Hossein Rahmani; Seyed Daryoush Moghaddas
Abstract
Introduction: Non-native species are one of the important threats to biodiversity. Some non-native fish species pose environmental impacts and are known as invasive species. Rivers of the southern Caspian Sea are home to a vast variety of native or commercial fish species. Non-native species invasiveness ...
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Introduction: Non-native species are one of the important threats to biodiversity. Some non-native fish species pose environmental impacts and are known as invasive species. Rivers of the southern Caspian Sea are home to 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 the Aquatic Species Invasiveness Screening Kit (AS-ISK) for non-native fish species of rivers in the southern Caspian Sea basin.Material and methods: AS-ISK was used to assess non-native (NN) fish that may pose a high potential risk of becoming invasive in rivers of the South Caspian Sea. Fifteen NN fish species were assessed, 14 of which are extant and 1 is horizon species in the risk assessment (RA) area. The statistical methods were used to compare the scores obtained by each assessor. The threshold score was calculated using receiver operating characteristic curve analysis. Also, the Köppen-Geiger climate system was used to match the climate between the 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 the lowest risk score among all NN fish species. There was not a statistically significant difference between assessor-specific mean risk scores. Threshold scores were 9.5 and 11.5 for AS-ISK and Basic Risk Assessment (BRA), respectively. The area under curve was 100%, which shows an excellent output for the 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. Confidence factors were different from 73% to 64%. All NN fish species were categorized in three lists i.e., black, grey and white in regard to their risk ranks in order to manage 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 policymakers in the aquaculture development plans.
Hossein Rahmani; Faeghe Radaei; Sara Haghparast; Seyedeh Mahdis Rekabi
Abstract
Introduction: Biological evaluation of water resources using macroinvertebrates is one of the most appropriate and most cost-effective methods in order to study human impacts on water ecosystems. Nutrition strategies are a typical feature that reflects the flexibility of species and can be part of a ...
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Introduction: Biological evaluation of water resources using macroinvertebrates is one of the most appropriate and most cost-effective methods in order to study human impacts on water ecosystems. Nutrition strategies are a typical feature that reflects the flexibility of species and can be part of a single action in the classification structure of societies. Feeding groups contribute to the metabolism of freshwater ecosystems, including nutrient cycles, reduced particle size (e.g shredder), facilitated the functioning of microparticles, Fungi and yeasts and carrying organic matter in the downstream. The aim of this study was to investigate the distribution of feeding groups of bentic macroinvertebrates as the basis of biological evaluation in the Chalous River as one of the protected rivers in Iran with unique ecological conditions. Material and methods: Macroinvertebrates were taken using surber sampler (with an approximate area of 0.1 m2 and mesh size of 360 µm) with 3 replicates in 9 stations each season, from June 2015 to March 2016. To compare the abundance of feeding groups in different stations and seasons, the Kruskal-Wallis test was used and a Mann-Whitney test was used to Paired comparison. Simperity tests (SIMPER) were used to determine the feeding groups that had the highest share (participation rate) in the similarity of each station and also the major disparity between the stations. Results and discussion: During the whole period of sampling, 26220 individuals of macroinvertebrates were separated, identified and counted, which were belonged to 3 phyla, 4 classes, 12 orders, 34 Families and 35 Genera. In this study, the highest total abundance of invertebrates in stations 6 and 8 was 15.04% and 16.97% of the different feeding groups, which can be due to the entry of organic matter By wastewater farms before these stations. Suspended solids along with non-eaten foods in salmon farms seem to play an important role in increasing the abundance of bentic macroinvertebrate in the bottom of fish farms. Functional feeding groups of macroinvertebrates in this study included five groups: Collector Gatherer, Collector Filter, Predator, Scraper and Shredder. Results showed that, the abundance of Collector Gatherer in station 8 is higher than other stations. The frequencies of Scraper and Shredder groups showed significant differences with other groups (p < 0.05). Also, Collector Filter group in station 6 is more abundant than other stations (p < 0.05). The results of the SIMPER analysis indicated a high degree of uniformity and reduction of variations at each station group seasonally. Conclusion: In general, the results of this study showed that the stations that were located after the fish farms in many seasons, alternately collector filter and collector gatherer feeding groups most frequent. However, based on the results of the SIMPER test, due to the increased presence of other feeding groups in stations after fish farms, the contribution of the filterer and gatherer groups to the combination of macroinvertebrates in comparison with other stations decreased.
Seyed Daryoush Moghaddas; Asghar Abdoli; Bahram Hassanzade Kiabi; Hossein Rahmani
Abstract
Introduction: The intentional and unintentional introduction of non-native fish species to the aquatic ecosystems of Iran has occurred with purposes such as enhancing aquaculture, ornamentation, biological control, and research. Some of them cause or have the potential to cause, significant environmental ...
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Introduction: The intentional and unintentional introduction of non-native fish species to the aquatic ecosystems of Iran has occurred with purposes such as enhancing aquaculture, ornamentation, biological control, and research. Some of them cause or have the potential to cause, significant environmental and socio-economic impacts on aquatic ecosystems and/or fish farms. The eradication of non-native fishes is impossible or very costly, especially in large areas. Screening and identifying the potential invasiveness of species are being increasingly used all over the world. The main aim of the present research was to assess the potential invasiveness of redbelly Tilapia Coptodon zillii in Anzali international wetland. Material and methods: Aquatic Species Invasiveness Screening Kit (AS-ISK) was used to identify redbelly Tilapia Coptodon zillii as a non-native fish that may pose a high potential risk of becoming invasion in Anzali Wetland. The model is able to discriminate between invasive and non-invasive aquatic organisms including non-native fishes by risk area-related threshold value. Also, the Köppen-Geiger climate system and Climatch software were used to match the climate between the native range of redbelly Tilapia and Anzali Wetland. The projected future climate change scenario was taken from relevant studies to carry out Climate Change Assessment (CCA) of the AS-ISK. Results and discussion: The output of the AS-ISK was 44 for redbelly Tilapia that was higher than the AS-ISK threshold value of the risk assessment area, which meant that the species pose a potential risk of becoming invasive in Anzali wetland. There was a high climate-mating between the native range of redbelly Tilapia and the assessed area when the Köppen-Geiger climate system was used. At least one native habitat of redbelly Tilapia in the system was in the same climate category as the studied area. Also, the Climatch model output was 0.87 that shows a high climate matching for the non-native fish. The CCA had an increasing effect on the total score of the AS-ISK. The factors that increased the AS-ISK score were climate-mating, probable climate change, biological attributes, and invasiveness history of other places that the species was introduced. The comparison of the results of this study and other relevant studies that used AS-ISK to assess potential invasiveness of redbelly Tilapia showed that the species had the potential of becoming an invader in Anzali Wetland as well as some other areas around the country. Conclusion: While non-native fishes are frequently used to enhance aquaculture in the country, a rapid assessment tool is required to avoid nuisance environmental impacts. The AS-ISK can be reliably used as a tool to predict the potential risk of becoming invasive in Anzali Wetland and elsewhere to be used by conservation managers, decision-makers, and policymakers in the aquaculture development plans.
