Freshwater habitats are vital for both humans and nature owing to their exceptional biodiversity and valuable ecosystem services, but they are currently facing serious threats. The designation and management of protected areas have been proposed as the most feasible way to ensure conservation objectives for the future. However, traditional approaches have not protected freshwater fauna effectively, especially freshwater fish.Previous studies have identified the most irreplaceable terrestrial places to achieve conservation goals. Here, the aim was to investigate how the present network of protected areas preserves irreplaceable rivers for freshwater fish.The irreplaceability of the world's river basins was calculated using International Union for the Conservation of Nature Red List distribution maps, considering the rarity, richness, and conservation status of their freshwater fish fauna. The overlap between irreplaceable basins and the present network of protected areas was also calculated.The results highlight the conservation significance of tropical rivers, particularly those in the Neotropics. The subset of the basins covering 30% of the most irreplaceable land surface (in line with the United Nations 30by30 target) encompasses 99% of freshwater fish species. However, protected areas do not seem to provide sufficient protection to these basins, as 89% of their surface area lies outside protected areas. Only 7% of freshwater ecoregions meet the United Nations 30by30 target.Given the context of climate change, allocating new protected areas becomes crucial in providing better survival opportunities for freshwater fish species. Despite the limitations inherent to the absence of total knowledge of freshwater fish biogeography and the irreplaceability index itself, this study identifies priority sites for their conservation that may help inform decision-making in the future to establish more effective protected areas.

Biodiversity loss is a global problem, accelerated by human-induced pressures. In the marine realm, one of the major threats to species conservation, together with climate change, is overfishing. In this context, having information on the conservation status of target commercial marine fish species becomes crucial for assuring safe standards. We put together fisheries statistics from the FAO, the IUCN Red List, FishBase, and RAM Legacy databases to understand to what extent top commercial species¿ conservation status has been assessed. Levels of assessment for top-fished species were higher than those for general commercial or highly commercial species, but almost half of the species have outdated assessments. We found no relation between IUCN Red List traits and FishBase Vulnerability Index, depreciating the latter value as a guidance for extinction threat. The RAM database suggests good management of more-threatened species in recent decades, but more data are required to assess whether the trend has reverted in recent years. Outdated IUCN Red List assessments can benefit from reputed stock assessments for new reassessments. The future of IUCN Red List evaluations for commercial fish species relies on integrating new parameters from fisheries sources and improved collaboration with fisheries stakeholders and managers.

IUCN Red List assessments for fish species can quickly become out of date. In recent years molecular techniques have added new ways of obtaining information about species distribution or populations. In this work, we propose the Iberian Peninsula as an example of reassessment needs in its endangered freshwater fish fauna. We compiled the list of freshwater fish species occurring in continental Spain and Portugal and examined their conservation status in global and national Red Lists. We retrieved records for these species in the Iberian Peninsula and calculated several biological indexes (richness and vulnerability indexes). Our results showed a patchy data coverage of fish records in the Iberian Peninsula. Threat levels reported within national Red Lists are higher than their global counterparts, reinforcing the necessity of improving and maintaining up to date national Red Lists. Iberian watersheds have moderate levels of threat and high levels of out of date assessments. The nearly fully completed genetic databases for Iberian fish species, along with the limited distribution of many endangered species and the necessity of update their assessments constitute an excellent opportunity to use data obtained from eDNA to improve species monitoring practices and their conservation status.

Global biodiversitytargets require us to identify species at risk of extinction and quantify status and trends of biodiversity. The Red List Index (RLI) tracks trends in the conservation status of entire species groups over time by monitoring changes in categories assigned to species. Here, we calculate this index for the world's fishes in 2010, using a sampled approach to the RLI based on a randomly selected sample of 1,500 species, and also present RLI splits for freshwater and marine systems separately. We further compare specific traits of a worldwide fish list to our sample to assess its representativeness. Overall, 15.1% of species in the sample were estimated to be threatened with extinction, resulting in a sampled RLI of 0.914 for all species, 0.968 in marine and 0.862 in freshwater ecosystems. Our sample showed fishing as the principal threat for marine species, and pollution by agricultural and forestry effluents for freshwater fishes. The sampled list provides a robust representation for tracking trends in the conservation status of the world's fishes, including disaggregated sampled indices for marine and freshwater fish. Reassessment and backcasting of this index is urgent to check the achievement of the commitments proposed in global biodiversity targets.

More than 33,500 fish species inhabit freshwater and marine environments, according to FishBase database records. The International Union for the Conservation of Nature (IUCN) has assessed the conservation status of approximately half of them, the lowest percentage in any vertebrate group. In order to identify what factors may underlie this assessment gap, several traits were examined related to distribution, life-history, taxonomy, conservation, and the economic relevance of species according to their assessment status. IUCN assessment patterns were explored and separate analyses were included for freshwater and marine species. The results showed that IUCN assessments were biased towards economically developed regions, species with early description dates and species covered by current IUCN specialist groups. Species living in remote areas or habitats were more likely to be unassessed. In particular, South America had low assessment levels. Other traits such as commercial importance did not influence the assessment status of fish species. We therefore encourage assessment in poorly assessed areas and taxonomic subgroups to prompt timely conservation action to prevent species extinctions.

Es una publicación que muestra las principales especies animales que habitan en la cuenca del río Baztan-Bidasoa. A lo largo de sus doscientas páginas y con el apoyo de cuidadas imágenes, cada especie cuenta con su descripción, con sus datos de distribución, el detalle de su biología y de su estado de conservación, facilitándonos su reconocimiento y aportándonos la información básica que nos va a permitir aprender sobre cada una de ellas.