Checklist of the ichthyofauna of Mamirauá Sustainable Development Reserve, Middle Solimões, Amazonas, Brazil: high richness in a large protected area of Western-Central Amazonia

Abstract

The present study reviews the records of occurrences of fish species found in the Mamirauá Sustainable Development Reserve (MSDR). The reserve is located in a large section of the middle Solimões River basin, in its interflow with Japurá River. For the elaboration of the list of fish species occurring in Mamirauá Reserve, we used a database of different studies on fish communities carried out in the area over the last three decades, in addition to the material deposited in the ichthyological collections of three scientific institutions, the National Institute for Amazon Research - INPA, the Mamirauá Sustainable Development Institute - IDSM and the Science and Technology Museum of the Catholic University of Rio Grande do Sul - PUCRS. The ichthyofauna of the MSDR is composed of 541 species, encompassing 45 families and 15 orders. These correspond to 20% of all valid species known for the entire Amazonia so far. As observed in other studies in the Neotropical Region, the more represented orders were Siluriformes (209 species) and Characiformes (185 species), followed by the Gymnotiformes (78 species). The results presented here demonstrate a considerable increase (86%) in the knowledge about the fish diversity found in Mamirauá Reserve, in relation to its first list of fish species, published in the 90's. This increase reflects not only the growth in number of studies on fish diversity in the area, with new surveys, but also the continuous taxonomic work on the collections, and descriptions of twenty-eight new species, with one hundred and ten type series. Further surveys are expected to take place in the Northwestern, more isolated areas of the Reserve, and will allow the identification of new occurrences, and may even unveil new fish species yet to be described to Science..

Detection and quantification of heavy metals in blood and milk of Amazon river dolphin (Inia geoffrensis) (Cetartiodactyla: Iniidae) using wavelength‐dispersive X‐ray fluorescence spectrometry

“…37 Many of them occur in the water bodies of the MSDR. 38,39 Thus, the concentrations of heavy metals in the milk of female Amazon river dolphin in this study may be a consequence of the metals transferred via food and bioaccumulation during the lactation period, which can last, on average, 2.8 years in Inia geoffrensis. 40 Martin and da Silva 41 showed that the Amazon river dolphin promotes habitat segregation, in which female dolphins and their calves are predominant in remote areas of the floodplains known as chavascais, while male dolphins are predominant in the main channels of the river.…”

“…The Amazon river dolphin is a top predator that consumes at least 43 fish species from 19 different families 37 . Many of them occur in the water bodies of the MSDR 38,39 . Thus, the concentrations of heavy metals in the milk of female Amazon river dolphin in this study may be a consequence of the metals transferred via food and bioaccumulation during the lactation period, which can last, on average, 2.8 years in Inia geoffrensis 40…”

“…Some species or genera (e.g., Pimelodus blockii, Crenicichla, Leporinus, Pellona , Sarrasalmus , Potamorhina , and Cichla ), which are also known prey of Amazon river dolphin and occur in the aquatic environment at the MSDR, 37–39 presented levels of chromium in their tissues higher than the limits allowed by Brazilian legislation (0.1 μg/g). This is an outcome of intense prospecting and mining activities 48,49 .…”

“…are known prey of Amazon river dolphin and occur in the aquatic environment located at the MSDR. [37][38][39] Thus, the high concentrations of these metals in the blood and milk of female Amazon river dolphin (e.g., potassium, chlorine, and calcium) suggest a response to a diet based on fish containing high levels of these metals in their organisms. Some species or genera (e.g., Pimelodus blockii, Crenicichla, Leporinus, Pellona, Sarrasalmus, Potamorhina, and Cichla), which are also known prey of Amazon river dolphin and occur in the aquatic environment at the MSDR, [37][38][39] presented levels of chromium in their tissues higher than the limits allowed by Brazilian legislation (0.1 μg/g).…”

“…Some species and genera analyzed by Cruz et al 50 and Machado and Duncan 54 (e.g., Pinirampus pirinampu, Mylossoma duriventre, Sorubim lima, Astronotus ocellatus, Brachyplatystoma filamentosum , Cichla spp., and Colossoma spp.) are known prey of Amazon river dolphin and occur in the aquatic environment located at the MSDR 37–39 . Thus, the high concentrations of these metals in the blood and milk of female Amazon river dolphin (e.g., potassium, chlorine, and calcium) suggest a response to a diet based on fish containing high levels of these metals in their organisms.…”