Lake returning to the Mamoré River

This photo was taken on the banks of the Mamoré, looking across at an oxbow lake as it empties back into the river. We had come to the edge of the big river as part of our survey and reconnaissance around Santa Ana in 2007. When a lake like this one breaks through the bank and pours back into the river, a huge number of fish comes along for the ride, and this fact is not lost on the birds that congregate over the breach, feasting on the fish. The lake is connected to the river for much of the year in the wet season (perhaps December to May), and then is isolated during the dry season (perhaps June to November). These kinds of seasonal changes are obviously important to plants, animals and people today, and they were likely important in the pre-Columbian past as well. This photo was taken on June 14, 2007, with a Canon PowerShot A640.

Finding a fish in the library

picture from newswise.com

On the right is Dr. Donald Stewart of the State University of New York College of Environmental Science and Forestry, who rediscovered a species of giant airbreathing catfish, Arapaima agassizii, but not in a river. Instead, the distinctive fish was found in the first monographs describing the Amazon river, from the early 1800s. The article in the scientific journal Copeia is here. It's a tidy conjunction of library research and field science, when something that can only be found in a few libraries is of use to scholars looking for fish in the field. The next step will be finding the species outside of the library.

Excavating a fish

It's not some kind of Lovecraft-inspired horror, although it was dug up from out of the ground. It is a buchere, or armored catfish, which turned up in excavations in 2011. We actually found two of the fish in one of our excavations, and another one scampering along in the woods. Buchere survive the dry season in Mojos by looking for mud puddles, and they can "walk" on their fins to find another damp spot. Because we were excavating in the ring ditch at Estancita Island, the location was just right for a buchere to spend the winter. Even a small difference in elevation changes the drainage pattern, and therefore the habits of plants and animals.