About 35 new fish species found in Bolivia


The number of fish species recorded in Bolivia’s Madidi National Park and Integrated Management Natural Area (PNANMI) has doubled to a staggering 333 species – with as many as 35 new to science – according to a study conducted as part of the Identidad Madidi Expedition, led by the Wildlife Conservation Society. The findings are described in the latest issue of Neotropical Hydrobiology and Aquatic Conservation. The study lists the fish species whose presence in Madidi has been confirmed, providing an estimate of the total fish richness of this protected area.


Species range in size from the invasive giant arapaima (Arapaima gigas), also known as pirucu or paiche, a mouth-breathing giant (it must breathe oxygen and regularly emerge to the surface to store air) weighing more than 200 kg and is more than 3 meters long , to the killifish (Anablepsoides beniensis) of the Rivulidae family, seasonally present in pools of water in natural savannahs and just 1.5 cm long. The list also includes the Amazon’s most attractive wild fish, the golden dorado (Salminus brasiliensis), as well as migratory catfish, from the Amazonian catfish (Brachyplatystoma filamentosum) to the tiny chipi chipi catfish, whose massive collective migration is a local phenomenon (Trichomycterus barbouri). Another killifish (Orestias sp.) is found in some of the highest Andean lakes, at 4,300m in Madidi, while in the ponds you can see the wonderful Amazon knifefish (Gymnotus carapo) and swamp eel (Synbranchus madeirae ), and in the fast-flowing streams of Amazonian headwaters, several species of naked catfish (Astroblepus spp.) are found, probably including several species new to science.

The biodiversity surveys and field research were conducted between 2015 and 2018 by specialists from the Wildlife Conservation Society (WCS), the Institut de Recherche pour le Développement de Montpellier (France) and the National Museum of Natural History and the ‘Institute of Ecology of the Universidad Mayor de San Andrés. Madidi is arguably the most biologically diverse protected area in the world , thanks to a unique elevation gradient of nearly 6,000 meters that spans the tropical Andes and the Amazon.


For four years, specialists conducted extensive ichthyological sampling at 13 sites in Madidi National Park, using different sampling techniques: electrofishing, gillnets, bottom trawls, hook-and-line nets and ichthyoplankton nets. Ichthyoplankton species were identified by genetic characterization (metabarcoding). In total, 333 species distributed in 43 families and 13 orders have been recorded. This number doubles the previously known ichthyofauna (161) in Madidi. The largest number of species is found in the order Characiformes (139 species; 41.7%), followed by Siluriformes (137 species; 41.1%) and Cichliformes (19 species; 5.7%), which together represent the 88.6% of species richness. The remaining 11.4% is distributed in 10 other orders.


Lead author of the study, Guido Miranda, of the Wildlife Conservation Society, said: ‘At 18,957.5 square kilometers (7,319 sq mi), Madidi covers 1.3% of the Madeira River basin, but it preserves 25% of the species known in the basin. Madidi also represents only 1.8% of the Bolivian territory, but preserves almost 40% of the ichthyofauna recorded in Bolivia. This study has more than doubled our knowledge of fish diversity in this incredible protected area, but with several sub-basins yet to be sampled in the park, this is just the beginning.”



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