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 ANGEL; BARRIGA, JUAN PABLO

HYDROBIOLOGIA

SPRINGER

Lugar: Berlin; Año: 2016 vol. 777 p. 243 - 254

0018-8158

The effects of the introduced rainbow trout (Oncorhynchus mykiss) on both habitat useand diel locomotor activity of the native Creole perch (Percichthys trucha)were assessed. Experiments were performed with juveniles of both species duringa 24-h period. Habitat use was measured in channels with different habitatcategories and diel locomotor activity was registered with an infrared sensor. Bothspecies used mainly cobbles. In the absence of O. mykiss, P. trucha usedmacrophytes and gravel secondarily, during dusk and midnight, respectively. Oncorhynchus mykiss used graveland macrophytes secondarily, during midday. In the presence of O. mykiss, P. trucha increased itsuse of macrophytes and decreased its use of less structured habitats. Percichthystrucha juveniles were more activeduring night. This pattern did not change in the presence of O.mykiss, nor was the intensity ofmovement affected. These results reveal the importance of structuredenvironments for juveniles of bothspecies. In particular, substrates of large size with interstitialspaces in between serve as shelter and reduce visual detection between individuals.Both the association of P. truchajuveniles with structured habitats and their nocturnal activity reducepredation risk.