Lateral migration of fish between an oxbow lake and an Amazonian headwater river

Researchers discovered that fish in Manu National Park, Peru, exhibit strategic lateral migration between Cocha Cashu oxbow lake and the adjacent Manu River during wet season flood pulses. The study found that most exiting fish were gravid, suggesting they leave the lake to spawn in the river or elsewhere, while entering fish had recently spawned and full stomachs, indicating successful foraging before migration. This behavior was consistent across species of similar size. To investigate these movements, the team used a bi-directional funnel trap in the connecting channel during high water interludes over two rainy seasons (2005–2006), capturing 4090 fish from 60 species and analyzing gonadal state and stomach contents.

Osorio, D., Terborgh, J., Alvarez, A., Ortega, H., Quispe, R., Chipollini, V., & Davenport, L. C. (2011). Lateral migration of fish between an oxbow lake and an Amazonian headwater river. Ecology of Freshwater Fish, 20(4), 619–627. Portico. https://doi.org/10.1111/j.1600-0633.2011.00511.x