Fish species inventory of Yasuní National Park, Ecuador

Despite limited access and rather deficient sampling in many lowland areas of eastern Ecuador, scientists have been able to demonstrate that this specific region of Amazonia houses extraordinarily high concentrations of species within several taxa – terrestrial and aquatic, plant and animal, vertebrate and invertebrate.

In this work, we developed an updated list of the ichthyofauna of the Yasuní National Park (YNP) based on an extensive literature review and databases of the most representative ichthyological collections from Ecuador. Our results yielded 457 species of freshwater fishes distributed in 45 families and 13 orders. This number substantially exceeded previous fish lists from YNP and accounts for a considerable proportion of species inhabiting the Napo River basin as well as the entire Amazon River basin.

The occurrence of far more species within this limited geographic space than have been previously reported, the services these species provide to humans, and the absence of alien species, thoroughly justifies the greater efforts and investment that should be allocated to the protection and management of western Amazonian lands and waters.

Methods
To compile a list of fish species occurring in the YNP, an updated database of species present in YNP was developed from previous lists of fish species known from the Napo Basin of Ecuador and Peru (Barriga 2012, Sanchez et al. 2013, Jézéquel et al. 2020). Later, this database was curated based on records occurring within and around the boundaries of YNP. All fish records, old and new, were validated by databases of the two major ichthyological collections in Ecuadorian museums: Museo de Historia Natural Gustavo Orcés – Escuela Politécnica Nacional (MEPN) and Colección Ictiológica del Instituto Nacional de Biodiversidad, Quito, Ecuador (MECN-DP). These records are the product of decades of expeditions to the Ecuadorian Amazon and curatorial activities of each museum. In addition, digital databases of fishes collections from the Field Museum of Natural History (FMNH) and National Museum of Natural Hitory (USNM), have been verified for records of several species absent in MEPN or MECN-DP. Because it is possible that fish species registered outside YNP boundaries occur within the reserve, for this study we included records from a 15 km range beyond YNP limits. We did not include records from other protected areas nearby or more geographically distant sites despite any ecological similarities. Finally, species classification and ordering was also updated to current taxonomic revisions of each group according to Eschmeyer’s Catalog of Fishes – California Academy of Sciences.