Molluscs are one of the most important taxa that significantly contribute to biodiversity, as they make up about a quarter of benthic species. They are a representative group in the benthos and can be used as indicators of the presence of non-native species in the marine environment. Therefore, to ensure the monitoring of our coastal environment, there is a need for a detailed list of the national malacofauna at any given time in order to detect newcomers. In this work, we have attempted to complete the inventory of molluscs in Bizerte.
Sampling was carried out between February and March 2024 at five stations. It allowed us to collect more than 1042 specimens representing 65 species. During this work, we reported the presence of the Red Sea mussel Brachidontes pharaonis in all the harvesting stations of Bizerte, representing a risk for the shellfish farming environment.
The latter is present and abundant in the Bizerte canal, signalling a potential risk for the shellfish farming environment. We were able to show the considerable threat that this species represents on the structure and biodiversity of the La Goulette ecosystem in 2023 and we report that the continued demographic growth of this species and the formation of mytilidae mats accompanied by a strong dominance of a small bivalve mytilaster. minimus can displace native species and reduce diversity. This can lead to competition for resources, clogging of aquaculture facilities and ecosystem alteration.
It is therefore crucial to issue an alert to encourage rapid detection in the shellfish farm in Bizerte and particularly that of Jouwewda. We strongly recommend the establishment of regular monitoring programs to detect Brachidonte pharaonis infestations early and intervene quickly.