Fish diversity of a tributary of the Meta River, in the flat highlands of the colombian Orinoquia

Abstract

The distribution and abundance of fishes for the Orinoco River basin drainages are influenced by hydrometric seasonality and the structural complexity of the habitat, so understanding how fish assemblages are structured on a temporal and spatial scale is essential for biological conservation. Therefore, the purpose of this study was to describe the fish assemblage for the Mitimiti stream and test the hypothesis of spatial and temporal variation. To do this, collections were made at four sampling stations on the Mitimiti stream, during three contrasting rainfall seasons, with the help of a 10 m x 1.5 m trawl net and a 2 mm mesh eye. The diversity of fish assemblages was analyzed using Hill numbers, abundance-based dissimilarity, and a Canonical Correspondence Analysis (CCA). In total, 2,493 individuals and 115 species were recorded, where the orders with the highest dominance were Characiformes and Blenniiformes. Regarding the diversity of order q = 0, no significant differences were found between the hydrological periods and the sampling stations, however, the low water period and St3 exhibited the highest species richness. The most dissimilar hydrological period was the high-water season and the variables that significantly influenced fish assemblage were water temperature (p = 0.02) and dissolved oxygen (p = 0.05).