Armando César Rodrigues Casimiro

Reproductive Aspects of Moenkhausia intermedia Eigenmann, 1908 (Pisces, Characidae) in the Upper Paraná River Basin, Brazil

The aim of this work was to determine the reproductive tactic of the population of Moenkhausia intermedia, inhabiting the Capivara Reservoir, lower Paranapanema River. Four different stretches of the reservoir were selected, and sampling was carried out quarterly, in the period from 2001 to 2004. Fish were captured utilizing gill nets, cast nets, and seine nets. Later, fish were identified and measured and had their sex identified. Here we describe sex proportion, standard length at first maturation (𝐿50), site and period of spawning, fecundity and type of spawning. The population showed an effective reproductive activity in the area, with the number of females higher than males and 𝐿50 corresponding to 6,1 cm and 5,5 cm, respectively. A greater intensity of spawning occurred in the warmest months. Reproductive activity was identified in all stretches studied, and the absolute fecundity average was 9611 oocytes per gonad, and the mean relative fecundity corresponded to 1065 oocytes/grams.

Biodiversity: is there light for native fish assemblages at the end of the Anthropocene tunnel?

Despite the environmental, political, social and financial problems arising from invasive species, Brazilian public actions and policies have often only emphasized the positive aspects of fish introductions. In the context of native species significant problems arise: is there any spark of light for native fish assemblages? In a river such as the Paranapanema, which is very important in the Paraná River basin, the effects caused by cascades of dams and reservoirs (11 in total) are difficult to measure, and create opportunities for new biological invasions. In the past three decades, the topic of introduced species has emerged and acquired more attention in the media and has relevance for national environmental agencies. The issue expanded after the Paraná State published in 2007, and then recognized in 2009, the first list of invasive non-native species in the country (Instituto Ambiental do Paraná, 2009). This list initially covered 54 species of flora and 69 species of fauna. In 2014, biological invasion researchers provided more information and reviewed the list, resulting in an updated version published in 2015 (Instituto Ambiental do Paraná, 2015). This update includes 71 plant species and 140 animal species, of which 75 are fishes (Instituto Ambiental do Paraná, 2015). The number of fishes is noteworthy because it represents an increase of 226%. This drastic modification is worrying researchers because many incorrect decisions are being made, considering mainly only the direct economic aspects of introductions and disregarding long-term environmental and public aspects (Pelicice et al., 2014). An example is the Bill PL 5989, which seeks the naturalization of non-native species with known negative effects. Another issue is the construction of fish transposition

First record of non-native hybrid catfish Pseudoplatystoma reticulatum × Leiarius marmoratus in the Upper Paraná River basin, Brazil: first record of non-native hybrid catfish

The aim of this study is to report the presence of a three non-native hybrid long-whiskered catfishes (family Pimelodidae) in the Upper Paraná River basin, Brazil. Genetic analyses demonstrated that the three presumptive hybrids were a result of the crossbreeding of Pseudoplatystoma reticulatum (central Amazonas River basin and Lower Paraná River) and Leiarius marmoratus (Amazonas, Essequibo and Orinoco rivers), producing a hybrid commonly known in Brazil as cachandiá. The potential threat to biodiversity, due to possible genetic contamination, competition and predation of wild stocks, of such artificially produced hybrid fishes is discussed.

The same old mistakes in aquaculture: the newly-available striped catfish Pangasianodon hypophthalmus is on its way to putting Brazilian freshwater ecosystems at risk

In the state of São Paulo in southeastern Brazil, a dangerous decree allows the culture of hybrids and non-native extralimital fish species in the Paraná and East Atlantic River basins. We recorded the illegal importation and sale of the non-native striped catfish Pangasianodon hypophthalmus in northeastern, central-western, southeastern, and southern areas of the country. This species is already consumed across Brazil and is cultivated for ornamental purposes. Besides escapes from fish farms and ‘fish and pays’, P. hypophthalmus can reach natural environments through aquarium dumping and ornamental ponds, motivated by its large size that reach after being sold at small size. The species has been introduced in many countries, and if established in Brazil, could put native Brazilian biodiversity and ecosystems at risk. Although importing specimens of P. hypophthalmus is prohibited by law, Decree 62.243/2016 in the state of São Paulo creates a new opportunity for invasion. In fact, once a novel fish species is moved to a new continent, it is irrational to supposed that it will stay static just in the area for which it was intended. In general, the fish disperse in the novel area on their own, by escapes from captivity or deliberate and illicit releases by persons or associations. The unwise attitude of Brazilian decision-makers and lay people in their attempt to develop aquaculture with non-native species goes against the objectives of responsible aquaculture based in native species.