Role of fish parasites as a biological indicator of water pollution

Fish is a commodity of potential public health concern as it could contaminated with a wide range of environmentally persistent chemicals, including heavy metals and parasitism. The present study aimed to investigate some of helminth parasites infecting the most of economically important marine fish in Egypt. The collected fish were Anguilla anguilla, Lethrinus lentjan, Pagrus pagrus, Saurida tumbil, Siganus revulatus, Solea solea, and Sparus aurata. The present investigation of parasitic infections was carried out by means of morphologic and morphometric characterization of the isolated parasites using light and scanning electron microscopy. In addition, molecular analyses of parasites SSU rDNA gene sequences and its phylogenetic relationships were applied to detect their exact taxonomy. The role of the recorded parasites as bio-indicators for water pollution was determined by measuring the concentration of some heavy metals (Fe, Zn, Ni, Cu, Cd, and Pb) in parasites and tissues of fish hosts.