La pêche, réduisant la densité de poissons, pourrait diminuer l'efficacité de la transmission du parasite. La présente étude vise à examiner la présence des isopodes gnathiid sur une espèce de poissons sauvages, les rougets, sous l'influence de l'activité de chalutage en comparant les données épidémiologiques de zones de chalutage et zone de non-chalutage. L'impact potentiel de gnathiids sur le rouget au sein d'une zone de non-chalutage de la mer Tyrrhénienne Sud (mer Méditerranée central) a été évalué analysant les indices épidémiologiques par rapport à la saison, le sexe, l'âge et le condition de l'hôte. La répartition spatiale de la prévalence était hétérogène avec le gros de gnathiids trouvés à l'intérieur de zone de non-chalut. De même, l'intensité et l'abondance ont montré des valeurs nettement plus élevées à l'intérieur du zone de non-chalut qu'à l'extérieur. A l'intérieur des zone de non-chalut variations temporelles de gnathiid infestation étaient évidents, avec la prévalence et l'intensité la plus faible pendant l'hiver, mais sans un caractère saisonnier. Gnathiids infection est pas liée au sexe et l'âge du rouget et n'a pas d'influence négative sur la condition de l'hôte. L'apparition de gnathiids, en dépit d'être des parasites temporaires et généralistes, reflète fortement le niveau de la densité de l'hôte et de protection de le site.
Fishing, reducing the density of fish, might decrease the efficiency of parasite transmission. The present study aims at examining the presence of gnathiid isopods on a wild fish species, the red mullet, under the influence of trawling activity by comparing epidemiological data of trawled and no-trawled areas. The potential impact of gnathiids on the red mullet within a no-trawled area (NTA) of the Southern Tyrrhenian Sea (Central Mediterranean Sea) has been assessed examining epidemiological indices in relation to season, sex, age and host condition. The spatial distribution of prevalence in the study was heterogeneous with the bulk of gnathiids found inside the NTA. Similarly, the intensity and abundance showed values significantly higher inside the NTA than outside. Inside the NTA temporal variations of gnathiid infestation were evident, with the lowest prevalence and intensity during winter but without a seasonal pattern. Gnathiids infection is not related to the sex and age of the red mullet and does not influence negatively the host condition. The occurrence of gnathiids, despite being temporary and generalist parasites, strongly reflects the host density and site protection level.
Epidemiology of gnathiid isopods on red mullet (Mullus barbatus barbatus) along the Tyrrhenian Sicilian coast (Mediterranean Sea)
Bottari Teresa;Rinelli Paola;Garofalo Germana;Fiorentino Fabio
2016
Abstract
Fishing, reducing the density of fish, might decrease the efficiency of parasite transmission. The present study aims at examining the presence of gnathiid isopods on a wild fish species, the red mullet, under the influence of trawling activity by comparing epidemiological data of trawled and no-trawled areas. The potential impact of gnathiids on the red mullet within a no-trawled area (NTA) of the Southern Tyrrhenian Sea (Central Mediterranean Sea) has been assessed examining epidemiological indices in relation to season, sex, age and host condition. The spatial distribution of prevalence in the study was heterogeneous with the bulk of gnathiids found inside the NTA. Similarly, the intensity and abundance showed values significantly higher inside the NTA than outside. Inside the NTA temporal variations of gnathiid infestation were evident, with the lowest prevalence and intensity during winter but without a seasonal pattern. Gnathiids infection is not related to the sex and age of the red mullet and does not influence negatively the host condition. The occurrence of gnathiids, despite being temporary and generalist parasites, strongly reflects the host density and site protection level.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.