Search

Comunicación presentada en la 19th International Conference on Diseases of Fish and Shellfish, celebrada en Oporto (Portugal) del 9 al 12 de septiembre de 2019., [Introduction]: The monogenean Sparicotyle chrysophrii and the cymothoid isopod Ceratothoa oestroides are among the most devastating ectoparasites in Mediterranean aquaculture, causing losses in gilthead sea bream (Sparus aurata) and European sea bass (Dicentrarchus labrax) production. Their life cycles and modes of transmission have not been fully elucidated and molecular resources for their investigation are extremely scarce. Being attracted by signals from conspecifics in aquaculture installations, the food and shelter availability in the farms, wild fish are generally recognised as reservoirs for parasite transmission to farmed fish. Viceversa, cultured stocks may also act as reservoirs of infectious stages, as they are present in concentrated numbers and density, and potentially more susceptible to disease than wild fish., [Methodology]: The potential extent of transmission of these two ectoparasites between wild and farmed fish populations has been evaluated by genotyping-by-sequencing approach, double digest Restriction-site Associated DNA sequencing (ddRAD-Seq), to generate a genome-wide SNP marker dataset. Parasites sampling was done across four large Mediterranean farming areas in Spain, Italy, Croatia and Greece, representing the largest collection of genotypes obtained from aquaculture and wild fish populations (n = 600)., [Results]: Expectedly, a considerable variability in number of reads, polymorphic loci and SNPs between individuals for both species was observed, while transfer between wild and reared parasite population was more enhanced in case of the isopod. [Conclusion]: The results provide a baseline for the development of new ecological and epidemiological measures for mitigation of two parasites, as the observed transfer seems to be highly conditioned by parasite and environment traits.

Trabajo presentado en la conferencia Molecular Helminthology: An Integrated Approach, celebrada en San Antonio (Estados Unidos) del 7 al 10 de abril de 2019., Parasite transmission between wild and farmed fish is poorly understood and controversial, although it has important implications for the reliable and sustainable use of aquatic resources. Wild fish are usually attracted by signals from conspecifics, the food and shelter availability in the farms, and general understanding is that they act as reservoirs for parasite transmission. In addition, cultured stocks may also act as reservoirs of infectious stages in the environment, as they are present in concentrated numbers and density, and potentially more susceptible to disease than wild fish. The monogenean Sparicotyle chrysophrii and the cymothoid isopod Ceratothoa oestroides are recognised as the most devastating ectoparasites in Mediterranean aquaculture, causing losses in gilthead sea bream (Sparus aurata) and European sea bass (Dicentrarchus labrax) production. Their life cycles and modes of transmission for both ectoparasites have not been fully elucidated and molecular resources for their investigation are extremely scarce. In order to analyse the potential extent of transmission of these two ectoparasites between wild and farmed fish populations, we have used a genotyping-bysequencing approach, double digest Restriction-site Associated DNA sequencing (ddRAD-Seq), to generate a genome-wide SNP marker dataset. Parasites sampling was done across four large Mediterranean farming areas in Spain, Italy, Croatia and Greece, representing the largest collection of genotypes obtained from aquaculture and wild fish populations. Expectedly, we observed a considerable variability in number of reads, polymorphic loci and SNPs between individuals for both species. The results provide a baseline for the development of new ecological and biological studies of these species, using new genomic tools and resources.

International audience

International audience

Captive populations of silver carp (Hypophthalmichthys molitrix), a major aquaculture species in Asia, would undoubtedly benefit from genetic monitoring and improvement programs. We report the isolation and preliminary characterization of 16 microsatellite loci derived from both conventional and microsatellite-enriched libraries. Inheritance studies confirmed the allelic nature of observed polymorphisms at all loci, while identifying null alleles at two loci. These loci, having varying degrees of polymorphism, should provide useful markers for applied genetic studies. A high degree of cross-amplification among 10 other cyprinid species suggests that these loci may have more widespread utility.

International audience

International audience