English

Abstract

This paper aim to provide information in the major parasitic pathogens found in Mediterranean mussel, Mytilus galloprovincialis from south Mediterranean population of the bay of M'diq, in Morocco. The parasitic prevalence in relation to the reproductive cycle and the environmental conditions were investigated, and potential determinants of the infection were discussed. Mussels were monthly collected from March 2009 to March 2011. To examine the reproductive stage of the M. galloprovincialis and pathological status, histological approach was taken for the analysis. Common parasites including regionally problematic Marteilia refringens were observed in the specimen. We found the Ciliophora-like Protozoan group in digestive diverticula (43.33% of hosts). Steinhausia mytilovum is observed in oocytes of the host, and its prevalence was up to 32%. The presence and absence of the Ciliophora-like group had a significant relationship with variation of salinity in the site (p<0.05), and the presence and absence of the S. mytilovum had a significant relationship with change in the gonadic index (p< 0.05). The negative impact of parasites upon the local population of M. galloprovincialis at the site was not major during the surveyed years. No mortality due to the parasitic diseases has been observed in mussels in M'diq. However, the found relationships between the parasite and host and environmental condition suggest that the variability of the environment in the site would cause unanticipated outbreaks. Considering the importance of mussels for Moroccan mytilicultre in the southern Alboran, comprehensive monitoring of the pathological status and host and environmental condition is necessary.