Hossein Rahmani; Seyed Daryoush Moghaddas
Abstract
Introduction: Non-native species are one of the important threats for biodiversity. Some of non-native fish species poses environmental impacts and are known as invasive species. rivers of south Caspian Sea are home of a vast variety of native or commercial fish species. Non-native species invasiveness ...
Read More
Introduction: Non-native species are one of the important threats for biodiversity. Some of non-native fish species poses environmental impacts and are known as invasive species. rivers of south Caspian Sea are home of a vast variety of native or commercial fish species. Non-native species invasiveness risk assessment tools are used to identify the species with high invasive potential risks and are used as a decision –making tool. The main aim of this study is to calibrate and validate Aquatic Species Invasiveness Screening kit for non-native fish species of rivers in south Caspian Sea basin. Materials and methods: Aquatic Species Invasiveness Screening Kit (AS-ISK) was used to assess non-native (NN) fish that may pose a high potential risk of becoming invasion in Rivers of South Caspian Sea. 15 NN fish species were assessed of which 14 are extant and 1 is horizon species in the risk assessment (RA) area. Two assessor independently have run the kit to NN fish species in the RA. The statistical methods were used to compare the scores that obtained by each assessor. Threshold score was calculated using receiver operating characteristic curve analysis. The model is able to discriminate between invasive and non-invasive aquatic organisms including non-native fishes by risk area-related threshold value. Also, Köppen-Geiger climate system were used to match the climate between native range of NN fish species and the risk assessment area. Results and discussion :Risk assessment of NN fish species led to the identification of 73 % of the species as potential invasive species in the RA area. Carassius gibelio and Carassius auratus achieved the highest risk score and Anguilla anguilla obtained lowest risk score among all NN fish species. There is not a statistically significant difference between assessor-specific mean risk scores. Threshold sores were 9.5 and 11.5 for AS-ISK and Basic Risk Assessment (BRA), respectively. Area under curve was 100% that means an excellent output for efficiency of the AS-ISK in the RA area. Eleven out of the 15 NN fish species were identified as potential invasive species and the rest as non-invasive NN species in the RA area. Confident factors were different from 73% to 64%. All NN fish species were categorized in three list black, grey and white in regard of their risk ranks in order to management prioritization. Conclusion: The AS-ISK efficiently identified NN fish species that pose a high risk of being/becoming invasive in rivers in the south Caspian Sea to prioritize them based on their risk rank and to support conservation managers, decision-makers and policy makers in the aquaculture development plans.
