Fish Species Composition, Distribution and Community Structure in Relation to Environmental Variation in a Semi-Arid Mountainous River Basin, Iran

Abstract

We analyzed spatial variation in fish species richness and community composition in the Karun River basin, Iran. Knowledge about fish diversity in the basin is incomplete and varies widely along spatial and temporal scales: The Karun is the longest river in Iran (950 km) with the largest drainage area (about 67,000 km2). Fish samples were collected from 54 sites from July through August 2019 using a backpack electro-fisher. Physico-chemical and habitat parameter data collected at each site included pH, conductivity (μS/cm), dissolved oxygen (mg/L), water temperature (°C), turbidity (NTU), stream width (m), stream depth (m), water velocity (m/s) and elevation (m). In total, 37 species were collected (5241 individuals weighing 110.67 kg). The species collected represented 12 families and 27 genera. A total of 13 endemic species (35.14%), 16 native species (43.24%), and eight non-native species (21.62%) were recorded. Diversity indices were calculated and used to measure the spatial variation in community composition. Relationships between native and endemic species assemblage structure and environmental descriptors were assessed using canonical correspondence analysis (CCA). The first two axes of the canonical correspondence analysis explained 62.57% of the variation in the data. Of the nine environmental descriptors analyzed, eight significantly affected species distribution; however, electrical conductivity and elevation were most influential. Our study provides up-to-date status information on the distribution of freshwater fishes in the Karun River basin. This information is essential for developing conservation and management strategies to support the long-term sustainability of fish populations in the Karun River basin.

Environmental impact assessment and conservation planning of a Middle‐Eastern River basin using a fish‐based tolerance index

“…The variable nature of the flows is modified by water withdrawal and dam operations (Khosravi et al, 2017). This study was limited to wadeable, upper portions of the watershed where backpack electrofishing equipment could be used (Figure 1) (Zare Shahraki et al, 2022b; Zare Shahraki et al, 2022a).…”

“…where a is the number of common sites characterized as stressed sites based both on the KFTI and PCA results and b is the number of stressed sites, based on the PCA results (Zare Shahraki et al, 2022b).…”

“…We also tested if native, endemic, and non‐native fish species differ in tolerance to the range of stressors that occur in the Karun River system. The KFTI complements a multi‐metric index (KFMMI) based on the same data developed in a companion study (Zare Shahraki, et al, 2022b). The KFTI has the potential to provide a less complex yet robust, fish‐based rapid assessment tool that can be used in studies where resources may be limited.…”

Freshwater as a Sustainable Resource and Generator of Secondary Resources in the 21st Century: Stressors, Threats, Risks, Management and Protection Strategies, and Conservation Approaches

“…); land conversion; overharvesting and overexploitation; introduction of exotic species; release of pollutants into the water, land, and air; climate change, etc. [ 86 , 119 , 120 , 121 , 122 , 123 , 124 , 125 , 126 , 127 , 128 , 129 , 130 , 131 , 132 , 133 , 134 ]. These are still a largely unquantified threat [ 135 ].…”

Distribution and ecological status of alien fish species in the Karun River Basin, Iran

“…communities could be described by environmental parameters(Huang et al 2019;Purevdorj et al 2022;Zare Shahraki et al 2022b). Based on the "forward selection method" and ordiR2step function, the most important variables were selected based on signi cance and adjusted squared R. Of the ten alien species collected, ve species (with frequency of occurrence higher than 5%) and 12 environmental variables (Zare Shahraki et al 2022b) (average value of three replicates) were selected (after a forward stepwise selection) for inclusion in the RDA.…”