Effect of water quality on growth of four fish species in the Iténez basin (Upper Madera, Amazon) Esther López Siangas & Marc Pouilly & Adamit Vallejos & Tamara Pérez & Danny Rejas Received: 12 May 2010 / Accepted: 9 April 2012 # Springer Science+Business Media B.V. 2012 Abstract Fish growth is an indicator of populations’ life conditions that could be used to detect stress due to contamination. In this study, age of fishes of four species (Psectrogaster essequibensis, Schizodon fas- ciatus, Triportheus angulatus and Pygocentrus natter- eri) from the Iténez basin (Upper Madera, Amazon) were estimated by otolith readings, and growth param- eters were estimated by using the Von Bertalanffy Growth Function. Populations of four sites were com- pared in order to detect the effect of natural and anthropogenical water chemistry differences. One of these sites was directly impacted by gold mining ac- tivities whereas the three others were only influenced by mild human activities and presented white or clear waters. Species growth coefficient (K) varied from 0.28 (P. nattereri), to 0.39 (P. essequibensis), 0.69 (S. fasciatus) and 1.71 (T. angulatus). Due to the limited size samples, these values have to be considered as preliminary regional approximation. For S. fasciatus, P. nattereri and T. angulatus, residuals analysis of the growth function showed differences among the three unimpacted sites. However, each species exhibited dif- ferent patterns of growth variations among sites, thus preventing to clearly demonstrate a general effect of water chemistry on the fish growth of these populations. On the contrary, for these three species fish growth appeared weaker in the gold-mining site. Keywords Otoliths . Age reading . Mercury . White water . Clear water Introduction Fish growth is an important ecological parameter that may serve as an indicator of life conditions of organ- isms. Most likely organisms that live in optimal envi- ronmental conditions will grow faster than those resigned to non-optimum or degraded environments. Therefore growth rates might be affected by climatic parameters (Guyette and Rabeni 1995; Black et al. 2008) or water contamination (Forrester et al. 2003). Three main types of water, chemically and biolog- ically different (white, clear and black waters; Sioli 1968), have been identified in the Amazonian rivers. White waters are reputed to be nutrient-rich and bio- logically more productive than clear or black waters, which are poor in nutrients. The influence of water type on fish growth has been scarcely studied in Am- azonian ecosystems. For example, in the Bolivian Amazon, Duponchelle et al. (2007) observed higher growth rates of Pygocentrus nattereri females in white Environ Biol Fish DOI 10.1007/s10641-012-0011-8 E. López Siangas : M. Pouilly : A. Vallejos : T. Pérez : D. Rejas Universidad Mayor de San Simón - Unidad de Limnología y Recursos Acuáticos (ULRA), Cochabamba, Bolivia M. Pouilly (*) Institut de Recherche pour le Développement (IRD) – UMR Borea, MNHN, 61 rue Buffon, 75005 Paris, France e-mail: pouilly@ird.fr