Author/Authors :
Sá-Oliveira, Júlio C Ichthyology and Limnology Laboratory - Federal University of Amapa (UNIFAP), Campus Universit ´ ario Marco Zero do Equador - ´ Rod. Juscelino Kubitscheck - KM-02 - 68903-419 Macapa - AP - Brazil , Ferrari, Stephen F Department of Ecology - Federal University of Sergipe - Avenida Marechal Rondon s/n Rosa Elze - 49000-100 Sao Crist ˜ ov´ ao - SE - Brazil , Gentil Vasconcelos, Huann C Ichthyology and Limnology Laboratory - Federal University of Amapa (UNIFAP), Campus Universit ´ ario Marco Zero do Equador - ´ Rod. Juscelino Kubitscheck - KM-02 - 68903-419 Macapa - AP - Brazil , Araujo, Andrea S Zoology Laboratory - Federal University of Amapa (UNIFAP) - Campus Universit ´ ario Marco Zero do Equador - ´ Rod. Juscelino Kubitscheck - KM-02 - 68903-419 Macapa - AP - Brazil , Costa Campos, Carlos E Herpetology Laboratory - Universidade Federal do Amapa (UNIFAP) - Rod. Juscelino Kubitscheck - KM-02 -´ 68903-419 Macapa - AP - Brazil , Gellis Mattos-Dias, Claudio A Instituto Federal do Amapa - Rod. BR-210, Km 03 - s/n - Brasil Novo. 68909-398 Macap ´ a - AP - Brazil , Fecury, Amanda A Departamento de Ciencias Biol ˆ ogicas e da Sa ´ ude - Federal University of Amap ´ a (UNIFAP) - ´ Campus Universitario Marco Zero do Equador - Rod. Juscelino Kubitscheck - KM-02 - 68903-419 Macap ´ a - AP - Brazil , Oliveira, Euzébio Federal University of Para (UFPA) - Campus Guam ´ a - 01 Rua Augusto Corr ´ ea - Guam ˆ a - 66075-110 Bel ´ em - PA - Brazil , Mendes-Junior, Raimundo N. G Cajari River Extractive Reserve - Instituto Chico Mendes de Conservac¸ao da Biodiversidade (ICMBio) - ˜ Rua Leopoldo Machado - 1126 - Centro - Macapa - AP, Brazil , Isaac, Victoria J Fisheries Biology Laboratory - Federal University of Para (UFPA) - Campus Guam ´ a - 01 Rua Augusto Corr ´ ea, Guam ˆ a - ´ 66075-110 Belem - PA - Brazil
Abstract :
The exploitation of resources by closely related species with similar niches may be mediated by differences in activity patterns, which may vary in nycthemeral scale and seasonal scale. Piranhas Serrasalmus gibbus and Serrasalmus rhombeus are Neotropical predators that occur sympatrically in many environments of the Amazon basin. To evaluate the strategies adopted by these two species in a restricted environment (a reservoir), nycthemeral and seasonal samples were made, identifying the composition of the diet and their activity patterns. A total of 402 specimens were collected: 341 S. gibbus and 61 S. rhombeus. Both species fed themselves
primarily on fish, with some seasonal variation being found in S. gibbus during the flood season, when plant material was consumed.
There was considerable temporal overlap in the foraging behavior of the two species, although S. rhombeus presented a bimodal
pattern of abundance over the 24-hour cycle. S. rhombeus was more active during the nighttime, between dusk and early morning,
whereas S. gibbus was active throughout the nycthemeral cycle. These findings indicate low levels of competition between the two species, which allowed for a considerable overlap in nighttime foraging, following distinct nycthemeral patterns of foraging activity and allowing their coexistence.
Keywords :
Resource Partitioning , Piranhas , Serrasalmus gibbus , Serrasalmus rhombeus , Amazonian Reservoir
