Population dynamics of two Andean Trichomycterus (Siluriformes: Trichomycteridae) species from Bolivia

Abstract

Abstract The species of Trichomycterus (Siluriformes: Trichomycteridae) are small catfish distributed throughout South and Central America, from Patagonia to Costa Rica, at elevations ranging from sea level to over 4,000 m. In Bolivia, 17 species have been recorded, but information about the status of their populations and their relationship with the environment is unknown. This study addressed the population dynamics of two species (T. cf. corduvensis and T. tiraquae) in an Andean river from the Cochabamba Department in Bolivia, over a hydrological cycle. Monthly abundance, size structure, condition factor (K), and the relationship between abundance and environmental factors were calculated using multiple regressions. Results indicated that T. cf. corduvensis is more abundant than T. tiraquae. The temporal variation in the abundance of both species is related to the hydrological cycle and local factors, without showing a clear habitat preference. Juvenile individuals predominate, and the condition factor did not vary significantly.