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 ...
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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.
Maryam Peymani; Asghar Abdoli; Seyed Daryoush Moghaddas
Abstract
Introduction: The introduction of invasive fish species into aquatic ecosystems causes various adverse ecological and socio-economic impacts. The first step in analyzing the effects of these species is to identify the risk. Then, different tools have been developed to identify potential invasive ...
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Introduction: The introduction of invasive fish species into aquatic ecosystems causes various adverse ecological and socio-economic impacts. The first step in analyzing the effects of these species is to identify the risk. Then, different tools have been developed to identify potential invasive species and evaluate the potential degree of their invasiveness to support decision-makers in analyzing the invasive risk of these species. This study aimed to assess the invasive potential of the non-native species redbelly tilapia (Coptodon zillii, Gervais 1848) in the Shadegan Wetland basin (the Karun and Jarahi catchments) using some of these tools.Material and methods: The level of risk for C. zillii in the trinational risk assessment protocol was determined based on the results of the two components "Probability of Establishment" and "Consequences of Establishment". In the German-Austrian Blacklist Information System (GABLIS), the invasive potential of the species was evaluated according to the distribution in the study area. The non-native species were screened by the Aquatic Species Invasiveness Screening Kit (AS-ISK) model according to the threshold of the assessment area; and the rank of species invasion was calculated based on the probability of species establishment, expansion, and environmental effects, using the Harmonia+ method. Also, the climate matching between the introduced and native range of the species was carried out with the Köppen-Geiger climate classification system.Results and discussion: The results of trinational risk assessment indicated that the species posed a high potential rank of placing at each step of introduction, establishment, and expansion potential and the possibility of economic and environmental impacts in the study area. The results of the GABLIS protocol showed that the non-native species C. zillii has been widely distributed in the risk assessment area and was placed on the blacklist and the subset management list (b3). In the AS-ISK risk assessment, the risk score of the species was 44, which was higher than the tool threshold (22.5) for the study area. This score indicates that this species has a high invasive risk in the wetland. The overall risk score in the Harmonia+ method, which is a function of invasiveness and species impacts, was assessed as high for the redbelly tilapia. Based on the results, the risk of establishment and dispersal of this species in the study area is high, and its environmental impacts are significant. Also, there was a high climate match between the risk assessment area and the native range of the species in the Köppen-Geiger climate classification system. Conclusions: The trinational risk assessment methods, GABLIS, AS-ISK, and Harmonia+ models were able to show the invasiveness of the non-native C. zillii in Shadegan Wetland basin as literature and field evidence demonstrate that the species has exerted strong and adverse impacts on native fishes and local people livelihood in the risk assessment area. Given the results of risk assessment methods and the risks posed by this species, it is highly recommended that large-scale control and management measures should be seriously implemented.
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.
Hussein Valikhani; Asghar Abdoli; Bahram HassanzadehKiabi; Farshad Nejat; Mohammad Sadeghsaba; Milad Khosravi
Volume 15, Issue 4 , January 2018, , Pages 29-44
Abstract
Introduction: Invasive fishes are a major threat to biodiversity of aquatic ecosystems. Tilapia species are invasive due to reproductive, diet and behavioral characteristics and high resistance to environmental conditions, pollution and diseases. So far, two exotic species Coptodon zillii and Oreochromis ...
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Introduction: Invasive fishes are a major threat to biodiversity of aquatic ecosystems. Tilapia species are invasive due to reproductive, diet and behavioral characteristics and high resistance to environmental conditions, pollution and diseases. So far, two exotic species Coptodon zillii and Oreochromis aureus and also a native species Iranocichla hormuzensis of these species were reported from Iran. In recent years, exotic tilapia species invaded Iran and its neighboring countries inland waters and have had significant ecological and economic impacts. The aim of this study is to do a preliminary survey on the status of exotic tilapia species in Khuzestan province, Iran. Material and methods: The present study was carried out from November 2014 to September 2015 to determine the abundance of tilapia species (C. zillii and O. aureus) in the Shadegan wetland and some local fishery markets in Khuzestan province. In addition to, we evaluated presence or absence of the species in some cyprinid fish farms in the province. Results and discussion: The results showed that the catchment and supply of C. zillii is high and the species is one of the dominated fish in the Shadegan Wetland. In this study, O. aureus was not caught from the Shadegan wetland but observations show that the species is dispersed to other areas, especially in rivers and its abundance is increased. The tilapia species especially C. zillii are pests in some fish farms and the reduction of fish production was noted. The presence of the species in some fish hatcheries is increased the possibility of their transfer to other regions. Conclusions: At the moment, it seems that the best course of action to take action against tilapia is to prevent them from entering to other bodies of water (especially by aquaculture). The continuous studies to determine various aspects of the introductions, potential range prediction, and regular monitoring should be also considered. Overall, a compilation method and also ecologically sustainable water management, reduction of water contaminants and decrease of fishing pressure on native species should be adopted for controlling and reducing of these species.
