OTTURI MarÍa Gabriela
The effects of invasive rainbow trout on habitat use and diel locomotor activity in the South American Creole perch: an experimental approach
OTTURI, MARÍA GABRIELA; BATTINI, MIGUEL ÁNGEL; BARRIGA, JUAN PABLO
Año: 2016 vol. 777 p. 243 - 243
The effects of the introduced rainbow trout (Oncorhynchus mykiss) on both habitat use and diel locomotor activity of the native Creole perch (Percichthys trucha) were assessed. Experiments were performed with juveniles of both species during a 24-h period. Habitat use was measured in channels with different habitat categories, and diel locomotor activity was registered with an infrared sensor. Both species used mainly cobbles. In the absence of O. mykiss, P. trucha used macrophytes and gravel secondarily, during dusk and midnight, respectively. Oncorhynchus mykiss used gravel and macrophytes secondarily, during midday. In the presence of O. mykiss, P. trucha increased its use of macrophytes and decreased its use of less structured habitats. Percichthys trucha juveniles were more active during night. This pattern did not change in the presence of O. mykiss, nor was the intensity of movement affected. These results reveal the importance of structured environments for juveniles of both species. In particular, substrates of large size with interstitial spaces in between serve as shelter and reduce visual detection between individuals. Both the association of P. trucha juveniles with structured habitats and their nocturnal activity reduce predation risk.