Percorrer por autor "Rassam, Hanane"
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- Fish hosts of the critically endangered Unio foucauldianus Pallary, 1036 (Mollusca: Unionidae)Publication . Benaissa, Hassan; Teixeira, Amílcar; Lopes-Lima, Manuel; Sousa, Ronaldo; Varandas, Simone; Rassam, Hanane; Ghamizi, MohamedUnio foucauldianus Pallaiy, 1936 (Unionidae) is a critically endangered freshwater mussel, with a small geographical distribution restricted to Morocco. As many other unionids, the life cycle of this species includes an obligatoiy parasitic phase using fish as hosts. Therefore, the knowledge of fish hosts is essential to develop any efficient conservation strategy devoted to this species. In this study, we used two approaches to assess the fish hosts of Unio foucauldianus: determination of infestation rates of fishes under natural conditions through a monthly (from January to June) sampling in Laabid (Oum Er Rbia basin) and N'Fis (Tensift basin) Rivers and laboratorial trials to assess metamorphose rates using different fish species from both rivers. The natural infestation offish showed a peak ofinfestation in May and juveniles only metamorphosed in the following native fish species: Luciobarbus ksibi (Boulenger, 1905), Carasobarbus fritschü (Günther, 1874), Luciobarbus zayanensis (Doadrio, Casal-López & Yahyaoui, 2016), Labeobarbus maroccanus (Günther, 1874) and Luciobarbus magniatlantis (Pellegrin, 1919). Given the increasing pressure on native fish species due to human activities, including the increased number ofnon-native fish introductions that did not function as hosts of U. foucauldianus, urgent conservation measures are needed to mitigate some of the threats on native ichthyofauna. Only an integrated framework comprising knowledge ofthe freshwater mussel biology and their native fish hosts can help th e conservation of U. foucauldianus in Morocco.
- Fish hosts of the freshwater mussel Unio foucauldianus Pallary, 1936Publication . Benaissa, Hassan; Teixeira, Amílcar; Lopes-Lima, Manuel; Sousa, Ronaldo; Varandas, Simone; Rassam, Hanane; Ghamizi, MohamedThe life cycle of Unio foucauldianus Pallary, 1936, a critically endangered freshwater mussel species (Bivalvia: Unionida), includes a parasitic phase using fish as hosts. Therefore, to develop more efficient conservation strategies it is essential to know which are the suitable fish hosts of U. foucauldianus. In this study, two approaches were used to assess the fish hosts of U. foucauldianus: the determination of infestation rates of fishes under natural conditions through monthly sampling (from January to June) in the Laabid River (Oum Rbia basin) and the N'Fis River (Tensift basin), and artificial infestation in laboratory trials using fish species from both rivers. The natural infestation of fish was detected from February to June, with a peak in May. Fully metamorphosed juveniles were only detected in native fish species, i.e. Luciobarbus ksibi (Boulenger, 1905), Carasobarbus fritschii (Günther, 1874), Luciobarbus zayanensis Doadrio, Casal‐lopez & Yahyaoui, 2016, Labeobarbus maroccanus (Günther, 1874), and Luciobarbus magniatlantis (Pellegrin, 1919). The two non‐native fish species used do not function as effective hosts. Given the increasing human pressure on native fish species in the Mediterranean biodiversity hotspot, including the increased number of non‐native fish introductions, urgent conservation measures are discussed for this and other freshwater mussel species.
- Preliminary data on fish hosts and their conservation importance for the critically endangered Pseudunio marocanus (Pallary, 1918)Publication . Benaissa, Hassan; Ghamizi, Mohamed; Teixeira, Amílcar; Sousa, Ronaldo; Rassam, Hanane; Varandas, Simone; Lopes-Lima, ManuelPseudunio marocanus (Pallary, 1918) is an endemic species of Morocco and is considered one of the world’s 100 most threatened species. The life cycle of this critically endangered freshwater mussel remains unknown. However, knowledge about the discharge period of its larvae and its ecological fish hosts is crucial to adopt more effective conservation strategies. Given this information gap, monitoring the presence of P. marocanus glochidia in fish from the Laabid River was carried out from January to May 2019 to determine the larvae discharge period. Two different approaches were used to assess the fish hosts of P. marocanus: (i) the determination of glochidia infestation rates of fishes in situ through monthly (from January to May) sampling in the Laabid River (Oum Er Rbia basin); and (ii) artificial infestation in laboratory trials using four fish species. A peak in glochidia discharge was observed at the end of February. Fully metamorphosed juveniles were detected in all native fish species, i.e. Luciobarbus ksibi (Boulenger, 1905), Carasobarbus fritschii (Günther, 1874), Luciobarbus zayanensis Doadrio, Casal-lopez and Yahyaoui, 2016, and Pterocapoeta maroccana Günther, 1874. For the first time, the glochidia discharge period and the fish hosts of P. marocanus were determined, and this information is vital to implement future conservation measures (i.e. propagation, reinforcement of populations, possible reintroductions of P. marocanus, careful management of river flow by upstream dams, and the prohibition of fishing activities during the critical glochidia discharge period). Given the increasing human pressure on freshwater habitats and biodiversity in Morocco, it is essential to preserve the native ichthyofauna to conserve this rare pearl mussel species.