Spatial heterogeneity among threatened fish assemblages with high endemicity underscores the urgency for conservation efforts

Data were collated from 17 past studies of fish assemblages in Lake Tana and its inflowing catchments, north-west Ethiopia. All but one has either been published in a peer-reviewed source or was available as a public dataset (References, below). Raw abundances were converted to percentages to overcome sampling differences between studies., and examined patterns in relative abundance between (a) IUCN red List extinction-threat status levels, (b) endemic versus presumed non-endemic species, (c) habitats, (d) catchments surrounding Lake Tana, and (e) sites upstream, downstream and in the absence of dams. We used multi-dimensional scaling analysis, PERMANOVA, and SIMPER procedures in PRIMER-e version 7.0.24 to establish patterns in assemblage structure in (c), (d), and (e).As Labeobarbus (Varicorhinus) beso had not been included in all studies, we omitted it from any assemblage structure analyses. Similarly, Labeobarbus fish that either appeared to be a hybrid or that could otherwise not be identified were also excluded from assemblage structure analyses. We also assigned the small number of L. degeni to L. nedgia due to taxonomic uncertainties.The following summarises the nature of data presented in each worksheet in our figshare data file.Worksheet 1Codes used elsewhere in the file for species, IUCN status, endemicity, habitat, and the location of sites relative to weirs.Worksheet 2List of original studies from which individual data sets were sourced.Worksheet 3Data summary across studies. Includes comparison across IUCN extinction-threat level and endemicity categories.Worksheet 4Data used in analysis of patterns in assemblage structure between geomorphic habitat zones.Worksheet 5Data used in analysis of patterns in assemblage structure between six of the catchments flowing into Lake Tana.Worksheet 6Comparison of relative abundances of IUCN extinction-threat categories between inflowing catchments and the three riverine geomorphic habitat zones.Worksheet 7Comparison of assemblage structures between riverine sites upstream, downstream and in the absence of weirs. For this, data were analysed just from Gebremedhin et al. (2017) and Teshome et al. (2021).