The Role of Endohelminths Parasite of Three commercial Fishes in Shatt Al-Arab River in Decreasing the Bioaccumulation of Some Heavy Metals

This study was aim to select three parasites that infect three different fish species in Shatt Al-Arab River: abu mullet Planiliza abu (Heckel) a native freshwater fish; green back mullet Planiliza subviridis (Val.), a marine fish that periodically enters the Shatt Al-Arab River for feeding, and Indian shad Tenualosa ilisha an anadromous fish enters the river for spawning. Examination of endoparasites of three fish species: P. abu, P. subviridis and T. ilisha, they were infected with the thornhead Neoechinorhynchus iraqensis Amin, Al-Sady, Mhaisen & Bassat, 2001, the thornhead N. dimorphospinus Amin & Sey, 1996, and a trematode Faustula basiri Hafeezullah & Siddiqi, 1970, respectively. Five heavy or trace metals (Aluminum, Arsenic, Boron, Chromium and Lead) were determined in each type of parasite and in muscles, liver and gills of each fish species. The measurements of each mineral were conducted on both infected and uninfected fishes to determine the effect of the internal parasites' efficiency on the accumulation of these metals in their tissues. The trematode was isolated from T. ilisha showed a high efficiency in reducing the accumulation of chromium (Cr) and lead (Pb) in fish tissues and arsenic (As) in the gills of infected T. ilisha. The marine thornhead worm (N. dimorphospinus) parasite P. subviridis showed greater efficiency in reducing chromium (Cr) concentrations in infected fish compared with the riverine thornhead (N. iraqensis) parasite P. abu. Lead (Pb) concentrations exceeded the international safe levels for human consumption in fish meat (0.5-2 mg.kg-1 meat); with concentrations 2.05-2.07, and 2.76 in muscles of T. ilisha and P. abu respectively. As well as Chromium and Aluminum and Arsenic concentrations exceeded the internationally safe levels for human consumption permitted in fish meat (1-2 meat, 1-5 and 1.72-2.3 mg.kg-1 respectively) with 2.25 and 19.38-67.53 and 2.34 respectively in T. ilisha, muscles. The aluminum concentration for the P. subviridis and P. abu are 2.71 and 42.63.