269 SummaryThe mugilids are among the most cosmopolitan teleost fishes and they are widely distributed in fresh, brackish and coastal marine waters of the tropical and temperate regions of the world. Liza aurata is one of eight mugilid species survive in Turkish waters. Parasite fauna of the golden grey mullet Liza aurata (Risso, 1810) collected from Lower Kızılırmak Delta in Samsun, Turkey were investigated in the present study. Standard parasitological investigation methods were applied and standard indices of infection were calculated. A total of 10 parasite species were identified and they are;

Parasites of the grey mulletMugil cephalus collected from Lower Kızılırmak Delta in Turkey were investigated. Trichodina puytoraci, Trichodina lepsii, Ligophorus mediterraneus, Ligophorus cephali, Gyrodactylus sp., Microcotyle mugilis, Ascocotyle (Phagicola) longa, Haplosplanchnus pachysomus, Diplostomum spathaceum, Tylodelphys clavata, Posthodiplostomum sp., Neoechinorhyncus agilis and Ergasilus lizae were identified. Overall infection prevalence (%), mean intensity and mean abundance values were 99.61%, 458.10 ± 75.72 and 456.30 ± 75.44, respectively. Infection indices of parasite species in relation to season, lakes/ lagoons and some physicochemical parameters of water such as temperature, salinity, dissolved oxygen and nitrate are determined and discussed. Posthodiplostomum sp. is a new parasite record for mugilids and Diplostomum spathaceum is the first record in M. cephalus, in the present study. Moreover, Ligophorus mediterraneus, Ligophorus cephali and Ergasilus lizae are new records for Turkish parasite fauna of fish and Mugil cephalus is a new host record for Neoechinorhyncus agilis in Turkey.

This study aimed to assess the health status of grey mullet Mugil cephalus by means of relative condition factor under the coexisting parasite groups within seasons. Fish were captured monthly in the Lower Kızılırmak Delta in Samsun, Turkey, from December 2011 to November 2012. A total of five taxonomic groups containing 13 parasite species were constituted: Trichodina (Trichodina puytoraci, T. lepsii), Monogenea (Ligophorus cephali, L. mediterraneus, Gyrodactylus sp., Microcotyle mugilis), Digenea (Ascocotyle (Phagicola) longa, Diplostomum spathaceum, Tylodelphys clavata, Posthodiplostomum sp., Haplosplanchnus pachysomus), Acanthocephala (Neoechinorhynchus agilis) and Copepoda (Ergasilus lizae). Only one mullet was not parasitized and 13.8%, 36.3%, 29.2%, 16.2% and 4.5% were infected by one, two, three, four and five parasite groups respectively. Health assessment of mullets was performed by means of relative condition factor based on weight–length relationship estimated by robust regression methods. General linear modelling was employed to investigate any effect of season and infection load on this condition measure. Potential impacts of multiple parasitism on the community, which have been largely overlooked in the literature, were first visually revealed by relating the levels of co‐infections (in terms of prevalence and intensity) to the seasons. Then, a correlation analysis was carried out between condition estimates and the log‐ratios of relative abundances of parasite groups. The results showed that mullets suffering from Monogenea–Digenea–Acanthocephala (M–D–A) and also along with Copepoda (M–D–A–C) co‐infection had weights less than expected (Kn < 1) under winter conditions. However, Trichodina involved co‐infections appeared to prefer large sized hosts (Kn > 1) particularly in autumn.