We are excited to have a guest blogger this week! Field Biologist Jeremy Tiemann and his colleague, M.H. Sabaj-Perez, recently headed down to Brazil for research on the Xingu River and were awesome enough to share their experience with us!
U.S. and Brazilian biologists are collaborating on an inventory of the fishes, mollusks, and crustaceans of the Xingu River, a large tributary of the Amazon River, in the state of Para, Brazil. With funding from the National Science Foundation, we joined other researchers from the U.S. and Brazil and sampled the lower Xingu near Altamira during the month of November 2014. This was the third expedition to the region. This stretch of river includes the area that will be affected by the construction of the Belo Monte Dam complex. During this time of year water levels are at their lowest point and many species of fishes become crowded together making them easier to collect. The goal of the project was to document the diversity of aquatic life and habitats in the various stretches of the lower Xingu prior to its modification by the dam complex.
The rio Xingu is home to an estimated 450 species of fishes and an unknown number of mollusks (mussels and snails) and crustaceans (crabs and shrimps). Sampling consisted of traditional fisheries techniques, and included cast netting, dip netting, seining, gill netting, trotlines, trawling, and hand-picking. Trawling was an effective way to not only collect fishes, but also mussels, sponges, and crabs.
The expedition consisted of three separate outings, and traveling during each outing was either by boats or a combination of trucks and boats. The first outing was from Altamira upstream to the mouth of the rio Iriri (5 days), the second outing was from Altamira downstream to cachoeira do Jericoá, in the heart of Volta Grande (5 days), and the third was at Porto de Moz at the Xingu mouth upstream to the lower-most rapids of Volta Grande. During each outing, two base camps were made from which small groups ventured out to sample. There was one day (2 nights) in Altamira between outings 1 & 2 and 2 & 3 to rest, restock, and change personnel. Each of the outings consisted of 14 scientists who were assisted by 8 local fishermen, boatmen, and cooks.
The expedition netted and preserved about 17,000 specimens of fishes, 4,000 specimens of mollusks, and 100 specimens of crustaceans from nearly 100 sites. These specimens will help document the diversity of aquatic life in the rio Xingu. Fishes collected varied in shape, size, and color from a two-inch Amazon Puffer (Colomesus asellus) to a 4+ foot Redtail Catfish (Phractocephalus hemioliopterus). Below are a few of the fishes collected.
Being near the equator and working over water, the Hoo-Rags were extremely useful in protecting my face, neck, and ears from the intense sun during our project. The Brazilian Hoo-Rag also doubled nicely as the flag during our team photos.