Rodrigo A. Torres

Fish and aquatic habitat conservation in South America: a continental overview with emphasis on neotropical systems.

Fish conservation in South America is a pressing issue. The biodiversity of fishes, just as with all other groups of plants and animals, is far from fully known. Continuing habitat loss may result in biodiversity losses before full species diversity is known. In this review, the main river basins of South America (Magdalena, Orinoco, Amazon and Paraná-La Plata system), together with key aquatic habitats (mangrove-fringed estuaries of the tropical humid, tropical semi-arid and subtropical regions) are analysed in terms of their characteristics and main concerns. Habitat loss was the main concern identified for all South American ecosystems. It may be caused by damming of rivers, deforestation, water pollution, mining, poor agricultural practice or inadequate management practice. Habitat loss has a direct consequence, which is a decrease in the availability of living resources, a serious social and economic issue, especially for South American nations which are all developing countries. The introduction of exotic species and overfishing were also identified as widespread across the continent and its main freshwater, coastal and marine ecosystems. Finally, suggestions are made to find ways to overcome these problems. The main suggestion is a change of paradigm and a new design for conservation actions, starting with integrated research and aiming at the co-ordinated and harmonized management of the main transboundary waters of the continent. The actions would be focused on habitat conservation and social rescue of the less well-off populations of indigenous and non-indigenous peoples. Energy and freshwater demands will also have to be rescaled in order to control habitat loss.

New nuclear primers for molecular studies of Epinephelidae fishes

The EPIC strategy was used in the present study in order to develop molecular markers for Epinephelus itajara. Twelve primers were designed for six genomic regions. The results of the study provide a number of appropriate new nuclear DNA markers for future genetic studies in several endangered/overexploited grouper species. The description of these markers will also expand the number of molecular tools available for the reconstruction of the life history of the different grouper species, in particular those in urgent need of effective protection measures.

Inter- and intra-basin phenotypic variation in two riverine cichlids from northeastern Brazil: potential eco-evolutionary damages of São Francisco interbasin water transfer

Intraspecific morphological variation can be generated by a set of historical and ecological processes, and can be induced by anthropogenic actions. One such activity that has large-scale environmental impacts in freshwater environments is interbasin water transfer. Brazil’s Mid-Northeastern Caatinga freshwater ecoregion is going through an interbasin diversion that will link waters from São Francisco ecoregion with the four major basins of Mid-Northeastern Caatinga. Here, we aimed to evaluate the morphological variation of two cichlids, Cichlasoma orientale and Crenicichla menezesi, from both ecoregions and test, whether this morphological variation is related to historical isolation among basins and/or to local water flow regimes, through mtDNA (cytb) and geometric morphometric approaches. Our results showed, for both species, significant morphological differences among basins. However, the comparisons between genetic and morphological differences among basins were not significant. Additionally, a significant shared morphological pattern between species (body depth and mouth position) among different habitats was found. These results reinforce a potential role of environmental pressures upon fish morphology, possibly through phenotypic plasticity. The evolutionary role of morphological responses in freshwater fish populations—especially in variable environments—is discussed, as well as the potential eco-evolutionary damages that might result from the artificial river connection.

Single nucleotide polymorphisms from cytochrome b gene as a useful protocol in forensic genetics against the illegal hunting of manatees: Trichechus manatus, Trichechus inunguis, Trichechus senegalensis, and Dugong dugon (Eutheria: Sirenia)

The identification of mitochondrial DNA polymorphisms is one of the most efficient methods for species differentiation. Genotyping of molecular markers using PCR/RFLP is a reliable, sensitive and inexpensive method for the detection of species specific mutations. The major causes of decline in Sirenia populations are accidental and intentional catches, collisions with boats and habitat loss. The goal of the present study was to identify, in silico, nucleotide mutations in the cytochrome b gene that can be used for the future development of forensic tools capable of using small tissue fragments to discriminate manatee meat from domesticated species meat commonly used as food sources (bovine, ovine, caprine and swine). DNA sequence alignments revealed two polymorphic sites distinguishing the manatee species from domestic species. The present study reinforced the power of cytochrome polymorphisms as powerful markers for species identification, which may be particularly useful for identifying vulnerable/endangered species. The data provided herein also suggest such mtDNA markers as important conservation tools for combating predatory manatee hunting for illegal meat trade in the Americas

Molecular taxonomy of Plagioscion Heckel (Perciformes, Sciaenidae) and evidence from mtDNA RFLP markers for an invasive species in the Paraná river, Southern Brazil

Mitochondrial RFLP markers were developed to examine whether Plagioscion squamosissimus (Heckel, 1840) is invasive in natural environments of the congener P. ternetzi in the Parana river, in southern Brazil. Specimens of P. squamosissimus and of the putative P. ternetzi (Boulenger, 1895) were obtained from the Negro river (Manaus, Amazonas, Brazil) and from Parana river, respectively. Fragments of the cytochrome b gene (900bp) were amplified by PCR and four restriction enzymes (Eco RI, Mbo I, Bam HI and Alu I) yielded the mitochondrial markers. An additional RFLP analysis with a cytochrome b gene sequence of Plagioncion sp. from GeneBank was carried out to validate the prior analysis. No genetic differentiation was found among either sample. While molecular variation in the cytochrome b analysis was no substantial among individuals, the combined analysis was important for demonstrating that there is no evidence for differentiation of the putative sample P. ternetzi from that of P. squamosissimus. The ecological implications of the introduced occurrence of P. squamosissimus, as well as the role of molecular taxonomic approaches for biodiversity studies are discussed.

Are Brazilian cervids at risk of prion diseases

ABSTRACT Prion diseases are neurodegenerative fatal disorders that affect human and non-human mammals. Chronic Wasting Disease (CWD) is a prion disease of cervids regarded as a public health problem in North America, and polymorphisms at specific codons in the PRNP gene are associated with this disease. To assess the potential CWD susceptibility of South American free-ranging deer, the presence of these polymorphisms was examined in Mazama gouazoubira, Ozotoceros bezoarticus and Blastocerus dichotomus. Despite the lack of CWD reports in Brazil, the examined codons (95, 96, 116, 132, 225, and 226) of the PRNP gene showed potential CWD susceptibility in Brazilian deer. Low abundancy of deer in Brazil possibly difficult both CWD proliferation and detection, however, CWD surveillance may not be neglected.

Trends on the Karyotype Acrocentrization Within Carangidae (Perciformes): A New Phylogenetic Evidence About a Traditional Marine Paradigm

Carangidae is a morphologically diverse family of marine fish, characterized by stable karyotypes, predominantly with 2n = 48, composed of acrocentric chromosomes (A). This stability is shared with other families of the order Perciformes, which resulted in the hypothesis that 48A is a plesiomorphic karyotype of the group. We tested this hypothesis in the Carangidae family using comparative phylogenetic methods, investigating the evolution of karyotype characters (including chromosome number, morphology, and number of chromosome arms per karyotype [fundamental number, FN]). Our analyses revealed that 2n = 48 is most likely the ancestral chromosome number for the family. However, an extremely variable number of FNs, always above 48, was observed in basal clades within the family and sister groups. On the other hand, the reduced FN = 48 was consistently observed only in the most derived clades, indicating a tendency for acrocentrization. The number of acrocentric chromosomes apparently was accompanied by a trend of reduction in the genome size (1C-value), suggesting that these changes might be correlated. Our data contradict the marine fish hypothesis that the 2n = 48 acrocentric karyotype is plesiomorphic, at least for Carangidae, and reveal the importance for the correct interpretation of karyotype in a temporal and phylogenetic context.

Diagnostic Cytochrome b gene profiles for the identification of paca (Cuniculus paca) bushmeat: implications for the monitoring of illegal hunting and wildlife trade.

Paca (Cuniculus paca Linnaeus, 1766) is the second largest rodent found in Brazil. The quality of the meat and a long tradition of hunting have contributed to the decline of the natural populations of this species. Hunting of paca is strictly prohibited in Brazil, but in spite of this restriction, no forensic tools are available for the identification of the meat. We describe an efficient method, based on single nucleotide polymorphisms of the cytochrome b gene, that can be used to differentiate biological material derived from paca from those of domestic species commonly used as sources of meat. The identification of the presence of C. paca in the samples was 100% reliable.

Primers for the amplification of the MHC IIβ chain exon 2 in the Atlantic goliath grouper ( Epinephelus itajara )

Abstract In the present study we designed a pair of primers to amplify the exon 2 of the MHC IIβ chain of the Atlantic goliath grouper, which is responsible for the recognition of pathogenic molecules and the regulation of the immune system. Future analyses of this region may provide an important database to understand the evolutionary processes affecting the populations of the goliath grouper, and to predict the conservation perspectives in the species.

New records and distribution extension of Hyphessobrycon itaparicensis Lima & Costa, 2001 (Characiformes: Characidae) in coastal drainages of Sergipe State, northeastern Brazil

The present study reports the first record of the small characid fish Hyphessobrycon itaparicensis Lima and Costa, 2001 in two coastal drainages of Sergipe State, Brazil. This species was collected in three sampling sites from Piaui and Sergipe river basins, both in the hydrographic ecoregion of Northeastern Mata Atlantica. Aspects of habitat, diet composition, phenotypic variation, molecular identification and distribution of H. itaparicensis are herein discussed.