The Amazonian dwarf cichlid Apistogramma agassizii (Steindachner, 1875) is a geographic mosaic of potentially tens of species : conservation implications

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 genusApistogramma, 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 particularApistogramma agassizii, present from the Amazon estuary up to the Ucayali and Maranon rivers in Peru. This study assessed the taxonomic status of 1,151 specimens ofA. agassiziicollected 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 nominalA. agassiziiwere 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 ofA. agassizii, ofApistogrammaspecies in general, and of other Amazonian cichlids are discussed

Influence of dietary protein and lipid levels on growth performance and the incidence of cannibalism in Pseudoplatystoma punctifer(Castelnau, 1855) larvae and early juveniles

WOS:000370008700010International audienceThe aim of the study was to evaluate the influence of different dietary protein and lipid levels and their ratios on larval growth, survival and the incidence of cannibalism in Pseudoplatystoma punctifer. Larvae were raised in a recirculation system from 3 to 26days post-fertilization (dpf) (2-25days post hatching, dph) at an initial density of 40 larvae L-1, 27.8 +/- 0.65 degrees C and 0L:24D photoperiod. Larvae were fed from 4 to 12 dpf with Artemia nauplii and weaned onto four different compound diets from 13 dpf within 3days, then fed exclusively with these diets until 26 dpf. These diets contained 30:15, 30:10, 45:15 or 45:10 protein:lipid (P:L) (in % of dry matter) levels. A control group was fed Artemia nauplii until 17 dpf and weaned thereafter with the 45P:10L compound diet. The experiment was carried out in triplicate. Results showed higher growth and survival rates and lower incidence of cannibalism in the group fed the 45P:15L diet than in the other treatments. Differences in larval survival and growth performance were associated with the higher protein and lipid content rather than the protein:lipid ratio of this diet. When comparing diets with the same protein level, the increase in dietary lipid led to an improvement in growth, suggesting that energy from lipids spares protein for growth in P.punctifer fingerlings. An Artemia feeding period longer than 12 dpf did not improve larval growth or survival

Proceedings of the 4th International Conference of the "Research Network on Amazonian Ichthyofauna" (RIIA)

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, Maranon 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