Claude Maillard

Biology of parasite populations: the differential specificity of the genus Helicometra Odhner, 1902 (Trematoda: Opecoelidae) in the Mediterranean Sea demonstrated by enzyme electrophoresis

Abstract An analysis of specificity of the genus Helicometra (Trematoda: Opecoelidae) for the five teleosts Zosterisessor ophiocephalus , Gobius niger (Gobiidae), Symphodus cinereus (Labridae), Anguilla anguilla (Anguillidae) and Blennius pavo (Blenniidae), which are sympatric in the Etang de Thau (Herault, France), was carried out using biosystematic investigation (enzymatic polymorphism). The results of this genetic analysis show that the genus Helicometra consists neither of a complex of strictly specific species nor of a single very polymorphous species with broad specificity. Indeed, the existence of at least three species is shown with different degrees of specificity for their final hosts (teleosts).

Enlargement of the host range of Polylabris tubicirrus (Monogenea, Polyopisthocotylea) under fish-farming conditions

In the Mediterranean Sea, Polylabris tubicirrus (Monogenea, Polyopisthocotylea) is found only on breams of the genus Diplodus : D. sargus, D. annularis, D. vulgaris. The discovery of this parasite on farmed gilt head sea breams (Sparus aurata) raises the problem of the enlargement of the host range of a parasite under artificial conditions of confinement, and of the potential danger this type of transfer can involve.

Biology of Serranicotyle labracis, ectoparasite of Dicentrarchus labrax (Teleostei): contribution to the study of its populations

Serranicotyle labracis (Van Beneden and Hesse, 1863) Maillard, Euzet and Silan, 1988 (synonym: Microcotyle labracis Van Beneden and Hesse, 1863) is a monogenean Polyopisthocotylea and a gill parasite of the bass Dicentrarchus labrax (Linné, 1758). Analysis of a western Mediterranean population of this parasite (Gulf of Lions, Languedoc, France) clarified several aspects of its biology. Its location in the gill biotope (Silan et al. 1987) was not fundamentally different from that found by Oliver (1977) and Winch (1983), but its distribution in host populations differed from that reported in the earlier studies; it displayed a negative binomial distribution in the study zone. At a finer level of observation, the behaviour of the hosts, as a function of degree of maturity and sex, appeared to determine more than any other factor the extent of infestation by the parasite. Previous suggestions in the literature to account for these differences in population dynamics are discussed.

Host specificity of fish trematodes investigated by experimental ichthyophagy

Abstract Maillard C. and Aussel J.-P. 1988. Host specificity of fish trematodes investigated by experimental ichthyophagy. International Journal for Parasitology18: 493–498. The host-specificity of fish trematodes was studied by experimental transfer of adult trematodes from fish to fish. The experiments were carried out with four species of teleosts caught in a lagoon of Languedoc (southern France): Zosterisessor ophiocephalus, Gobius niger (Gobiidae), Symphodus cinereus (Labridae) and Anguilla anguilla (Anguillidae). The adult trematodes of the genus Helicometra (Opecoelidae) were placed in small gelatin capsules which were inserted by mouth into the stomach of anesthetized and disinfected fish. The results of experimental transfer show that at least three forms of Helicometra can be distinguished in the lagoon rather than a single polymorphic species.