Peculiar cases of intracardiac parasitism in the pilchard, Sardina pilchardus (Walbaum), by a pennellid copepod belonging to the genus Lernaeenicus

Abstract. The pilchard, Sardina pilchardus (Walbaum), is parasitized in coastal waters in the Languedoc-Roussillon region (South of France) by a copepod species which belongs to the genus Lernaeenicus (Siphonostomatoida, Pennellidae). These mesoparasites become established in various parts of the body of the host (eye, lateral muscle or muscle at the bases of fins). Examination of specimens which had penetrated at the root of pectoral fins revealed that some had penetrated the heart. A curious case of transcardiac parasitism was observed. Host tissue reactions caused by the presence of parasites are described.