The occurrence and density of some molluscs species in different areas of Basrah province, southern of Iraq and first record of The invasive golden mussel Limnoperna fortunei (Dunker, 1857)

Abstract The study was conducted to compare the distribution and composition of the Molluscs community in 4 ecosystems (4 sites) in southern of Iraq, namely: (Site 1)- in Euphrates River at Al-Madinah city, (Site 2)- in Shatt Al-Arab at Al-Sharsh area, (Site 3)- in the Garmat Ali River at Al-Mashib area and Site 4- in the Al-seba area. Samples were collected from study sites during a period of January to August 2019. (11) species from the class Gastropoda and (4) species from the class Bivalves, species were predominated in most of the study months which are species: Melenodies nodosa, Bellamya bengalensis and Melanopsis turbculata from Gastropoda and two of the species are bivalve: Corbicula fluminalis and Limnoperna fortunei (Dunker, 1857), and the last species, L. fortunei, was recorded in the current study for the first time in freshwater of Iraq. The total biodiversity values of Molluscs at the Euphrates River at Al-Madinah area (Site. 1), Al-Sharsh area (Site 2), Al-Mashib area (Site 3) and Al-seba area (Site 4) were 3.1, 2.9, 2.4, 1.8, respectively, and It was noted that the highest seasonal densities of the species in the current study were recorded in the winter season, reaching 1013, 905, 762 and 639 individuals / m2 in four sites, respectively. Resumo O estudo foi realizado para comparar a distribuição e composição da comunidade de moluscos em quatro ecossistemas (quatro locais) no sul do Iraque, a saber: Local 1- no rio Eufrates, na cidade de Al-Madinah, Local 2- em Shatt Al-Arab na área de Al-Sharsh, Local 3- no rio Garmat Ali na área de Al-Mashib, e Local 4- na área de Al-Seba. As amostras foram coletadas nos locais de estudo durante um período de janeiro a agosto de 2019. Onze espécies da classe Gastropoda e quatro espécies da classe Bivalves predominaram espécies na maioria dos meses de estudo, que são as espécies Melenodies nodosa, Bellamya bengalensis e Melanopsis turbculata, de Gastropoda, e duas das espécies, Corbicula fluminalis e Limnoperna fortunei (Dunker, 1857), de Bivalvia, e L. fortunei, foram registradas pela primeira vez em água doce do Iraque. Os valores totais de biodiversidade de moluscos no rio Eufrates na área de Al-Madinah (Local 1), área de Al-Sharsh (Local 2), área de Al-Mashib (Local 3) e área de Al-Seba (Local 4) foram 3,1, 2,9, 2,4, 1,8, respectivamente, e notou-se que as maiores densidades sazonais da espécie no presente estudo foram registradas na estação de inverno, chegando a 1013, 905, 762 e 639 indivíduos/m2 em