Browsing by Autor "Guillain Estivals"

Now showing 1 - 4 of 4

Exceptional Genetic Differentiation at a Micro-geographic Scale in Apistogramma agassizii (Steindachner, 1875) from the Peruvian Amazon: Sympatric Speciation?
(Springer Science+Business Media, 2022) Guillain Estivals; Fabrice Duponchelle; Carmen Rosa GARCÍA-DÁVILA; Uwe Römer; Cédric Mariac; Jean‐François Renno
Species‐level ichthyoplankton dynamics for 97 fishes in two major river basins of the Amazon using quantitative metabarcoding
(Wiley, 2021) Cédric Mariac; Jean‐François Renno; Carmen Rosa GARCÍA-DÁVILA; Yves Vigouroux; Eduardo Mejia; Carlos Angulo Chávez; Diana CASTRO-RUIZ; Guillain Estivals; Christian Nolorbe; Aurea Rosa GARCÍA-VÁSQUEZ
The Amazon basin holds the world's largest freshwater fish diversity. Information on the intensity and timing of reproductive ecology of Amazonian fish is scant. We use a metabarcoding method by capture using a single probe to quantify species-level ichthyoplankton dynamics. We sampled the Marañón and the Ucayali rivers in Peru monthly for 2 years. We identified 97 species that spawned mainly during the flood start, the flood end or the receding periods, although some species had spawning activity in more than one period. This information was new for 40 of the species in the Amazon basin and 80 species in Peru. Most species ceased spawning for a month during a strong hydrological anomaly in January 2016, demonstrating the rapidity with which they react to environmental modifications during the breeding season. We also document another unreported event in the Amazon basin, the inverse phenology of species belonging to one genus (Triportheus). Overall larval flow in the Marañón was more than twice that of the Ucayali, including for most commercial species (between two and 20 times higher), whereas the Ucayali accounts for ~80% of the fisheries landings in the region. Our results are discussed in the light of the main anthropogenic threats to fishes, hydropower dam construction and the Hidrovía Amazónica, and should serve as a pre-impact baseline.
The Amazonian dwarf cichlid <scp><i>Apistogramma agassizii</i></scp> (Steindachner, 1875) is a geographic mosaic of potentially tens of species: Conservation implications
(Wiley, 2020) Guillain Estivals; Fabrice Duponchelle; Uwe Römer; Carmen Rosa GARCÍA-DÁVILA; Etienne Airola; Margot Deléglise; Jean‐François Renno
Abstract Assessing biodiversity and understanding how it works is a prerequisite for species conservation. The Amazon basin is one of the main biodiversity hotspots where fish are heavily exploited for ornamental purposes. The ornamental trade heavily exploits the genus Apistogramma , which is one of the most species‐rich among Neotropical cichlids with 94 formally described species. This number is certainly underestimated owing to the limitations of conventional taxonomy, which is still too often based solely on morphological criteria and sometimes on few individuals. Most species of this genus have a high degree of endemism and are highly prized on the ornamental market, which could put them at risk. A few species are supposed to have extensive distributions, and in particular Apistogramma agassizii , present from the Amazon estuary up to the Ucayali and Marañon rivers in Peru. This study assessed the taxonomic status of 1,151 specimens of A. agassizii collected from 35 sites around Iquitos in the Peruvian Amazon. On the basis of molecular analyses (nuclear and mitochondrial DNA) and mate choice experiments, at least three biological species within the nominal A. agassizii were evidenced in the sampling area, which is extremely small compared with the known distribution of the species as initially described. According to the molecular calibrations, these three species would have diverged during the Plio‐Pleistocene. Two of them seem to be endemic from small sub‐basins, one from the Nanay River and the other from the Apayacu/Ampiyacu systems. A possible scenario that may explain the evolutionary history of these species is proposed. The conservation implications of these results on the estimation of the diversity of A. agassizii , of Apistogramma species in general, and of other Amazonian cichlids are discussed.
Using barcoding of larvae for investigating the breeding seasons of pimelodid catfishes from the Marañon, Napo and Ucayali rivers in the Peruvian Amazon
(Wiley, 2015) Carmen Rosa GARCÍA-DÁVILA; Diana CASTRO-RUIZ; Jean‐François Renno; Werner Chota-Macuyama; Fernando M. Carvajal‐Vallejos; Homero Sánchez; Carlos Angulo Chávez; Christian Nolorbe; Jhon Alvarado; Guillain Estivals
Amazonian ichthyofauna has one of the richest specific diversities on earth. However, life history strategies of most species remain poorly-known owing to logistical difficulties, although this information is essential for species conservation and sustainable fisheries management. An inventory of specific diversity in plankton samples might be an efficient way of studying breeding seasons and breeding localities of fish species, providing their precise taxonomic identification can be ensured. Herein, using barcoding of the cytochrome c oxidase subunit I (COI) gene, species were identified in monthly plankton samples collected in the lower reaches of the Napo, Marañón and Ucayali rivers. A total of 16 species of pimelodid catfish were identified. For the most abundant species, two tendencies were observed, with breeding periods preferentially occurring during rising and high water periods (Brachyplatystoma filamentosum, Pimelodus blochii) or during receding and low water periods (Brachyplatystoma rousseauxii, Brachyplatystoma platynemum, Brachyplatystoma vaillantii, Hypophthalmus edentatus, Hypophthalmus marginatus). For all of these species except for B. rousseauxii, this is new information for the Peruvian Amazon. Their reproductive behaviours are discussed in term of adaptive strategies to environmental conditions, where hydrological cycles play essential roles in resource accessibility and dispersal capabilities.