Assessing the impacts of the introduced channel catfishIctalurus punctatususing the comparative functional response approach

Abstract

In the metric “Relative Impact Potential” (RIP), the functional response (FR) of a non‐native species can be compared with that of a native analogue and combined with the species abundance to predict its environmental impact. Here, using the River Guaraguaçu (Brazil) as a case study, this methodology was implemented to identify the impacts of the non‐native channel catfish Ictalurus punctatus (Rafinesque) compared with a native species Rhamdia quelen (Quoy & Gaimard) towards small prey fish. Both species exhibited Type II FRs, but handling times were lower for I. punctatus, resulting in a greater maximum feeding rate in this species. Consequently, an RIP > 1 was found, indicating that I. punctatus represents a superior impact to prey compared with its native analogue. These results demonstrate that I. punctatus is a potential threat to small endangered fish species; therefore, policies to avoid escapes from aquaculture should be created and the abundance of I. punctatus controlled.

Four priority areas to advance invasion science in the face of rapid environmental change

“…For example, prey switching (frequency-dependent predation) is a classical concept that has until recently been virtually ignored by invasion science (Cuthbert et al 2018(Cuthbert et al , 2019. In recent years, the classical functional responsethe relationship between per capita consumption and resource density (Solomon 1949;Holling 1959)-has been adapted and applied to forecasting and explaining non-native species impacts through multi-species comparisons (Dick et al 2017a;2017b;Dickey et al 2018;Faria et al 2019). The rationale for exploring these experimental approaches is that invasion success and impact are often mediated by resource acquisition, a concept at the foundation of many hypotheses in invasion science (Catford et al 2009;Ricciardi et al 2013;Jeschke and Heger 2018) and that is relevant for both animals and plants (Rossiter-Racher et al 2009;Ehrenfeld 2010).…”

Short communication: First record of Arapaima gigas (Schinz, 1822) (Teleostei: Osteoglossomorpha), in the Brantas River, Sidoarjo, East Java, Indonesia

“…Non-native species may have neutral or even beneficial effects on native biota and ecosystems (Cope and Winterbourn 2004;Johnson et al 2009); others become invasive and establish spreading populations that negatively impact the recipient environment and its biota (Mack et al 2000). The entry of non-native fish into local waters can increase the potential threat of extinction in small fish compared to local predator fish in terms of maximum feeding rate (Faria et al 2019). Additive nonnative species will also effect synergizing of ecosystem, a network of beneficial direct and indirect interactions of community, leads to a population burst of current species where high abundance of the non-native species will reduce local populations even extirpating the native population (Braga et al 2017).…”

More of the same: new policies continue fostering the use of non-native fish in Brazil

“…However, C. gariepinus and I. punctatus were never relevant to the Brazilian markets and failed in aquaculture. In addition, these two species escaped from confinement, having environmental impacts on the native aquatic biota of the Atlantic Forest (Weyl et al 2016, Faria et al 2019. Today, C. gariepinus may be found in several Brazilian ecosystems (Vitule et al 2006, Weyl et al 2016, and the same is expected in the case of P. hypophthalmus in the future.…”