari River), I planned to explore further up the Ventuari to see how many other undescribed fish communities might await us there. In 2010, I received a grant from the National Geographic Committee for Research and Exploration that allowed me to assemble an expedition to travel even further upriver, this time to the Yekuana community of Cacurí, almost 60 river km past Salto Tencua.

        Joining me on this expedition were fellow ichthyologists Mark Sabaj Pérez (Collection Manager of fishes at the Academy of Natural Sciences), David Werneke (Collection Manager of fishes at the Auburn University Museum), Tiago Carvalho (then completing a PhD at the University of Louisiana, Lafayette), Vanessa Meza-Vargas (from the Museum of San Marcos in Lima, Peru), and José Birindelli (then completing a PhD at the University of São Paulo). Also joining me on this expedition was river ecologist Katie Roach (then completing a PhD at Texas A&M University), with whom I was beginning a study of the nutrient stoichiometry of loricariid catfishes.

        Departing at the end of March, we followed a now familiar route, driving from the University of the Llanos, Ezequiel Zamora to Puerto Ayacucho, then taking a boat to Macaruco at the confluence of the Orinoco and Ventuari rivers before continuing upriver to Salto Tencua. Just reaching Salto Tencua took us over two weeks of travel. To complete the final leg to Cacurí, Oscar, Tiago, Vanessa and I had to ride in a trailor behind a tractor for 8 hours. Once in Cacuri, after meeting with the village council to arrange for a boat and permission to fish, we were finally able to collect – and we were not disappointed. Once again, many of the fishes we collected were new to science, including a likely new genus of cichlid, a new loricariid catfish species in the genus Exastilithoxus and, most spectacularly of all, a new, large, seed-eating species of serrasalmid. 

        Shortly after returning to Tencua from Cacurí, Mark, David, Tiago, and Katie departed via charter flight from San Juan de Manapiare, and they were replaced by José Birindelli. José flew in from Brazil to help Vanessa, Oscar and I continue fishing as we travelled back down the Ventuari and Orinoco to Puerto Ayacucho. From Puerto Ayacucho, we took a side trip by truck to the Caura River to collect a single tissue and specimen of the only species of Chaetostoma from the Venezuelan Guiana Shield: C. vasquezi.

        Specimens collected during this trip are now cataloged at AUM, ANSP, MCNG and MZUSP (field number prefix VEN10), where they continue to benefit ichthyological research. Published papers that have already benefited from collections and observations made during this trip include the following:

Work

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1. Vanessa and Dave guard our pile of luggage at the Valencia airport. 2. Mark and Tiago review specimens at MCNG. 3. Tissuing a number of fish we collected from the Tucupido River near Guanare, where an apparent pesticide spill caused many large fish to be much easier to collect than usual. 4. Group photo before departing on our long drive from Guanare to Puerto Ayacucho. 5. The Ministry of Agriculture fish collection in Puerto Ayacucho. 6. Group photo near the Raudales Autures. 7. Katie collecting water nutrient data among the basalt boulders of the Raudales Autures. 8. Tissuing. 9. Katie continues here ecological data collection into the night. 10. Mark photographs a Dekeyseria in the piece of wood where it was hiding. 11. The aquatic caecilian Potamotyphlus kaupii. 12. Our research vessel the Lupe Melys docked for the night. 13. Taking photos during the magic hour. 14. A rotenone station near the confluence of the Orinoco and Ventuari rivers. 15. Tiago makes his own plaque at Manaca, a sport-fishing lodge on the upper Orinoco. 16. A pile of fish collected via gill net. 17. Loricariid specimens drying in a field oven, to be later ground and analyzed for nutrients. 18. Oscar admires the rack of a fileted Cichla temensis. 19. Team Corroncho. 20. Katie and Vanessa with parrot cichlids (Hoplarchus psitticus). 21. Our hammocks hung in the main lodge of Cacurí. 22. Oscar points to a lure made of a local seed and a hook (23.), which a fisherman from Cacurí was using to fish for an endemic serrasalmid. 24. The Manapiare River at the landing for San Juan de Manapiare. 25. Mark and Dave pack specimens for export. 26. Dave, Mark, Katie, and Tiago board the plane back to Puerto Ayacucho. 27. José in the bow, heading up the Manapiare. 28. Setting a gill net. 29. Tissueing onboard the Lupe Melys. 30. Enjoying the magic hour. 31. José holds up a Hemiancistrus cf. subviridis collected near Samariapo. 32. A few large fish caught by bag-seining the Orinoco main channel near Caicara del Orinoco. 33. José throws his cast net in the Caura River. 34. Vanessa and I with our prize – a specimen of Chaetostoma vasquezi caught in a gill-net drapped around the base of a large boulder. 35. Preparing to give a seminar at UNELLEZ. 36. One last group photo with (L to R) José, Vanessa, me, Oscar, Otto Castillo (Curator of Fishes at MCNG), and Alvaro Cedeño.

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1. Moenkhausia copei, 2. Hyphessobrycon sp., 3. Moenkhausia oligolepis, 4. Exodon paradoxus, 5. Creagrutus phasma, 6. Creagrutus maxillaris, 7. Carnegiella marthae.  8. Pareiodon orinocensis, 9. Characidium cf. declivirostre, 10. Pseudanos winterbottomi, 11. Characidium longum, 12. Characidium zebra, 13. Typhlobelus guacamaya, one of the smallest species of catfishes in the world, 14. Leptocharacidium omospilus, 15. a series of variously amelanistic Ancistrus macrophthalmus, 16. Pseudolithoxus kelsorum Lujan & Birindelli 2011, a new species discovered during this expedition, 17. a juvenile Pellona cf. flavipinnus.

Sponsors

This fieldwork was sponsored by the National Geographic Committee for Research and Exploration grant #8721-09, the Coypu Foundation, and

The Aquatic Critter Inc. 

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