Metazoan Parasites of the Mediterranean Garfish <i>Belone belone gracilis</i> (Teleostei: Belonidae) as a Tool for Stock Discrimination

Abstract

The aim of the present study was to provide a current survey of metazoan parasites of the Mediterranean garfish Belone belone gracilis Lowe, 1839 off Tunisian coast and their potential use as biological tags for discriminate stocks. Parasitological analysis of 453 specimens of B. b. gracilis along the eastern Tunisian coast revealed the presence of ten species of metazoan parasites: one monogenean Axine belones Abildgaard, 1794; four digeneans Lecithostaphylus retroflexus (Molin, 1859), Tergestia acanthocephala (Stossich, 1887) Stossich, 1899, Aponurus laguncula Looss, 1907 and Condylocotyla pilodora (metacercaria) Pearson et Prévot, 1985; one copepod Bomolochus bellones Burmeister, 1835; two isopods Irona nana Schioedte et Meinert, 1884 and Nerocila orbignyi (Guérin-Méneville, 1832); 1 acanthocephalan Telosentis exiguus (Von Linstow, 1901) and one nematod Anisakid larvae. Discriminant analysis using parasites as biological tags, allowed identifying two stocks of B. b. gracilis . Digenea L. retroflexus , A. laguncula and Anisakid larvae were the most important species in determining the position of sampled fishes from the central coast off Tunisia. Metacercaria C. pilodora characterized specimens from the Southern coast off Tunisia. These results were corroborated by comparing parameters of prevalence and mean abundance between zones. Discriminant analysis used for the separation of B. b. gracilis between seasons in both localities showed that a seasonal variation affected mainly specimens from the center suggesting seasonal move of fishes.