First Report of Aphanurus stossichii (Digenea: Hemiuridae) from Engraulis encrasicolus on the Turkish Coast of the Black Sea, with Light and Scanning Electron Microscopic Observations

Objective: The aim of this study is to investigate in detail the morphological features of the digenean parasite Aphanurus stossichii isolated from the European anchovy Engraulis encrasicolus using light and scanning electron microscopy (SEM).
Methods: The specimens of A. stossichii were obtained from the pharynx and stomach of the European E. encrasicolus caught by commercial fishing vessels in the Black Sea. Parasites were killed in a hot normal saline solution, preserved in to 70% ethanol for light microscopic (LM) studies, and in 2.5% glutaraldehyde for SEM. The morphological diagnostic features of A. stossichii were studied in detail under both LM and SEM.
Results: The morphological characteristics of the examined adult A. stossichii specimens were found to be similar to the original descriptions describing the basic characteristics of forebody and hindbody shape, the position and shape of the vitellarium, ovary, and and testes, and the shapes of oral and ventral sucker. The measurement data for all morphological diagnostics were provided; photomicrographs of each part of the parasite were presented. Infection prevalence, mean intensity and mean abundance values were 8.89%, 4.5 and 0.4, respectively.
Conclusion: All available records of A. stossichii morphology are based on light microscope, this is the first study to identification the morphological features of the parasite with SEM. This research is the first on A. stossichii presence in E. encrasicolus on the Turkish Black Sea coast.