Parasites of the invasive American blue crab Callinectes sapidus Rathbun, 1896 (Decapoda, Portunidae) in coastal ecosystems of Morocco: A One-Health approach

Abstract

Crustaceans are a well-represented group in coastal environments. Their health is often linked to that of humans and together they are linked to the health of the environment. Therefore, such interconnection is the basis of the ’One Health’ concept. Invasive non-native species pose a risk as possible carriers of invasive parasites and/or en- hancers for native parasites, which can lead to a loss of native biodiversity and to dis- ease/mortality of indigenous species as well as risks to human health. The American blue crab Callinectes sapidus Rathbun, 1896, native to the western Atlantic, has been established in various Moroccan coastal ecosystems with the recent interest for human consumption. As such, it constitutes a good model for understanding biological invasions in the context of the ’One Health’ concept. The main objective of this study is to understand the interactions between the blue crab and its parasites in Morocco and the western Atlantic to assess their effects on native biodiversity, associated marine diseases, and risks to human health. A literature survey revealed several parasites associated with C. sapidus both in native and in introduced areas. Preliminary dissections of 13 specimens from Morocco and examination of their organs under a stereomi- croscope did not reveal any parasites. Similar dissection and examination of 21 specimens from the western Atlantic revealed seven parasites, including a digenean, a haplosporidean, and a nematode. As the taxonomical range varies from micro- to macroparasites, various morphological and genetic diagnostic methods will be used to monitor the presence of po- tentially invasive parasite lineages associated to the American blue crab in Morocco and the western Atlantic. Comparison of specimens from the western Atlantic coast and Morocco will allow us to test the enemy release hypothesis and to check for parasite spillover or spillback events and the impacts related to the bioinvasion of the American blue crab in Morocco.