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Abstract: Gyrodactylus aff. mugili Zhukov, 1970 (Monogenoidea: Gyrodactylidae) is recorded and described from the gill lamellae of 11 of 35 greenback mullet, Chelon subviridis (Valenciennes) (minimum prevalence 31%), from the brackish waters of the Shatt Al-Arab Estuary in southern iraq. The gyrodactylid was also found on the gill lamellae of one of eight speigler's mullet, Valamugil speigleri (Bleeker), from the brackish waters of the shatt Al-Basrah canal (minimum prevalence 13%). Fifteen Klunzinger's mullet, Liza klunzingeri (Day), and 13 keeled mullet, Liza carinata (Valenciennes), collected and examined from southern iraqi waters, were apparently uninfected. The gyrodactylids from the greenback mullet and speigler's mullet were considered to have affinity to G. mugili Zhukov, 1970, and along with G. mugili may represent members of a species complex occurring on mullets in the indo-Pacific region. A single damaged gyrodactylid from the external surfaces of the abu mullet, Liza abu (Heckel), was insufficient for species identification. Previously identified species of Gyrodactylus recorded on L. abu in Iraq by various authors were considered possible misidentifications or accidental infections.
Keywords: Gyrodactylidea, Gyrodactylus mugili, species complex, Chelon subviridis, Liza abu, Liza carinata, Liza klunzingeri, Valamugil speigleri, mullets, Asia, Shatt Al-Arab River, Shatt Al-Arab Estuary
The Mugilidae (Mugiliformes), comprising 17 genera and 72 valid species commonly called mullets or grey mullets (Eschmeyer and Fong 2013, Froese and Pauly 2013), includes mostly marine and brackish-water coastal fishes occurring in tropical and temperate seas worldwide. Mullets are euryhaline, with many species moving into freshwater from marine habitats for short periods. Only one, the abu mullet, Liza abu (Heckel), of southwestern Asia (Iraq, Iran, Pakistan, Turkey and Syria) is restricted to fresh and brackish waters (Thomson 1997, Froese and Pauly 2013). Mullets are herbivorous and/or detritivorous fishes, feeding on algae, diatoms and small invertebrates associated with algae, and detritus obtained from bottom muds and sands (coad 2010). In southern iraq, mullets, particularly L. abu, Klunzinger's mullet, Liza klunzingeri (Day), and greenback mullet, Chelon subviridis (Valenciennes), are commercially fished and comprise economically important local food sources (Coad 2010).
Investigations into the polyonchoinean parasites (Monogenoidea) of mullets have focused primarily on those occurring on their gill lamellae; about 50 species of Ligophorus Euzet et Suriano, 1977 (Dactylogyridea: Dactylogyridae) have been recorded from these hosts worldwide (see Dmitrieva...