Conservation Status of the “Piracanjuba” Brycon orbignyanus (Valenciennes, 1850) (Characiformes, Bryconidae): Basis for Management Programs.
Revista Biodiversidade Brasileira – BioBrasil, 7(1): 18-33,
The excessive exploitation of freshwater resources has been caused by many impacts on natural populations, especially on fish. Different factors related to pollution, overfishing, introduction of exotic species, construction of dams, and destruction of riparian vegetation can cause changes on the current populations and interfere with their equilibrium. In this context, Brycon orbignyanus, popularly known as “piracanjuba”, is an endangered fish species affected by overfishing and environmental degradation. The quality of the meat and its aggressive behavior in the practice of sport and professional fishing, occurring concomitantly to continuous changes in the habitat, has resulted in the fast depletion of natural stocks and resulted in its addition to the list of endangered Brazilian fish species. The species has its distribution along the La Plata River basin, which has in its upper parts highly impacted by demographic occupation, dam constructions, and agricultural farm activities in marginal areas. Habitat changes lead the wild groups of this species to shift to less affected regions, being presently restricted to a few far rivers and small tributaries that remain in preserved environmental conditions. In order to obtain a better view of the real situation of B. orbignyanus populations, the aim of this work is the development of effective management programs for the conservation of this species. The article brings together information available in the literature and provides biological and population information about its current geographic distribution, the main threats to the equilibrium in the changing environments of occurrence, the genetic characteristics of populations, and the prospects for use in conservation programs.
Conservation of Brycon orbignyanus natural populations and stocks for their reproductive, genetic, environmental sustainability: A model for species threatened with extinction.
Cien. Inv. Agr. 36(2):191-208. http://dx.doi.org/10.4067/S0718-16202009000200004
Several ecological and climatic factors, especially those related to human activities, have been contributing to the disappearance of natural populations of piracanjuba (Brycon orbignyanus). Due to the importance of these fish to the ecosystems in which they are located and their qualities of fast growth and ability to adapt to controlled environments, producers have expressed increased interest in recent years in using this species, with particular aims of increasing production, and participation in conservation programs. In this study, strategies for the sustainable management of B. orbignyanus are idealized and discussed, with the goals of perfecting the reproductive, genetic, environmental and sanitary management of this species and suggestions for improving monitoring stocks maintained in captivity and natural populations. These strategies can be used as models for other migratory species threatened with extinction.
A phylogenetic analysis of Brycon and Henochilus (Characiformes, Characidae, Bryconinae) based on the mitochondrial gene 16S rRNA.
Genetics and Molecular Biology, 31 (1, suppl): 366-371
The genus Brycon, the largest subunit of the Bryconinae, has 42 valid species distributed from southern Mexico to the La Plata River in Argentina. Henochilus is a monotypic genus, comprising a single species (H. wheatlandii) found in the upper Rio Doce basin. In the present study, partial sequences of the mitochondrial gene 16S were obtained for fifteen species of Brycon and for Henochilus wheatlandii. The results showed that the genus Brycon is paraphyletic, since Henochilus is the sister-group of B. ferox and B. insignis. The most basal species analyzed were the trans-Andean species B. henni, B. petrosus, and B. chagrensis.
The endangered species Brycon orbignyanus: genetic analysis and definition of priority areas for conservation.
Environ Biol Fish 98: 1845–1855. https://doi.org/10.1007/s10641-015-0402-8
Currently, biodiversity is threatened by several factors often associated with human population growth and the extension of areas occupied by human activity. In particular, freshwater fish fauna is affected by overfishing, deforestation, water pollution, introduction of exotic species and habitat fragmentation promoted by hydroelectric dams, among other environmental impact factors. Several action plans to preserve ichthyofauna biodiversity have been adopted; however, these plans frequently cover only a small number of species, and decisions are often made without strong scientific support. This study aimed to evaluate the genetic aspects of wild groups of Brycon orbignyanus, an endangered fish species, using microsatellites and D-loop regions to identify the genetic structure of the samples and to establish priority areas for conservation based on the genetic patterns of this species. The results indicated that the samples showed levels of genetic variability compatible with others studies with Neotropical fishes. However, the results obtained in the analysis of molecular variance (AMOVA) for microsatellites (F ST = 0.258) and D-loop (F ST = 0.234) and the interpopulation fixation index revealed that B. orbignyanus was structured in different subpopulations in the La Plata River basin; the areas with better environmental conditions also showed subgroups with higher rates of genetic variability. Future conservation actions addressing these sites should consider two different management units: the complex formed by the Ivinhema River, Upper Paraná, Camargo Port and Ilha Grande groups; and the complex formed by the Verde River and Sucuriu River groups.