The invasive blue crab Callinectessapidus Rathbun, 1896 (Decapoda, Portunidae) is rapidly expanding its distributional range in the north-western Mediterranean coast of Morocco.

In this study, we report the first occurrence of Callinectessapidus in the rivers of 'Oued Tani' (Martil) and 'Oued Negro' (Fnideq), based on 127 individuals of the blue crab caught from November 2022 to August 2023. Additionally, we were able to determine the potential consequences of C.sapidus on the indigenous species as well as the socioeconomic implications on artisanal fisheries activities. This research highlights further data that reinforces recent findings on recorded blue crab from various locations along the Moroccan coastline.