Introduction de poissons dans les milieux aquatiques continentaux : «Quid de leurs parasites ?»

Abstract

The introduction of an animal species into a new environment means, in fact, the introduction of a host-parasite system (HPS). These HPSs, which are characterized by longlasting interactions between host populations and their parasite communities, are the result of a long coevolution and represent a delicate equilibrium. From several examples chosen among platyhelminths, the present paper illustrates the destiny of some parasitical populations following the introduction of their hosts. Some of these examples are related to holoxenous life-cycles (Monogenea) and others to heteroxenous ones (Bucephalus polymorphus, Trematoda and Bothriocephalus acheilognathi, Cestoda). As regards the introduction of such host-parasite systems, the author suggests three recommendations that take into account data about parasitical specificity, the type of life-cycle, and potentially pathological effects : 1) Try to avoid the introduction of hosts, some parasites of which can have selected pathogenic mechanisms that favour their transmission; 2) Do not introduce hosts harbouring euryxenic parasites that could give rise to new host-parasite systems; 3) Try beforehand to estimate which biotic or abiotic factors may improve parasite transmission.