Mário Luís Orsi

Introdução de espécies de peixes por escapes acidentais de tanques de cultivo em rios da Bacia do Rio Paraná, Brasil

Species composition and abundance of fishes that escaped from aquaculture facilities during catastrophic flooding in the Paranapanema and Tibagi rivers, in January, 1997 was estimated. In all , 1,292,000 adult individuais belonging to 11 species and 1 hybrid, were introduced into these rivers; only one species was native. The disaster is attributed to the illegal occupation of the river banks, and the non observance of standard measures designed to avoid escapement.

Analysis by RAPD of the genetic structure of Astyanax altiparanae (Pisces, Characiformes) in reservoirs on the Paranapanema River, Brazil

In this study, the RAPD technique was used to analyze the genetic structure of populations of the fish Astyanax altiparanae (Characidae, Tetragonopterinae) living in the lower, middle and upper Paranapanema River, Brazil. The aim was to assess this structure regarding fish handling and conservation programs. The genetic variability (P) was found to be 42.64%, 75% and 75% in the low, middle and upper reaches, respectively. The dendrogram of genetic similarity, obtained by comparative analysis of the sets of samples from the three sites, showed the formation of three clusters. All of the genetic parameters used indicate that the population in the lower Paranapanema is genetically different from those in the middle and upper sections. The theta P test shows that the low Paranapanema is highly differentiated from the middle (0.2813) and upper (0.2912) Paranapanema, while the differentiation between the last two is moderate (0.0895). The data obtained in the present work suggest that recolonization and conservation studies should not be focused on the species A. altiparanae as such, but on the conservation units, because they are the genetically differentiated populations.

Biologia populacional de Astyanax altiparanae Garutti & Britski (Teleostei, Characidae) do médio Rio Paranapanema, Paraná, Brasil

This study was carried out with the following objective: determine the Astyanax altiparanae population structure. Four localities in the Paranapanema river basin were chosen (low Tibagi river) with distinct environmental characteristics. Sampling was carried out monthly from January 1997 to February 1998. A total of 1553 individuals were captured with constancy in all the river extensions, with greatest abundance in the Congonhas river (76%). There was variation among the river extensions in the development phase, length class and spatial distribution of the captured specimens, showing that the species has a differentiated population structure although with similar growth. Therefore, the results suggested that the species has a great adaptive capacity to exploit and using differentiated strategies in terms of population structure. This showed that the species has a strong tendency to r strategic behavior. It showed, however, preference for developing all its biological cycle at the Congonhas river first extension. This was probably due to environmental conditions favorable to the maintenance of the specie.

Ocorrência e ecologia trófica de quatro espécies de Astyanax (Characidae) em diferentes rios da bacia do rio Tibagi, Paraná, Brasil

Stretches of the Rivers Fortaleza, Iapo and Tibagi were monthly sampled with gillnets of different mesh sizes and castnets from May 2001 to April 2002 in the Tibagi River basin. Specimens of four species of the Astyanax genera were captured. In order to assess how they use habitat and food resources in the different rivers, their constancy was calculated and the number of specimens was compared by using the Bray-Curtis similarity analysis. The composition (percentage) of food items consumed was ordered by using the Principal Components Analysis (PCA). The proportion of different food items in the diet was assessed and classified according to type (animal or plant material) and origin (allochtonous or autochtonous). The low similarity and constancy showed differences in the type of habitat preferred by the four fish species. Astyanax altiparanae Garutti & Britski, 2000 and A. fasciatus (Cuvier, 1819) were present in the large rivers but were constant only in the Tibagi River. Astyanax eigenmanniorum (Cope, 1894) was present in all rivers but prefers habitats in the mouth of affluents of large rivers. Astyanax scabripinnis (Jenyns, 1842) was restricted to Fortaleza River, a small Tibagi River affluent. The number of food items consumed by the different species varied from 11 to 23. Among the main food, three items were common for the four species: 1- plant residuals (leaves and seeds from the earth community of plants), 2- insect residuals (from different origins and unidentified) and 3- aquatic vegetation. So plants and insects were the main food consumed by all the species. Astyanax eigenmanniorum showed the highest distinction in the diet composition among the species studied. Such distinction was due to its ability of exploring an abundant food resource: the aquatic plants that were consumed together with portions of coal/sediments near the rocky shores at the Iapo River. The similarity of the origin and type of food consumed by the four species and the differences in terms of the habitat occupied may explain why one species is abundant and constant in only one of the river stretches studied.

Fish passage ladders from Canoas Complex - Paranapanema River: evaluation of genetic structure maintenance of Salminus brasiliensis (Teleostei: Characiformes)

The aim of this study, utilizing RAPD techniques, was to determine the genetic variability of Salminus brasiliensis groups collected at passage ladders of the hydroelectric plants (HEP) Canoas I and Canoas II - Paranapanema River (Brazil), as well as to estimate the population structure through different parameters of genetic diversity. The data obtained allowed us to conclude that S. brasiliensis of the Canoas Complex has a moderate index of genetic variability ( > 42.00%) when compared to that of other migratory fish species. All genetic diversity analyses (distance = 0.015 and genetic identity = 0.985, FST =0.018, AMOVA) were signs of low genetic differentiation, and they led to the clustering of S. brasiliensis from Canoas I and Canoas II. This suggests that the species is genetically structured as a single population. Some findings indicate that this population of S. brasiliensis comes from the Capivara Reservoir (Canoas I downstream), probably fed by the Tibagi and Cinzas Rivers. Literature data denote that after fish transposition by passage ladders of the Canoas Complex, the migratory species are not concluding the reproductive cycle. This mechanism, therefore, could be one more impact factor causing the depletion in downstream recruitment, which could in medium and long term be compromising the natural S. brasiliensis population in the middle Paranapanema River.

Diversidade de peixes do reservatório da UHE Escola Engenharia Mackenzie (Capivara), Rio Paranapanema, bacia do alto rio Paraná, Brasil, e a importância dos grandes tributários na sua manutenção

As especies foram coletadas em quatro trechos ao longo de um gradiente formado pelo reservatorio UHE Escola Engenharia Mackenzie (Capivara). A diversidade de especies foi analisada pela constância, indice de Shannon-Wiener e similaridade da composicao entre trechos atraves do coeficiente de Jaccard. O reservatorio tem uma riqueza de peixes composta por 67 especies incluidas em 5 ordens; 47% das especies sao constantes, 15 % sao acessorias e 28% sao acidentais. Os maiores indices de diversidade de Shannon-Wiener e similaridade de Jaccard foram obtidos em Cinzas e Tibagi, que sao os trechos mais distantes da barragem e que apresentam grandes tributarios. Os menores indices foram encontrados em Cruzalia e Porecatu, os quais correspondem aos trechos com caracteristicas, respectivamente, de ambientes lotico e semi-lotico. Este trabalho demonstra a extrema importância da presenca dos tributarios para a manutencao da diversidade das especies em um reservatorio, em funcao da preservacao das caracteristicas originais do sistema lotico naqueles trechos e consequente reducao do impacto do represamento.

Removing the abyss between conservation science and policy decisions in Brazil

The executive and legislative branches of Brazilian government have either proposed or taken a variety of initiatives that threaten biodiversity and ecosystems. Opposition by the scientific community has largely been ignored by decision-makers. In this short essay, we present recent examples of harmful policies that have great potential to erode biodiversity, and we suggest ways to communicate scientific knowledge to decision- makers. If the current gap between conservation science and policies is not filled, the country will threaten the maintenance of its natural capital and, consequently, the sustainability of essential societal activities in the long term.

Dispersão de Lernaea cyprinacea (Linnaeus) (Crustácea, Copepoda) na região norte do estado do Paraná, Brasil

Inside of the parasitoses context in fish, the study was successful to us verified the lerniose was present in the north area of the State. It had reached the native fish in the basin of the river Tibagi. For the study, visits were made to the aquaculture and samples collected in the area of Sertanopolis on the river Tibagi. We verified that the lerniose was growing in the area and had already reached several species of native fish of the river Tibagi. This concein for ali the researchers of the area, as well as the producers of fish.

Atividade alimentar de espécies de peixe do rio Tibagi, relacionada com o desenvolvimento de gordura e das gônadas

The fish assemblage in a stretch of Tibagi river was studied during the period of one year, throught monthly sampling. It was observed that four fish species (Schizodon intermedius Garavello & Britski, 1990, Acestrorhynchus lacustris Reinhardt, 1874, Pimelodus maculatus Lacepede, 1803 and Steindachnerina insculpta Fernandez-Yepez, 1948) were very frequent and they represent all the main trophic groups. In order to characterize feeding activity, fat storage and reproduction the means degree of repletion, fat and maturation, obtained for each species in each month were compared among the four fish species. Steindachnerina insculpta, a detritivovous species was the one with the highest feeding activity while A. lacustris, a piscivorous fish, showed the lowest feeding activity. For these two species it was clearly observed a sequence of events: higher feeding activity followed by higher fat storage followed by reproduction, that was not observed for P. maculatus and S. intermedius. The variations in feeding activity and fat storage showed by P. maculatus and S. intermedius might be related to their diets.

The “Tilapia Law” encouraging non-native fish threatens Amazonian River basins

Freshwater ecosystems in Brazil, arguably the most diverse on the planet, have been disturbed by several threats in the past years, particularly competition for water and subsequent water abstraction, urbanization, severe drought, dam construction/water diversion, pollution from different sources, commercial exploitation, and the introduction of non-native species (Agostinho et al. 2005; Vitule et al. 2015; Lima et al. 2015; Winemiller et al. 2016). A worrying example is the federal law 5989/2009 that intends to naturalize non-native fish species by decree in Brazil, some of which have a high invasion potential, such as the carps Aristichthys nobilis, Ctenopharyngodon idella, Cyprinus carpio, Hypophthalmichthys molitrix and tilapias Oreochromis spp. (Lima et al. 2012; Vitule