Variation in the carbon isotope composition of Semaprochilodus insignis, a detritivorous fish associated with oligotrophic and eutrophic Amazonian rivers

The Amazonian freshwater fish, Semaprochilodus insignis, varies in carbon isotopic composition during residence in different habitats within its home range. The results indicate that carbon produced in black‐water systems contributes to fish stocks harvested from white‐water systems, and S. insignis populations in the Central Amazonia are more integrated than previously thought.