Diet shift of Red Belly Pacu Piaractus brachypomus (Cuvier, 1818) (Characiformes: Serrasalmidae), a Neotropical fish, in the Sepik-Ramu River Basin, Papua New Guinea

Abstract

Introduction of fish species is a globally widespread practice that causes losses of native species and homogenization of diversity within and across continents. Diet assessments are important tools to depict the ecological function of species introduced into novel ecosystem and possible direct and indirect ecological effects. In this study, we compare the diet of Piaractus brachypomus, a mainly frugivorous Neotropical fish, introduced into the Sepik-Ramu River Basin (Papua New Guinea) nearly two decades ago, to that of similar size individuals from Neotropical populations in the Amazon and Orinoco River basins (South America). In contrast to native populations that feed mainly on terrestrial plants and invertebrates, the diet of introduced P. brachypomus is mainly composed of fish remains and aquatic plants, while terrestrial plants are frequently consumed but in relatively smaller amounts. These findings show that P. brachypomus has an inherently plastic diet that can be adjusted when displaced to a novel geographic area. While trophic plasticity increases the likelihood of a species to establish breeding populations after its introduction, it also reduces our ability to predict negative effects on native species.La introducción de peces es una práctica que se extiende globalmente y que causa perdida de especies nativas y homogenización de la diversidad dentro y entre continentes. Los estudios de dieta son herramientas útiles para definir la función ecológica de una especie introducida en un ecosistema nuevo y los posibles efectos directos e indirectos. En este estudio describimos la dieta de Piaractus brachypomus, una especie de pez Neotropical principalmente frugívora, que fue introducida en el río Sepik (Papua Nueva Guinea) hace casi dos décadas; y la comparamos con aquella de individuos de tamaño corporal similar de poblaciones nativas en las cuencas de los ríos Amazonas y Orinoco (América del Sur). En contraste con las poblaciones nativas que se alimentan principalmente de frutas y semillas, plantas e invertebrados terrestres, la dieta de individuos de P. brachypomus introducidos se compone principalmente de restos de peces y plantas acuáticas, mientras que plantas terrestres son consumidas frecuentemente pero en pequeñas cantidades. Estos resultados indican que P. brachypomus tiene una dieta plástica que puede adaptarse cuando la especie se desplaza a un área geográfica nueva. A pesar de que la plasticidad trófica aumenta la probabilidad de que una especie establezca poblaciones reproductivas después de la introducción, también reduce nuestra habilidad de predecir los efectos negativos sobre especies nativas.

New Record of Exotic Fish Red Bellied Pacu, Piaractus Brachypomus (Cuvier, 1818) From Vellayani Fresh Waterlake, Southwest Coast Of India

“…The teeth of Pacu are adapted for cracking open the hard shells of nuts and seeds. Despite being mostly vegetarian during the growth period, the adults will feed on smaller animals such as insects, smaller fish and even mammalian body parts, as pointed by gut content analysis of Red Bellied Pacu from the Sepik-Ramu River Basin, Papua New Guinea (Sandra Bibiana Correa et al, 2015). The stomach content analysis of Red Bellied Pacu revealed that the main food was plants or detritus matters and fruits as per the above mentioned study.…”

Viability of Seeds Consumed by Fishes in a Lowland Forest in the Brazilian Central Amazon

“…Piaractus brachypomus was the only species of Characiformes in which all fish captured had seeds in the digestive tract. A study carried out by Correa, Betancur-R, de Mérona, and Armbruster (2014) showed that fruits and seeds are the dominant items in the diet of this species during the flood period, since young and adult specimens are highly adapted to exploit this food source (Lucas, 2008). The contribution to the seed dispersal by P. brachypomus and C. macropomum was investigated by Anderson et al.…”

Biotic Indicators for Ecological State Change in Amazonian Floodplains

“…Permanent diet shifts among frugivorous fishes have been reported in response to translocation (e.g., Piaractus brachypomus, Serrasalmidae; Correa et al. 2014 ) or hydrological alteration after damming (e.g., Mylossoma duriventre, Serrasalmidae , Brycon gouldingi and B. falcatus, Bryconidae; Albrecht et al. 2009 , Melo et al.…”