NEOTROPICAL FRESHWATER FISHES: A dataset of occurrence and abundance of freshwater fishes in the Neotropics

The Neotropical region hosts 4225 freshwater fish species, ranking first among the world's most diverse regions for freshwater fishes. Our NEOTROPICAL FRESHWATER FISHES data set is the first to produce a large-scale Neotropical freshwater fish inventory, covering the entire Neotropical region from Mexico and the Caribbean in the north to the southern limits in Argentina, Paraguay, Chile, and Uruguay. We compiled 185,787 distribution records, with unique georeferenced coordinates, for the 4225 species, represented by occurrence and abundance data. The number of species for the most numerous orders are as follows: Characiformes (1289), Siluriformes (1384), Cichliformes (354), Cyprinodontiformes (245), and Gymnotiformes (135). The most recorded species was the characid Astyanax fasciatus (4696 records). We registered 116,802 distribution records for native species, compared to 1802 distribution records for nonnative species. The main aim of the NEOTROPICAL FRESHWATER FISHES data set was to make these occurrence and abundance data accessible for international researchers to develop ecological and macroecological studies, from local to regional scales, with focal fish species, families, or orders. We anticipate that the NEOTROPICAL FRESHWATER FISHES data set will be valuable for studies on a wide range of ecological processes, such as trophic cascades, fishery pressure, the effects of habitat loss and fragmentation, and the impacts of species invasion and climate change. There are no copyright restrictions on the data, and please cite this data paper when using the data in publications.

Diet and resource sharing by two Pimelodidae species in a Southeastern Brazilian reservoir

Abstract: Fish can vary their diet and feeding dynamics according to biotic and abiotic factors. There is insufficient knowledge regarding these factors in reservoirs, which limits the management of these areas. The aim of this study was to determine the diet of two related and most collected fish species, verify the influence of biotic and abiotic factors on their diet, and also verify the existence of resource sharing by them in an upstream Brazilian reservoir. Fish abundance in the reservoir was calculated and data were provided by 176 specimens of Iheringichthys labrosus (Lütken, 1874) and 255 specimens of Pimelodus maculatus Lacépède, 1803 collected in Camargos reservoir, MG, Brazil. Stomach contents were analysed through the frequency of occurrence and volumetric methods. PERMANOVA analysis was done to evaluate the influence of biotic (Species and Size class) and abiotic factors (Season and Site) on the diets. The Alimentary Index (AI) and feeding overlap Index (Pianka) were also estimated. A NMDS analysis was conducted to visualize the food categories responsible for interspecific difference. The ingested items were grouped into 18 categories, of which 17 were found in both species. Feeding resources were significantly related to the biotic (Species: Pseudo F = 2.583, P = 0.001; Size Class: Pseudo F = 1.646, P = 0.001) and abiotic (Season: Pseudo F = 2.458, P = 0.006) factors. I. labrosus showed an invertivorous diet while P. maculatus an omnivorous diet and both species were not exclusively benthophagus as typically reported. Food overlap occurred intraspecifically and interspecifically (Pianka 0.61 to 0.97 and 0.61 to 0.66, respectively) and overlap also occurred in three of the four analysed seasons (Pianka 0.66 to 0.91). The diet overlap found between two of the most fished species and the low fish productivity may indicate the limitation of resources in this reservoir and should be considered for management of this area.